/src/libcups/cups/ipp.c

Source
//
// Internet Printing Protocol functions for CUPS.
//
// Copyright © 2021-2026 by OpenPrinting.
// Copyright © 2007-2021 by Apple Inc.
// Copyright © 1997-2007 by Easy Software Products, all rights reserved.
//
// Licensed under Apache License v2.0.  See the file "LICENSE" for more
// information.
//

#include "cups-private.h"
#include <regex.h>
#ifdef _WIN32
#  include <io.h>
#endif // _WIN32


//
// Local globals...
//

static cups_mutex_t regex_mutex = CUPS_MUTEX_INITIALIZER;
          // Mutex for regular expressions
static bool   regex_init = false;
          // Have regular expressions been initialized?
static regex_t    lang_regex; // Regular expression for naturalLanguage
static regex_t    mime_regex; // Regular expression for mimeMediaType


//
// Local functions...
//

static ipp_attribute_t  *ipp_add_attr(ipp_t *ipp, const char *name, ipp_tag_t group_tag, ipp_tag_t value_tag, size_t num_values);
static void   ipp_free_values(ipp_attribute_t *attr, size_t element, size_t count);
static char   *ipp_get_code(const char *locale, char *buffer, size_t bufsize) _CUPS_NONNULL(1,2);
static bool   ipp_is_valid_language(const char *name, const char *lang);
static bool   ipp_is_valid_mimetype(const char *name, const char *type);
static char   *ipp_lang_code(const char *locale, char *buffer, size_t bufsize) _CUPS_NONNULL(1,2);
static size_t   ipp_length(ipp_t *ipp, int collection);
static ssize_t    ipp_read_file(int *fd, ipp_uchar_t *buffer, size_t length);
static ssize_t    ipp_read_http(http_t *http, ipp_uchar_t *buffer, size_t length);
static ipp_state_t  ipp_read_io(void *src, ipp_io_cb_t cb, bool blocking, ipp_t *parent, ipp_t *ipp, int depth);
static bool   ipp_regex_begin(void);
static void   ipp_regex_end(void);
static void   ipp_set_error(ipp_status_t status, const char *format, ...);
static _ipp_value_t *ipp_set_value(ipp_t *ipp, ipp_attribute_t **attr, size_t element);
static ssize_t    ipp_write_file(int *fd, ipp_uchar_t *buffer, size_t length);


//
// '_cupsBufferGet()' - Get a read/write buffer.
//

char *          // O - Buffer
_cupsBufferGet(size_t size)   // I - Size required
{
  _cups_buffer_t  *buffer;  // Current buffer
  _cups_globals_t *cg = _cupsGlobals();
          // Global data


  for (buffer = cg->cups_buffers; buffer; buffer = buffer->next)
    if (!buffer->used && buffer->size >= size)
      break;

  if (!buffer)
  {
    if ((buffer = malloc(sizeof(_cups_buffer_t) + size - 1)) == NULL)
      return (NULL);

    buffer->next     = cg->cups_buffers;
    buffer->size     = size;
    cg->cups_buffers = buffer;
  }

  buffer->used = 1;

  return (buffer->d);
}


//
// '_cupsBufferRelease()' - Release a read/write buffer.
//

void
_cupsBufferRelease(char *b)   // I - Buffer to release
{
  _cups_buffer_t  *buffer;  // Buffer


  // Mark this buffer as unused...
  buffer       = (_cups_buffer_t *)(b - offsetof(_cups_buffer_t, d));
  buffer->used = 0;
}


//
// 'ippAddBoolean()' - Add a boolean attribute to an IPP message.
//
// The "ipp" argument refers to an IPP message previously created using
// the @link ippNew@, @link ippNewRequest@, or  @link ippNewResponse@ functions.
//
// The "group" argument specifies the IPP attribute group tag: none
// (`IPP_TAG_ZERO`, for member attributes), document (`IPP_TAG_DOCUMENT`),
// event notification (`IPP_TAG_EVENT_NOTIFICATION`), operation
// (`IPP_TAG_OPERATION`), printer (`IPP_TAG_PRINTER`), subscription
// (`IPP_TAG_SUBSCRIPTION`), or unsupported (`IPP_TAG_UNSUPPORTED_GROUP`).
//

ipp_attribute_t *     // O - New attribute
ippAddBoolean(ipp_t      *ipp,    // I - IPP message
              ipp_tag_t  group,   // I - IPP group
              const char *name,   // I - Name of attribute
              bool       value)   // I - Value of attribute
{
  ipp_attribute_t *attr;    // New attribute


  DEBUG_printf("ippAddBoolean(ipp=%p, group=%02x(%s), name=\"%s\", value=%d)", (void *)ipp, group, ippTagString(group), name, value);

  // Range check input...
  if (!ipp || !name || group < IPP_TAG_ZERO || group == IPP_TAG_END || group >= IPP_TAG_UNSUPPORTED_VALUE)
    return (NULL);

  // Create the attribute...
  if ((attr = ipp_add_attr(ipp, name, group, IPP_TAG_BOOLEAN, 1)) == NULL)
    return (NULL);

  attr->values[0].boolean = value;

  return (attr);
}


//
// 'ippAddBooleans()' - Add an array of boolean values.
//
// The "ipp" argument refers to an IPP message previously created using
// the @link ippNew@, @link ippNewRequest@, or  @link ippNewResponse@ functions.
//
// The "group" argument specifies the IPP attribute group tag: none
// (`IPP_TAG_ZERO`, for member attributes), document (`IPP_TAG_DOCUMENT`),
// event notification (`IPP_TAG_EVENT_NOTIFICATION`), operation
// (`IPP_TAG_OPERATION`), printer (`IPP_TAG_PRINTER`), subscription
// (`IPP_TAG_SUBSCRIPTION`), or unsupported (`IPP_TAG_UNSUPPORTED_GROUP`).
//

ipp_attribute_t *     // O - New attribute
ippAddBooleans(ipp_t      *ipp,   // I - IPP message
               ipp_tag_t  group,  // I - IPP group
         const char *name,  // I - Name of attribute
         size_t     num_values, // I - Number of values
         const bool *values)  // I - Values
{
  size_t    i;    // Looping var
  ipp_attribute_t *attr;    // New attribute
  _ipp_value_t    *value;   // Current value


  DEBUG_printf("ippAddBooleans(ipp=%p, group=%02x(%s), name=\"%s\", num_values=%u, values=%p)", (void *)ipp, group, ippTagString(group), name, (unsigned)num_values, (void *)values);

  // Range check input...
  if (!ipp || !name || group < IPP_TAG_ZERO || group == IPP_TAG_END || group >= IPP_TAG_UNSUPPORTED_VALUE || num_values < 1)
    return (NULL);

  // Create the attribute...
  if ((attr = ipp_add_attr(ipp, name, group, IPP_TAG_BOOLEAN, num_values)) == NULL)
    return (NULL);

  if (values)
  {
    for (i = num_values, value = attr->values; i > 0; i --, value ++)
      value->boolean = *values++;
  }

  return (attr);
}


//
// 'ippAddCollection()' - Add a collection value.
//
// The "ipp" argument refers to an IPP message previously created using
// the @link ippNew@, @link ippNewRequest@, or @link ippNewResponse@ functions.
//
// The "group" argument specifies the IPP attribute group tag: none
// (`IPP_TAG_ZERO`, for member attributes), document (`IPP_TAG_DOCUMENT`),
// event notification (`IPP_TAG_EVENT_NOTIFICATION`), operation
// (`IPP_TAG_OPERATION`), printer (`IPP_TAG_PRINTER`), subscription
// (`IPP_TAG_SUBSCRIPTION`), or unsupported (`IPP_TAG_UNSUPPORTED_GROUP`).
//
// The "name" argument specifies the name of the attribute, while the "value"
// argument provides an IPP message containing the collection member attributes.
//
// > **Note:** You must call the @link ippDelete@ function on the "value"
// > argument to make sure the memory used by the value is released.
//

ipp_attribute_t *     // O - New attribute
ippAddCollection(ipp_t      *ipp, // I - IPP message
                 ipp_tag_t  group,  // I - IPP group
     const char *name,  // I - Name of attribute
     ipp_t      *value) // I - Value
{
  ipp_attribute_t *attr;    // New attribute


  DEBUG_printf("ippAddCollection(ipp=%p, group=%02x(%s), name=\"%s\", value=%p)", (void *)ipp, group, ippTagString(group), name, (void *)value);

  // Range check input...
  if (!ipp || !name || group < IPP_TAG_ZERO || group == IPP_TAG_END || group >= IPP_TAG_UNSUPPORTED_VALUE)
    return (NULL);

  // Create the attribute...
  if ((attr = ipp_add_attr(ipp, name, group, IPP_TAG_BEGIN_COLLECTION, 1)) == NULL)
    return (NULL);

  attr->values[0].collection = value;

  if (value)
    value->use ++;

  return (attr);
}


//
// 'ippAddCollections()' - Add an array of collection values.
//
// The "ipp" argument refers to an IPP message previously created using
// the @link ippNew@, @link ippNewRequest@, or  @link ippNewResponse@ functions.
//
// The "group" argument specifies the IPP attribute group tag: none
// (`IPP_TAG_ZERO`, for member attributes), document (`IPP_TAG_DOCUMENT`),
// event notification (`IPP_TAG_EVENT_NOTIFICATION`), operation
// (`IPP_TAG_OPERATION`), printer (`IPP_TAG_PRINTER`), subscription
// (`IPP_TAG_SUBSCRIPTION`), or unsupported (`IPP_TAG_UNSUPPORTED_GROUP`).
//
// The "name" argument specifies the name of the attribute, while the
// "num_values" and "values" arguments provide IPP messages containing the
// collection member attributes for each value.
//
// > **Note:** You must call the @link ippDelete@ function on each of the
// > "values" arguments to make sure the memory used by the value is released.
//

ipp_attribute_t *     // O - New attribute
ippAddCollections(
    ipp_t       *ipp,     // I - IPP message
    ipp_tag_t   group,      // I - IPP group
    const char  *name,      // I - Name of attribute
    size_t      num_values,   // I - Number of values
    const ipp_t **values)   // I - Values
{
  size_t    i;    // Looping var
  ipp_attribute_t *attr;    // New attribute
  _ipp_value_t    *value;   // Current value


  DEBUG_printf("ippAddCollections(ipp=%p, group=%02x(%s), name=\"%s\", num_values=%u, values=%p)", (void *)ipp, group, ippTagString(group), name, (unsigned)num_values, (void *)values);

  // Range check input...
  if (!ipp || !name || group < IPP_TAG_ZERO || group == IPP_TAG_END || group >= IPP_TAG_UNSUPPORTED_VALUE || num_values < 1)
    return (NULL);

  // Create the attribute...
  if ((attr = ipp_add_attr(ipp, name, group, IPP_TAG_BEGIN_COLLECTION, num_values)) == NULL)
    return (NULL);

  if (values)
  {
    for (i = num_values, value = attr->values; i > 0; i --, value ++)
    {
      value->collection = (ipp_t *)*values++;
      value->collection->use ++;
    }
  }

  return (attr);
}


//
// 'ippAddCredentialsString()' - Add a credentials string attribute to an IPP message.
//
// This function adds a 1setOf text attribute to an IPP message corresponding to
// the specified credentials string.
//
// The "ipp" argument refers to an IPP message previously created using
// the @link ippNew@, @link ippNewRequest@, or  @link ippNewResponse@ functions.
//
// The "group" argument specifies the IPP attribute group tag: none
// (`IPP_TAG_ZERO`, for member attributes), document (`IPP_TAG_DOCUMENT`),
// event notification (`IPP_TAG_EVENT_NOTIFICATION`), operation
// (`IPP_TAG_OPERATION`), printer (`IPP_TAG_PRINTER`), subscription
// (`IPP_TAG_SUBSCRIPTION`), or unsupported (`IPP_TAG_UNSUPPORTED_GROUP`).
//

ipp_attribute_t *     // O - New attribute
ippAddCredentialsString(
    ipp_t      *ipp,      // I - IPP message
    ipp_tag_t  group,     // I - IPP group
    const char *name,     // I - Attribute name
    const char *credentials)    // I - Credentials string
{
  ipp_attribute_t *attr;    // New attribute
  char      *cvalue,  // Copied value
      *cstart,  // Start of value
      *cptr;    // Pointer into copied value
  size_t    i,    // Looping var
      num_values; // Number of values


  // Range check input...
  if (!ipp || !name || !credentials)
    return (NULL);

  // Copy the value string and figure out the number of values...
  if ((cvalue = strdup(credentials)) == NULL)
    return (NULL);

  for (num_values = 0, cptr = cvalue; cptr;)
  {
    // Find the next delimiter
    if (*cptr && *cptr != '\r' && *cptr != '\n')
      num_values ++;

    cstart = cptr;
    if ((cptr = strchr(cstart, '\r')) != NULL)
    {
      // Skip CR or CR LF
      if (cptr[1] == '\n')
        cptr += 2;
      else
        cptr ++;
    }
    else if ((cptr = strchr(cstart, '\n')) != NULL)
    {
      // Skip LF
      cptr ++;
    }
  }

  // Create the empty attribute and copy the values...
  if ((attr = ippAddStrings(ipp, group, IPP_TAG_TEXT, name, num_values, NULL, NULL)) != NULL)
  {
    for (i = 0, cptr = cvalue; cptr && i < num_values;)
    {
      cstart = cptr;
      if ((cptr = strchr(cptr, '\r')) != NULL)
      {
        // Terminate on CR
        *cptr++ = '\0';
        if (*cptr == '\n')
          cptr ++;     // Skip LF
      }
      else if ((cptr = strchr(cstart, '\n')) != NULL)
      {
        // Terminate on LF
        *cptr++ = '\0';
      }

      if (*cstart)
        attr->values[i++].string.text = _cupsStrAlloc(cstart);
    }
  }

  // Free the copied string and return...
  free(cvalue);

  return (attr);
}


//
// 'ippAddDate()' - Add a dateTime attribute to an IPP message.
//
// The "ipp" argument refers to an IPP message previously created using
// the @link ippNew@, @link ippNewRequest@, or  @link ippNewResponse@ functions.
//
// The "group" argument specifies the IPP attribute group tag: none
// (`IPP_TAG_ZERO`, for member attributes), document (`IPP_TAG_DOCUMENT`),
// event notification (`IPP_TAG_EVENT_NOTIFICATION`), operation
// (`IPP_TAG_OPERATION`), printer (`IPP_TAG_PRINTER`), subscription
// (`IPP_TAG_SUBSCRIPTION`), or unsupported (`IPP_TAG_UNSUPPORTED_GROUP`).
//

ipp_attribute_t *     // O - New attribute
ippAddDate(ipp_t             *ipp,  // I - IPP message
           ipp_tag_t         group, // I - IPP group
     const char        *name, // I - Name of attribute
     const ipp_uchar_t *value)  // I - Value
{
  ipp_attribute_t *attr;    // New attribute


  DEBUG_printf("ippAddDate(ipp=%p, group=%02x(%s), name=\"%s\", value=%p)", (void *)ipp, group, ippTagString(group), name, (void *)value);

  // Range check input...
  if (!ipp || !name || !value || group < IPP_TAG_ZERO || group == IPP_TAG_END || group >= IPP_TAG_UNSUPPORTED_VALUE)
    return (NULL);

  // Create the attribute...
  if ((attr = ipp_add_attr(ipp, name, group, IPP_TAG_DATE, 1)) == NULL)
    return (NULL);

  memcpy(attr->values[0].date, value, 11);

  return (attr);
}


//
// 'ippAddInteger()' - Add a integer attribute to an IPP message.
//
// This function adds an integer or enum attribute to an IPP message.
//
// The "ipp" argument refers to an IPP message previously created using
// the @link ippNew@, @link ippNewRequest@, or  @link ippNewResponse@ functions.
//
// The "group" argument specifies the IPP attribute group tag: none
// (`IPP_TAG_ZERO`, for member attributes), document (`IPP_TAG_DOCUMENT`),
// event notification (`IPP_TAG_EVENT_NOTIFICATION`), operation
// (`IPP_TAG_OPERATION`), printer (`IPP_TAG_PRINTER`), subscription
// (`IPP_TAG_SUBSCRIPTION`), or unsupported (`IPP_TAG_UNSUPPORTED_GROUP`).
//
// Supported values include enum (`IPP_TAG_ENUM`) and integer
// (`IPP_TAG_INTEGER`).
//

ipp_attribute_t *     // O - New attribute
ippAddInteger(ipp_t      *ipp,    // I - IPP message
              ipp_tag_t  group,   // I - IPP group
        ipp_tag_t  value_tag, // I - Type of attribute
              const char *name,   // I - Name of attribute
              int        value)   // I - Value of attribute
{
  ipp_attribute_t *attr;    // New attribute


  DEBUG_printf("ippAddInteger(ipp=%p, group=%02x(%s), type=%02x(%s), name=\"%s\", value=%d)", (void *)ipp, group, ippTagString(group), value_tag, ippTagString(value_tag), name, value);

  value_tag &= IPP_TAG_CUPS_MASK;

  // Special-case for legacy usage: map out-of-band attributes to new ippAddOutOfBand function...
  if (value_tag >= IPP_TAG_UNSUPPORTED_VALUE && value_tag <= IPP_TAG_ADMINDEFINE)
    return (ippAddOutOfBand(ipp, group, value_tag, name));

  // Range check input...
  if (!ipp || !name || group < IPP_TAG_ZERO || group == IPP_TAG_END || group >= IPP_TAG_UNSUPPORTED_VALUE || (value_tag != IPP_TAG_INTEGER && value_tag != IPP_TAG_ENUM))
    return (NULL);

  // Create the attribute...
  if ((attr = ipp_add_attr(ipp, name, group, value_tag, 1)) == NULL)
    return (NULL);

  attr->values[0].integer = value;

  return (attr);
}


//
// 'ippAddIntegers()' - Add an array of integer values.
//
// The "ipp" argument refers to an IPP message previously created using
// the @link ippNew@, @link ippNewRequest@, or  @link ippNewResponse@ functions.
//
// The "group" argument specifies the IPP attribute group tag: none
// (`IPP_TAG_ZERO`, for member attributes), document (`IPP_TAG_DOCUMENT`),
// event notification (`IPP_TAG_EVENT_NOTIFICATION`), operation
// (`IPP_TAG_OPERATION`), printer (`IPP_TAG_PRINTER`), subscription
// (`IPP_TAG_SUBSCRIPTION`), or unsupported (`IPP_TAG_UNSUPPORTED_GROUP`).
//
// Supported values include enum (`IPP_TAG_ENUM`) and integer
// (`IPP_TAG_INTEGER`).
//

ipp_attribute_t *     // O - New attribute
ippAddIntegers(ipp_t      *ipp,   // I - IPP message
               ipp_tag_t  group,  // I - IPP group
         ipp_tag_t  value_tag,  // I - Type of attribute
         const char *name,  // I - Name of attribute
         size_t     num_values, // I - Number of values
         const int  *values)  // I - Values
{
  size_t    i;    // Looping var
  ipp_attribute_t *attr;    // New attribute
  _ipp_value_t    *value;   // Current value


  DEBUG_printf("ippAddIntegers(ipp=%p, group=%02x(%s), type=%02x(%s), name=\"%s\", num_values=%u, values=%p)", (void *)ipp, group, ippTagString(group), value_tag, ippTagString(value_tag), name, (unsigned)num_values, (void *)values);

  value_tag &= IPP_TAG_CUPS_MASK;

  // Range check input...
  if (!ipp || !name || group < IPP_TAG_ZERO || group == IPP_TAG_END || group >= IPP_TAG_UNSUPPORTED_VALUE || (value_tag != IPP_TAG_INTEGER && value_tag != IPP_TAG_ENUM) || num_values < 1)
    return (NULL);

  // Create the attribute...
  if ((attr = ipp_add_attr(ipp, name, group, value_tag, num_values)) == NULL)
    return (NULL);

  if (values)
  {
    for (i = num_values, value = attr->values; i > 0; i --, value ++)
      value->integer = *values++;
  }

  return (attr);
}


//
// 'ippAddOctetString()' - Add an octetString value to an IPP message.
//
// The "ipp" argument refers to an IPP message previously created using
// the @link ippNew@, @link ippNewRequest@, or  @link ippNewResponse@ functions.
//
// The "group" argument specifies the IPP attribute group tag: none
// (`IPP_TAG_ZERO`, for member attributes), document (`IPP_TAG_DOCUMENT`),
// event notification (`IPP_TAG_EVENT_NOTIFICATION`), operation
// (`IPP_TAG_OPERATION`), printer (`IPP_TAG_PRINTER`), subscription
// (`IPP_TAG_SUBSCRIPTION`), or unsupported (`IPP_TAG_UNSUPPORTED_GROUP`).
//

ipp_attribute_t *     // O - New attribute
ippAddOctetString(ipp_t      *ipp,  // I - IPP message
                  ipp_tag_t  group, // I - IPP group
                  const char *name, // I - Name of attribute
                  const void *data, // I - octetString data
      size_t     datalen) // I - Length of data in bytes
{
  ipp_attribute_t *attr;    // New attribute


  // Range check input...
  if (!ipp || !name || group < IPP_TAG_ZERO || group == IPP_TAG_END || group >= IPP_TAG_UNSUPPORTED_VALUE || datalen > IPP_MAX_LENGTH)
    return (NULL);

  if ((attr = ipp_add_attr(ipp, name, group, IPP_TAG_STRING, 1)) == NULL)
    return (NULL);

  // Initialize the attribute data...
  attr->values[0].unknown.length = datalen;

  if (data)
  {
    if ((attr->values[0].unknown.data = malloc((size_t)datalen)) == NULL)
    {
      ippDeleteAttribute(ipp, attr);
      return (NULL);
    }

    memcpy(attr->values[0].unknown.data, data, (size_t)datalen);
  }

  // Return the new attribute...
  return (attr);
}


//
// 'ippAddOutOfBand()' - Add an out-of-band value to an IPP message.
//
// The "ipp" argument refers to an IPP message previously created using
// the @link ippNew@, @link ippNewRequest@, or  @link ippNewResponse@ functions.
//
// The "group" argument specifies the IPP attribute group tag: none
// (`IPP_TAG_ZERO`, for member attributes), document (`IPP_TAG_DOCUMENT`),
// event notification (`IPP_TAG_EVENT_NOTIFICATION`), operation
// (`IPP_TAG_OPERATION`), printer (`IPP_TAG_PRINTER`), subscription
// (`IPP_TAG_SUBSCRIPTION`), or unsupported (`IPP_TAG_UNSUPPORTED_GROUP`).
//
// Supported out-of-band values include unsupported-value
// (`IPP_TAG_UNSUPPORTED_VALUE`), default (`IPP_TAG_DEFAULT`), unknown
// (`IPP_TAG_UNKNOWN`), no-value (`IPP_TAG_NOVALUE`), not-settable
// (`IPP_TAG_NOTSETTABLE`), delete-attribute (`IPP_TAG_DELETEATTR`), and
// admin-define (`IPP_TAG_ADMINDEFINE`).
//

ipp_attribute_t *     // O - New attribute
ippAddOutOfBand(ipp_t      *ipp,  // I - IPP message
                ipp_tag_t  group, // I - IPP group
                ipp_tag_t  value_tag, // I - Type of attribute
    const char *name) // I - Name of attribute
{
  DEBUG_printf("ippAddOutOfBand(ipp=%p, group=%02x(%s), value_tag=%02x(%s), name=\"%s\")", (void *)ipp, group, ippTagString(group), value_tag, ippTagString(value_tag), name);

  value_tag &= IPP_TAG_CUPS_MASK;

  // Range check input...
  if (!ipp || !name || group < IPP_TAG_ZERO || group == IPP_TAG_END || group >= IPP_TAG_UNSUPPORTED_VALUE || (value_tag != IPP_TAG_UNSUPPORTED_VALUE && value_tag != IPP_TAG_DEFAULT && value_tag != IPP_TAG_UNKNOWN && value_tag != IPP_TAG_NOVALUE && value_tag != IPP_TAG_NOTSETTABLE && value_tag != IPP_TAG_DELETEATTR && value_tag != IPP_TAG_ADMINDEFINE))
    return (NULL);

  // Create the attribute...
  return (ipp_add_attr(ipp, name, group, value_tag, 1));
}


//
// 'ippAddRange()' - Add a range of values to an IPP message.
//
// The "ipp" argument refers to an IPP message previously created using
// the @link ippNew@, @link ippNewRequest@, or  @link ippNewResponse@ functions.
//
// The "group" argument specifies the IPP attribute group tag: none
// (`IPP_TAG_ZERO`, for member attributes), document (`IPP_TAG_DOCUMENT`),
// event notification (`IPP_TAG_EVENT_NOTIFICATION`), operation
// (`IPP_TAG_OPERATION`), printer (`IPP_TAG_PRINTER`), subscription
// (`IPP_TAG_SUBSCRIPTION`), or unsupported (`IPP_TAG_UNSUPPORTED_GROUP`).
//
// The "lower" argument must be less than or equal to the `upper" argument.
//

ipp_attribute_t *     // O - New attribute
ippAddRange(ipp_t      *ipp,    // I - IPP message
            ipp_tag_t  group,   // I - IPP group
      const char *name,   // I - Name of attribute
      int        lower,   // I - Lower value
      int        upper)   // I - Upper value
{
  ipp_attribute_t *attr;    // New attribute


  DEBUG_printf("ippAddRange(ipp=%p, group=%02x(%s), name=\"%s\", lower=%d, upper=%d)", (void *)ipp, group, ippTagString(group), name, lower, upper);

  // Range check input...
  if (!ipp || !name || group < IPP_TAG_ZERO || group == IPP_TAG_END || group >= IPP_TAG_UNSUPPORTED_VALUE)
    return (NULL);

  // Create the attribute...
  if ((attr = ipp_add_attr(ipp, name, group, IPP_TAG_RANGE, 1)) == NULL)
    return (NULL);

  attr->values[0].range.lower = lower;
  attr->values[0].range.upper = upper;

  return (attr);
}


//
// 'ippAddRanges()' - Add ranges of values to an IPP message.
//
// The "ipp" argument refers to an IPP message previously created using
// the @link ippNew@, @link ippNewRequest@, or  @link ippNewResponse@ functions.
//
// The "group" argument specifies the IPP attribute group tag: none
// (`IPP_TAG_ZERO`, for member attributes), document (`IPP_TAG_DOCUMENT`),
// event notification (`IPP_TAG_EVENT_NOTIFICATION`), operation
// (`IPP_TAG_OPERATION`), printer (`IPP_TAG_PRINTER`), subscription
// (`IPP_TAG_SUBSCRIPTION`), or unsupported (`IPP_TAG_UNSUPPORTED_GROUP`).
//

ipp_attribute_t *     // O - New attribute
ippAddRanges(ipp_t      *ipp,   // I - IPP message
             ipp_tag_t  group,    // I - IPP group
       const char *name,    // I - Name of attribute
       size_t     num_values, // I - Number of values
       const int  *lower,   // I - Lower values
       const int  *upper)   // I - Upper values
{
  size_t    i;    // Looping var
  ipp_attribute_t *attr;    // New attribute
  _ipp_value_t    *value;   // Current value


