/*

 * No copyright is claimed.  This code is in the public domain; do with

 * it what you wish.

 */

#ifndef UTIL_LINUX_BUFFER

#define UTIL_LINUX_BUFFER

#include <stddef.h>

#include <stdarg.h>

/*

 * The data is always zero-terminated at END, and the space between END and

 * BEGIN + SZ is kept zeroed; ul_buffer_alloc_data() zero-fills the newly

 * allocated space and the append functions always terminate the data.

 *

 * Keep this invariant in mind when adding a new ul_buffer_*() function,

 * ul_buffer_reset_data() depends on it to avoid clearing the whole

 * allocation.

 */

struct ul_buffer {

  char *begin;    /* begin of the data */

  char *end;    /* current end of data */

  size_t sz;    /* allocated space for data */

  size_t chunksize;

  char *encoded;    /* encoded data (from mbs_safe_encode_to_buffer)) */

  size_t encoded_sz;  /* space allocated for encoded data */

  size_t *ptrs;   /* saved positions; offset from BEGIN plus 1, zero means unset */

  size_t nptrs;   /* number of saved positions */

};

#define UL_INIT_BUFFER { .begin = NULL }

void ul_buffer_reset_data(struct ul_buffer *buf);

void ul_buffer_free_data(struct ul_buffer *buf);

/*

 * This is a variant of ul_buffer_free_data(). Instead of freeing the

 * BEGIN member, this function transfers its ownership to the caller.

 *

 * If the BEGIN member points to an empty C string,

 * ul_buffer_steal_string() frees the buffer and returns NULL.

 */

char *ul_buffer_steal_string(struct ul_buffer *buf);

int ul_buffer_is_empty(struct ul_buffer *buf);

void ul_buffer_set_chunksize(struct ul_buffer *buf, size_t sz);

void ul_buffer_refer_string(struct ul_buffer *buf, char *str);

int ul_buffer_alloc_data(struct ul_buffer *buf, size_t sz);

int ul_buffer_append_data(struct ul_buffer *buf, const char *data, size_t sz);

int ul_buffer_append_char(struct ul_buffer *buf, const char c);

int ul_buffer_append_string(struct ul_buffer *buf, const char *str);

int ul_buffer_append_ntimes(struct ul_buffer *buf, size_t n, const char *str);

int ul_buffer_appendf(struct ul_buffer *buf, const char *format, ...)

  __attribute__ ((__format__ (__printf__, 2, 3)));

int ul_buffer_appendvf(struct ul_buffer *buf, const char *format, va_list ap)

  __attribute__ ((__format__ (__printf__, 2, 0)));

int ul_buffer_set_data(struct ul_buffer *buf, const char *data, size_t sz);

char *ul_buffer_get_data(struct ul_buffer *buf,  size_t *sz, size_t *width);

char *ul_buffer_get_string(struct ul_buffer *buf,  size_t *sz, size_t *width);

char *ul_buffer_get_safe_data(struct ul_buffer *buf, size_t *sz, size_t *width, const char *safechars);

size_t ul_buffer_get_bufsiz(struct ul_buffer *buf);

size_t ul_buffer_get_datasiz(struct ul_buffer *buf);

int ul_buffer_save_pointer(struct ul_buffer *buf, unsigned short ptr_idx);

char *ul_buffer_get_pointer(struct ul_buffer *buf, unsigned short  ptr_idx);

size_t ul_buffer_get_pointer_length(struct ul_buffer *buf, unsigned short ptr_idx);

size_t ul_buffer_get_safe_pointer_width(struct ul_buffer *buf, unsigned short ptr_idx);

/*

 * Include xalloc.h first to use the buffer_x*() functions.

 */

#ifdef XALLOC_EXIT_CODE

static inline int ul_buffer_xappend_string(struct ul_buffer *buf, const char *str)

{

  int r = ul_buffer_append_string(buf, str);

  if (r < 0)

    err(XALLOC_EXIT_CODE, "cannot allocate buffer");

  return r;

}

static inline int ul_buffer_xappend_char(struct ul_buffer *buf, const char c)

{

  int r = ul_buffer_append_char(buf, c);

  if (r < 0)

    err(XALLOC_EXIT_CODE, "cannot allocate buffer");

  return r;

}

static inline

__attribute__ ((__format__ (__printf__, 2, 0)))

int ul_buffer_xappendvf(struct ul_buffer *buf, const char *format, va_list ap)

{

  int r = ul_buffer_appendvf(buf, format, ap);

  if (r < 0)

    err(XALLOC_EXIT_CODE, "cannot allocate buffer");

  return r;

}

static inline

__attribute__ ((__format__ (__printf__, 2, 3)))

int ul_buffer_xappendf(struct ul_buffer *buf, const char *format, ...)

{

  va_list ap;

  int res;

  va_start(ap, format);

  res = ul_buffer_xappendvf(buf, format, ap);

  va_end(ap);

  return res;

}

#endif/* XALLOC_EXIT_CODE */

#endif /* UTIL_LINUX_BUFFER */