  DEBUG_printf("ippAddRanges(ipp=%p, group=%02x(%s), name=\"%s\", num_values=%u, lower=%p, upper=%p)", (void *)ipp, group, ippTagString(group), name, (unsigned)num_values, (void *)lower, (void *)upper);

  // Range check input...
  if (!ipp || !name || group < IPP_TAG_ZERO || group == IPP_TAG_END || group >= IPP_TAG_UNSUPPORTED_VALUE || num_values < 1)
    return (NULL);

  // Create the attribute...
  if ((attr = ipp_add_attr(ipp, name, group, IPP_TAG_RANGE, num_values)) == NULL)
    return (NULL);

  if (lower && upper)
  {
    for (i = num_values, value = attr->values; i > 0; i --, value ++)
    {
      value->range.lower = *lower++;
      value->range.upper = *upper++;
    }
  }

  return (attr);
}


//
// 'ippAddResolution()' - Add a resolution value to an IPP message.
//
// The "ipp" argument refers to an IPP message previously created using
// the @link ippNew@, @link ippNewRequest@, or  @link ippNewResponse@ functions.
//
// The "group" argument specifies the IPP attribute group tag: none
// (`IPP_TAG_ZERO`, for member attributes), document (`IPP_TAG_DOCUMENT`),
// event notification (`IPP_TAG_EVENT_NOTIFICATION`), operation
// (`IPP_TAG_OPERATION`), printer (`IPP_TAG_PRINTER`), subscription
// (`IPP_TAG_SUBSCRIPTION`), or unsupported (`IPP_TAG_UNSUPPORTED_GROUP`).
//

ipp_attribute_t *     // O - New attribute
ippAddResolution(ipp_t      *ipp, // I - IPP message
           ipp_tag_t  group,  // I - IPP group
     const char *name,  // I - Name of attribute
     ipp_res_t  units,  // I - Units for resolution
     int        xres, // I - X resolution
     int        yres) // I - Y resolution
{
  ipp_attribute_t *attr;    // New attribute


  DEBUG_printf("ippAddResolution(ipp=%p, group=%02x(%s), name=\"%s\", units=%d, xres=%d, yres=%d)", (void *)ipp, group, ippTagString(group), name, units, xres, yres);

  // Range check input...
  if (!ipp || !name || group < IPP_TAG_ZERO || group == IPP_TAG_END || group >= IPP_TAG_UNSUPPORTED_VALUE || units < IPP_RES_PER_INCH || units > IPP_RES_PER_CM || xres < 0 || yres < 0)
    return (NULL);

  // Create the attribute...
  if ((attr = ipp_add_attr(ipp, name, group, IPP_TAG_RESOLUTION, 1)) == NULL)
    return (NULL);

  attr->values[0].resolution.xres  = xres;
  attr->values[0].resolution.yres  = yres;
  attr->values[0].resolution.units = units;

  return (attr);
}


//
// 'ippAddResolutions()' - Add resolution values to an IPP message.
//
// The "ipp" argument refers to an IPP message previously created using
// the @link ippNew@, @link ippNewRequest@, or  @link ippNewResponse@ functions.
//
// The "group" argument specifies the IPP attribute group tag: none
// (`IPP_TAG_ZERO`, for member attributes), document (`IPP_TAG_DOCUMENT`),
// event notification (`IPP_TAG_EVENT_NOTIFICATION`), operation
// (`IPP_TAG_OPERATION`), printer (`IPP_TAG_PRINTER`), subscription
// (`IPP_TAG_SUBSCRIPTION`), or unsupported (`IPP_TAG_UNSUPPORTED_GROUP`).
//

ipp_attribute_t *     // O - New attribute
ippAddResolutions(ipp_t      *ipp,  // I - IPP message
            ipp_tag_t  group, // I - IPP group
      const char *name, // I - Name of attribute
      size_t     num_values,// I - Number of values
      ipp_res_t  units, // I - Units for resolution
      const int  *xres, // I - X resolutions
      const int  *yres) // I - Y resolutions
{
  size_t    i;    // Looping var
  ipp_attribute_t *attr;    // New attribute
  _ipp_value_t    *value;   // Current value


  DEBUG_printf("ippAddResolutions(ipp=%p, group=%02x(%s), name=\"%s\", num_value=%u, units=%d, xres=%p, yres=%p)", (void *)ipp, group, ippTagString(group), name, (unsigned)num_values, units, (void *)xres, (void *)yres);

  // Range check input...
  if (!ipp || !name || group < IPP_TAG_ZERO || group == IPP_TAG_END || group >= IPP_TAG_UNSUPPORTED_VALUE || num_values < 1 || units < IPP_RES_PER_INCH || units > IPP_RES_PER_CM)
    return (NULL);

  // Create the attribute...
  if ((attr = ipp_add_attr(ipp, name, group, IPP_TAG_RESOLUTION, num_values)) == NULL)
    return (NULL);

  if (xres && yres)
  {
    for (i = num_values, value = attr->values; i > 0; i --, value ++)
    {
      value->resolution.xres  = *xres++;
      value->resolution.yres  = *yres++;
      value->resolution.units = units;
    }
  }

  return (attr);
}


//
// 'ippAddSeparator()' - Add a group separator to an IPP message.
//
// The "ipp" argument refers to an IPP message previously created using
// the @link ippNew@, @link ippNewRequest@, or  @link ippNewResponse@ functions.
//

ipp_attribute_t *     // O - New attribute
ippAddSeparator(ipp_t *ipp)   // I - IPP message
{
  DEBUG_printf("ippAddSeparator(ipp=%p)", (void *)ipp);

  // Range check input...
  if (!ipp)
    return (NULL);

  // Create the attribute...
  return (ipp_add_attr(ipp, NULL, IPP_TAG_ZERO, IPP_TAG_ZERO, 0));
}


//
// 'ippAddString()' - Add a language-encoded string to an IPP message.
//
// The "ipp" argument refers to an IPP message previously created using
// the @link ippNew@, @link ippNewRequest@, or  @link ippNewResponse@ functions.
//
// The "group" argument specifies the IPP attribute group tag: none
// (`IPP_TAG_ZERO`, for member attributes), document (`IPP_TAG_DOCUMENT`),
// event notification (`IPP_TAG_EVENT_NOTIFICATION`), operation
// (`IPP_TAG_OPERATION`), printer (`IPP_TAG_PRINTER`), subscription
// (`IPP_TAG_SUBSCRIPTION`), or unsupported (`IPP_TAG_UNSUPPORTED_GROUP`).
//
// Supported string values include charset (`IPP_TAG_CHARSET`), keyword
// (`IPP_TAG_KEYWORD`), language (`IPP_TAG_LANGUAGE`), mimeMediaType
// (`IPP_TAG_MIMETYPE`), name (`IPP_TAG_NAME`), nameWithLanguage
// (@code IPP_TAG_NAMELANG), text (`IPP_TAG_TEXT`), textWithLanguage
// (`IPP_TAG_TEXTLANG`), uri (`IPP_TAG_URI`), and uriScheme
// (`IPP_TAG_URISCHEME`).
//
// The "language" argument must be non-`NULL` for nameWithLanguage and
// textWithLanguage string values and must be `NULL` for all other string values.
//

ipp_attribute_t *     // O - New attribute
ippAddString(ipp_t      *ipp,   // I - IPP message
             ipp_tag_t  group,    // I - IPP group
       ipp_tag_t  value_tag,  // I - Type of attribute
             const char *name,    // I - Name of attribute
             const char *language,  // I - Language code
             const char *value)   // I - Value
{
  ipp_tag_t   temp_tag; // Temporary value tag (masked)
  ipp_attribute_t *attr;    // New attribute
  char      code[IPP_MAX_LANGUAGE];
          // Charset/language code buffer


  DEBUG_printf("ippAddString(ipp=%p, group=%02x(%s), value_tag=%02x(%s), name=\"%s\", language=\"%s\", value=\"%s\")", (void *)ipp, group, ippTagString(group), value_tag, ippTagString(value_tag), name, language, value);

  // Range check input...
  temp_tag = (ipp_tag_t)((int)value_tag & IPP_TAG_CUPS_MASK);

#if 0
  if (!ipp || !name || group < IPP_TAG_ZERO ||
      group == IPP_TAG_END || group >= IPP_TAG_UNSUPPORTED_VALUE ||
      (temp_tag < IPP_TAG_TEXT && temp_tag != IPP_TAG_TEXTLANG &&
       temp_tag != IPP_TAG_NAMELANG) || temp_tag > IPP_TAG_MIMETYPE)
    return (NULL);

  if ((temp_tag == IPP_TAG_TEXTLANG || temp_tag == IPP_TAG_NAMELANG)
          != (language != NULL))
    return (NULL);
#else
  if (!ipp || !name || group < IPP_TAG_ZERO || group == IPP_TAG_END || group >= IPP_TAG_UNSUPPORTED_VALUE)
    return (NULL);
#endif // 0

  // See if we need to map charset, language, or locale values...
  if (language && ((int)value_tag & IPP_TAG_CUPS_CONST) && strcmp(language, ipp_lang_code(language, code, sizeof(code))))
    value_tag = temp_tag;   // Don't do a fast copy
  else if (value && value_tag == (ipp_tag_t)(IPP_TAG_CHARSET | IPP_TAG_CUPS_CONST) && strcmp(value, ipp_get_code(value, code, sizeof(code))))
    value_tag = temp_tag;   // Don't do a fast copy
  else if (value && value_tag == (ipp_tag_t)(IPP_TAG_LANGUAGE | IPP_TAG_CUPS_CONST) && strcmp(value, ipp_lang_code(value, code, sizeof(code))))
    value_tag = temp_tag;   // Don't do a fast copy

  // Create the attribute...
  if ((attr = ipp_add_attr(ipp, name, group, value_tag, 1)) == NULL)
    return (NULL);

  // Initialize the attribute data...
  if ((int)value_tag & IPP_TAG_CUPS_CONST)
  {
    attr->values[0].string.language = (char *)language;
    attr->values[0].string.text     = (char *)value;
  }
  else
  {
    if (language)
      attr->values[0].string.language = _cupsStrAlloc(ipp_lang_code(language, code, sizeof(code)));

    if (value)
    {
      if (value_tag == IPP_TAG_CHARSET)
  attr->values[0].string.text = _cupsStrAlloc(ipp_get_code(value, code, sizeof(code)));
      else if (value_tag == IPP_TAG_LANGUAGE)
  attr->values[0].string.text = _cupsStrAlloc(ipp_lang_code(value, code, sizeof(code)));
      else
  attr->values[0].string.text = _cupsStrAlloc(value);
    }
  }

  return (attr);
}


//
// 'ippAddStringf()' - Add a formatted string to an IPP message.
//
// The "ipp" argument refers to an IPP message previously created using
// the @link ippNew@, @link ippNewRequest@, or  @link ippNewResponse@ functions.
//
// The "group" argument specifies the IPP attribute group tag: none
// (`IPP_TAG_ZERO`, for member attributes), document
// (`IPP_TAG_DOCUMENT`), event notification
// (`IPP_TAG_EVENT_NOTIFICATION`), operation (`IPP_TAG_OPERATION`),
// printer (`IPP_TAG_PRINTER`), subscription (`IPP_TAG_SUBSCRIPTION`),
// or unsupported (`IPP_TAG_UNSUPPORTED_GROUP`).
//
// Supported string values include charset (`IPP_TAG_CHARSET`), keyword
// (`IPP_TAG_KEYWORD`), language (`IPP_TAG_LANGUAGE`), mimeMediaType
// (`IPP_TAG_MIMETYPE`), name (`IPP_TAG_NAME`), nameWithLanguage
// (@code IPP_TAG_NAMELANG), text (`IPP_TAG_TEXT`), textWithLanguage
// (`IPP_TAG_TEXTLANG`), uri (`IPP_TAG_URI`), and uriScheme
// (`IPP_TAG_URISCHEME`).
//
// The "language" argument must be non-`NULL` for nameWithLanguage
// and textWithLanguage string values and must be `NULL` for all other
// string values.
//
// The "format" argument uses formatting characters compatible with the
// printf family of standard functions.  Additional arguments follow it as
// needed.  The formatted string is truncated as needed to the maximum length of
// the corresponding value type.
//

ipp_attribute_t *     // O - New attribute
ippAddStringf(ipp_t      *ipp,    // I - IPP message
              ipp_tag_t  group,   // I - IPP group
        ipp_tag_t  value_tag, // I - Type of attribute
        const char *name,   // I - Name of attribute
        const char *language, // I - Language code (`NULL` for default)
        const char *format, // I - Printf-style format string
        ...)      // I - Additional arguments as needed
{
  ipp_attribute_t *attr;    // New attribute
  va_list   ap;   // Argument pointer


  va_start(ap, format);
  attr = ippAddStringfv(ipp, group, value_tag, name, language, format, ap);
  va_end(ap);

  return (attr);
}


//
// 'ippAddStringfv()' - Add a formatted string to an IPP message.
//
// The "ipp" argument refers to an IPP message previously created using
// the @link ippNew@, @link ippNewRequest@, or  @link ippNewResponse@ functions.
//
// The "group" argument specifies the IPP attribute group tag: none
// (`IPP_TAG_ZERO`, for member attributes), document
// (`IPP_TAG_DOCUMENT`), event notification
// (`IPP_TAG_EVENT_NOTIFICATION`), operation (`IPP_TAG_OPERATION`),
// printer (`IPP_TAG_PRINTER`), subscription (`IPP_TAG_SUBSCRIPTION`),
// or unsupported (`IPP_TAG_UNSUPPORTED_GROUP`).
//
// Supported string values include charset (`IPP_TAG_CHARSET`), keyword
// (`IPP_TAG_KEYWORD`), language (`IPP_TAG_LANGUAGE`), mimeMediaType
// (`IPP_TAG_MIMETYPE`), name (`IPP_TAG_NAME`), nameWithLanguage
// (@code IPP_TAG_NAMELANG), text (`IPP_TAG_TEXT`), textWithLanguage
// (`IPP_TAG_TEXTLANG`), uri (`IPP_TAG_URI`), and uriScheme
// (`IPP_TAG_URISCHEME`).
//
// The "language" argument must be non-`NULL` for nameWithLanguage
// and textWithLanguage string values and must be `NULL` for all other
// string values.
//
// The "format" argument uses formatting characters compatible with the
// printf family of standard functions.  Additional arguments are passed in the
// stdarg pointer "ap".  The formatted string is truncated as needed to the
// maximum length of the corresponding value type.
//

ipp_attribute_t *     // O - New attribute
ippAddStringfv(ipp_t      *ipp,   // I - IPP message
               ipp_tag_t  group,  // I - IPP group
         ipp_tag_t  value_tag,  // I - Type of attribute
         const char *name,  // I - Name of attribute
         const char *language,  // I - Language code (`NULL` for default)
         const char *format,  // I - Printf-style format string
         va_list    ap)   // I - Additional arguments
{
  char    buffer[IPP_MAX_TEXT + 4];
          // Formatted text string
  ssize_t bytes,      // Length of formatted value
    max_bytes;    // Maximum number of bytes for value


  // Range check input...
  if (!ipp || !name || group < IPP_TAG_ZERO || group == IPP_TAG_END || group >= IPP_TAG_UNSUPPORTED_VALUE || (value_tag < IPP_TAG_TEXT && value_tag != IPP_TAG_TEXTLANG && value_tag != IPP_TAG_NAMELANG) || value_tag > IPP_TAG_MIMETYPE || !format)
    return (NULL);

  if ((value_tag == IPP_TAG_TEXTLANG || value_tag == IPP_TAG_NAMELANG) != (language != NULL))
    return (NULL);

  // Format the string...
  if (!strcmp(format, "%s"))
  {
    // Optimize the simple case...
    const char *s = va_arg(ap, char *);

    if (!s)
      s = "(null)";

    bytes = (ssize_t)strlen(s);
    cupsCopyString(buffer, s, sizeof(buffer));
  }
  else
  {
    // Do a full formatting of the message...
    if ((bytes = vsnprintf(buffer, sizeof(buffer), format, ap)) < 0)
      return (NULL);
  }

  // Limit the length of the string...
  switch (value_tag)
  {
    default :
    case IPP_TAG_TEXT :
    case IPP_TAG_TEXTLANG :
        max_bytes = IPP_MAX_TEXT;
        break;

    case IPP_TAG_NAME :
    case IPP_TAG_NAMELANG :
        max_bytes = IPP_MAX_NAME;
        break;

    case IPP_TAG_CHARSET :
        max_bytes = IPP_MAX_CHARSET;
        break;

    case IPP_TAG_KEYWORD :
        max_bytes = IPP_MAX_KEYWORD;
        break;

    case IPP_TAG_LANGUAGE :
        max_bytes = IPP_MAX_LANGUAGE;
        break;

    case IPP_TAG_MIMETYPE :
        max_bytes = IPP_MAX_MIMETYPE;
        break;

    case IPP_TAG_URI :
        max_bytes = IPP_MAX_URI;
        break;

    case IPP_TAG_URISCHEME :
        max_bytes = IPP_MAX_URISCHEME;
        break;
  }

  if (bytes >= max_bytes)
  {
    // Safely truncate the UTF-8 string...
    char  *bufmax,    // Buffer at max_bytes
    *bufptr;    // Pointer into buffer

    bufptr = buffer + strlen(buffer) - 1;
    bufmax = buffer + max_bytes - 1;

    while (bufptr > bufmax)
    {
      if (*bufptr & 0x80)
      {
        while ((*bufptr & 0xc0) == 0x80 && bufptr > buffer)
          bufptr --;
      }

      if (bufptr > buffer)
        bufptr --;
    }

    *bufptr = '\0';
  }

  // Add the formatted string and return...
  return (ippAddString(ipp, group, value_tag, name, language, buffer));
}


//
// 'ippAddStrings()' - Add language-encoded strings to an IPP message.
//
// The "ipp" argument refers to an IPP message previously created using
// the @link ippNew@, @link ippNewRequest@, or  @link ippNewResponse@ functions.
//
// The "group" argument specifies the IPP attribute group tag: none
// (`IPP_TAG_ZERO`, for member attributes), document (`IPP_TAG_DOCUMENT`),
// event notification (`IPP_TAG_EVENT_NOTIFICATION`), operation
// (`IPP_TAG_OPERATION`), printer (`IPP_TAG_PRINTER`), subscription
// (`IPP_TAG_SUBSCRIPTION`), or unsupported (`IPP_TAG_UNSUPPORTED_GROUP`).
//
// Supported string values include charset (`IPP_TAG_CHARSET`), keyword
// (`IPP_TAG_KEYWORD`), language (`IPP_TAG_LANGUAGE`), mimeMediaType
// (`IPP_TAG_MIMETYPE`), name (`IPP_TAG_NAME`), nameWithLanguage
// (@code IPP_TAG_NAMELANG), text (`IPP_TAG_TEXT`), textWithLanguage
// (`IPP_TAG_TEXTLANG`), uri (`IPP_TAG_URI`), and uriScheme
// (`IPP_TAG_URISCHEME`).
//
// The "language" argument must be non-`NULL` for nameWithLanguage and
// textWithLanguage string values and must be `NULL` for all other string values.
//

ipp_attribute_t *     // O - New attribute
ippAddStrings(
    ipp_t              *ipp,    // I - IPP message
    ipp_tag_t          group,   // I - IPP group
    ipp_tag_t          value_tag, // I - Type of attribute
    const char         *name,   // I - Name of attribute
    size_t             num_values,  // I - Number of values
    const char         *language, // I - Language code (`NULL` for default)
    const char * const *values)   // I - Values
{
  size_t    i;    // Looping var
  ipp_tag_t   temp_tag; // Temporary value tag (masked)
  ipp_attribute_t *attr;    // New attribute
  _ipp_value_t    *value;   // Current value
  char      code[32]; // Language/charset value buffer


  DEBUG_printf("ippAddStrings(ipp=%p, group=%02x(%s), value_tag=%02x(%s), name=\"%s\", num_values=%u, language=\"%s\", values=%p)", (void *)ipp, group, ippTagString(group), value_tag, ippTagString(value_tag), name, (unsigned)num_values, language, (void *)values);

  // Range check input...
  temp_tag = (ipp_tag_t)((int)value_tag & IPP_TAG_CUPS_MASK);

#if 0
  if (!ipp || !name || group < IPP_TAG_ZERO || group == IPP_TAG_END || group >= IPP_TAG_UNSUPPORTED_VALUE || (temp_tag < IPP_TAG_TEXT && temp_tag != IPP_TAG_TEXTLANG && temp_tag != IPP_TAG_NAMELANG) || temp_tag > IPP_TAG_MIMETYPE || num_values < 1)
    return (NULL);

  if ((temp_tag == IPP_TAG_TEXTLANG || temp_tag == IPP_TAG_NAMELANG) != (language != NULL))
    return (NULL);
#else
  if (!ipp || !name || group < IPP_TAG_ZERO || group == IPP_TAG_END || group >= IPP_TAG_UNSUPPORTED_VALUE || num_values < 1)
    return (NULL);
#endif // 0

  // See if we need to map charset, language, or locale values...
  if (language && ((int)value_tag & IPP_TAG_CUPS_CONST) && strcmp(language, ipp_lang_code(language, code, sizeof(code))))
  {
    value_tag = temp_tag;   // Don't do a fast copy
  }
  else if (values && value_tag == (ipp_tag_t)(IPP_TAG_CHARSET | IPP_TAG_CUPS_CONST))
  {
    for (i = 0; i < num_values; i ++)
    {
      if (strcmp(values[i], ipp_get_code(values[i], code, sizeof(code))))
      {
  value_tag = temp_tag;   // Don't do a fast copy
        break;
      }
    }
  }
  else if (values && value_tag == (ipp_tag_t)(IPP_TAG_LANGUAGE | IPP_TAG_CUPS_CONST))
  {
    for (i = 0; i < num_values; i ++)
    {
      if (strcmp(values[i], ipp_lang_code(values[i], code, sizeof(code))))
      {
  value_tag = temp_tag;   // Don't do a fast copy
        break;
      }
    }
  }

  // Create the attribute...
  if ((attr = ipp_add_attr(ipp, name, group, value_tag, num_values)) == NULL)
    return (NULL);

  // Initialize the attribute data...
  for (i = num_values, value = attr->values; i > 0; i --, value ++)
  {
    if (language)
    {
      if (value == attr->values)
      {
        if ((int)value_tag & IPP_TAG_CUPS_CONST)
          value->string.language = (char *)language;
        else
          value->string.language = _cupsStrAlloc(ipp_lang_code(language, code, sizeof(code)));
      }
      else
      {
  value->string.language = attr->values[0].string.language;
      }
    }

    if (values)
    {
      if ((int)value_tag & IPP_TAG_CUPS_CONST)
        value->string.text = (char *)*values++;
      else if (value_tag == IPP_TAG_CHARSET)
  value->string.text = _cupsStrAlloc(ipp_get_code(*values++, code, sizeof(code)));
      else if (value_tag == IPP_TAG_LANGUAGE)
  value->string.text = _cupsStrAlloc(ipp_lang_code(*values++, code, sizeof(code)));
      else
  value->string.text = _cupsStrAlloc(*values++);
    }
  }

  return (attr);
}


//
// 'ippContainsInteger()' - Determine whether an attribute contains the
//                          specified value or is within the list of ranges.
//
// This function returns `true` when the attribute contains either a matching
// integer or enum value, or the value falls within one of the rangeOfInteger
// values for the attribute.
//

bool          // O - `true` on a match, `false` on no match
ippContainsInteger(
    ipp_attribute_t *attr,    // I - Attribute
    int             value)    // I - Integer/enum value
{
  size_t  i;      // Looping var
  _ipp_value_t  *avalue;    // Current attribute value


  // Range check input...
  if (!attr)
    return (false);

  if (attr->value_tag != IPP_TAG_INTEGER && attr->value_tag != IPP_TAG_ENUM && attr->value_tag != IPP_TAG_RANGE)
    return (false);

  // Compare...
  if (attr->value_tag == IPP_TAG_RANGE)
  {
    // Check ranges...
    for (i = attr->num_values, avalue = attr->values; i > 0; i --, avalue ++)
    {
      if (value >= avalue->range.lower && value <= avalue->range.upper)
        return (true);
    }
  }
  else
  {
    // Check discrete values...
    for (i = attr->num_values, avalue = attr->values; i > 0; i --, avalue ++)
    {
      if (value == avalue->integer)
        return (true);
    }
  }

  return (false);
}


//
// 'ippContainsString()' - Determine whether an attribute contains the
//                         specified string value.
//
// This function returns `true` when the attribute contains a matching charset,
// keyword, naturalLanguage, mimeMediaType, name, text, uri, or uriScheme value.
//

bool          // O - `true` on a match, `false` on no match
ippContainsString(
    ipp_attribute_t *attr,    // I - Attribute
    const char      *value)   // I - String value
{
  size_t  i;      // Looping var
  _ipp_value_t  *avalue;    // Current attribute value


  DEBUG_printf("ippContainsString(attr=%p, value=\"%s\")", (void *)attr, value);

  // Range check input...
  if (!attr || !value)
  {
    DEBUG_puts("1ippContainsString: Returning false (bad input)");
    return (false);
  }

  // Compare...
  DEBUG_printf("1ippContainsString: attr %s, %s%s with %u values.", attr->name, (attr->value_tag & IPP_TAG_CUPS_CONST) ? "(const)" : "", ippTagString(attr->value_tag), (unsigned)attr->num_values);

  switch (attr->value_tag & IPP_TAG_CUPS_MASK)
  {
    case IPP_TAG_CHARSET :
    case IPP_TAG_KEYWORD :
    case IPP_TAG_LANGUAGE :
    case IPP_TAG_URI :
    case IPP_TAG_URISCHEME :
  for (i = attr->num_values, avalue = attr->values; i > 0; i --, avalue ++)
  {
    DEBUG_printf("1ippContainsString: value[%u]=\"%s\"", (unsigned)(attr->num_values - i), avalue->string.text);

    if (avalue->string.text && !strcmp(value, avalue->string.text))
    {
      DEBUG_puts("1ippContainsString: Returning true (match)");
      return (true);
    }
        }
        break;

    case IPP_TAG_MIMETYPE :
    case IPP_TAG_NAME :
    case IPP_TAG_NAMELANG :
    case IPP_TAG_TEXT :
    case IPP_TAG_TEXTLANG :
  for (i = attr->num_values, avalue = attr->values; i > 0; i --, avalue ++)
  {
    DEBUG_printf("1ippContainsString: value[%u]=\"%s\"", (unsigned)(attr->num_values - i), avalue->string.text);

    if (avalue->string.text && !_cups_strcasecmp(value, avalue->string.text))
    {
      DEBUG_puts("1ippContainsString: Returning true (match)");
      return (true);
    }
        }
        break;

    default :
        break;
  }

  DEBUG_puts("1ippContainsString: Returning false (no match)");

  return (false);
}


//
// 'ippCopyAttribute()' - Copy an attribute.
//
// This function copies an attribute to another IPP message.  When "quickcopy"
// is `true`, a shallow reference copy of the attribute is created - this should
// only be done as long as the original source IPP message will not be freed for
// the life of the destination.
//


ipp_attribute_t *     // O - New attribute
ippCopyAttribute(
    ipp_t           *dst,   // I - Destination IPP message
    ipp_attribute_t *srcattr,   // I - Attribute to copy
    bool            quickcopy)    // I - `true` for a referenced copy, `false` for a new copy
{
  size_t    i;    // Looping var
  ipp_tag_t   srctag,   // Source value tag
      dstcopy;  // Copy bit for quick copies
  ipp_attribute_t *dstattr; // Destination attribute
  _ipp_value_t    *srcval,  // Source value
      *dstval;  // Destination value


  DEBUG_printf("ippCopyAttribute(dst=%p, srcattr=%p, quickcopy=%s)", (void *)dst, (void *)srcattr, quickcopy ? "true" : "false");

  // Range check input...
  if (!dst || !srcattr)
    return (NULL);

  // Copy it...
  dstcopy = (quickcopy && (srcattr->value_tag & IPP_TAG_CUPS_CONST)) ? IPP_TAG_CUPS_CONST : 0;
  srctag  = srcattr->value_tag & IPP_TAG_CUPS_MASK;

  switch (srctag)
  {
    case IPP_TAG_ZERO :
        dstattr = ippAddSeparator(dst);
  break;

    case IPP_TAG_UNSUPPORTED_VALUE :
    case IPP_TAG_DEFAULT :
    case IPP_TAG_UNKNOWN :
    case IPP_TAG_NOVALUE :
    case IPP_TAG_NOTSETTABLE :
    case IPP_TAG_DELETEATTR :
    case IPP_TAG_ADMINDEFINE :
        dstattr = ippAddOutOfBand(dst, srcattr->group_tag, srctag, srcattr->name);
        break;

    case IPP_TAG_INTEGER :
    case IPP_TAG_ENUM :
    case IPP_TAG_BOOLEAN :
    case IPP_TAG_DATE :
    case IPP_TAG_RESOLUTION :
    case IPP_TAG_RANGE :
        if ((dstattr = ipp_add_attr(dst, srcattr->name, srcattr->group_tag, srctag, srcattr->num_values)) != NULL)
    memcpy(dstattr->values, srcattr->values, (size_t)srcattr->num_values * sizeof(_ipp_value_t));
        break;

    case IPP_TAG_TEXT :
    case IPP_TAG_NAME :
    case IPP_TAG_RESERVED_STRING :
    case IPP_TAG_KEYWORD :
    case IPP_TAG_URI :
    case IPP_TAG_URISCHEME :
    case IPP_TAG_CHARSET :
    case IPP_TAG_LANGUAGE :
    case IPP_TAG_MIMETYPE :
        if ((dstattr = ippAddStrings(dst, srcattr->group_tag, (ipp_tag_t)(srctag | dstcopy), srcattr->name, srcattr->num_values, NULL, NULL)) == NULL)
          break;

        if (dstcopy)
  {
    // Can safely quick-copy these string values...
    memcpy(dstattr->values, srcattr->values, (size_t)srcattr->num_values * sizeof(_ipp_value_t));
        }
  else
  {
    // Otherwise do a normal reference counted copy...
    for (i = srcattr->num_values, srcval = srcattr->values, dstval = dstattr->values; i > 0; i --, srcval ++, dstval ++)
      dstval->string.text = _cupsStrAlloc(srcval->string.text);
  }
        break;

    case IPP_TAG_TEXTLANG :
    case IPP_TAG_NAMELANG :
        if ((dstattr = ippAddStrings(dst, srcattr->group_tag, (ipp_tag_t)(srctag | dstcopy), srcattr->name, srcattr->num_values, NULL, NULL)) == NULL)
          break;

        if (dstcopy)
  {
    // Can safely quick-copy these string values...
    memcpy(dstattr->values, srcattr->values, (size_t)srcattr->num_values * sizeof(_ipp_value_t));
        }
  else if (srcattr->value_tag & IPP_TAG_CUPS_CONST)
  {
    // Otherwise do a normal reference counted copy...
    for (i = srcattr->num_values, srcval = srcattr->values, dstval = dstattr->values; i > 0; i --, srcval ++, dstval ++)
    {
      if (srcval == srcattr->values)
              dstval->string.language = _cupsStrAlloc(srcval->string.language);
      else
              dstval->string.language = dstattr->values[0].string.language;

      dstval->string.text = _cupsStrAlloc(srcval->string.text);
          }
        }
        break;

    case IPP_TAG_BEGIN_COLLECTION :
        if (quickcopy)
        {
    for (i = srcattr->num_values, srcval = srcattr->values, dstattr = NULL; i > 0; i --, srcval ++)
    {
      if (srcval->collection)
      {
        if (dstattr)
    ippSetCollection(dst, &dstattr, ippGetCount(dstattr), srcval->collection);
        else
    dstattr = ippAddCollection(dst, srcattr->group_tag, srcattr->name, srcval->collection);
      }
    }
  }
  else
  {
    for (i = srcattr->num_values, srcval = srcattr->values, dstattr = NULL; i > 0; i --, srcval ++)
    {
      if (srcval->collection)
      {
        ipp_t *col = ippNew();  // Copy of collection

              if (!col)
              {
                ippDeleteAttribute(dst, dstattr);
                return (NULL);
              }

        ippCopyAttributes(col, srcval->collection, false, /*cb*/NULL, /*cb_data*/NULL);

        if (dstattr)
    ippSetCollection(dst, &dstattr, ippGetCount(dstattr), col);
        else
    dstattr = ippAddCollection(dst, srcattr->group_tag, srcattr->name, col);

              col->use --;
      }
    }
  }
        break;

    case IPP_TAG_STRING :
    default :
        if ((dstattr = ipp_add_attr(dst, srcattr->name, srcattr->group_tag, srctag, srcattr->num_values)) == NULL)
          break;

        for (i = srcattr->num_values, srcval = srcattr->values, dstval = dstattr->values; i > 0; i --, srcval ++, dstval ++)
  {
    dstval->unknown.length = srcval->unknown.length;

    if (dstval->unknown.length > 0)
    {
      if ((dstval->unknown.data = malloc((size_t)dstval->unknown.length)) == NULL)
        dstval->unknown.length = 0;
      else
        memcpy(dstval->unknown.data, srcval->unknown.data, (size_t)dstval->unknown.length);
    }
  }
        break; // anti-compiler-warning-code
  }

  return (dstattr);
}


//
// 'ippCopyAttributes()' - Copy attributes from one IPP message to another.
//
// This function copies zero or more attributes from the source to the
// destination IPP message.  When "quickcopy" is `true`, a shallow reference
// copy of the attribute is created - this should only be done as long as the
// original source IPP message will not be freed for the life of the
// destination.
//
// The "cb" and "cb_data" arguments provide a generic way to "filter" the
// attributes that are copied - the function must return `true` to copy the
// attribute or `false` to skip it.  The function may also choose to do a
// partial copy of the source attribute itself and return `false` to tell this
// function to skip it.
//

bool          // O - `true` on success, `false` on error
ippCopyAttributes(
    ipp_t         *dst,     // I - Destination IPP message
    ipp_t         *src,     // I - Source IPP message
    bool          quickcopy,    // I - `true` for a referenced copy, `false` for a new copy
    ipp_copy_cb_t cb,     // I - Copy callback or `NULL` for none
    void          *cb_data)   // I - Callback data pointer
{
  ipp_attribute_t *srcattr; // Source attribute


  DEBUG_printf("ippCopyAttributes(dst=%p, src=%p, quickcopy=%s, cb=%p, cb_data=%p)", (void *)dst, (void *)src, quickcopy ? "true" : "false", (void *)cb, cb_data);

  // Range check input...
  if (!dst || !src)
    return (false);

  // Loop through source attributes and copy as needed...
  for (srcattr = src->attrs; srcattr; srcattr = srcattr->next)
  {
    if (!cb || (*cb)(cb_data, dst, srcattr))
    {
      if (!ippCopyAttribute(dst, srcattr, quickcopy))
        return (false);
    }
  }

  return (true);
}


//
// 'ippCopyCredentialsString()' - Copy a credentials value from an IPP attribute.
//
// This function concatenates the 1setOf text credential values of an attribute,
// separated by newlines.  The returned string must be freed using the `free`
// function.
//

char *          // O - Combined string or `NULL` on error
ippCopyCredentialsString(
    ipp_attribute_t *attr)    // I - Attribute
{
  char    *s = NULL,   // Combined string
    *ptr;     // Pointer into string
  size_t  i,      // Looping var
    slen;     // Length of combined string


  if (attr && ippGetValueTag(attr) == IPP_TAG_TEXT)
  {
    // Loop through string values and add up the total length...
    for (i = 0, slen = 0; i < attr->num_values; i ++)
    {
      if (attr->values[i].string.text)
        slen += strlen(attr->values[i].string.text) + 1;
    }

    if (slen > 0)
    {
      // Allocate memory...
      if ((s = malloc(slen + 1)) != NULL)
      {
  for (i = 0, ptr = s; i < attr->num_values; i ++)
  {
    if (attr->values[i].string.text)
    {
      size_t len = strlen(attr->values[i].string.text);
            // Length of string

      memcpy(ptr, attr->values[i].string.text, len);
      ptr += len;
      *ptr++ = '\n';
    }
  }

  *ptr = '\0';
      }
    }
  }

  return (s);
}


//
// 'ippDateToTime()' - Convert from RFC 2579 Date/Time format to time in
//                     seconds.
//

time_t          // O - UNIX time value
ippDateToTime(const ipp_uchar_t *date)  // I - RFC 2579 date info
{
  struct tm unixdate;   // UNIX date/time info
  time_t  t;      // Computed time


  if (!date)
    return (0);

  memset(&unixdate, 0, sizeof(unixdate));

  // RFC-2579 date/time format is:
  //
  //    Byte(s)  Description
  //    -------  -----------
  //    0-1      Year (0 to 65535)
  //    2        Month (1 to 12)
  //    3        Day (1 to 31)
  //    4        Hours (0 to 23)
  //    5        Minutes (0 to 59)
  //    6        Seconds (0 to 60, 60 = "leap second")
  //    7        Deciseconds (0 to 9)
  //    8        +/- UTC
  //    9        UTC hours (0 to 14)
  //    10       UTC minutes (0 to 59)
  unixdate.tm_year = ((date[0] << 8) | date[1]) - 1900;
  unixdate.tm_mon  = date[2] - 1;
  unixdate.tm_mday = date[3];
  unixdate.tm_hour = date[4];
  unixdate.tm_min  = date[5];
  unixdate.tm_sec  = date[6];

#if _WIN32
  if ((t = _mkgmtime(&unixdate)) < 0)
    return (0);

#elif defined(HAVE_TIMEGM)
  if ((t = timegm(&unixdate)) < 0)
    return (0);

#else
  if ((t = mktime(&unixdate)) < 0)
    return (0);

#  if defined(HAVE_TM_GMTOFF)
  // Adjust the time value using the "tm_gmtoff" and "tm_isdst" members.  As
  // noted by M-HT on Github, this DST hack will fail in timezones where the
  // DST offset is not one hour, such as Australia/Lord_Howe.  Fortunately,
  // this is unusual and most systems support the "timegm" function...
  t += unixdate.tm_gmtoff - 3600 * unixdate.tm_isdst;
#  else
  // Adjust the time value using the even more legacy "timezone" variable,
  // which also reflects any DST offset...
  t += timezone;
#  endif // HAVE_TM_GMTOFF
#endif // _WIN32

  // Subtract the UTC timezone offset to get the actual time_t value...
  if (date[8] == '-')
    t += date[9] * 3600 + date[10] * 60;// "t - -offset" is "t + offset"
  else
    t -= date[9] * 3600 + date[10] * 60;// "t - offset"

  return (t);
}


//
// 'ippDelete()' - Delete an IPP message.
//

void
ippDelete(ipp_t *ipp)     // I - IPP message
{
  ipp_attribute_t *attr,    // Current attribute
      *next;    // Next attribute


  DEBUG_printf("ippDelete(ipp=%p)", (void *)ipp);

  if (!ipp)
    return;

  ipp->use --;
  if (ipp->use > 0)
  {
    DEBUG_printf("4debug_retain: %p IPP message (use=%u)", (void *)ipp, (unsigned)ipp->use);
    return;
  }

  DEBUG_printf("4debug_free: %p IPP message", (void *)ipp);

  for (attr = ipp->attrs; attr != NULL; attr = next)
  {
    next = attr->next;

    DEBUG_printf("4debug_free: %p %s %s%s (%u values)", (void *)attr, attr->name, attr->num_values > 1 ? "1setOf " : "", ippTagString(attr->value_tag), (unsigned)attr->num_values);

    ipp_free_values(attr, 0, attr->num_values);

    if (attr->name)
      _cupsStrFree(attr->name);

    free(attr);
  }

  free(ipp);
}


//
// 'ippDeleteAttribute()' - Delete a single attribute in an IPP message.
//

void
ippDeleteAttribute(
    ipp_t           *ipp,   // I - IPP message
    ipp_attribute_t *attr)    // I - Attribute to delete
{
  ipp_attribute_t *current, // Current attribute
      *prev;    // Previous attribute


  DEBUG_printf("ippDeleteAttribute(ipp=%p, attr=%p(%s))", (void *)ipp, (void *)attr, attr ? attr->name : "(null)");

  // Range check input...
  if (!attr)
    return;

  DEBUG_printf("4debug_free: %p %s %s%s (%u values)", (void *)attr, attr->name, attr->num_values > 1 ? "1setOf " : "", ippTagString(attr->value_tag), (unsigned)attr->num_values);

  // Find the attribute in the list...
  if (ipp)
  {
    for (current = ipp->attrs, prev = NULL; current; prev = current, current = current->next)
    {
      if (current == attr)
      {
  // Found it, remove the attribute from the list...
  if (prev)
    prev->next = current->next;
  else
    ipp->attrs = current->next;

  if (current == ipp->last)
    ipp->last = prev;

        break;
      }
    }

    if (!current)
      return;
  }

  // Free memory used by the attribute...
  ipp_free_values(attr, 0, attr->num_values);

  if (attr->name)
    _cupsStrFree(attr->name);

  free(attr);
}


//
// 'ippDeleteValues()' - Delete values in an attribute.
//
// This function deletes one or more values in an attribute.  The "element"
// argument specifies the first value to delete, starting at `0`.  It must be
// less than the number of values returned by @link ippGetCount@.
//
// The "attr" argument may be modified as a result of setting the value,
// which will set the variable to `NULL`.
//
// Deleting all values in an attribute deletes the attribute.
//

bool          // O  - `true` on success, `false` on failure
ippDeleteValues(
    ipp_t           *ipp,   // I  - IPP message
    ipp_attribute_t **attr,   // IO - Attribute
    size_t          element,    // I  - Index of first value to delete (`0`-based)
    size_t          count)    // I  - Number of values to delete
{
  // Range check input...
  if (!ipp || !attr || !*attr || element >= (*attr)->num_values || !count || (element + count) >= (*attr)->num_values)
    return (false);

  // If we are deleting all values, just delete the attribute entirely.
  if (count == (*attr)->num_values)
  {
    ippDeleteAttribute(ipp, *attr);
    *attr = NULL;
    return (true);
  }

  // Otherwise free the values in question and return.
  ipp_free_values(*attr, element, count);

  return (true);
}


//
// 'ippFindAttribute()' - Find a named attribute in an IPP message.
//
// This function finds the first occurrence of a named attribute in an IPP
// message.  The attribute name can contain a hierarchical list of attribute and
// member names separated by slashes, for example "media-col/media-size".
//

ipp_attribute_t *     // O - Matching attribute
ippFindAttribute(ipp_t      *ipp, // I - IPP message
                 const char *name,  // I - Name of attribute
     ipp_tag_t  type) // I - Type of attribute
{
  DEBUG_printf("2ippFindAttribute(ipp=%p, name=\"%s\", type=%02x(%s))", (void *)ipp, name, type, ippTagString(type));

  // Range check input...
  if (!ipp || !name)
    return (NULL);

  // Reset the current attribute pointer...
  ipp->find->attr  = NULL;
  ipp->find->idx   = 0;
  ipp->find->atend = false;

  // Search for the attribute...
  return (ippFindNextAttribute(ipp, name, type));
}


//
// 'ippFindNextAttribute()' - Find the next named attribute in an IPP message.
//
// This function finds the next named attribute in an IPP message.  The
// attribute name can contain a hierarchical list of attribute and member names
// separated by slashes, for example "media-col/media-size".
//

ipp_attribute_t *     // O - Matching attribute
ippFindNextAttribute(ipp_t      *ipp, // I - IPP message
                     const char *name,  // I - Name of attribute
         ipp_tag_t  type) // I - Type of attribute
{
  ipp_attribute_t *attr,    // Current attribute
      *childattr; // Child attribute
  ipp_tag_t   value_tag;  // Value tag
  char      parent[1024], // Parent attribute name
      *child = NULL; // Child attribute name


  DEBUG_printf("2ippFindNextAttribute(ipp=%p, name=\"%s\", type=%02x(%s))", (void *)ipp, name, type, ippTagString(type));

  // Range check input...
  if (!ipp || !name)
    return (NULL);

  DEBUG_printf("3ippFindNextAttribute: atend=%s", ipp->find->atend ? "true" : "false");

  if (ipp->find->atend)
    return (NULL);

  if (strchr(name, '/'))
  {
    // Search for child attribute...
    cupsCopyString(parent, name, sizeof(parent));
    if ((child = strchr(parent, '/')) == NULL)
    {
      DEBUG_puts("3ippFindNextAttribute: Attribute name too long.");
      return (NULL);
    }

    *child++ = '\0';

    if (ipp->find->attr && ipp->find->attr->name && ipp->find->attr->value_tag == IPP_TAG_BEGIN_COLLECTION && !strcmp(parent, ipp->find->attr->name))
    {
      while (ipp->find->idx < ipp->find->attr->num_values)
      {
        if ((childattr = ippFindNextAttribute(ipp->find->attr->values[ipp->find->idx].collection, child, type)) != NULL)
          return (childattr);

        ipp->find->idx ++;
        if (ipp->find->idx < ipp->find->attr->num_values && ipp->find->attr->values[ipp->find->idx].collection)
          ipp->find->attr->values[ipp->find->idx].collection->find->attr = NULL;
      }

      ipp->find->attr = ipp->find->attr->next;
      ipp->find->idx  = 0;

      if (!ipp->find->attr)
      {
        ipp->find->atend = true;
        return (NULL);
      }
    }

    if (!ipp->find->attr)
    {
      ipp->find->attr = ipp->attrs;
      ipp->find->idx  = 0;
    }

    name = parent;
    attr = ipp->find->attr;
  }
  else if (ipp->find->attr)
  {
    attr = ipp->find->attr->next;
  }
  else
  {
    attr = ipp->attrs;
  }

  for (; attr != NULL; ipp->prev = attr, attr = attr->next)
  {
    DEBUG_printf("4ippFindAttribute: attr=%p, name=\"%s\"", (void *)attr, attr->name);

    value_tag = (ipp_tag_t)(attr->value_tag & IPP_TAG_CUPS_MASK);

    if (attr->name != NULL && strcmp(attr->name, name) == 0 && (value_tag == type || type == IPP_TAG_ZERO || name == parent || (value_tag == IPP_TAG_TEXTLANG && type == IPP_TAG_TEXT) || (value_tag == IPP_TAG_NAMELANG && type == IPP_TAG_NAME)))
    {
      ipp->find->attr = attr;

      if (name == parent && attr->value_tag == IPP_TAG_BEGIN_COLLECTION)
      {
        size_t i;     // Looping var

        for (i = 0; i < attr->num_values; i ++)
        {
    if ((childattr = ippFindAttribute(attr->values[i].collection, child, type)) != NULL)
    {
      attr->values[0].collection->find->idx = i;
      return (childattr);
    }
        }
      }
      else
      {
        return (attr);
      }
    }
  }

  // If we get this far, we didn't find it...
  ipp->find->attr  = NULL;
  ipp->find->atend = true;

  return (NULL);
}


//
// 'ippGetBoolean()' - Get a boolean value for an attribute.
//
// The "element" argument specifies which value to get from `0` to
// `ippGetCount(attr) - 1`.
//

bool          // O - Boolean value or `false` on error
ippGetBoolean(ipp_attribute_t *attr,  // I - IPP attribute
              size_t          element)  // I - Value number (`0`-based)
{
  // Range check input...
  if (!attr || attr->value_tag != IPP_TAG_BOOLEAN || element >= attr->num_values)
    return (false);

  // Return the value...
  return (attr->values[element].boolean);
}


//
// 'ippGetCollection()' - Get a collection value for an attribute.
//
// The "element" argument specifies which value to get from `0` to
// `ippGetCount(attr) - 1`.
//

ipp_t *         // O - Collection value or `NULL` on error
ippGetCollection(
    ipp_attribute_t *attr,    // I - IPP attribute
    size_t          element)    // I - Value number (`0`-based)
{
  // Range check input...
  if (!attr || attr->value_tag != IPP_TAG_BEGIN_COLLECTION || element >= attr->num_values)
    return (NULL);

  // Return the value...
  return (attr->values[element].collection);
}


//
// 'ippGetCount()' - Get the number of values in an attribute.
//

size_t          // O - Number of values or 0 on error
ippGetCount(ipp_attribute_t *attr)  // I - IPP attribute
{
  // Range check input...
  if (!attr)
    return (0);

  // Return the number of values...
  return (attr->num_values);
}


//
// 'ippGetDate()' - Get a dateTime value for an attribute.
//
// The "element" argument specifies which value to get from `0` to
// `ippGetCount(attr) - 1`.
//

const ipp_uchar_t *     // O - dateTime value or `NULL`
ippGetDate(ipp_attribute_t *attr, // I - IPP attribute
           size_t          element) // I - Value number (`0`-based)
{
  // Range check input...
  if (!attr || attr->value_tag != IPP_TAG_DATE || element >= attr->num_values)
    return (NULL);

  // Return the value...
  return (attr->values[element].date);
}


//
// 'ippGetFirstAttribute()' - Return the first attribute in the message.
//

ipp_attribute_t *     // O - First attribute or `NULL` if none
ippGetFirstAttribute(ipp_t *ipp)  // I - IPP message
{
  // Range check input...
  if (!ipp)
    return (NULL);

  if (!ipp->find)
    ipp->find = ipp->fstack;

  ipp->find->attr  = ipp->attrs;
  ipp->find->idx   = 0;
  ipp->find->atend = ipp->find->attr == NULL;

  // Return the first attribute...
  return (ipp->find->attr);
}


//
// 'ippGetGroupTag()' - Get the group associated with an attribute.
//

ipp_tag_t       // O - Group tag or `IPP_TAG_ZERO` on error
ippGetGroupTag(ipp_attribute_t *attr) // I - IPP attribute
{
  // Range check input...
  if (!attr)
    return (IPP_TAG_ZERO);

  // Return the group...
  return (attr->group_tag);
}


//
// 'ippGetInteger()' - Get the integer/enum value for an attribute.
//
// The "element" argument specifies which value to get from `0` to
// `ippGetCount(attr) - 1`.
//

int         // O - Value or `0` on error
ippGetInteger(ipp_attribute_t *attr,  // I - IPP attribute
              size_t          element)  // I - Value number (`0`-based)
{
  // Range check input...
  if (!attr || (attr->value_tag != IPP_TAG_INTEGER && attr->value_tag != IPP_TAG_ENUM) || element >= attr->num_values)
    return (0);

  // Return the value...
  return (attr->values[element].integer);
}


//
// 'ippGetLength()' - Compute the length of an IPP message.
//

size_t          // O - Size of IPP message
ippGetLength(ipp_t *ipp)    // I - IPP message
{
  return (ipp_length(ipp, 0));
}


//
// 'ippGetName()' - Get the attribute name.
//

const char *        // O - Attribute name or `NULL` for separators
ippGetName(ipp_attribute_t *attr) // I - IPP attribute
{
  // Range check input...
  if (!attr)
    return (NULL);

  // Return the name...
  return (attr->name);
}


//
// 'ippGetNextAttribute()' - Return the next attribute in the message.
//

ipp_attribute_t *     // O - Next attribute or `NULL` if none
ippGetNextAttribute(ipp_t *ipp)   // I - IPP message
{
  // Range check input...
  if (!ipp || !ipp->find || !ipp->find->attr)
    return (NULL);

  ipp->find->attr  = ipp->find->attr->next;
  ipp->find->atend = ipp->find->attr == NULL;

  // Return the next attribute...
  return (ipp->find->attr);
}


//
// 'ippGetOctetString()' - Get an octetString value from an IPP attribute.
//
// The "element" argument specifies which value to get from '0' to
// `ippGetCount(attr) - 1`.
//

void *          // O - Pointer to octetString data
ippGetOctetString(
    ipp_attribute_t *attr,    // I - IPP attribute
    size_t          element,    // I - Value number (`0`-based)
    size_t          *datalen)   // O - Length of octetString data
{
  // Range check input...
  if (!attr || (attr->value_tag != IPP_TAG_STRING && attr->value_tag != IPP_TAG_EXTENSION) || element >= attr->num_values)
  {
    if (datalen)
      *datalen = 0;

    return (NULL);
  }

  // Return the values...
  if (datalen)
    *datalen = attr->values[element].unknown.length;

  return (attr->values[element].unknown.data);
}


//
// 'ippGetOperation()' - Get the operation ID in an IPP message.
//

ipp_op_t        // O - Operation ID or 0 on error
ippGetOperation(ipp_t *ipp)   // I - IPP request message
{
  // Range check input...
  if (!ipp)
    return ((ipp_op_t)0);

  // Return the value...
  return ((ipp_op_t)ipp->request.op_status);
}


//
// 'ippGetRange()' - Get a rangeOfInteger value from an attribute.
//
// The "element" argument specifies which value to get from `0` to
// `ippGetCount(attr) - 1`.
//

int         // O - Lower value of range or 0
ippGetRange(ipp_attribute_t *attr,  // I - IPP attribute
      size_t          element,  // I - Value number (`0`-based)
      int             *uppervalue)// O - Upper value of range
{
  // Range check input...
  if (!attr || attr->value_tag != IPP_TAG_RANGE || element >= attr->num_values)
  {
    if (uppervalue)
      *uppervalue = 0;

    return (0);
  }

  // Return the values...
  if (uppervalue)
    *uppervalue = attr->values[element].range.upper;

  return (attr->values[element].range.lower);
}


//
// 'ippGetRequestId()' - Get the request ID from an IPP message.
//

int         // O - Request ID or 0 on error
ippGetRequestId(ipp_t *ipp)   // I - IPP message
{
  // Range check input...
  if (!ipp)
    return (0);

  // Return the request ID...
  return (ipp->request.request_id);
}


//
// 'ippGetResolution()' - Get a resolution value for an attribute.
//
// The "element" argument specifies which value to get from `0` to
// `ippGetCount(attr) - 1`.
//

int         // O - Horizontal/cross feed resolution or 0
ippGetResolution(
    ipp_attribute_t *attr,    // I - IPP attribute
    size_t          element,    // I - Value number (`0`-based)
    int             *yres,    // O - Vertical/feed resolution
    ipp_res_t       *units)   // O - Units for resolution
{
  // Range check input...
  if (!attr || attr->value_tag != IPP_TAG_RESOLUTION || element >= attr->num_values)
  {
    if (yres)
      *yres = 0;

    if (units)
      *units = (ipp_res_t)0;

    return (0);
  }

  // Return the value...
  if (yres)
    *yres = attr->values[element].resolution.yres;

  if (units)
    *units = attr->values[element].resolution.units;

  return (attr->values[element].resolution.xres);
}


//
// 'ippGetState()' - Get the IPP message state.
//

ipp_state_t       // O - IPP message state value
ippGetState(ipp_t *ipp)     // I - IPP message
{
  // Range check input...
  if (!ipp)
    return (IPP_STATE_IDLE);

  // Return the value...
  return (ipp->state);
}


//
// 'ippGetStatusCode()' - Get the status code from an IPP response or event message.
//

ipp_status_t        // O - Status code in IPP message
ippGetStatusCode(ipp_t *ipp)    // I - IPP response or event message
{
  // Range check input...
  if (!ipp)
    return (IPP_STATUS_ERROR_INTERNAL);

  // Return the value...
  return ((ipp_status_t)ipp->request.op_status);
}


//
// 'ippGetString()' - Get the string and optionally the language code for an attribute.
//
// The "element" argument specifies which value to get from `0` to
// `ippGetCount(attr) - 1`.
//

const char *
ippGetString(ipp_attribute_t *attr, // I - IPP attribute
             size_t          element, // I - Value number (`0`-based)
       const char      **language)// O - Language code (`NULL` for don't care)
{
  ipp_tag_t tag;      // Value tag


  // Range check input...
  tag = ippGetValueTag(attr);

  if (!attr || element >= attr->num_values || (tag != IPP_TAG_TEXTLANG && tag != IPP_TAG_NAMELANG && (tag < IPP_TAG_TEXT || tag > IPP_TAG_MIMETYPE)))
    return (NULL);

  // Return the value...
  if (language)
    *language = attr->values[element].string.language;

  return (attr->values[element].string.text);
}


//
// 'ippGetValueTag()' - Get the value tag for an attribute.
//

ipp_tag_t       // O - Value tag or `IPP_TAG_ZERO` on error
ippGetValueTag(ipp_attribute_t *attr) // I - IPP attribute
{
  // Range check input...
  if (!attr)
    return (IPP_TAG_ZERO);

  // Return the value...
  return (attr->value_tag & IPP_TAG_CUPS_MASK);
}


//
// 'ippGetVersion()' - Get the major and minor version number from an IPP message.
//

int         // O - Major version number or 0 on error
ippGetVersion(ipp_t *ipp,   // I - IPP message
              int   *minor)   // O - Minor version number or `NULL` for don't care
{
  // Range check input...
  if (!ipp)
  {
    if (minor)
      *minor = 0;

    return (0);
  }

  // Return the value...
  if (minor)
    *minor = ipp->request.version[1];

  return (ipp->request.version[0]);
}


//
// 'ippNew()' - Allocate a new IPP message.
//

ipp_t *         // O - New IPP message
ippNew(void)
{
  ipp_t     *temp;    // New IPP message
  _cups_globals_t *cg = _cupsGlobals();
          // Global data


  DEBUG_puts("ippNew()");

  if ((temp = (ipp_t *)calloc(1, sizeof(ipp_t))) != NULL)
  {
    // Set default version - usually 2.0...
    DEBUG_printf("4debug_alloc: %p IPP message", (void *)temp);

    if (!cg->client_conf_loaded)
      _cupsSetDefaults();

    temp->request.version[0] = (ipp_uchar_t)(cg->server_version / 10);
    temp->request.version[1] = (ipp_uchar_t)(cg->server_version % 10);
    temp->use                = 1;
    temp->find               = temp->fstack;
  }

  DEBUG_printf("1ippNew: Returning %p", (void *)temp);

  return (temp);
}


//
//  'ippNewRequest()' - Allocate a new IPP request message.
//
// The new request message is initialized with the "attributes-charset" and
// "attributes-natural-language" attributes added. The
// "attributes-natural-language" value is derived from the current locale.
//

ipp_t *         // O - IPP request message
ippNewRequest(ipp_op_t op)    // I - Operation code
{
  ipp_t   *request;   // IPP request message
  cups_lang_t *language;    // Current language localization
  static int  request_id = 0;   // Current request ID
  static cups_mutex_t request_mutex = CUPS_MUTEX_INITIALIZER;
          // Mutex for request ID


  DEBUG_printf("ippNewRequest(op=%02x(%s))", op, ippOpString(op));

  // Create a new IPP message...
  if ((request = ippNew()) == NULL)
    return (NULL);

  // Set the operation and request ID...
  cupsMutexLock(&request_mutex);

  request->request.op_status  = (short)op;
  request->request.request_id = ++request_id;

  cupsMutexUnlock(&request_mutex);

  // Use UTF-8 as the character set...
  ippAddString(request, IPP_TAG_OPERATION, IPP_CONST_TAG(IPP_TAG_CHARSET), "attributes-charset", NULL, "utf-8");

  // Get the language from the current locale...
  language = cupsLangDefault();

  ippAddString(request, IPP_TAG_OPERATION, IPP_CONST_TAG(IPP_TAG_LANGUAGE), "attributes-natural-language", NULL, cupsLangGetName(language));

  // Return the new request...
  return (request);
}


//
// 'ippNewResponse()' - Allocate a new IPP response message.
//
// The new response message is initialized with the same "version-number",
// "request-id", "attributes-charset", and "attributes-natural-language" as the
// provided request message.  If the "attributes-charset" or
// "attributes-natural-language" attributes are missing from the request,
// 'utf-8' and a value derived from the current locale are substituted,
// respectively.
//

ipp_t *         // O - IPP response message
ippNewResponse(ipp_t *request)    // I - IPP request message
{
  ipp_t     *response;  // IPP response message
  ipp_attribute_t *attr;    // Current attribute


  // Range check input...
  if (!request)
    return (NULL);

  // Create a new IPP message...
  if ((response = ippNew()) == NULL)
    return (NULL);

  // Copy the request values over to the response...
  response->request.version[0] = request->request.version[0];
  response->request.version[1] = request->request.version[1];
  response->request.request_id = request->request.request_id;

  // The first attribute MUST be attributes-charset...
  attr = request->attrs;

  if (attr && attr->name && !strcmp(attr->name, "attributes-charset") && attr->group_tag == IPP_TAG_OPERATION && attr->value_tag == IPP_TAG_CHARSET && attr->num_values == 1)
  {
    // Copy charset from request...
    ippAddString(response, IPP_TAG_OPERATION, IPP_TAG_CHARSET, "attributes-charset", NULL, attr->values[0].string.text);
  }
  else
  {
    // Use "utf-8" as the default...
    ippAddString(response, IPP_TAG_OPERATION, IPP_CONST_TAG(IPP_TAG_CHARSET), "attributes-charset", NULL, "utf-8");
  }

  // Then attributes-natural-language...
  if (attr)
    attr = attr->next;

  if (attr && attr->name && !strcmp(attr->name, "attributes-natural-language") && attr->group_tag == IPP_TAG_OPERATION && attr->value_tag == IPP_TAG_LANGUAGE && attr->num_values == 1)
  {
    // Copy language from request...
    ippAddString(response, IPP_TAG_OPERATION, IPP_TAG_LANGUAGE, "attributes-natural-language", NULL, attr->values[0].string.text);
  }
  else
  {
    // Use the language from the current locale...
    cups_lang_t *language = cupsLangDefault();
          // Current locale

    ippAddString(response, IPP_TAG_OPERATION, IPP_CONST_TAG(IPP_TAG_LANGUAGE), "attributes-natural-language", NULL, cupsLangGetName(language));
  }

  return (response);
}


//
// 'ippRead()' - Read data for an IPP message from a HTTP connection.
//

ipp_state_t       // O - Current state
ippRead(http_t *http,     // I - HTTP connection
        ipp_t  *ipp)      // I - IPP data
{
  DEBUG_printf("ippRead(http=%p, ipp=%p), data_remaining=" CUPS_LLFMT, (void *)http, (void *)ipp, CUPS_LLCAST (http ? http->data_remaining : -1));

  if (!http || !ipp)
    return (IPP_STATE_ERROR);

  DEBUG_printf("2ippRead: http->state=%d, http->used=%d", http->state, http->used);

  return (ipp_read_io(http, (ipp_io_cb_t)ipp_read_http, http->blocking, /*parent*/NULL, ipp, /*depth*/0));
}


//
// 'ippReadFile()' - Read data for an IPP message from a file.
//

ipp_state_t       // O - Current state
ippReadFile(int   fd,     // I - HTTP data
            ipp_t *ipp)     // I - IPP data
{
  DEBUG_printf("ippReadFile(fd=%d, ipp=%p)", fd, (void *)ipp);

  if (!ipp)
    return (IPP_STATE_ERROR);

  return (ipp_read_io(&fd, (ipp_io_cb_t)ipp_read_file, /*blocking*/true, /*parent*/NULL, ipp, /*depth*/0));
}


//
// 'ippReadIO()' - Read data for an IPP message.
//

ipp_state_t       // O - Current state
ippReadIO(void        *src,   // I - Data source
          ipp_io_cb_t cb,   // I - Read callback function
    bool        blocking,   // I - Use blocking IO?
    ipp_t       *parent,    // I - Parent request, if any
          ipp_t       *ipp)   // I - IPP data
{
  DEBUG_printf("ippReadIO(src=%p, cb=%p, blocking=%d, parent=%p, ipp=%p)", (void *)src, (void *)cb, blocking, (void *)parent, (void *)ipp);

  if (!src || !ipp)
    return (IPP_STATE_ERROR);

  return (ipp_read_io(src, cb, blocking, parent, ipp, /*depth*/0));
}


//
// 'ippRestore()' - Restore a previously saved find position.
//

void
ippRestore(ipp_t *ipp)      // I - IPP message
{
  if (ipp)
  {
    if (ipp->find > ipp->fstack)
      ipp->find --;
    else
      ipp->find = NULL;
  }
}


//
// 'ippSave()' - Save the current find position.
//

void
ippSave(ipp_t *ipp)     // I - IPP message
{
  if (ipp && ipp->find < (ipp->fstack + _IPP_MAX_FIND))
  {
    ipp->find[1] = ipp->find[0];
    ipp->find ++;
  }
}


//
// 'ippSetBoolean()' - Set a boolean value in an attribute.
//
// The "ipp" argument refers to an IPP message previously created using
// the @link ippNew@, @link ippNewRequest@, or  @link ippNewResponse@ functions.
//
// The "attr" argument may be modified as a result of setting the value.
//
// The "element" argument specifies which value to set from `0` to
// `ippGetCount(attr)`.
//

bool          // O  - `true` on success, `false` on failure
ippSetBoolean(ipp_t           *ipp, // I  - IPP message
              ipp_attribute_t **attr, // IO - IPP attribute
              size_t          element,  // I  - Value number (`0`-based)
              bool            boolvalue)// I  - Boolean value
{
  _ipp_value_t  *value;     // Current value


  // Range check input...
  if (!ipp || !attr || !*attr || (*attr)->value_tag != IPP_TAG_BOOLEAN || element > (*attr)->num_values)
    return (false);

  // Set the value and return...
  if ((value = ipp_set_value(ipp, attr, element)) != NULL)
    value->boolean = boolvalue;

  return (value != NULL);
}


//
// 'ippSetCollection()' - Set a collection value in an attribute.
//
// The "ipp" argument refers to an IPP message previously created using
// the @link ippNew@, @link ippNewRequest@, or  @link ippNewResponse@ functions.
//
// The "attr" argument may be modified as a result of setting the value.
//
// The "element" argument specifies which value to set from `0` to
// `ippGetCount(attr)`.
//

bool          // O  - `true` on success, `false` on failure
ippSetCollection(
    ipp_t           *ipp,   // I  - IPP message
    ipp_attribute_t **attr,   // IO - IPP attribute
    size_t          element,    // I  - Value number (`0`-based)
    ipp_t           *colvalue)    // I  - Collection value
{
  _ipp_value_t  *value;     // Current value


  // Range check input...
  if (!ipp || !attr || !*attr || (*attr)->value_tag != IPP_TAG_BEGIN_COLLECTION || element > (*attr)->num_values || !colvalue)
    return (false);

  // Set the value and return...
  if ((value = ipp_set_value(ipp, attr, element)) != NULL)
  {
    if (value->collection)
      ippDelete(value->collection);

    value->collection = colvalue;
    colvalue->use ++;
  }

  return (value != NULL);
}


//
// 'ippSetDate()' - Set a dateTime value in an attribute.
//
// The "ipp" argument refers to an IPP message previously created using
// the @link ippNew@, @link ippNewRequest@, or  @link ippNewResponse@ functions.
//
// The "attr" argument may be modified as a result of setting the value.
//
// The "element" argument specifies which value to set from `0` to
// `ippGetCount(attr)`.
//

bool          // O  - `true` on success, `false` on failure
ippSetDate(ipp_t             *ipp,  // I  - IPP message
           ipp_attribute_t   **attr,  // IO - IPP attribute
           size_t            element, // I  - Value number (`0`-based)
           const ipp_uchar_t *datevalue)// I  - dateTime value
{
  _ipp_value_t  *value;     // Current value


  // Range check input...
  if (!ipp || !attr || !*attr || ((*attr)->value_tag != IPP_TAG_DATE && (*attr)->value_tag != IPP_TAG_NOVALUE && (*attr)->value_tag != IPP_TAG_UNKNOWN) || element > (*attr)->num_values || !datevalue)
    return (false);

  // Set the value and return...
  if ((value = ipp_set_value(ipp, attr, element)) != NULL)
  {
    (*attr)->value_tag = IPP_TAG_DATE;
    memcpy(value->date, datevalue, sizeof(value->date));
  }

  return (value != NULL);
}


//
// 'ippSetGroupTag()' - Set the group tag of an attribute.
//
// The "ipp" argument refers to an IPP message previously created using
// the @link ippNew@, @link ippNewRequest@, or  @link ippNewResponse@ functions.
//
// The "attr" argument may be modified as a result of setting the value.
//
// The "group" argument specifies the IPP attribute group tag: none
// (`IPP_TAG_ZERO`, for member attributes), document (`IPP_TAG_DOCUMENT`),
// event notification (`IPP_TAG_EVENT_NOTIFICATION`), operation
// (`IPP_TAG_OPERATION`), printer (`IPP_TAG_PRINTER`), subscription
// (`IPP_TAG_SUBSCRIPTION`), or unsupported (`IPP_TAG_UNSUPPORTED_GROUP`).
//

bool          // O  - `true` on success, `false` on failure
ippSetGroupTag(
    ipp_t           *ipp,   // I  - IPP message
    ipp_attribute_t **attr,   // IO - Attribute
    ipp_tag_t       group_tag)    // I  - Group tag
{
  // Range check input - group tag must be 0x01 to 0x0F, per RFC 8011...
  if (!ipp || !attr || !*attr || group_tag < IPP_TAG_ZERO || group_tag == IPP_TAG_END || group_tag >= IPP_TAG_UNSUPPORTED_VALUE)
    return (false);

  // Set the group tag and return...
  (*attr)->group_tag = group_tag;

  return (true);
}


//
// 'ippSetInteger()' - Set an integer or enum value in an attribute.
//
// The "ipp" argument refers to an IPP message previously created using
// the @link ippNew@, @link ippNewRequest@, or  @link ippNewResponse@ functions.
//
// The "attr" argument may be modified as a result of setting the value.
//
// The "element" argument specifies which value to set from `0` to
// `ippGetCount(attr)`.
//

bool          // O  - `true` on success, `false` on failure
ippSetInteger(ipp_t           *ipp, // I  - IPP message
              ipp_attribute_t **attr, // IO - IPP attribute
              size_t          element,  // I  - Value number (`0`-based)
              int             intvalue) // I  - Integer/enum value
{
  _ipp_value_t  *value;     // Current value


  // Range check input...
  if (!ipp || !attr || !*attr || ((*attr)->value_tag != IPP_TAG_INTEGER && (*attr)->value_tag != IPP_TAG_ENUM && (*attr)->value_tag != IPP_TAG_NOVALUE && (*attr)->value_tag != IPP_TAG_UNKNOWN) || element > (*attr)->num_values)
    return (false);

  // Set the value and return...
  if ((value = ipp_set_value(ipp, attr, element)) != NULL)
  {
    if ((*attr)->value_tag != IPP_TAG_ENUM)
      (*attr)->value_tag = IPP_TAG_INTEGER;

    value->integer = intvalue;
  }

  return (value != NULL);
}


//
// 'ippSetName()' - Set the name of an attribute.
//
// The "ipp" argument refers to an IPP message previously created using
// the @link ippNew@, @link ippNewRequest@, or  @link ippNewResponse@ functions.
//
// The "attr" argument may be modified as a result of setting the value.
//

bool          // O  - `true` on success, `false` on failure
ippSetName(ipp_t           *ipp,  // I  - IPP message
     ipp_attribute_t **attr,  // IO - IPP attribute
     const char      *name) // I  - Attribute name
{
  char  *temp;        // Temporary name value


  // Range check input...
  if (!ipp || !attr || !*attr || !name)
    return (false);

  // Set the value and return...
  if ((temp = _cupsStrAlloc(name)) != NULL)
  {
    if ((*attr)->name)
      _cupsStrFree((*attr)->name);

    (*attr)->name = temp;
  }

  return (temp != NULL);
}


//
// 'ippSetOctetString()' - Set an octetString value in an IPP attribute.
//
// The "ipp" argument refers to an IPP message previously created using
// the @link ippNew@, @link ippNewRequest@, or  @link ippNewResponse@ functions.
//
// The "attr" argument may be modified as a result of setting the value.
//
// The "element" argument specifies which value to set from `0` to
// `ippGetCount(attr)`.
//

bool          // O  - `true` on success, `false` on failure
ippSetOctetString(
    ipp_t           *ipp,   // I  - IPP message
    ipp_attribute_t **attr,   // IO - IPP attribute
    size_t          element,    // I  - Value number (`0`-based)
    const void      *data,    // I  - Pointer to octetString data
    size_t          datalen)    // I  - Length of octetString data
{
  _ipp_value_t  *value;     // Current value


  // Range check input...
  if (!ipp || !attr || !*attr || ((*attr)->value_tag != IPP_TAG_STRING && (*attr)->value_tag != IPP_TAG_NOVALUE && (*attr)->value_tag != IPP_TAG_UNKNOWN && (*attr)->value_tag != IPP_TAG_EXTENSION) || element > (*attr)->num_values || datalen > IPP_MAX_LENGTH)
    return (false);

  // Set the value and return...
  if ((value = ipp_set_value(ipp, attr, element)) != NULL)
  {
    if ((int)((*attr)->value_tag) & IPP_TAG_CUPS_CONST)
    {
      // Just copy the pointer...
      value->unknown.data   = (void *)data;
      value->unknown.length = datalen;
    }
    else
    {
      // Copy the data...
      (*attr)->value_tag = IPP_TAG_STRING;

      if (value->unknown.data)
      {
        // Free previous data...
  free(value->unknown.data);

  value->unknown.data   = NULL;
        value->unknown.length = 0;
      }

      if (datalen > 0)
      {
  void  *temp;      // Temporary data pointer

  if ((temp = malloc((size_t)datalen)) != NULL)
  {
    memcpy(temp, data, (size_t)datalen);

    value->unknown.data   = temp;
    value->unknown.length = datalen;
  }
  else
  {
    return (false);
  }
      }
    }
  }

  return (value != NULL);
}


//
// 'ippSetOperation()' - Set the operation ID in an IPP request message.
//
// The "ipp" argument refers to an IPP message previously created using
// the @link ippNew@, @link ippNewRequest@, or  @link ippNewResponse@ functions.
//

bool          // O  - `true` on success, `false` on failure
ippSetOperation(ipp_t    *ipp,    // I - IPP request message
                ipp_op_t op)    // I - Operation ID
{
  // Range check input...
  if (!ipp)
    return (false);

  // Set the operation and return...
  ipp->request.op_status = (short)op;

  return (true);
}


//
// 'ippSetRange()' - Set a rangeOfInteger value in an attribute.
//
// The "ipp" argument refers to an IPP message previously created using
// the @link ippNew@, @link ippNewRequest@, or  @link ippNewResponse@ functions.
//
// The "attr" argument may be modified as a result of setting the value.
//
// The "element" argument specifies which value to set from `0` to
// `ippGetCount(attr)`.
//

bool          // O  - `true` on success, `false` on failure
ippSetRange(ipp_t           *ipp, // I  - IPP message
            ipp_attribute_t **attr, // IO - IPP attribute
            size_t          element,  // I  - Value number (`0`-based)
      int             lowervalue, // I  - Lower bound for range
      int             uppervalue) // I  - Upper bound for range
{
  _ipp_value_t  *value;     // Current value


  // Range check input...
  if (!ipp || !attr || !*attr || ((*attr)->value_tag != IPP_TAG_RANGE && (*attr)->value_tag != IPP_TAG_NOVALUE && (*attr)->value_tag != IPP_TAG_UNKNOWN) || element > (*attr)->num_values || lowervalue > uppervalue)
    return (false);

  // Set the value and return...
  if ((value = ipp_set_value(ipp, attr, element)) != NULL)
  {
    (*attr)->value_tag = IPP_TAG_RANGE;
    value->range.lower = lowervalue;
    value->range.upper = uppervalue;
  }

  return (value != NULL);
}


//
// 'ippSetRequestId()' - Set the request ID in an IPP message.
//
// The "ipp" argument refers to an IPP message previously created using
// the @link ippNew@, @link ippNewRequest@, or  @link ippNewResponse@ functions.
//
// The "request_id" argument must be greater than 0.
//

bool          // O  - `true` on success, `false` on failure
ippSetRequestId(ipp_t *ipp,   // I - IPP message
                int   request_id) // I - Request ID
{
  // Range check input; not checking request_id values since ipptool wants to
  // send invalid values for conformance testing and a bad request_id does not
  // affect the encoding of a message...
  if (!ipp)
    return (false);

  // Set the request ID and return...
  ipp->request.request_id = request_id;

  return (true);
}


//
// 'ippSetResolution()' - Set a resolution value in an attribute.
//
// The "ipp" argument refers to an IPP message previously created using
// the @link ippNew@, @link ippNewRequest@, or  @link ippNewResponse@ functions.
//
// The "attr" argument may be modified as a result of setting the value.
//
// The "element" argument specifies which value to set from `0` to
// `ippGetCount(attr)`.
//

bool          // O  - `true` on success, `false` on failure
ippSetResolution(
    ipp_t           *ipp,   // I  - IPP message
    ipp_attribute_t **attr,   // IO - IPP attribute
    size_t          element,    // I  - Value number (`0`-based)
    ipp_res_t       unitsvalue,   // I  - Resolution units
    int             xresvalue,    // I  - Horizontal/cross feed resolution
    int             yresvalue)    // I  - Vertical/feed resolution
{
  _ipp_value_t  *value;     // Current value


  // Range check input...
  if (!ipp || !attr || !*attr || ((*attr)->value_tag != IPP_TAG_RESOLUTION && (*attr)->value_tag != IPP_TAG_NOVALUE && (*attr)->value_tag != IPP_TAG_UNKNOWN) || element > (*attr)->num_values || xresvalue <= 0 || yresvalue <= 0 || unitsvalue < IPP_RES_PER_INCH || unitsvalue > IPP_RES_PER_CM)
    return (false);

  // Set the value and return...
  if ((value = ipp_set_value(ipp, attr, element)) != NULL)
  {
    (*attr)->value_tag      = IPP_TAG_RESOLUTION;
    value->resolution.units = unitsvalue;
    value->resolution.xres  = xresvalue;
    value->resolution.yres  = yresvalue;
  }

  return (value != NULL);
}


//
// 'ippSetState()' - Set the current state of the IPP message.
//

bool          // O  - `true` on success, `false` on failure
ippSetState(ipp_t       *ipp,   // I - IPP message
            ipp_state_t state)    // I - IPP state value
{
  // Range check input...
  if (!ipp)
    return (false);

  // Set the state and return...
  ipp->state   = state;
  ipp->current = NULL;

  return (true);
}


//
// 'ippSetStatusCode()' - Set the status code in an IPP response or event message.
//
// The "ipp" argument refers to an IPP message previously created using
// the @link ippNew@, @link ippNewRequest@, or  @link ippNewResponse@ functions.
//

bool          // O  - `true` on success, `false` on failure
ippSetStatusCode(ipp_t        *ipp, // I - IPP response or event message
                 ipp_status_t status) // I - Status code
{
  // Range check input...
  if (!ipp)
    return (false);

  // Set the status code and return...
  ipp->request.op_status = (short)status;

  return (true);
}


//
// 'ippSetString()' - Set a string value in an attribute.
//
// The "ipp" argument refers to an IPP message previously created using
// the @link ippNew@, @link ippNewRequest@, or  @link ippNewResponse@ functions.
//
// The "attr" argument may be modified as a result of setting the value.
//
// The "element" argument specifies which value to set from `0` to
// `ippGetCount(attr)`.
//

bool          // O  - `true` on success, `false` on failure
ippSetString(ipp_t           *ipp,  // I  - IPP message
             ipp_attribute_t **attr,  // IO - IPP attribute
             size_t          element, // I  - Value number (`0`-based)
       const char      *strvalue) // I  - String value
{
  char    *temp;      // Temporary string
  _ipp_value_t  *value;     // Current value
  ipp_tag_t value_tag;    // Value tag


  // Range check input...
  if (attr && *attr)
    value_tag = (*attr)->value_tag & IPP_TAG_CUPS_MASK;
  else
    value_tag = IPP_TAG_ZERO;

  if (!ipp || !attr || !*attr || (value_tag < IPP_TAG_TEXT && value_tag != IPP_TAG_TEXTLANG && value_tag != IPP_TAG_NAMELANG && value_tag != IPP_TAG_NOVALUE && value_tag != IPP_TAG_UNKNOWN) || value_tag > IPP_TAG_MIMETYPE || element > (*attr)->num_values || !strvalue)
    return (false);

  // Set the value and return...
  if ((value = ipp_set_value(ipp, attr, element)) != NULL)
  {
    if (value_tag == IPP_TAG_NOVALUE || value_tag == IPP_TAG_UNKNOWN)
      (*attr)->value_tag = IPP_TAG_KEYWORD;

    if (element > 0)
      value->string.language = (*attr)->values[0].string.language;

    if ((int)((*attr)->value_tag) & IPP_TAG_CUPS_CONST)
    {
      value->string.text = (char *)strvalue;
    }
    else if ((temp = _cupsStrAlloc(strvalue)) != NULL)
    {
      if (value->string.text)
        _cupsStrFree(value->string.text);

      value->string.text = temp;
    }
    else
    {
      return (false);
    }
  }

  return (value != NULL);
}


//
// 'ippSetStringf()' - Set a formatted string value of an attribute.
//
// The "ipp" argument refers to an IPP message previously created using
// the @link ippNew@, @link ippNewRequest@, or  @link ippNewResponse@ functions.
//
// The "attr" argument may be modified as a result of setting the value.
//
// The "element" argument specifies which value to set from `0` to
// `ippGetCount(attr)`.
//
// The "format" argument uses formatting characters compatible with the
// printf family of standard functions.  Additional arguments follow it as
// needed.  The formatted string is truncated as needed to the maximum length of
// the corresponding value type.
//

bool          // O  - `true` on success, `false` on failure
ippSetStringf(ipp_t           *ipp, // I  - IPP message
              ipp_attribute_t **attr, // IO - IPP attribute
              size_t          element,  // I  - Value number (`0`-based)
        const char      *format,  // I  - Printf-style format string
        ...)      // I  - Additional arguments as needed
{
  int   ret;      // Return value
  va_list ap;     // Pointer to additional arguments


  va_start(ap, format);
  ret = ippSetStringfv(ipp, attr, element, format, ap);
  va_end(ap);

  return (ret);
}


//
// 'ippSetStringf()' - Set a formatted string value of an attribute.
//
// The "ipp" argument refers to an IPP message previously created using
// the @link ippNew@, @link ippNewRequest@, or  @link ippNewResponse@ functions.
//
// The "attr" argument may be modified as a result of setting the value.
//
// The "element" argument specifies which value to set from `0` to
// `ippGetCount(attr)`.
//
// The "format" argument uses formatting characters compatible with the
// printf family of standard functions.  Additional arguments follow it as
// needed.  The formatted string is truncated as needed to the maximum length of
// the corresponding value type.
//

bool          // O  - `true` on success, `false` on failure
ippSetStringfv(ipp_t           *ipp,  // I  - IPP message
               ipp_attribute_t **attr,  // IO - IPP attribute
               size_t          element, // I  - Value number (`0`-based)
         const char      *format, // I  - Printf-style format string
         va_list         ap)  // I  - Pointer to additional arguments
{
  ipp_tag_t value_tag;    // Value tag
  char    buffer[IPP_MAX_TEXT + 4];
          // Formatted text string
  ssize_t bytes,      // Length of formatted value
    max_bytes;    // Maximum number of bytes for value


  // Range check input...
  if (attr && *attr)
    value_tag = (*attr)->value_tag & IPP_TAG_CUPS_MASK;
  else
    value_tag = IPP_TAG_ZERO;

  if (!ipp || !attr || !*attr || (value_tag < IPP_TAG_TEXT && value_tag != IPP_TAG_TEXTLANG && value_tag != IPP_TAG_NAMELANG && value_tag != IPP_TAG_NOVALUE && value_tag != IPP_TAG_UNKNOWN) || value_tag > IPP_TAG_MIMETYPE || !format)
    return (false);

  // Format the string...
  if (!strcmp(format, "%s"))
  {
    // Optimize the simple case...
    const char *s = va_arg(ap, char *);

    if (!s)
      s = "(null)";

    bytes = (ssize_t)strlen(s);
    cupsCopyString(buffer, s, sizeof(buffer));
  }
  else
  {
    // Do a full formatting of the message...
    if ((bytes = vsnprintf(buffer, sizeof(buffer), format, ap)) < 0)
      return (0);
  }

  // Limit the length of the string...
  switch (value_tag)
  {
    default :
    case IPP_TAG_TEXT :
    case IPP_TAG_TEXTLANG :
        max_bytes = IPP_MAX_TEXT;
        break;

    case IPP_TAG_NAME :
    case IPP_TAG_NAMELANG :
        max_bytes = IPP_MAX_NAME;
        break;

    case IPP_TAG_CHARSET :
        max_bytes = IPP_MAX_CHARSET;
        break;

    case IPP_TAG_NOVALUE :
    case IPP_TAG_UNKNOWN :
    case IPP_TAG_KEYWORD :
        max_bytes = IPP_MAX_KEYWORD;
        break;

    case IPP_TAG_LANGUAGE :
        max_bytes = IPP_MAX_LANGUAGE;
        break;

    case IPP_TAG_MIMETYPE :
        max_bytes = IPP_MAX_MIMETYPE;
        break;

    case IPP_TAG_URI :
        max_bytes = IPP_MAX_URI;
        break;

    case IPP_TAG_URISCHEME :
        max_bytes = IPP_MAX_URISCHEME;
        break;
  }

  if (bytes >= max_bytes)
  {
    // Safely truncate the UTF-8 string...
    char  *bufmax,    // Buffer at max_bytes
    *bufptr;    // Pointer into buffer

    bufptr = buffer + strlen(buffer) - 1;
    bufmax = buffer + max_bytes - 1;

    while (bufptr > bufmax)
    {
      if (*bufptr & 0x80)
      {
        while ((*bufptr & 0xc0) == 0x80 && bufptr > buffer)
          bufptr --;
      }

      if (bufptr > buffer)
        bufptr --;
    }

    *bufptr = '\0';
  }

  // Set the formatted string and return...
  return (ippSetString(ipp, attr, element, _cupsStrAlloc(buffer)));
}


//
// 'ippSetValueTag()' - Set the value tag of an attribute.
//
// The "ipp" argument refers to an IPP message previously created using
// the @link ippNew@, @link ippNewRequest@, or  @link ippNewResponse@ functions.
//
// The "attr" argument may be modified as a result of setting the value.
//
// Integer (`IPP_TAG_INTEGER`) values can be promoted to rangeOfInteger
// (`IPP_TAG_RANGE`) values, the various string tags can be promoted to name
// (`IPP_TAG_NAME`) or nameWithLanguage (`IPP_TAG_NAMELANG`) values, text
// (`IPP_TAG_TEXT`) values can be promoted to textWithLanguage
// (`IPP_TAG_TEXTLANG`) values, and all values can be demoted to the various
// out-of-band value tags such as no-value (`IPP_TAG_NOVALUE`). All other
// changes will be rejected.
//
// Promoting a string attribute to nameWithLanguage or textWithLanguage adds the
// language code in the "attributes-natural-language" attribute or, if not
// present, the language code for the current locale.
//

bool          // O  - `true` on success, `false` on failure
ippSetValueTag(
    ipp_t          *ipp,    // I  - IPP message
    ipp_attribute_t **attr,   // IO - IPP attribute
    ipp_tag_t       value_tag)    // I  - Value tag
{
  size_t  i;      // Looping var
  _ipp_value_t  *value;     // Current value
  int   integer;    // Current integer value
  cups_lang_t *language;    // Current language
  char    code[32];   // Language code
  ipp_tag_t temp_tag;   // Temporary value tag


  DEBUG_printf("ippSetValueTag(ipp=%p, attr=%p(%p), value_tag=0x%x(%s))", ipp, attr, attr ? *attr : NULL, value_tag, ippTagString(value_tag));

  // Range check input...
  if (!ipp || !attr || !*attr)
    return (false);

  // If there is no change, return immediately...
  temp_tag = (ipp_tag_t)((int)((*attr)->value_tag) & IPP_TAG_CUPS_MASK);

  if (value_tag == temp_tag)
  {
    DEBUG_puts("2ippSetValueTag: No change.");
    return (true);
  }

  // Otherwise implement changes as needed...
  switch (value_tag)
  {
    case IPP_TAG_UNSUPPORTED_VALUE :
    case IPP_TAG_DEFAULT :
    case IPP_TAG_UNKNOWN :
    case IPP_TAG_NOVALUE :
    case IPP_TAG_NOTSETTABLE :
    case IPP_TAG_DELETEATTR :
    case IPP_TAG_ADMINDEFINE :
        // Free any existing values...
        if ((*attr)->num_values > 0)
          ipp_free_values(*attr, 0, (*attr)->num_values);

        // Set out-of-band value...
        (*attr)->value_tag = value_tag;
        break;

    case IPP_TAG_RANGE :
        if (temp_tag != IPP_TAG_INTEGER)
        {
          DEBUG_printf("2ippSetValueTag: Unable to convert %s to rangeOfInteger.", ippTagString(temp_tag));
          return (false);
        }

        for (i = (*attr)->num_values, value = (*attr)->values; i > 0; i --, value ++)
        {
          integer            = value->integer;
          value->range.lower = value->range.upper = integer;
          DEBUG_printf("2ippSetValueTag: values[%u].lower=%d, .upper=%d", (unsigned)((*attr)->num_values - i), value->range.lower, value->range.upper);
        }

        (*attr)->value_tag = IPP_TAG_RANGE;
        break;

    case IPP_TAG_NAME :
        if (temp_tag != IPP_TAG_KEYWORD)
        {
          DEBUG_printf("2ippSetValueTag: Unable to convert %s to name.", ippTagString(temp_tag));
          return (false);
        }

        (*attr)->value_tag = (ipp_tag_t)(IPP_TAG_NAME | ((*attr)->value_tag & IPP_TAG_CUPS_CONST));
        break;

    case IPP_TAG_NAMELANG :
    case IPP_TAG_TEXTLANG :
        if (value_tag == IPP_TAG_NAMELANG && (temp_tag != IPP_TAG_NAME && temp_tag != IPP_TAG_KEYWORD))
        {
          DEBUG_printf("2ippSetValueTag: Unable to convert %s to nameWithLanguage.", ippTagString(temp_tag));
          return (false);
        }

        if (value_tag == IPP_TAG_TEXTLANG && temp_tag != IPP_TAG_TEXT)
        {
          DEBUG_printf("2ippSetValueTag: Unable to convert %s to textWithLanguage.", ippTagString(temp_tag));
          return (false);
        }

        if (ipp->attrs && ipp->attrs->next && ipp->attrs->next->name && !strcmp(ipp->attrs->next->name, "attributes-natural-language") && (ipp->attrs->next->value_tag & IPP_TAG_CUPS_MASK) == IPP_TAG_LANGUAGE)
        {
          // Use the language code from the IPP message...
    (*attr)->values[0].string.language = _cupsStrAlloc(ipp->attrs->next->values[0].string.text);
        }
        else
        {
          // Otherwise, use the language code corresponding to the locale...
    language = cupsLangDefault();
    (*attr)->values[0].string.language = _cupsStrAlloc(ipp_lang_code(cupsLangGetName(language), code, sizeof(code)));
        }

  DEBUG_printf("2ippSetValueTag: values[0].string.language=\"%s\"(%p)", (*attr)->values[0].string.language, (*attr)->values[0].string.language);

        for (i = (*attr)->num_values - 1, value = (*attr)->values + 1; i > 0; i --, value ++)
        {
          value->string.language = (*attr)->values[0].string.language;
          DEBUG_printf("2ippSetValueTag: values[%u].string.language=\"%s\"(%s)", (unsigned)((*attr)->num_values - i), value->string.language, value->string.language);
        }

        if ((int)(*attr)->value_tag & IPP_TAG_CUPS_CONST)
        {
          // Make copies of all values...
    for (i = (*attr)->num_values, value = (*attr)->values; i > 0; i --, value ++)
    {
      value->string.text = _cupsStrAlloc(value->string.text);
      DEBUG_printf("2ippSetValueTag: values[%u].string.text=\"%s\"(%s)", (unsigned)((*attr)->num_values - i), value->string.text, value->string.text);
    }
        }

        (*attr)->value_tag = IPP_TAG_NAMELANG;
        break;

    case IPP_TAG_KEYWORD :
        if (temp_tag == IPP_TAG_NAME || temp_tag == IPP_TAG_NAMELANG)
        {
          DEBUG_printf("2ippSetValueTag: Ignoring change of %s to keyword.", ippTagString(temp_tag));
          break;      // Silently "allow" name -> keyword
        }

        DEBUG_printf("2ippSetValueTag: Unable to convert %s to keyword.", ippTagString(temp_tag));
        return (false);

    case IPP_TAG_EXTENSION :
        if (temp_tag == IPP_TAG_STRING && value_tag == IPP_TAG_EXTENSION)
        {
          // Allow octetString -> extension
          (*attr)->value_tag = value_tag;
          DEBUG_puts("2ippSetValueTag: Changing octetString to extension.");
          break;
        }

    default :
        DEBUG_printf("2ippSetValueTag: Unable to convert %s to %s.", ippTagString(temp_tag), ippTagString(value_tag));
        return (false);
  }

  DEBUG_puts("2ippSetValueTag: Successful.");
  return (true);
}


//
// 'ippSetVersion()' - Set the version number in an IPP message.
//
// The "ipp" argument refers to an IPP message previously created using
// the @link ippNew@, @link ippNewRequest@, or  @link ippNewResponse@ functions.
//
// The valid version numbers are currently 1.0, 1.1, 2.0, 2.1, and 2.2.
//

bool          // O - `true` on success, `false` on failure
ippSetVersion(ipp_t *ipp,   // I - IPP message
              int   major,    // I - Major version number (major.minor)
              int   minor)    // I - Minor version number (major.minor)
{
  // Range check input...
  if (!ipp || major < 0 || minor < 0)
    return (false);

  // Set the version number...
  ipp->request.version[0] = (ipp_uchar_t)major;
  ipp->request.version[1] = (ipp_uchar_t)minor;

  return (true);
}


//
// 'ippTimeToDate()' - Convert from time in seconds to RFC 2579 format.
//

const ipp_uchar_t *     // O - RFC-2579 date/time data
ippTimeToDate(time_t t)     // I - Time in seconds
{
  struct tm unixdate;   // UNIX unixdate/time info
  ipp_uchar_t *date = _cupsGlobals()->ipp_date;
          // RFC-2579 date/time data


  // RFC-2579 date/time format is:
  //
  //   Byte(s)  Description
  //   -------  -----------
  //   0-1      Year (0 to 65535)
  //   2        Month (1 to 12)
  //   3        Day (1 to 31)
  //   4        Hours (0 to 23)
  //   5        Minutes (0 to 59)
  //   6        Seconds (0 to 60, 60 = "leap second")
  //   7        Deciseconds (0 to 9)
  //   8        +/- UTC
  //   9        UTC hours (0 to 11)
  //   10       UTC minutes (0 to 59)
  gmtime_r(&t, &unixdate);
  unixdate.tm_year += 1900;

  date[0]  = (ipp_uchar_t)(unixdate.tm_year >> 8);
  date[1]  = (ipp_uchar_t)(unixdate.tm_year);
  date[2]  = (ipp_uchar_t)(unixdate.tm_mon + 1);
  date[3]  = (ipp_uchar_t)unixdate.tm_mday;
  date[4]  = (ipp_uchar_t)unixdate.tm_hour;
  date[5]  = (ipp_uchar_t)unixdate.tm_min;
  date[6]  = (ipp_uchar_t)unixdate.tm_sec;
  date[7]  = 0;
  date[8]  = '+';
  date[9]  = 0;
  date[10] = 0;

  return (date);
}


//
// 'ippValidateAttribute()' - Validate the contents of an attribute.
//
// This function validates the contents of an attribute based on the name and
// value tag.  `true` is returned if the attribute is valid, `false` otherwise.
// On failure, @link cupsGetErrorString@ is set to a human-readable message.
//

bool          // O - `true` if valid, `false` otherwise
ippValidateAttribute(
    ipp_attribute_t *attr)    // I - Attribute
{
  ipp_tag_t value_tag;    // Masked value tag
  _ipp_value_t  *value;     // Current value
  size_t  i;      // Looping var
  char    scheme[64],   // Scheme from URI
    userpass[256],    // Username/password from URI
    hostname[256],    // Hostname from URI
    resource[1024];   // Resource from URI
  int   port,     // Port number from URI
    uri_status;   // URI separation status
  const char  *ptr;     // Pointer into string
  ipp_attribute_t *colattr;   // Collection attribute
  ipp_uchar_t *date;      // Current date value


  // Skip separators.
  if (!attr->name)
    return (true);

  // Validate the attribute name.
  for (ptr = attr->name; *ptr; ptr ++)
  {
    if (!isalnum(*ptr & 255) && *ptr != '-' && *ptr != '.' && *ptr != '_')
      break;
  }

  if (*ptr || ptr == attr->name)
  {
    ipp_set_error(IPP_STATUS_ERROR_BAD_REQUEST, _("\"%s\": Bad attribute name - invalid character (RFC 8011 section 5.1.4)."), attr->name);
    return (false);
  }

  if ((ptr - attr->name) > 255)
  {
    ipp_set_error(IPP_STATUS_ERROR_BAD_REQUEST, _("\"%s\": Bad attribute name - bad length %d (RFC 8011 section 5.1.4)."), attr->name, (int)(ptr - attr->name));
    return (false);
  }

  value_tag = attr->value_tag & IPP_TAG_CUPS_MASK;

  switch (value_tag)
  {
    case IPP_TAG_INTEGER :
        break;

    case IPP_TAG_BOOLEAN :
        for (i = attr->num_values, value = attr->values; i > 0; i --, value ++)
  {
    if (value->boolean != 0 && value->boolean != 1)
    {
      ipp_set_error(IPP_STATUS_ERROR_BAD_REQUEST, _("\"%s\": Bad boolean value %d (RFC 8011 section 5.1.21)."), attr->name, value->boolean);
      return (false);
    }
  }
        break;

    case IPP_TAG_ENUM :
        for (i = attr->num_values, value = attr->values; i > 0; i --, value ++)
  {
    if (value->integer < 1)
    {
      ipp_set_error(IPP_STATUS_ERROR_BAD_REQUEST, _("\"%s\": Bad enum value %d - out of range (RFC 8011 section 5.1.5)."), attr->name, value->integer);
            return (false);
    }
  }
        break;

    case IPP_TAG_STRING :
        for (i = attr->num_values, value = attr->values; i > 0; i --, value ++)
  {
    if (value->unknown.length > IPP_MAX_OCTETSTRING)
    {
      ipp_set_error(IPP_STATUS_ERROR_BAD_REQUEST, _("\"%s\": Bad octetString value - bad length %d (RFC 8011 section 5.1.20)."), attr->name, value->unknown.length);
      return (false);
    }
  }
        break;

    case IPP_TAG_DATE :
        for (i = attr->num_values, value = attr->values; i > 0; i --, value ++)
  {
    date = value->date;

          if (date[2] < 1 || date[2] > 12)
    {
      ipp_set_error(IPP_STATUS_ERROR_BAD_REQUEST, _("\"%s\": Bad dateTime month %u (RFC 8011 section 5.1.15)."), attr->name, date[2]);
      return (false);
    }

          if (date[3] < 1 || date[3] > 31)
    {
      ipp_set_error(IPP_STATUS_ERROR_BAD_REQUEST, _("\"%s\": Bad dateTime day %u (RFC 8011 section 5.1.15)."), attr->name, date[3]);
      return (false);
    }

          if (date[4] > 23)
    {
      ipp_set_error(IPP_STATUS_ERROR_BAD_REQUEST, _("\"%s\": Bad dateTime hours %u (RFC 8011 section 5.1.15)."), attr->name, date[4]);
      return (false);
    }

          if (date[5] > 59)
    {
      ipp_set_error(IPP_STATUS_ERROR_BAD_REQUEST, _("\"%s\": Bad dateTime minutes %u (RFC 8011 section 5.1.15)."), attr->name, date[5]);
      return (false);
    }

          if (date[6] > 60)
    {
      ipp_set_error(IPP_STATUS_ERROR_BAD_REQUEST, _("\"%s\": Bad dateTime seconds %u (RFC 8011 section 5.1.15)."), attr->name, date[6]);
      return (false);
    }

          if (date[7] > 9)
    {
      ipp_set_error(IPP_STATUS_ERROR_BAD_REQUEST, _("\"%s\": Bad dateTime deciseconds %u (RFC 8011 section 5.1.15)."), attr->name, date[7]);
      return (false);
    }

          if (date[8] != '-' && date[8] != '+')
    {
      ipp_set_error(IPP_STATUS_ERROR_BAD_REQUEST, _("\"%s\": Bad dateTime UTC sign '%c' (RFC 8011 section 5.1.15)."), attr->name, date[8]);
      return (false);
    }

          if (date[9] > 14)
    {
      // Kiribata has a UTC+14 time zone, RFC 2579 calls for UTC+13 support, errata filed...
      ipp_set_error(IPP_STATUS_ERROR_BAD_REQUEST, _("\"%s\": Bad dateTime UTC hours %u (RFC 8011 section 5.1.15)."), attr->name, date[9]);
      return (false);
    }

          if (date[10] > 59)
    {
      ipp_set_error(IPP_STATUS_ERROR_BAD_REQUEST, _("\"%s\": Bad dateTime UTC minutes %u (RFC 8011 section 5.1.15)."), attr->name, date[10]);
      return (false);
    }
  }
        break;

    case IPP_TAG_RESOLUTION :
        for (i = attr->num_values, value = attr->values; i > 0; i --, value ++)
  {
    if (value->resolution.xres <= 0)
    {
      ipp_set_error(IPP_STATUS_ERROR_BAD_REQUEST, _("\"%s\": Bad resolution value %dx%d%s - cross feed resolution must be positive (RFC 8011 section 5.1.16)."), attr->name, value->resolution.xres, value->resolution.yres, value->resolution.units == IPP_RES_PER_INCH ? "dpi" : value->resolution.units == IPP_RES_PER_CM ? "dpcm" : "unknown");
      return (false);
    }

    if (value->resolution.yres <= 0)
    {
      ipp_set_error(IPP_STATUS_ERROR_BAD_REQUEST, _("\"%s\": Bad resolution value %dx%d%s - feed resolution must be positive (RFC 8011 section 5.1.16)."), attr->name, value->resolution.xres, value->resolution.yres, value->resolution.units == IPP_RES_PER_INCH ? "dpi" : value->resolution.units == IPP_RES_PER_CM ? "dpcm" : "unknown");
            return (false);
    }

    if (value->resolution.units != IPP_RES_PER_INCH && value->resolution.units != IPP_RES_PER_CM)
    {
      ipp_set_error(IPP_STATUS_ERROR_BAD_REQUEST, _("\"%s\": Bad resolution value %dx%d%s - bad units value (RFC 8011 section 5.1.16)."), attr->name, value->resolution.xres, value->resolution.yres, value->resolution.units == IPP_RES_PER_INCH ? "dpi" : value->resolution.units == IPP_RES_PER_CM ? "dpcm" : "unknown");
      return (false);
    }
  }
        break;

    case IPP_TAG_RANGE :
        for (i = attr->num_values, value = attr->values; i > 0; i --, value ++)
  {
    if (value->range.lower > value->range.upper)
    {
      ipp_set_error(IPP_STATUS_ERROR_BAD_REQUEST, _("\"%s\": Bad rangeOfInteger value %d-%d - lower greater than upper (RFC 8011 section 5.1.14)."), attr->name, value->range.lower, value->range.upper);
      return (false);
    }
  }
        break;

    case IPP_TAG_BEGIN_COLLECTION :
        for (i = attr->num_values, value = attr->values; i > 0; i --, value ++)
  {
    for (colattr = value->collection->attrs;
         colattr;
         colattr = colattr->next)
    {
      if (!ippValidateAttribute(colattr))
        return (false);
    }
  }
        break;

    case IPP_TAG_TEXT :
    case IPP_TAG_TEXTLANG :
        if (value_tag == IPP_TAG_TEXTLANG)
        {
          if (!ipp_regex_begin())
            return (false);
        }

        for (i = attr->num_values, value = attr->values; i > 0; i --, value ++)
  {
    if (value_tag == IPP_TAG_TEXTLANG && !ipp_is_valid_language(attr->name, value->string.language))
    {
      ipp_regex_end();
      return (false);
    }

    for (ptr = value->string.text; *ptr; ptr ++)
    {
      if ((*ptr & 0xe0) == 0xc0)
      {
        if ((ptr[1] & 0xc0) != 0x80)
          break;

        ptr ++;
      }
      else if ((*ptr & 0xf0) == 0xe0)
      {
        if ((ptr[1] & 0xc0) != 0x80 || (ptr[2] & 0xc0) != 0x80)
          break;

        ptr += 2;
      }
      else if ((*ptr & 0xf8) == 0xf0)
      {
        if ((ptr[1] & 0xc0) != 0x80 || (ptr[2] & 0xc0) != 0x80 || (ptr[3] & 0xc0) != 0x80)
          break;

        ptr += 3;
      }
      else if (*ptr & 0x80)
      {
        break;
      }
      else if ((*ptr < ' ' && *ptr != '\n' && *ptr != '\r' && *ptr != '\t') || *ptr == 0x7f)
      {
        break;
      }
    }

          if (*ptr)
          {
      if (value_tag == IPP_TAG_TEXTLANG)
        ipp_regex_end();

      if (*ptr < ' ' || *ptr == 0x7f)
      {
        ipp_set_error(IPP_STATUS_ERROR_BAD_REQUEST, _("\"%s\": Bad text value \"%s\" - bad control character (PWG 5100.14 section 8.3)."), attr->name, value->string.text);
        return (false);
      }
      else
      {
        ipp_set_error(IPP_STATUS_ERROR_BAD_REQUEST, _("\"%s\": Bad text value \"%s\" - bad UTF-8 sequence (RFC 8011 section 5.1.2)."), attr->name, value->string.text);
        return (false);
      }
          }

    if ((ptr - value->string.text) > (IPP_MAX_TEXT - 1))
    {
      if (value_tag == IPP_TAG_TEXTLANG)
        ipp_regex_end();

      ipp_set_error(IPP_STATUS_ERROR_BAD_REQUEST, _("\"%s\": Bad text value \"%s\" - bad length %d (RFC 8011 section 5.1.2)."), attr->name, value->string.text, (int)(ptr - value->string.text));
      return (false);
    }
  }

  if (value_tag == IPP_TAG_TEXTLANG)
    ipp_regex_end();
        break;

    case IPP_TAG_NAME :
    case IPP_TAG_NAMELANG :
        if (value_tag == IPP_TAG_NAMELANG)
        {
          if (!ipp_regex_begin())
            return (false);
        }

        for (i = attr->num_values, value = attr->values; i > 0; i --, value ++)
  {
    if (value_tag == IPP_TAG_NAMELANG && !ipp_is_valid_language(attr->name, value->string.language))
    {
      ipp_regex_end();
      return (false);
    }

    for (ptr = value->string.text; *ptr; ptr ++)
    {
      if ((*ptr & 0xe0) == 0xc0)
      {
        if ((ptr[1] & 0xc0) != 0x80)
          break;

        ptr ++;
      }
      else if ((*ptr & 0xf0) == 0xe0)
      {
        if ((ptr[1] & 0xc0) != 0x80 || (ptr[2] & 0xc0) != 0x80)
          break;

        ptr += 2;
      }
      else if ((*ptr & 0xf8) == 0xf0)
      {
        if ((ptr[1] & 0xc0) != 0x80 || (ptr[2] & 0xc0) != 0x80 || (ptr[3] & 0xc0) != 0x80)
          break;

        ptr += 3;
      }
      else if (*ptr & 0x80)
      {
        break;
      }
      else if (*ptr < ' ' || *ptr == 0x7f)
      {
        break;
      }
    }

    if (*ptr)
    {
      if (value_tag == IPP_TAG_NAMELANG)
        ipp_regex_end();

      if (*ptr < ' ' || *ptr == 0x7f)
      {
        ipp_set_error(IPP_STATUS_ERROR_BAD_REQUEST, _("\"%s\": Bad name value \"%s\" - bad control character (PWG 5100.14 section 8.1)."), attr->name, value->string.text);
        return (false);
      }
      else
      {
        ipp_set_error(IPP_STATUS_ERROR_BAD_REQUEST, _("\"%s\": Bad name value \"%s\" - bad UTF-8 sequence (RFC 8011 section 5.1.3)."), attr->name, value->string.text);
        return (false);
      }
          }

    if ((ptr - value->string.text) > (IPP_MAX_NAME - 1))
    {
      if (value_tag == IPP_TAG_NAMELANG)
        ipp_regex_end();

      ipp_set_error(IPP_STATUS_ERROR_BAD_REQUEST, _("\"%s\": Bad name value \"%s\" - bad length %d (RFC 8011 section 5.1.3)."), attr->name, value->string.text, (int)(ptr - value->string.text));
      return (false);
    }
  }

  if (value_tag == IPP_TAG_NAMELANG)
    ipp_regex_end();
        break;

    case IPP_TAG_KEYWORD :
        for (i = attr->num_values, value = attr->values; i > 0; i --, value ++)
  {
    for (ptr = value->string.text; *ptr; ptr ++)
    {
      if (!isalnum(*ptr & 255) && *ptr != '-' && *ptr != '.' && *ptr != '_')
        break;
    }

    if (*ptr || ptr == value->string.text)
    {
      ipp_set_error(IPP_STATUS_ERROR_BAD_REQUEST, _("\"%s\": Bad keyword value \"%s\" - invalid character (RFC 8011 section 5.1.4)."), attr->name, value->string.text);
      return (false);
    }

    if ((ptr - value->string.text) > (IPP_MAX_KEYWORD - 1))
    {
      ipp_set_error(IPP_STATUS_ERROR_BAD_REQUEST, _("\"%s\": Bad keyword value \"%s\" - bad length %d (RFC 8011 section 5.1.4)."), attr->name, value->string.text, (int)(ptr - value->string.text));
      return (false);
    }
  }
        break;

    case IPP_TAG_URI :
        for (i = attr->num_values, value = attr->values; i > 0; i --, value ++)
  {
    uri_status = httpSeparateURI(HTTP_URI_CODING_ALL, value->string.text, scheme, sizeof(scheme), userpass, sizeof(userpass), hostname, sizeof(hostname), &port, resource, sizeof(resource));

    if (uri_status < HTTP_URI_STATUS_OK)
    {
      ipp_set_error(IPP_STATUS_ERROR_BAD_REQUEST, _("\"%s\": Bad URI value \"%s\" - %s (RFC 8011 section 5.1.6)."), attr->name, value->string.text, httpURIStatusString(uri_status));
      return (false);
    }

    if (strlen(value->string.text) > (IPP_MAX_URI - 1))
    {
      ipp_set_error(IPP_STATUS_ERROR_BAD_REQUEST, _("\"%s\": Bad URI value \"%s\" - bad length %d (RFC 8011 section 5.1.6)."), attr->name, value->string.text, (int)strlen(value->string.text));
    }
  }
        break;

    case IPP_TAG_URISCHEME :
        for (i = attr->num_values, value = attr->values; i > 0; i --, value ++)
  {
    ptr = value->string.text;
    if (islower(*ptr & 255))
    {
      for (ptr ++; *ptr; ptr ++)
      {
        if (!islower(*ptr & 255) && !isdigit(*ptr & 255) && *ptr != '+' && *ptr != '-' && *ptr != '.')
                break;
      }
    }

    if (*ptr || ptr == value->string.text)
    {
      ipp_set_error(IPP_STATUS_ERROR_BAD_REQUEST, _("\"%s\": Bad uriScheme value \"%s\" - bad characters (RFC 8011 section 5.1.7)."), attr->name, value->string.text);
      return (false);
    }

    if ((ptr - value->string.text) > (IPP_MAX_URISCHEME - 1))
    {
      ipp_set_error(IPP_STATUS_ERROR_BAD_REQUEST, _("\"%s\": Bad uriScheme value \"%s\" - bad length %d (RFC 8011 section 5.1.7)."), attr->name, value->string.text, (int)(ptr - value->string.text));
      return (false);
    }
  }
        break;

    case IPP_TAG_CHARSET :
        for (i = attr->num_values, value = attr->values; i > 0; i --, value ++)
  {
    for (ptr = value->string.text; *ptr; ptr ++)
    {
      if (!isprint(*ptr & 255) || isupper(*ptr & 255) || isspace(*ptr & 255))
        break;
    }

    if (*ptr || ptr == value->string.text)
    {
      ipp_set_error(IPP_STATUS_ERROR_BAD_REQUEST, _("\"%s\": Bad charset value \"%s\" - bad characters (RFC 8011 section 5.1.8)."), attr->name, value->string.text);
      return (false);
    }

    if ((ptr - value->string.text) > (IPP_MAX_CHARSET - 1))
    {
      ipp_set_error(IPP_STATUS_ERROR_BAD_REQUEST, _("\"%s\": Bad charset value \"%s\" - bad length %d (RFC 8011 section 5.1.8)."), attr->name, value->string.text, (int)(ptr - value->string.text));
      return (false);
    }
  }
        break;

    case IPP_TAG_LANGUAGE :
        if (!ipp_regex_begin())
          return (false);

        for (i = attr->num_values, value = attr->values; i > 0; i --, value ++)
  {
    if (!ipp_is_valid_language(attr->name, value->string.text))
    {
      ipp_regex_end();
      return (false);
    }
  }

  ipp_regex_end();
        break;

    case IPP_TAG_MIMETYPE :
        if (!ipp_regex_begin())
          return (false);

        for (i = attr->num_values, value = attr->values; i > 0; i --, value ++)
  {
    if (!ipp_is_valid_mimetype(attr->name, value->string.text))
    {
      ipp_regex_end();
      return (false);
    }
  }

  ipp_regex_end();
        break;

    default :
        break;
  }

  return (true);
}


//
// 'ippValidateAttributes()' - Validate all attributes in an IPP message.
//
// This function validates the contents of the IPP message, including each
// attribute.  Like @link ippValidateAttribute@, @link cupsGetErrorString@ is
// set to a human-readable message on failure.
//

bool          // O - `true` if valid, `false` otherwise
ippValidateAttributes(ipp_t *ipp) // I - IPP message
{
  ipp_attribute_t *attr;    // Current attribute


  if (!ipp)
    return (true);

  for (attr = ipp->attrs; attr; attr = attr->next)
  {
    if (!ippValidateAttribute(attr))
      return (false);
  }

  return (true);
}


//
// 'ippWrite()' - Write data for an IPP message to a HTTP connection.
//

ipp_state_t       // O - Current state
ippWrite(http_t *http,      // I - HTTP connection
         ipp_t  *ipp)     // I - IPP data
{
  DEBUG_printf("ippWrite(http=%p, ipp=%p)", (void *)http, (void *)ipp);

  if (!http)
    return (IPP_STATE_ERROR);

  return (ippWriteIO(http, (ipp_io_cb_t)httpWrite, http->blocking, NULL, ipp));
}


//
// 'ippWriteFile()' - Write data for an IPP message to a file.
//

ipp_state_t       // O - Current state
ippWriteFile(int   fd,      // I - HTTP data
             ipp_t *ipp)    // I - IPP data
{
  DEBUG_printf("ippWriteFile(fd=%d, ipp=%p)", fd, (void *)ipp);

  ipp->state = IPP_STATE_IDLE;

  return (ippWriteIO(&fd, (ipp_io_cb_t)ipp_write_file, true, NULL, ipp));
}


//
// 'ippWriteIO()' - Write data for an IPP message.
//

ipp_state_t       // O - Current state
ippWriteIO(void        *dst,    // I - Destination
           ipp_io_cb_t cb,    // I - Write callback function
     bool        blocking,  // I - Use blocking IO?
     ipp_t       *parent,   // I - Parent IPP message
           ipp_t       *ipp)    // I - IPP data
{
  size_t    i;    // Looping var
  int     n;    // Length of data
  unsigned char   *buffer,  // Data buffer
      *bufptr;  // Pointer into buffer
  ipp_attribute_t *attr;    // Current attribute
  _ipp_value_t    *value;   // Current value


  DEBUG_printf("ippWriteIO(dst=%p, cb=%p, blocking=%d, parent=%p, ipp=%p)", (void *)dst, (void *)cb, blocking, (void *)parent, (void *)ipp);

  if (!dst || !ipp)
    return (IPP_STATE_ERROR);

  if ((buffer = (unsigned char *)_cupsBufferGet(IPP_BUF_SIZE)) == NULL)
  {
    DEBUG_puts("1ippWriteIO: Unable to get write buffer");
    return (IPP_STATE_ERROR);
  }

  switch (ipp->state)
  {
    case IPP_STATE_IDLE :
        ipp->state ++; // Avoid common problem...

    case IPP_STATE_HEADER :
        if (parent == NULL)
  {
    // Send the request header:
    //
    //                 Version = 2 bytes
    //   Operation/Status Code = 2 bytes
    //              Request ID = 4 bytes
    //                   Total = 8 bytes
          bufptr = buffer;

    *bufptr++ = ipp->request.version[0];
    *bufptr++ = ipp->request.version[1];
    *bufptr++ = (ipp_uchar_t)(ipp->request.op_status >> 8);
    *bufptr++ = (ipp_uchar_t)ipp->request.op_status;
    *bufptr++ = (ipp_uchar_t)(ipp->request.request_id >> 24);
    *bufptr++ = (ipp_uchar_t)(ipp->request.request_id >> 16);
    *bufptr++ = (ipp_uchar_t)(ipp->request.request_id >> 8);
    *bufptr++ = (ipp_uchar_t)ipp->request.request_id;

    DEBUG_printf("2ippWriteIO: version=%d.%d", buffer[0], buffer[1]);
    DEBUG_printf("2ippWriteIO: op_status=%04x", ipp->request.op_status);
    DEBUG_printf("2ippWriteIO: request_id=%d", ipp->request.request_id);

          if ((*cb)(dst, buffer, (size_t)(bufptr - buffer)) < 0)
    {
      DEBUG_puts("1ippWriteIO: Could not write IPP header...");
      _cupsBufferRelease((char *)buffer);
      return (IPP_STATE_ERROR);
    }
  }

  // Reset the state engine to point to the first attribute
  // in the request/response, with no current group.
        ipp->state   = IPP_STATE_ATTRIBUTE;
  ipp->current = ipp->attrs;
  ipp->curtag  = IPP_TAG_ZERO;

  DEBUG_printf("1ippWriteIO: ipp->current=%p", (void *)ipp->current);

        // If blocking is disabled, stop here...
        if (!blocking)
    break;

    case IPP_STATE_ATTRIBUTE :
        while (ipp->current != NULL)
  {
    // Write this attribute...
    bufptr = buffer;
    attr   = ipp->current;

    ipp->current = ipp->current->next;

          if (!parent)
    {
      if (ipp->curtag != attr->group_tag)
      {
        // Send a group tag byte...
        ipp->curtag = attr->group_tag;

        if (attr->group_tag == IPP_TAG_ZERO)
    continue;

        DEBUG_printf("2ippWriteIO: wrote group tag=%x(%s)", attr->group_tag, ippTagString(attr->group_tag));
        *bufptr++ = (ipp_uchar_t)attr->group_tag;
      }
      else if (attr->group_tag == IPP_TAG_ZERO)
      {
        continue;
      }
    }

    DEBUG_printf("1ippWriteIO: %s (%s%s)", attr->name, attr->num_values > 1 ? "1setOf " : "", ippTagString(attr->value_tag));

    // Write the attribute tag and name.
    //
    // The attribute name length does not include the trailing nul
    // character in the source string.
    //
    // Collection values (parent != NULL) are written differently...
          if (parent == NULL)
    {
      // Get the length of the attribute name, and make sure it won't overflow the buffer...
            if ((n = (int)strlen(attr->name)) > (IPP_BUF_SIZE - 8))
      {
        DEBUG_printf("1ippWriteIO: Attribute name too long (%d)", n);
        _cupsBufferRelease((char *)buffer);
        return (IPP_STATE_ERROR);
      }

      // Write the value tag, name length, and name string...
      DEBUG_printf("2ippWriteIO: writing value tag=%x(%s)", attr->value_tag, ippTagString(attr->value_tag));
            DEBUG_printf("2ippWriteIO: writing name=%d,\"%s\"", n, attr->name);

      *bufptr++ = (ipp_uchar_t)attr->value_tag;
      *bufptr++ = (ipp_uchar_t)(n >> 8);
      *bufptr++ = (ipp_uchar_t)n;
      memcpy(bufptr, attr->name, (size_t)n);
      bufptr += n;
          }
    else
    {
      // Get the length of the attribute name, and make sure it won't overflow the buffer...
            if ((n = (int)strlen(attr->name)) > (IPP_BUF_SIZE - 12))
      {
        DEBUG_printf("1ippWriteIO: Attribute name too long (%d)", n);
        _cupsBufferRelease((char *)buffer);
        return (IPP_STATE_ERROR);
      }

      // Write the member name tag, name length, name string, value tag,
      // and empty name for the collection member attribute...
            DEBUG_printf("2ippWriteIO: writing value tag=%x(memberName)", IPP_TAG_MEMBERNAME);
            DEBUG_printf("2ippWriteIO: writing name=%d,\"%s\"", n, attr->name);
            DEBUG_printf("2ippWriteIO: writing value tag=%x(%s)", attr->value_tag, ippTagString(attr->value_tag));
            DEBUG_puts("2ippWriteIO: writing name=0,\"\"");

            *bufptr++ = IPP_TAG_MEMBERNAME;
      *bufptr++ = 0;
      *bufptr++ = 0;
      *bufptr++ = (ipp_uchar_t)(n >> 8);
      *bufptr++ = (ipp_uchar_t)n;
      memcpy(bufptr, attr->name, (size_t)n);
      bufptr += n;

            if (attr->value_tag > 0xff)
            {
              *bufptr++ = IPP_TAG_EXTENSION;
        *bufptr++ = (ipp_uchar_t)(attr->value_tag >> 24);
        *bufptr++ = (ipp_uchar_t)(attr->value_tag >> 16);
        *bufptr++ = (ipp_uchar_t)(attr->value_tag >> 8);
        *bufptr++ = (ipp_uchar_t)attr->value_tag;
            }
            else
            {
        *bufptr++ = (ipp_uchar_t)attr->value_tag;
      }

            *bufptr++ = 0;
            *bufptr++ = 0;
    }

    // Now write the attribute value(s)...
    switch (attr->value_tag & ~IPP_TAG_CUPS_CONST)
    {
      case IPP_TAG_UNSUPPORTED_VALUE :
      case IPP_TAG_DEFAULT :
      case IPP_TAG_UNKNOWN :
      case IPP_TAG_NOVALUE :
      case IPP_TAG_NOTSETTABLE :
      case IPP_TAG_DELETEATTR :
      case IPP_TAG_ADMINDEFINE :
    *bufptr++ = 0;
    *bufptr++ = 0;
          break;

      case IPP_TAG_INTEGER :
      case IPP_TAG_ENUM :
          for (i = 0, value = attr->values; i < attr->num_values; i ++, value ++)
    {
                  if ((IPP_BUF_SIZE - (bufptr - buffer)) < 9)
      {
                    if ((*cb)(dst, buffer, (size_t)(bufptr - buffer)) < 0)
              {
          DEBUG_puts("1ippWriteIO: Could not write IPP attribute...");
          _cupsBufferRelease((char *)buffer);
                return (IPP_STATE_ERROR);
              }

        bufptr = buffer;
      }

      if (i)
      {
        // Arrays and sets are done by sending additional values with a zero-length name...
                    *bufptr++ = (ipp_uchar_t)attr->value_tag;
        *bufptr++ = 0;
        *bufptr++ = 0;
      }

            // Integers and enumerations are both 4-byte signed
      // (twos-complement) values.
      //
      // Put the 2-byte length and 4-byte value into the buffer...
            *bufptr++ = 0;
      *bufptr++ = 4;
      *bufptr++ = (ipp_uchar_t)(value->integer >> 24);
      *bufptr++ = (ipp_uchar_t)(value->integer >> 16);
      *bufptr++ = (ipp_uchar_t)(value->integer >> 8);
      *bufptr++ = (ipp_uchar_t)value->integer;
    }
    break;

      case IPP_TAG_BOOLEAN :
          for (i = 0, value = attr->values; i < attr->num_values; i ++, value ++)
    {
                  if ((IPP_BUF_SIZE - (bufptr - buffer)) < 6)
      {
                    if ((*cb)(dst, buffer, (size_t)(bufptr - buffer)) < 0)
              {
          DEBUG_puts("1ippWriteIO: Could not write IPP attribute...");
          _cupsBufferRelease((char *)buffer);
                return (IPP_STATE_ERROR);
              }

        bufptr = buffer;
      }

      if (i)
      {
        // Arrays and sets are done by sending additional values with a zero-length name...
                    *bufptr++ = (ipp_uchar_t)attr->value_tag;
        *bufptr++ = 0;
        *bufptr++ = 0;
      }

      // Boolean values are 1-byte; 0 = false, 1 = true.
      //
      // Put the 2-byte length and 1-byte value into the buffer...
            *bufptr++ = 0;
      *bufptr++ = 1;
      *bufptr++ = (ipp_uchar_t)value->boolean;
    }
    break;

      case IPP_TAG_TEXT :
      case IPP_TAG_NAME :
      case IPP_TAG_KEYWORD :
      case IPP_TAG_URI :
      case IPP_TAG_URISCHEME :
      case IPP_TAG_CHARSET :
      case IPP_TAG_LANGUAGE :
      case IPP_TAG_MIMETYPE :
          for (i = 0, value = attr->values; i < attr->num_values; i ++, value ++)
    {
      if (i)
      {
        // Arrays and sets are done by sending additional values with a zero-length name...
              DEBUG_printf("2ippWriteIO: writing value tag=%x(%s)", attr->value_tag, ippTagString(attr->value_tag));
              DEBUG_printf("2ippWriteIO: writing name=0,\"\"");

                    if ((IPP_BUF_SIZE - (bufptr - buffer)) < 3)
        {
                      if ((*cb)(dst, buffer, (size_t)(bufptr - buffer)) < 0)
                {
      DEBUG_puts("1ippWriteIO: Could not write IPP attribute...");
      _cupsBufferRelease((char *)buffer);
            return (IPP_STATE_ERROR);
                }

          bufptr = buffer;
        }

                    *bufptr++ = (ipp_uchar_t)attr->value_tag;
        *bufptr++ = 0;
        *bufptr++ = 0;
      }

                  if (value->string.text != NULL)
                    n = (int)strlen(value->string.text);
      else
        n = 0;

                  if (n > (IPP_BUF_SIZE - 2))
      {
        DEBUG_printf("1ippWriteIO: String too long (%d)", n);
        _cupsBufferRelease((char *)buffer);
        return (IPP_STATE_ERROR);
      }

                  DEBUG_printf("2ippWriteIO: writing string=%d,\"%s\"", n, value->string.text);

                  if ((int)(IPP_BUF_SIZE - (bufptr - buffer)) < (n + 2))
      {
                    if ((*cb)(dst, buffer, (size_t)(bufptr - buffer)) < 0)
              {
          DEBUG_puts("1ippWriteIO: Could not write IPP attribute...");
          _cupsBufferRelease((char *)buffer);
                return (IPP_STATE_ERROR);
              }

        bufptr = buffer;
      }

      // All simple strings consist of the 2-byte length and
      // character data without the trailing nul normally found
      // in C strings.  Also, strings cannot be longer than IPP_MAX_LENGTH
      // bytes since the 2-byte length is a signed (twos-complement)
      // value.
      //
      // Put the 2-byte length and string characters in the buffer.
            *bufptr++ = (ipp_uchar_t)(n >> 8);
      *bufptr++ = (ipp_uchar_t)n;

      if (n > 0)
      {
        memcpy(bufptr, value->string.text, (size_t)n);
        bufptr += n;
      }
    }
    break;

      case IPP_TAG_DATE :
          for (i = 0, value = attr->values; i < attr->num_values; i ++, value ++)
    {
                  if ((IPP_BUF_SIZE - (bufptr - buffer)) < 16)
      {
                    if ((*cb)(dst, buffer, (size_t)(bufptr - buffer)) < 0)
              {
          DEBUG_puts("1ippWriteIO: Could not write IPP attribute...");
          _cupsBufferRelease((char *)buffer);
                return (IPP_STATE_ERROR);
              }

        bufptr = buffer;
      }

      if (i)
      {
        // Arrays and sets are done by sending additional values with a zero-length name...
                    *bufptr++ = (ipp_uchar_t)attr->value_tag;
        *bufptr++ = 0;
        *bufptr++ = 0;
      }

      // Date values consist of a 2-byte length and an
      // 11-byte date/time structure defined by RFC 1903.
      //
      // Put the 2-byte length and 11-byte date/time
      // structure in the buffer.
            *bufptr++ = 0;
      *bufptr++ = 11;
      memcpy(bufptr, value->date, 11);
      bufptr += 11;
    }
    break;

      case IPP_TAG_RESOLUTION :
          for (i = 0, value = attr->values; i < attr->num_values; i ++, value ++)
    {
                  if ((IPP_BUF_SIZE - (bufptr - buffer)) < 14)
      {
                    if ((*cb)(dst, buffer, (size_t)(bufptr - buffer)) < 0)
              {
          DEBUG_puts("1ippWriteIO: Could not write IPP attribute...");
          _cupsBufferRelease((char *)buffer);
          return (IPP_STATE_ERROR);
              }

        bufptr = buffer;
      }

      if (i)
      {
        // Arrays and sets are done by sending additional values with a zero-length name...
                    *bufptr++ = (ipp_uchar_t)attr->value_tag;
        *bufptr++ = 0;
        *bufptr++ = 0;
      }

      // Resolution values consist of a 2-byte length,
      // 4-byte horizontal resolution value, 4-byte vertical
      // resolution value, and a 1-byte units value.
      //
      // Put the 2-byte length and resolution value data
      // into the buffer.
            *bufptr++ = 0;
      *bufptr++ = 9;
      *bufptr++ = (ipp_uchar_t)(value->resolution.xres >> 24);
      *bufptr++ = (ipp_uchar_t)(value->resolution.xres >> 16);
      *bufptr++ = (ipp_uchar_t)(value->resolution.xres >> 8);
      *bufptr++ = (ipp_uchar_t)value->resolution.xres;
      *bufptr++ = (ipp_uchar_t)(value->resolution.yres >> 24);
      *bufptr++ = (ipp_uchar_t)(value->resolution.yres >> 16);
      *bufptr++ = (ipp_uchar_t)(value->resolution.yres >> 8);
      *bufptr++ = (ipp_uchar_t)value->resolution.yres;
      *bufptr++ = (ipp_uchar_t)value->resolution.units;
    }
    break;

      case IPP_TAG_RANGE :
          for (i = 0, value = attr->values; i < attr->num_values; i ++, value ++)
    {
                  if ((IPP_BUF_SIZE - (bufptr - buffer)) < 13)
      {
                    if ((*cb)(dst, buffer, (size_t)(bufptr - buffer)) < 0)
              {
          DEBUG_puts("1ippWriteIO: Could not write IPP attribute...");
          _cupsBufferRelease((char *)buffer);
                return (IPP_STATE_ERROR);
              }

        bufptr = buffer;
      }

      if (i)
      {
        // Arrays and sets are done by sending additional values with a zero-length name...
                    *bufptr++ = (ipp_uchar_t)attr->value_tag;
        *bufptr++ = 0;
        *bufptr++ = 0;
      }

      // Range values consist of a 2-byte length,
      // 4-byte lower value, and 4-byte upper value.
      //
      // Put the 2-byte length and range value data
      // into the buffer.
            *bufptr++ = 0;
      *bufptr++ = 8;
      *bufptr++ = (ipp_uchar_t)(value->range.lower >> 24);
      *bufptr++ = (ipp_uchar_t)(value->range.lower >> 16);
      *bufptr++ = (ipp_uchar_t)(value->range.lower >> 8);
      *bufptr++ = (ipp_uchar_t)value->range.lower;
      *bufptr++ = (ipp_uchar_t)(value->range.upper >> 24);
      *bufptr++ = (ipp_uchar_t)(value->range.upper >> 16);
      *bufptr++ = (ipp_uchar_t)(value->range.upper >> 8);
      *bufptr++ = (ipp_uchar_t)value->range.upper;
    }
    break;

      case IPP_TAG_TEXTLANG :
      case IPP_TAG_NAMELANG :
          for (i = 0, value = attr->values; i < attr->num_values; i ++, value ++)
    {
      if (i)
      {
        // Arrays and sets are done by sending additional values with a zero-length name...
                    if ((IPP_BUF_SIZE - (bufptr - buffer)) < 3)
        {
                      if ((*cb)(dst, buffer, (size_t)(bufptr - buffer)) < 0)
                {
      DEBUG_puts("1ippWriteIO: Could not write IPP attribute...");
      _cupsBufferRelease((char *)buffer);
            return (IPP_STATE_ERROR);
                }

          bufptr = buffer;
        }

                    *bufptr++ = (ipp_uchar_t)attr->value_tag;
        *bufptr++ = 0;
        *bufptr++ = 0;
      }

      // textWithLanguage and nameWithLanguage values consist
      // of a 2-byte length for both strings and their
      // individual lengths, a 2-byte length for the
      // character string, the character string without the
      // trailing nul, a 2-byte length for the character
      // set string, and the character set string without
      // the trailing nul.
                  n = 4;

      if (value->string.language != NULL)
                    n += (int)strlen(value->string.language);

      if (value->string.text != NULL)
                    n += (int)strlen(value->string.text);

                  if (n > (IPP_BUF_SIZE - 2))
      {
        DEBUG_printf("1ippWriteIO: text/nameWithLanguage value too long (%d)", n);
        _cupsBufferRelease((char *)buffer);
        return (IPP_STATE_ERROR);
                  }

                  if ((int)(IPP_BUF_SIZE - (bufptr - buffer)) < (n + 2))
      {
                    if ((*cb)(dst, buffer, (size_t)(bufptr - buffer)) < 0)
              {
          DEBUG_puts("1ippWriteIO: Could not write IPP attribute...");
          _cupsBufferRelease((char *)buffer);
                return (IPP_STATE_ERROR);
              }

        bufptr = buffer;
      }

      // Length of entire value
            *bufptr++ = (ipp_uchar_t)(n >> 8);
      *bufptr++ = (ipp_uchar_t)n;

      // Length of language
      if (value->string.language != NULL)
        n = (int)strlen(value->string.language);
      else
        n = 0;

            *bufptr++ = (ipp_uchar_t)(n >> 8);
      *bufptr++ = (ipp_uchar_t)n;

      // Language
      if (n > 0)
      {
        memcpy(bufptr, value->string.language, (size_t)n);
        bufptr += n;
      }

      // Length of text
                  if (value->string.text != NULL)
        n = (int)strlen(value->string.text);
      else
        n = 0;

            *bufptr++ = (ipp_uchar_t)(n >> 8);
      *bufptr++ = (ipp_uchar_t)n;

      // Text
      if (n > 0)
      {
        memcpy(bufptr, value->string.text, (size_t)n);
        bufptr += n;
      }
    }
    break;

            case IPP_TAG_BEGIN_COLLECTION :
          for (i = 0, value = attr->values; i < attr->num_values; i ++, value ++)
    {
      // Collections are written with the begin-collection
      // tag first with a value of 0 length, followed by the
      // attributes in the collection, then the end-collection
      // value...
                  if ((IPP_BUF_SIZE - (bufptr - buffer)) < 5)
      {
                    if ((*cb)(dst, buffer, (size_t)(bufptr - buffer)) < 0)
              {
          DEBUG_puts("1ippWriteIO: Could not write IPP attribute...");
          _cupsBufferRelease((char *)buffer);
                return (IPP_STATE_ERROR);
              }

        bufptr = buffer;
      }

      if (i)
      {
        // Arrays and sets are done by sending additional values with a zero-length name...
                    *bufptr++ = (ipp_uchar_t)attr->value_tag;
        *bufptr++ = 0;
        *bufptr++ = 0;
      }

      // Write a data length of 0 and flush the buffer...
            *bufptr++ = 0;
      *bufptr++ = 0;

                  if ((*cb)(dst, buffer, (size_t)(bufptr - buffer)) < 0)
            {
        DEBUG_puts("1ippWriteIO: Could not write IPP attribute...");
        _cupsBufferRelease((char *)buffer);
              return (IPP_STATE_ERROR);
            }

      bufptr = buffer;

      // Then write the collection attribute...
                  value->collection->state = IPP_STATE_IDLE;

      if (ippWriteIO(dst, cb, 1, ipp, value->collection) == IPP_STATE_ERROR)
      {
        DEBUG_puts("1ippWriteIO: Unable to write collection value");
        _cupsBufferRelease((char *)buffer);
        return (IPP_STATE_ERROR);
      }
    }
    break;

            default :
          for (i = 0, value = attr->values; i < attr->num_values; i ++, value ++)
    {
      if (i)
      {
        // Arrays and sets are done by sending additional values with a zero-length name...
                    if ((IPP_BUF_SIZE - (bufptr - buffer)) < 3)
        {
                      if ((*cb)(dst, buffer, (size_t)(bufptr - buffer)) < 0)
                {
      DEBUG_puts("1ippWriteIO: Could not write IPP attribute...");
      _cupsBufferRelease((char *)buffer);
            return (IPP_STATE_ERROR);
                }

          bufptr = buffer;
        }

                    *bufptr++ = (ipp_uchar_t)attr->value_tag;
        *bufptr++ = 0;
        *bufptr++ = 0;
      }

      // An unknown value might some new value that a
      // vendor has come up with. It consists of a
      // 2-byte length and the bytes in the unknown
      // value buffer.
                  n = value->unknown.length;

                  if (n > (IPP_BUF_SIZE - 2))
      {
        DEBUG_printf("1ippWriteIO: Data length too long (%d)", n);
        _cupsBufferRelease((char *)buffer);
        return (IPP_STATE_ERROR);
      }

                  if ((int)(IPP_BUF_SIZE - (bufptr - buffer)) < (n + 2))
      {
                    if ((*cb)(dst, buffer, (size_t)(bufptr - buffer)) < 0)
              {
          DEBUG_puts("1ippWriteIO: Could not write IPP attribute...");
          _cupsBufferRelease((char *)buffer);
                return (IPP_STATE_ERROR);
              }

        bufptr = buffer;
      }

      // Length of unknown value
            *bufptr++ = (ipp_uchar_t)(n >> 8);
      *bufptr++ = (ipp_uchar_t)n;

      // Value
      if (n > 0)
      {
        memcpy(bufptr, value->unknown.data, (size_t)n);
        bufptr += n;
      }
    }
    break;
    }

    // Write the data out...
    if (bufptr > buffer)
    {
      if ((*cb)(dst, buffer, (size_t)(bufptr - buffer)) < 0)
      {
        DEBUG_puts("1ippWriteIO: Could not write IPP attribute...");
        _cupsBufferRelease((char *)buffer);
        return (IPP_STATE_ERROR);
      }

      DEBUG_printf("2ippWriteIO: wrote %d bytes", (int)(bufptr - buffer));
    }

          // If blocking is disabled and we aren't at the end of the attribute
          // list, stop here...
          if (!blocking && ipp->current)
      break;
  }

  if (ipp->current == NULL)
  {
    // Done with all of the attributes; add the end-of-attributes
    // tag or end-collection attribute...
          if (parent == NULL)
    {
            buffer[0] = IPP_TAG_END;
      n         = 1;
    }
    else
    {
            buffer[0] = IPP_TAG_END_COLLECTION;
      buffer[1] = 0; // empty name
      buffer[2] = 0;
      buffer[3] = 0; // empty value
      buffer[4] = 0;
      n         = 5;
    }

    if ((*cb)(dst, buffer, (size_t)n) < 0)
    {
      DEBUG_puts("1ippWriteIO: Could not write IPP end-tag...");
      _cupsBufferRelease((char *)buffer);
      return (IPP_STATE_ERROR);
    }

    ipp->state = IPP_STATE_DATA;
  }
        break;

    case IPP_STATE_DATA :
        break;

    default :
        break; // anti-compiler-warning-code
  }

  _cupsBufferRelease((char *)buffer);

  return (ipp->state);
}


//
// 'ipp_add_attr()' - Add a new attribute to the message.
//

static ipp_attribute_t *    // O - New attribute
ipp_add_attr(ipp_t      *ipp,   // I - IPP message
             const char *name,    // I - Attribute name or NULL
             ipp_tag_t  group_tag,  // I - Group tag or IPP_TAG_ZERO
             ipp_tag_t  value_tag,  // I - Value tag or IPP_TAG_ZERO
             size_t     num_values) // I - Number of values
{
  size_t    alloc_values; // Number of values to allocate
  ipp_attribute_t *attr;    // New attribute


  DEBUG_printf("4ipp_add_attr(ipp=%p, name=\"%s\", group_tag=0x%x, value_tag=0x%x, num_values=%u)", (void *)ipp, name, group_tag, value_tag, (unsigned)num_values);

  // Range check input...
  if (!ipp || (name && strlen(name) >= IPP_MAX_KEYWORD))
    return (NULL);

  // Allocate memory, rounding the allocation up as needed...
  if (num_values <= 1)
    alloc_values = 1;
  else
    alloc_values = (num_values + IPP_MAX_VALUES - 1) & (size_t)~(IPP_MAX_VALUES - 1);

  attr = calloc(1, sizeof(ipp_attribute_t) + (size_t)(alloc_values - 1) * sizeof(_ipp_value_t));

  if (attr)
  {
    // Initialize attribute...
    DEBUG_printf("4debug_alloc: %p %s %s%s (%u values)", (void *)attr, name, num_values > 1 ? "1setOf " : "", ippTagString(value_tag), (unsigned)num_values);

    if (name)
      attr->name = _cupsStrAlloc(name);

    attr->group_tag  = group_tag;
    attr->value_tag  = value_tag;
    attr->num_values = num_values;

    // Add it to the end of the linked list...
    if (ipp->last)
      ipp->last->next = attr;
    else
      ipp->attrs = attr;

    ipp->prev = ipp->last;
    ipp->last = ipp->current = attr;
  }

  DEBUG_printf("5ipp_add_attr: Returning %p", (void *)attr);

  return (attr);
}


//
// 'ipp_free_values()' - Free attribute values.
//

static void
ipp_free_values(ipp_attribute_t *attr,  // I - Attribute to free values from
                size_t          element,// I - First value to free
                size_t          count)  // I - Number of values to free
{
  size_t  i;      // Looping var
  _ipp_value_t  *value;     // Current value


  DEBUG_printf("4ipp_free_values(attr=%p, element=%u, count=%u)", (void *)attr, (unsigned)element, (unsigned)count);

  if (!(attr->value_tag & IPP_TAG_CUPS_CONST))
  {
    // Free values as needed...
    switch (attr->value_tag)
    {
      case IPP_TAG_TEXTLANG :
      case IPP_TAG_NAMELANG :
    if (element == 0 && count == attr->num_values && attr->values[0].string.language)
    {
      _cupsStrFree(attr->values[0].string.language);
      attr->values[0].string.language = NULL;
    }
    // Fall through to other string values

      case IPP_TAG_TEXT :
      case IPP_TAG_NAME :
      case IPP_TAG_RESERVED_STRING :
      case IPP_TAG_KEYWORD :
      case IPP_TAG_URI :
      case IPP_TAG_URISCHEME :
      case IPP_TAG_CHARSET :
      case IPP_TAG_LANGUAGE :
      case IPP_TAG_MIMETYPE :
    for (i = count, value = attr->values + element; i > 0; i --, value ++)
    {
      _cupsStrFree(value->string.text);
      value->string.text = NULL;
    }
    break;

      case IPP_TAG_UNSUPPORTED_VALUE :
      case IPP_TAG_DEFAULT :
      case IPP_TAG_UNKNOWN :
      case IPP_TAG_NOVALUE :
      case IPP_TAG_NOTSETTABLE :
      case IPP_TAG_DELETEATTR :
      case IPP_TAG_ADMINDEFINE :
      case IPP_TAG_INTEGER :
      case IPP_TAG_ENUM :
      case IPP_TAG_BOOLEAN :
      case IPP_TAG_DATE :
      case IPP_TAG_RESOLUTION :
      case IPP_TAG_RANGE :
    break;

      case IPP_TAG_BEGIN_COLLECTION :
    for (i = count, value = attr->values + element; i > 0; i --, value ++)
    {
      ippDelete(value->collection);
      value->collection = NULL;
    }
    break;

      case IPP_TAG_STRING :
      default :
    for (i = count, value = attr->values + element; i > 0; i --, value ++)
    {
      if (value->unknown.data)
      {
        free(value->unknown.data);
        value->unknown.data = NULL;
      }
    }
    break;
    }
  }

  // If we are not freeing values from the end, move the remaining values up...
  if ((element + count) < attr->num_values)
    memmove(attr->values + element, attr->values + element + count, (size_t)(attr->num_values - count - element) * sizeof(_ipp_value_t));

  attr->num_values -= count;
}


//
// 'ipp_get_code()' - Convert a C locale/charset name into an IPP language/charset code.
//
// This typically converts strings of the form "ll_CC", "ll-REGION", and "CHARSET_NUMBER"
// to "ll-cc", "ll-region", and "charset-number", respectively.
//

static char *       // O - Language code string
ipp_get_code(const char *value,   // I - Locale/charset string
             char       *buffer,  // I - String buffer
             size_t     bufsize)  // I - Size of string buffer
{
  char  *bufptr,      // Pointer into buffer
  *bufend;      // End of buffer


  // Convert values to lowercase and change _ to - as needed...
  for (bufptr = buffer, bufend = buffer + bufsize - 1; *value && bufptr < bufend; value ++)
  {
    if (*value == '_')
      *bufptr++ = '-';
    else
      *bufptr++ = (char)_cups_tolower(*value);
  }
  *bufptr = '\0';

  // Return the converted string...
  return (buffer);
}


//
// 'ipp_is_valid_language()' - Determine whether a language string is valid.
//

static bool       // O - `true` if valid, `false` if bad
ipp_is_valid_language(const char *name, // I - Attribute name
                      const char *lang) // I - Language string
{
  if (regexec(&lang_regex, lang, 0, NULL, 0))
  {
    ipp_set_error(IPP_STATUS_ERROR_BAD_REQUEST, _("\"%s\": Bad naturalLanguage value \"%s\" - bad characters (RFC 8011 section 5.1.9)."), name, lang);
    return (false);
  }

  if (strlen(lang) > (IPP_MAX_LANGUAGE - 1))
  {
    ipp_set_error(IPP_STATUS_ERROR_BAD_REQUEST, _("\"%s\": Bad naturalLanguage value \"%s\" - bad length %d (RFC 8011 section 5.1.9)."), name, lang, (int)strlen(lang));
    return (false);
  }

  return (true);
}


//
// 'ipp_is_valid_mimetype()' - Determine whether a MIME media type string is valid.
//

static bool       // O - `true` if valid, `false` if bad
ipp_is_valid_mimetype(const char *name, // I - Attribute name
                      const char *type) // I - mimeMediaType string
{
  if (regexec(&mime_regex, type, 0, NULL, 0))
  {
    ipp_set_error(IPP_STATUS_ERROR_BAD_REQUEST, _("\"%s\": Bad mimeMediaType value \"%s\" - bad characters (RFC 8011 section 5.1.10)."), name, type);
    return (false);
  }

  if (strlen(type) > (IPP_MAX_MIMETYPE - 1))
  {
    ipp_set_error(IPP_STATUS_ERROR_BAD_REQUEST, _("\"%s\": Bad mimeMediaType value \"%s\" - bad length %d (RFC 8011 section 5.1.10)."), name, type, (int)strlen(type));
    return (false);
  }

  return (true);
}


//
// 'ipp_lang_code()' - Convert a C locale name into an IPP language code.
//
// This typically converts strings of the form "ll_CC" and "ll-REGION" to "ll-cc" and
// "ll-region", respectively.  It also converts the "C" (POSIX) locale to "en".
//

static char *       // O - Language code string
ipp_lang_code(const char *locale, // I - Locale string
              char       *buffer, // I - String buffer
              size_t     bufsize) // I - Size of string buffer
{
  // Map POSIX ("C") locale to generic English, otherwise convert the locale string as-is.
  if (!_cups_strcasecmp(locale, "c"))
  {
    cupsCopyString(buffer, "en", bufsize);
    return (buffer);
  }
  else
  {
    return (ipp_get_code(locale, buffer, bufsize));
  }
}


//
// 'ipp_length()' - Compute the length of an IPP message or collection value.
//

static size_t       // O - Size of IPP message
ipp_length(ipp_t *ipp,      // I - IPP message or collection
           int   collection)    // I - 1 if a collection, 0 otherwise
{
  size_t    i;    // Looping var
  size_t    bytes;    // Number of bytes
  ipp_attribute_t *attr;    // Current attribute
  ipp_tag_t   group;    // Current group
  _ipp_value_t    *value;   // Current value


  DEBUG_printf("3ipp_length(ipp=%p, collection=%d)", (void *)ipp, collection);

  if (!ipp)
  {
    DEBUG_puts("4ipp_length: Returning 0 bytes");
    return (0);
  }

  // Start with 8 bytes for the IPP message header...
  bytes = collection ? 0 : 8;

  // Then add the lengths of each attribute...
  group = IPP_TAG_ZERO;

  for (attr = ipp->attrs; attr != NULL; attr = attr->next)
  {
    if (attr->group_tag != group && !collection)
    {
      group = attr->group_tag;
      if (group == IPP_TAG_ZERO)
  continue;

      bytes ++; // Group tag
    }

    if (!attr->name)
      continue;

    DEBUG_printf("5ipp_length: attr->name=\"%s\", attr->num_values=%u, bytes=" CUPS_LLFMT, attr->name, (unsigned)attr->num_values, CUPS_LLCAST bytes);

    if ((attr->value_tag & ~IPP_TAG_CUPS_CONST) < IPP_TAG_EXTENSION)
      bytes += (size_t)attr->num_values;// Value tag for each value
    else
      bytes += (size_t)(5 * attr->num_values);
          // Value tag for each value
    bytes += (size_t)(2 * attr->num_values);
          // Name lengths
    bytes += strlen(attr->name);  // Name
    bytes += (size_t)(2 * attr->num_values);
          // Value lengths

    if (collection)
      bytes += 5;     // Add membername overhead

    switch (attr->value_tag & ~IPP_TAG_CUPS_CONST)
    {
      case IPP_TAG_UNSUPPORTED_VALUE :
      case IPP_TAG_DEFAULT :
      case IPP_TAG_UNKNOWN :
      case IPP_TAG_NOVALUE :
      case IPP_TAG_NOTSETTABLE :
      case IPP_TAG_DELETEATTR :
      case IPP_TAG_ADMINDEFINE :
          break;

      case IPP_TAG_INTEGER :
      case IPP_TAG_ENUM :
          bytes += (size_t)(4 * attr->num_values);
    break;

      case IPP_TAG_BOOLEAN :
          bytes += (size_t)attr->num_values;
    break;

      case IPP_TAG_TEXT :
      case IPP_TAG_NAME :
      case IPP_TAG_KEYWORD :
      case IPP_TAG_URI :
      case IPP_TAG_URISCHEME :
      case IPP_TAG_CHARSET :
      case IPP_TAG_LANGUAGE :
      case IPP_TAG_MIMETYPE :
    for (i = 0, value = attr->values; i < attr->num_values; i ++, value ++)
    {
      if (value->string.text)
        bytes += strlen(value->string.text);
    }
    break;

      case IPP_TAG_DATE :
          bytes += (size_t)(11 * attr->num_values);
    break;

      case IPP_TAG_RESOLUTION :
          bytes += (size_t)(9 * attr->num_values);
    break;

      case IPP_TAG_RANGE :
          bytes += (size_t)(8 * attr->num_values);
    break;

      case IPP_TAG_TEXTLANG :
      case IPP_TAG_NAMELANG :
          bytes += (size_t)(4 * attr->num_values);
          // Charset + text length

    for (i = 0, value = attr->values; i < attr->num_values; i ++, value ++)
    {
      if (value->string.language)
        bytes += strlen(value->string.language);

      if (value->string.text)
        bytes += strlen(value->string.text);
    }
    break;

      case IPP_TAG_BEGIN_COLLECTION :
    for (i = 0, value = attr->values; i < attr->num_values; i ++, value ++)
            bytes += ipp_length(value->collection, 1);
    break;

      default :
    for (i = 0, value = attr->values; i < attr->num_values; i ++, value ++)
            bytes += (size_t)value->unknown.length;
    break;
    }
  }

  // Finally, add 1 byte for the "end of attributes" tag or 5 bytes for the "end of collection" tag and return...
  if (collection)
    bytes += 5;
  else
    bytes ++;

  DEBUG_printf("4ipp_length: Returning " CUPS_LLFMT " bytes", CUPS_LLCAST bytes);

  return (bytes);
}


//
// 'ipp_read_file()' - Read IPP data from a file.
//

static ssize_t        // O - Number of bytes read
ipp_read_file(int         *fd,    // I - File descriptor
              ipp_uchar_t *buffer,  // O - Read buffer
        size_t      length) // I - Number of bytes to read
{
#ifdef _WIN32
  return ((ssize_t)read(*fd, buffer, (unsigned)length));
#else
  return (read(*fd, buffer, length));
#endif // _WIN32
}


//
// 'ipp_read_http()' - Semi-blocking read on a HTTP connection...
//

static ssize_t        // O - Number of bytes read
ipp_read_http(http_t      *http,  // I - Client connection
              ipp_uchar_t *buffer,  // O - Buffer for data
        size_t      length) // I - Total length
{
  ssize_t tbytes,     // Total bytes read
    bytes;      // Bytes read this pass


  DEBUG_printf("7ipp_read_http(http=%p, buffer=%p, length=%d)", (void *)http, (void *)buffer, (int)length);

  // Loop until all bytes are read...
  for (tbytes = 0, bytes = 0; tbytes < (int)length; tbytes += bytes, buffer += bytes)
  {
    DEBUG_printf("9ipp_read_http: tbytes=" CUPS_LLFMT ", http->state=%d", CUPS_LLCAST tbytes, http->state);

    if (http->state == HTTP_STATE_WAITING)
      break;

    if (http->used == 0 && !http->blocking)
    {
      // Wait up to 10 seconds for more data on non-blocking sockets...
      if (!httpWait(http, 10000))
      {
  // Signal no data...
  bytes = -1;
  break;
      }
    }
    else if (http->used == 0 && http->timeout_value > 0)
    {
      // Wait up to timeout seconds for more data on blocking sockets...
      if (!httpWait(http, (int)(1000 * http->timeout_value)))
      {
  // Signal no data...
  bytes = -1;
  break;
      }
    }

    if ((bytes = httpRead(http, (char *)buffer, length - (size_t)tbytes)) < 0)
    {
#ifdef _WIN32
      break;
#else
      if (errno != EAGAIN && errno != EINTR)
  break;

      bytes = 0;
#endif // _WIN32
    }
    else if (bytes == 0)
    {
      break;
    }
  }

  // Return the number of bytes read...
  if (tbytes == 0 && bytes < 0)
    tbytes = -1;

  DEBUG_printf("8ipp_read_http: Returning " CUPS_LLFMT " bytes", CUPS_LLCAST tbytes);

  return (tbytes);
}


//
// 'ipp_read_io()' - Read data for an IPP message.
//

static ipp_state_t      // O - Current state
ipp_read_io(void        *src,   // I - Data source
            ipp_io_cb_t cb,   // I - Read callback function
      bool        blocking, // I - Use blocking IO?
      ipp_t       *parent,  // I - Parent request, if any
            ipp_t       *ipp,   // I - IPP data
            int         depth)    // I - Depth of collection
{
  int     n;    // Length of data
  unsigned char   *buffer,  // Data buffer
      string[IPP_MAX_TEXT],
          // Small string buffer
      *bufptr,  // Pointer into buffer
      *bufend;  // End of buffer
  ipp_attribute_t *attr = NULL; // Current attribute
  ipp_tag_t   tag;    // Current tag
  ipp_tag_t   value_tag;  // Current value tag
  _ipp_value_t    *value;   // Current value


  DEBUG_printf("ipp_read_io(src=%p, cb=%p, blocking=%d, parent=%p, ipp=%p, depth=%d)", (void *)src, (void *)cb, blocking, (void *)parent, (void *)ipp, depth);
  DEBUG_printf("2ipp_read_io: ipp->state=%d", ipp->state);

  if (depth > 10)
  {
    _cupsSetError(IPP_STATUS_ERROR_INTERNAL, _("IPP message nested too deeply."), true);
    return (IPP_STATE_ERROR);
  }

  if ((buffer = (unsigned char *)_cupsBufferGet(IPP_BUF_SIZE)) == NULL)
  {
    DEBUG_puts("1ipp_read_io: Unable to get read buffer.");
    return (IPP_STATE_ERROR);
  }

  switch (ipp->state)
  {
    case IPP_STATE_IDLE :
        ipp->state ++; // Avoid common problem...

    case IPP_STATE_HEADER :
        if (parent == NULL)
  {
          // Get the request header...
          if ((*cb)(src, buffer, 8) < 8)
    {
      DEBUG_puts("1ipp_read_io: Unable to read header.");
      goto rollback;
    }

          // Then copy the request header over...
          ipp->request.version[0]  = buffer[0];
          ipp->request.version[1]  = buffer[1];
          ipp->request.op_status   = (short)((buffer[2] << 8) | buffer[3]);
          ipp->request.request_id  = (buffer[4] << 24) | (buffer[5] << 16) | (buffer[6] << 8) | buffer[7];

          DEBUG_printf("2ipp_read_io: version=%d.%d", buffer[0], buffer[1]);
    DEBUG_printf("2ipp_read_io: op_status=%04x", ipp->request.op_status);
    DEBUG_printf("2ipp_read_io: request_id=%d", ipp->request.request_id);
        }

        ipp->state   = IPP_STATE_ATTRIBUTE;
  ipp->current = NULL;
  ipp->curtag  = IPP_TAG_ZERO;
  ipp->prev    = ipp->last;

        // If blocking is disabled, stop here...
        if (!blocking)
    break;

    case IPP_STATE_ATTRIBUTE :
        for (;;)
  {
    if ((*cb)(src, buffer, 1) < 1)
    {
      DEBUG_puts("1ipp_read_io: Callback returned EOF/error");
      goto rollback;
    }

    DEBUG_printf("2ipp_read_io: ipp->current=%p, ipp->prev=%p", (void *)ipp->current, (void *)ipp->prev);

    // Read this attribute...
          tag = (ipp_tag_t)buffer[0];

    if (tag == IPP_TAG_END)
    {
      // No more attributes left...
            DEBUG_puts("2ipp_read_io: IPP_TAG_END.");

      ipp->state = IPP_STATE_DATA;
      break;
    }
    else if (tag == IPP_TAG_ZERO || (tag == IPP_TAG_OPERATION && ipp->curtag != IPP_TAG_ZERO))
    {
      _cupsSetError(IPP_STATUS_ERROR_INTERNAL, _("Invalid group tag."), true);
      DEBUG_printf("1ipp_read_io: bad tag 0x%02x.", tag);
      goto rollback;
    }
          else if (tag < IPP_TAG_UNSUPPORTED_VALUE)
    {
      // Group tag...  Set the current group and continue...
            if (parent)
            {
        _cupsSetError(IPP_STATUS_ERROR_INTERNAL, _("Invalid group tag."), true);
        DEBUG_printf("1ipp_read_io: bad tag 0x%02x.", tag);
        goto rollback;
            }
            else if (ipp->curtag == tag)
            {
        ipp->prev = ippAddSeparator(ipp);
            }
            else if (ipp->current)
      {
        ipp->prev = ipp->current;
      }

      ipp->curtag  = tag;
      ipp->current = NULL;
      attr         = NULL;
      DEBUG_printf("2ipp_read_io: group tag=%x(%s), ipp->prev=%p", tag, ippTagString(tag), (void *)ipp->prev);
      continue;
    }

          DEBUG_printf("2ipp_read_io: value tag=%x(%s)", tag, ippTagString(tag));

    // Get the name...
          if ((*cb)(src, buffer, 2) < 2)
    {
      DEBUG_puts("1ipp_read_io: unable to read name length.");
      goto rollback;
    }

          n = (buffer[0] << 8) | buffer[1];

          if (n >= IPP_MAX_KEYWORD)
    {
      _cupsSetError(IPP_STATUS_ERROR_INTERNAL, _("IPP attribute name larger than 255 bytes."), true);
      DEBUG_printf("1ipp_read_io: bad name length %d.", n);
      goto rollback;
    }

          DEBUG_printf("2ipp_read_io: name length=%d", n);

          if (n && parent)
          {
            _cupsSetError(IPP_STATUS_ERROR_INTERNAL, _("Invalid named IPP attribute in collection."), true);
            DEBUG_puts("1ipp_read_io: bad attribute name in collection.");
      goto rollback;
          }
          else if (n == 0 && tag != IPP_TAG_MEMBERNAME && tag != IPP_TAG_END_COLLECTION)
    {
      // More values for current attribute...
            if (ipp->current == NULL)
      {
        _cupsSetError(IPP_STATUS_ERROR_INTERNAL, _("IPP attribute has no name."), true);
        DEBUG_puts("1ipp_read_io: Attribute without name and no current.");
        goto rollback;
      }

            attr      = ipp->current;
      value_tag = (ipp_tag_t)(attr->value_tag & IPP_TAG_CUPS_MASK);

      // Make sure we aren't adding a new value of a different type...
      if (value_tag == IPP_TAG_ZERO)
      {
        // Setting the value of a collection member...
        attr->value_tag = tag;
      }
      else if (value_tag == IPP_TAG_TEXTLANG || value_tag == IPP_TAG_NAMELANG || (value_tag >= IPP_TAG_TEXT && value_tag <= IPP_TAG_MIMETYPE))
            {
        // String values can sometimes come across in different forms; accept sets of differing values...
        if (tag != IPP_TAG_TEXTLANG && tag != IPP_TAG_NAMELANG && (tag < IPP_TAG_TEXT || tag > IPP_TAG_MIMETYPE) && tag != IPP_TAG_NOVALUE)
        {
    _cupsSetError(IPP_STATUS_ERROR_INTERNAL, _("IPP 1setOf attribute with incompatible value tags."), true);
    DEBUG_printf("1ipp_read_io: 1setOf value tag %x(%s) != %x(%s)", value_tag, ippTagString(value_tag), tag, ippTagString(tag));
    goto rollback;
        }

              if (value_tag != tag)
              {
                DEBUG_printf("1ipp_read_io: Converting %s attribute from %s to %s.", attr->name, ippTagString(value_tag), ippTagString(tag));
    if (!ippSetValueTag(ipp, &attr, tag))
      goto rollback;
        }
            }
      else if (value_tag == IPP_TAG_INTEGER || value_tag == IPP_TAG_RANGE)
            {
        // Integer and rangeOfInteger values can sometimes be mixed; accept sets of differing values...
        if (tag != IPP_TAG_INTEGER && tag != IPP_TAG_RANGE)
        {
    _cupsSetError(IPP_STATUS_ERROR_INTERNAL, _("IPP 1setOf attribute with incompatible value tags."), true);
    DEBUG_printf("1ipp_read_io: 1setOf value tag %x(%s) != %x(%s)", value_tag, ippTagString(value_tag), tag, ippTagString(tag));
    goto rollback;
        }

              if (value_tag == IPP_TAG_INTEGER && tag == IPP_TAG_RANGE)
              {
                // Convert integer values to rangeOfInteger values...
    DEBUG_printf("1ipp_read_io: Converting %s attribute to rangeOfInteger.", attr->name);
                ippSetValueTag(ipp, &attr, IPP_TAG_RANGE);
              }
            }
      else if (value_tag != tag)
      {
        _cupsSetError(IPP_STATUS_ERROR_INTERNAL, _("IPP 1setOf attribute with incompatible value tags."), true);
        DEBUG_printf("1ipp_read_io: value tag %x(%s) != %x(%s)", value_tag, ippTagString(value_tag), tag, ippTagString(tag));
        goto rollback;
            }

      // Finally, reallocate the attribute array as needed...
      if ((value = ipp_set_value(ipp, &attr, attr->num_values)) == NULL)
        goto rollback;
    }
    else if (tag == IPP_TAG_MEMBERNAME)
    {
      // Name must be length 0!
      if (n)
      {
        _cupsSetError(IPP_STATUS_ERROR_INTERNAL, _("IPP member name is not empty."), true);
        DEBUG_puts("1ipp_read_io: member name not empty.");
        goto rollback;
      }
      else if (!parent)
      {
        _cupsSetError(IPP_STATUS_ERROR_INTERNAL, _("IPP member attribute outside of collection."), true);
        DEBUG_puts("1ipp_read_io: member attribute outside of collection.");
        goto rollback;
      }

            if (ipp->current)
        ipp->prev = ipp->current;

      attr = ipp->current = ipp_add_attr(ipp, NULL, ipp->curtag, IPP_TAG_ZERO, 1);
      if (!attr)
      {
        _cupsSetError(IPP_STATUS_ERROR_INTERNAL, strerror(errno), false);
        DEBUG_puts("1ipp_read_io: unable to allocate attribute.");
        goto rollback;
      }

      DEBUG_printf("2ipp_read_io: membername, ipp->current=%p, ipp->prev=%p", (void *)ipp->current, (void *)ipp->prev);

      value = attr->values;
    }
    else if (tag != IPP_TAG_END_COLLECTION)
    {
      // New attribute; read the name and add it...
      if ((*cb)(src, buffer, (size_t)n) < n)
      {
        _cupsSetError(IPP_STATUS_ERROR_INTERNAL, _("Unable to read IPP attribute name."), true);
        DEBUG_puts("1ipp_read_io: unable to read name.");
        goto rollback;
      }

      buffer[n] = '\0';

            if (ipp->current)
        ipp->prev = ipp->current;

      if ((attr = ipp->current = ipp_add_attr(ipp, (char *)buffer, ipp->curtag, tag, 1)) == NULL)
      {
        _cupsSetError(IPP_STATUS_ERROR_INTERNAL, strerror(errno), false);
        DEBUG_puts("1ipp_read_io: unable to allocate attribute.");
        goto rollback;
      }

      DEBUG_printf("2ipp_read_io: name=\"%s\", ipp->current=%p, ipp->prev=%p", buffer, (void *)ipp->current, (void *)ipp->prev);

      value = attr->values;
    }
    else
    {
      attr  = NULL;
      value = NULL;
    }

    if ((*cb)(src, buffer, 2) < 2)
    {
      DEBUG_puts("1ipp_read_io: unable to read value length.");
      goto rollback;
    }

    n = (buffer[0] << 8) | buffer[1];
          DEBUG_printf("2ipp_read_io: value length=%d", n);

    if (n >= IPP_BUF_SIZE)
    {
      _cupsSetError(IPP_STATUS_ERROR_INTERNAL,
        _("IPP value larger than 32767 bytes."), true);
      DEBUG_printf("1ipp_read_io: bad value length %d.", n);
      goto rollback;
    }

    switch (tag)
    {
      case IPP_TAG_INTEGER :
      case IPP_TAG_ENUM :
    if (n != 4)
    {
      if (tag == IPP_TAG_INTEGER)
        _cupsSetError(IPP_STATUS_ERROR_INTERNAL, _("IPP integer value not 4 bytes."), true);
      else
        _cupsSetError(IPP_STATUS_ERROR_INTERNAL, _("IPP enum value not 4 bytes."), true);
      DEBUG_printf("1ipp_read_io: bad integer value length %d.", n);
      goto rollback;
    }

          if ((*cb)(src, buffer, 4) < 4)
    {
            DEBUG_puts("1ipp_read_io: Unable to read integer value.");
      goto rollback;
    }

    n = (buffer[0] << 24) | (buffer[1] << 16) | (buffer[2] << 8) | buffer[3];

                if (attr->value_tag == IPP_TAG_RANGE)
                  value->range.lower = value->range.upper = n;
                else
      value->integer = n;
          break;

      case IPP_TAG_BOOLEAN :
    if (n != 1)
    {
      _cupsSetError(IPP_STATUS_ERROR_INTERNAL, _("IPP boolean value not 1 byte."),
                    1);
      DEBUG_printf("1ipp_read_io: bad boolean value length %d.", n);
      goto rollback;
    }

          if ((*cb)(src, buffer, 1) < 1)
    {
            DEBUG_puts("1ipp_read_io: Unable to read boolean value.");
      goto rollback;
    }

                value->boolean = (char)buffer[0];
          break;

      case IPP_TAG_UNSUPPORTED_VALUE :
      case IPP_TAG_DEFAULT :
      case IPP_TAG_UNKNOWN :
      case IPP_TAG_NOVALUE :
      case IPP_TAG_NOTSETTABLE :
      case IPP_TAG_DELETEATTR :
      case IPP_TAG_ADMINDEFINE :
          // These value types are not supposed to have values, however
    // some vendors (Brother) do not implement IPP correctly and so
    // we need to map non-empty values to text...
          if (attr->value_tag == tag)
    {
      if (n == 0)
        break;

      attr->value_tag = IPP_TAG_TEXT;
    }

      case IPP_TAG_TEXT :
      case IPP_TAG_NAME :
      case IPP_TAG_RESERVED_STRING :
      case IPP_TAG_KEYWORD :
      case IPP_TAG_URI :
      case IPP_TAG_URISCHEME :
      case IPP_TAG_CHARSET :
      case IPP_TAG_LANGUAGE :
      case IPP_TAG_MIMETYPE :
          if (n > 0)
          {
      if ((*cb)(src, buffer, (size_t)n) < n)
      {
        DEBUG_puts("1ipp_read_io: unable to read string value.");
        goto rollback;
      }
    }

    buffer[n] = '\0';
    value->string.text = _cupsStrAlloc((char *)buffer);
    DEBUG_printf("2ipp_read_io: value=\"%s\"(%p)", value->string.text, value->string.text);
          break;

      case IPP_TAG_DATE :
    if (n != 11)
    {
      _cupsSetError(IPP_STATUS_ERROR_INTERNAL, _("IPP date value not 11 bytes."), true);
      DEBUG_printf("1ipp_read_io: bad date value length %d.", n);
      goto rollback;
    }

          if ((*cb)(src, value->date, 11) < 11)
    {
            DEBUG_puts("1ipp_read_io: Unable to read date value.");
      goto rollback;
    }
          break;

      case IPP_TAG_RESOLUTION :
    if (n != 9)
    {
      _cupsSetError(IPP_STATUS_ERROR_INTERNAL, _("IPP resolution value not 9 bytes."), true);
      DEBUG_printf("1ipp_read_io: bad resolution value length %d.", n);
      goto rollback;
    }

          if ((*cb)(src, buffer, 9) < 9)
    {
            DEBUG_puts("1ipp_read_io: Unable to read resolution value.");
      goto rollback;
    }

                value->resolution.xres  = (buffer[0] << 24) | (buffer[1] << 16) | (buffer[2] << 8) | buffer[3];
                value->resolution.yres  = (buffer[4] << 24) | (buffer[5] << 16) | (buffer[6] << 8) | buffer[7];
                value->resolution.units =
        (ipp_res_t)buffer[8];
          break;

      case IPP_TAG_RANGE :
    if (n != 8)
    {
      _cupsSetError(IPP_STATUS_ERROR_INTERNAL, _("IPP rangeOfInteger value not 8 bytes."), true);
      DEBUG_printf("1ipp_read_io: bad rangeOfInteger value length %d.", n);
      goto rollback;
    }

          if ((*cb)(src, buffer, 8) < 8)
    {
            DEBUG_puts("1ipp_read_io: Unable to read range value.");
      goto rollback;
    }

                value->range.lower = (buffer[0] << 24) | (buffer[1] << 16) | (buffer[2] << 8) | buffer[3];
                value->range.upper = (buffer[4] << 24) | (buffer[5] << 16) | (buffer[6] << 8) | buffer[7];
          break;

      case IPP_TAG_TEXTLANG :
      case IPP_TAG_NAMELANG :
          if (n < 4)
    {
      if (tag == IPP_TAG_TEXTLANG)
        _cupsSetError(IPP_STATUS_ERROR_INTERNAL, _("IPP textWithLanguage value less than minimum 4 bytes."), true);
      else
        _cupsSetError(IPP_STATUS_ERROR_INTERNAL, _("IPP nameWithLanguage value less than minimum 4 bytes."), true);
      DEBUG_printf("1ipp_read_io: bad stringWithLanguage value length %d.", n);
      goto rollback;
    }

          if ((*cb)(src, buffer, (size_t)n) < n)
    {
            DEBUG_puts("1ipp_read_io: Unable to read string w/language value.");
      goto rollback;
    }

                bufptr = buffer;
                bufend = buffer + n;

          // textWithLanguage and nameWithLanguage are composite values:
    //
    //   language-length
    //   language
    //   text-length
    //   text
    n = (bufptr[0] << 8) | bufptr[1];

    if ((bufptr + 2 + n + 2) > bufend || n >= (int)sizeof(string))
    {
      _cupsSetError(IPP_STATUS_ERROR_INTERNAL, _("IPP language length overflows value."), true);
      DEBUG_printf("1ipp_read_io: bad language value length %d.", n);
      goto rollback;
    }
    else if (n >= IPP_MAX_LANGUAGE)
    {
      _cupsSetError(IPP_STATUS_ERROR_INTERNAL, _("IPP language length too large."), true);
      DEBUG_printf("1ipp_read_io: bad language value length %d.", n);
      goto rollback;
    }

    memcpy(string, bufptr + 2, (size_t)n);
    string[n] = '\0';

    value->string.language = _cupsStrAlloc((char *)string);

                bufptr += 2 + n;
    n = (bufptr[0] << 8) | bufptr[1];

    if ((bufptr + 2 + n) > bufend)
    {
      _cupsSetError(IPP_STATUS_ERROR_INTERNAL, _("IPP string length overflows value."), true);
      DEBUG_printf("1ipp_read_io: bad string value length %d.", n);
      goto rollback;
    }

    bufptr[2 + n] = '\0';
                value->string.text = _cupsStrAlloc((char *)bufptr + 2);
          break;

            case IPP_TAG_BEGIN_COLLECTION :
          // Oh boy, here comes a collection value, so read it...
                value->collection = ippNew();

                if (n > 0)
    {
      _cupsSetError(IPP_STATUS_ERROR_INTERNAL, _("IPP begCollection value not 0 bytes."), true);
            DEBUG_puts("1ipp_read_io: begCollection tag with value length > 0.");
      goto rollback;
    }

    if (ipp_read_io(src, cb, 1, ipp, value->collection, depth + 1) == IPP_STATE_ERROR)
    {
            DEBUG_puts("1ipp_read_io: Unable to read collection value.");
      goto rollback;
    }
                break;

            case IPP_TAG_END_COLLECTION :
                if (n > 0)
    {
      _cupsSetError(IPP_STATUS_ERROR_INTERNAL, _("IPP endCollection value not 0 bytes."), true);
            DEBUG_puts("1ipp_read_io: endCollection tag with value length > 0.");
      goto rollback;
    }

    _cupsBufferRelease((char *)buffer);

          DEBUG_puts("1ipp_read_io: endCollection tag...");
    return (ipp->state = IPP_STATE_DATA);

            case IPP_TAG_MEMBERNAME :
          // The value is the name of the member in the collection, which
    // we need to carry over...
    if (n == 0)
    {
      _cupsSetError(IPP_STATUS_ERROR_INTERNAL, _("IPP memberName value is empty."), true);
            DEBUG_puts("1ipp_read_io: Empty member name value.");
      goto rollback;
    }
    else if (n >= IPP_MAX_KEYWORD)
    {
      _cupsSetError(IPP_STATUS_ERROR_INTERNAL, _("IPP memberName larger than 255 bytes."), true);
            DEBUG_puts("1ipp_read_io: Member name too large.");
      goto rollback;
    }
    else if ((*cb)(src, buffer, (size_t)n) < n)
    {
            DEBUG_puts("1ipp_read_io: Unable to read member name value.");
      goto rollback;
    }

    buffer[n] = '\0';
    attr->name = _cupsStrAlloc((char *)buffer);

          // Since collection members are encoded differently than
    // regular attributes, make sure we don't start with an
    // empty value...
                attr->num_values --;

    DEBUG_printf("2ipp_read_io: member name=\"%s\"", attr->name);
    break;

            case IPP_TAG_STRING :
            default : // Other unsupported values
                if (tag == IPP_TAG_STRING && n > IPP_MAX_LENGTH)
    {
      _cupsSetError(IPP_STATUS_ERROR_INTERNAL, _("IPP octetString length too large."), true);
      DEBUG_printf("1ipp_read_io: bad octetString value length %d.", n);
      goto rollback;
    }

                value->unknown.length = (size_t)n;

          if (n > 0)
    {
      if ((value->unknown.data = malloc((size_t)n)) == NULL)
      {
        _cupsSetError(IPP_STATUS_ERROR_INTERNAL, strerror(errno), false);
        DEBUG_puts("1ipp_read_io: Unable to allocate value");
        goto rollback;
      }

            if ((*cb)(src, value->unknown.data, (size_t)n) < n)
      {
              DEBUG_puts("1ipp_read_io: Unable to read unsupported value.");
        goto rollback;
      }
    }
    else
    {
      value->unknown.data = NULL;
    }
          break;
    }

          // If blocking is disabled, stop here...
          if (!blocking)
      break;
  }
        break;

    case IPP_STATE_DATA :
        break;

    default :
        break; // anti-compiler-warning-code
  }

  DEBUG_printf("1ipp_read_io: returning ipp->state=%d.", ipp->state);
  _cupsBufferRelease((char *)buffer);

  return (ipp->state);

  // If we get here, there was an error that required us to roll back the last
  // attribute read in order to keep the IPP message valid...
  rollback:

  DEBUG_puts("1ipp_read_io: <<rollback>>");

  _cupsBufferRelease((char *)buffer);

  if (attr)
    ippDeleteAttribute(ipp, attr);

  return (IPP_STATE_ERROR);
}


//
// 'ipp_regex_begin()' - Start using validation regular expressions.
//

static bool       // O - `true` on success, `false` on failure
ipp_regex_begin(void)
{
  int   r;      // regcomp() error code


  // Take a lock...
  cupsMutexLock(&regex_mutex);

  // If the regular expressions have not been initialized, do so now...
  if (!regex_init)
  {
    regex_init = true;

    // The following regular expression is derived from the ABNF for
    // language tags in RFC 4646.  All I can say is that this is the
    // easiest way to check the values...
    if ((r = regcomp(&lang_regex,
         "^("
         "(([a-z]{2,3}(-[a-z][a-z][a-z]){0,3})|[a-z]{4,8})"
              // language
         "(-[a-z][a-z][a-z][a-z]){0,1}" // script
         "(-([a-z][a-z]|[0-9][0-9][0-9])){0,1}"
              // region
         "(-([a-z]{5,8}|[0-9][0-9][0-9]))*" // variant
         "(-[a-wy-z](-[a-z0-9]{2,8})+)*"  // extension
         "(-x(-[a-z0-9]{1,8})+)*"   // privateuse
         "|"
         "x(-[a-z0-9]{1,8})+"   // privateuse
         "|"
         "[a-z]{1,3}(-[a-z][0-9]{2,8}){1,2}"// grandfathered
         ")$",
         REG_NOSUB | REG_EXTENDED)) != 0)
    {
      char  temp[256];    // Temporary error string

      regerror(r, &lang_regex, temp, sizeof(temp));
      ipp_set_error(IPP_STATUS_ERROR_INTERNAL, _("Unable to compile naturalLanguage regular expression: %s."), temp);
      cupsMutexUnlock(&regex_mutex);
      return (false);
    }


    // The following regular expression is derived from the ABNF for
    // MIME media types in RFC 2045 and 4288.  All I can say is that this is
    // the easiest way to check the values...
    if ((r = regcomp(&mime_regex,
         "^"
         "[-a-zA-Z0-9!#$&.+^_]{1,127}"  // type-name
         "/"
         "[-a-zA-Z0-9!#$&.+^_]{1,127}"  // subtype-name
         "(;[-a-zA-Z0-9!#$&.+^_]{1,127}=" // argument=
         "([-a-zA-Z0-9!#$&.+^_]{1,127}|\"[^\"]*\"))*"
              // value
         "$",
         REG_NOSUB | REG_EXTENDED)) != 0)
    {
      char  temp[256];    // Temporary error string

      regerror(r, &mime_regex, temp, sizeof(temp));
      ipp_set_error(IPP_STATUS_ERROR_BAD_REQUEST, _("Unable to compile mimeMediaType regular expression: %s."), temp);
      cupsMutexUnlock(&regex_mutex);
      return (false);
    }
  }

  return (true);
}


//
// 'ipp_regex_end()' - Finish using validation regular expressions.
//

static void
ipp_regex_end(void)
{
  cupsMutexUnlock(&regex_mutex);
}


//
// 'ipp_set_error()' - Set a formatted, localized error string.
//

static void
ipp_set_error(ipp_status_t status,  // I - Status code
              const char   *format, // I - Printf-style error string
        ...)      // I - Additional arguments as needed
{
  va_list ap;     // Pointer to additional args
  char    buffer[2048];   // Message buffer
  cups_lang_t *lang = cupsLangDefault();
          // Current language


  va_start(ap, format);
  vsnprintf(buffer, sizeof(buffer), cupsLangGetString(lang, format), ap);
  va_end(ap);

  _cupsSetError(status, buffer, 0);
}


//
// 'ipp_set_value()' - Get the value element from an attribute, expanding it as
//                     needed.
//

static _ipp_value_t *     // O  - IPP value element or NULL on error
ipp_set_value(ipp_t           *ipp, // IO - IPP message
              ipp_attribute_t **attr, // IO - IPP attribute
              size_t          element)  // I  - Value number (`0`-based)
{
  ipp_attribute_t *temp,    // New attribute pointer
      *current, // Current attribute in list
      *prev;    // Previous attribute in list
  size_t    alloc_values; // Allocated values


  // If we are setting an existing value element, return it...
  temp = *attr;

  if (temp->num_values <= 1)
    alloc_values = 1;
  else
    alloc_values = (temp->num_values + IPP_MAX_VALUES - 1) & (size_t)~(IPP_MAX_VALUES - 1);

  if (element < alloc_values)
  {
    if (element >= temp->num_values)
      temp->num_values = element + 1;

    return (temp->values + element);
  }

  // Otherwise re-allocate the attribute - we allocate in groups of
  // IPP_MAX_VALUE values when num_values > 1.
  if (alloc_values < IPP_MAX_VALUES)
    alloc_values = IPP_MAX_VALUES;
  else
    alloc_values += IPP_MAX_VALUES;

  DEBUG_printf("4ipp_set_value: Reallocating for up to %u values.", (unsigned)alloc_values);

  // Reallocate memory...
  if ((temp = realloc(temp, sizeof(ipp_attribute_t) + (size_t)(alloc_values - 1) * sizeof(_ipp_value_t))) == NULL)
  {
    _cupsSetError(IPP_STATUS_ERROR_INTERNAL, strerror(errno), false);
    DEBUG_puts("4ipp_set_value: Unable to resize attribute.");
    return (NULL);
  }

  // Zero the new memory...
  memset(temp->values + temp->num_values, 0, (size_t)(alloc_values - temp->num_values) * sizeof(_ipp_value_t));

  if (temp != *attr)
  {
    // Reset pointers in the list...
#ifndef __clang_analyzer__
    DEBUG_printf("4debug_free: %p %s", (void *)*attr, temp->name);
#endif // !__clang_analyzer__
    DEBUG_printf("4debug_alloc: %p %s %s%s (%u)", (void *)temp, temp->name, temp->num_values > 1 ? "1setOf " : "", ippTagString(temp->value_tag), (unsigned)temp->num_values);

    if (ipp->current == *attr && ipp->prev && ipp->prev->next == *attr)
    {
      // Use current "previous" pointer...
      prev = ipp->prev;
    }
    else
    {
      // Find this attribute in the linked list...
      for (prev = NULL, current = ipp->attrs; current && current != *attr; prev = current, current = current->next)
        ;        // Loop until we find the attribute

      if (!current)
      {
  // This is a serious error!
  *attr = temp;
  _cupsSetError(IPP_STATUS_ERROR_INTERNAL, _("IPP attribute is not a member of the message."), true);
  DEBUG_puts("4ipp_set_value: Unable to find attribute in message.");
  return (NULL);
      }
    }

    if (prev)
      prev->next = temp;
    else
      ipp->attrs = temp;

    ipp->current = temp;
    ipp->prev    = prev;

    if (ipp->last == *attr)
      ipp->last = temp;

    *attr = temp;
  }

  // Return the value element...
  if (element >= temp->num_values)
    temp->num_values = element + 1;

  return (temp->values + element);
}


//
// 'ipp_write_file()' - Write IPP data to a file.
//

static ssize_t        // O - Number of bytes written
ipp_write_file(int         *fd,   // I - File descriptor
               ipp_uchar_t *buffer, // I - Data to write
               size_t      length)  // I - Number of bytes to write
{
#ifdef _WIN32
  return ((ssize_t)write(*fd, buffer, (unsigned)length));
#else
  return (write(*fd, buffer, length));
#endif // _WIN32
}

Coverage Report

Created: 2026-09-14 07:07