/* -*- Mode: c; c-basic-offset: 4; indent-tabs-mode: t; tab-width: 8; -*- */

/* cairo - a vector graphics library with display and print output

 *

 * The code in this file is derived from GLib's gutf8.c and

 *   ultimately from libunicode. It is relicensed under the

 *   dual LGPL/MPL with permission of the original authors.

 *

 * Copyright © 1999 Tom Tromey

 * Copyright © 2005 Red Hat, Inc

 *

 * This library is free software; you can redistribute it and/or

 * modify it either under the terms of the GNU Lesser General Public

 * License version 2.1 as published by the Free Software Foundation

 * (the "LGPL") or, at your option, under the terms of the Mozilla

 * Public License Version 1.1 (the "MPL"). If you do not alter this

 * notice, a recipient may use your version of this file under either

 * the MPL or the LGPL.

 *

 * You should have received a copy of the LGPL along with this library

 * in the file COPYING-LGPL-2.1; if not, write to the Free Software

 * Foundation, Inc., 51 Franklin Street, Suite 500, Boston, MA 02110-1335, USA

 * You should have received a copy of the MPL along with this library

 * in the file COPYING-MPL-1.1

 *

 * The contents of this file are subject to the Mozilla Public License

 * Version 1.1 (the "License"); you may not use this file except in

 * compliance with the License. You may obtain a copy of the License at

 * http://www.mozilla.org/MPL/

 *

 * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY

 * OF ANY KIND, either express or implied. See the LGPL or the MPL for

 * the specific language governing rights and limitations.

 *

 * The Original Code is the cairo graphics library.

 *

 * The Initial Developer of the Original Code is Tom Tromey.

 *  and Red Hat, Inc.

 *

 * Contributor(s):

 *  Owen Taylor <otaylor@redhat.com>

 */

#include "cairoint.h"

#include "cairo-error-private.h"

#define UTF8_COMPUTE(Char, Mask, Len)               \

  if (Char < 128)                   \

    {                       \

      Len = 1;                      \

      Mask = 0x7f;                    \

    }                        \

  else if ((Char & 0xe0) == 0xc0)               \

    {                       \

      Len = 2;                      \

      Mask = 0x1f;                    \

    }                        \

  else if ((Char & 0xf0) == 0xe0)               \

    {                       \

      Len = 3;                      \

      Mask = 0x0f;                    \

    }                        \

  else if ((Char & 0xf8) == 0xf0)               \

    {                       \

      Len = 4;                      \

      Mask = 0x07;                    \

    }                        \

  else if ((Char & 0xfc) == 0xf8)               \

    {                       \

      Len = 5;                      \

      Mask = 0x03;                    \

    }                        \

  else if ((Char & 0xfe) == 0xfc)               \

    {                       \

      Len = 6;                      \

      Mask = 0x01;                    \

    }                        \

  else                        \

    Len = -1;

#define UTF8_LENGTH(Char)              \

  ((Char) < 0x80 ? 1 :                 \

   ((Char) < 0x800 ? 2 :               \

    ((Char) < 0x10000 ? 3 :            \

     ((Char) < 0x200000 ? 4 :          \

      ((Char) < 0x4000000 ? 5 : 6)))))

#define UTF8_GET(Result, Chars, Count, Mask, Len)           \

  (Result) = (Chars)[0] & (Mask);               \

  for ((Count) = 1; (Count) < (Len); ++(Count))             \

    {                       \

      if (((Chars)[(Count)] & 0xc0) != 0x80)             \

  {                     \

    (Result) = -1;                  \

    break;                    \

  }                      \

      (Result) <<= 6;                   \

      (Result) |= ((Chars)[(Count)] & 0x3f);              \

    }

#define UNICODE_VALID(Char)                   \

    ((Char) < 0x110000 &&                     \

     (((Char) & 0xFFFFF800) != 0xD800) &&     \

     ((Char) < 0xFDD0 || (Char) > 0xFDEF) &&  \

     ((Char) & 0xFFFE) != 0xFFFE)

static const char utf8_skip_data[256] = {

    1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,

    1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,

    1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,

    1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,

    1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,

    1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,

    2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,

    3,3,3,3,3,3,3,3,3,3,3,3,3,3,3,3,4,4,4,4,4,4,4,4,5,5,5,5,6,6,1,1

};

#define UTF8_NEXT_CHAR(p) ((p) + utf8_skip_data[*(unsigned char *)(p)])

/* Converts a sequence of bytes encoded as UTF-8 to a Unicode character.

 * If @p does not point to a valid UTF-8 encoded character, results are

 * undefined.

 **/

static uint32_t

_utf8_get_char (const unsigned char *p)

{

    int i, mask = 0, len;

    uint32_t result;

    unsigned char c = (unsigned char) *p;

    UTF8_COMPUTE (c, mask, len);

    if (len == -1)

  return (uint32_t)-1;

    UTF8_GET (result, p, i, mask, len);

    return result;

}

/* Like _utf8_get_char, but take a maximum length

 * and return (uint32_t)-2 on incomplete trailing character

 */

static uint32_t

_utf8_get_char_extended (const unsigned char *p,

       long         max_len)

{

    int i, len;

    uint32_t wc = (unsigned char) *p;

    if (wc < 0x80) {

  return wc;

    } else if (wc < 0xc0) {

  return (uint32_t)-1;

    } else if (wc < 0xe0) {

  len = 2;

  wc &= 0x1f;

    } else if (wc < 0xf0) {

  len = 3;

  wc &= 0x0f;

    } else if (wc < 0xf8) {

  len = 4;

  wc &= 0x07;

    } else if (wc < 0xfc) {

  len = 5;

  wc &= 0x03;

    } else if (wc < 0xfe) {

  len = 6;

  wc &= 0x01;

    } else {

  return (uint32_t)-1;

    }

    if (max_len >= 0 && len > max_len) {

  for (i = 1; i < max_len; i++) {

      if ((((unsigned char *)p)[i] & 0xc0) != 0x80)

    return (uint32_t)-1;

  }

  return (uint32_t)-2;

    }

    for (i = 1; i < len; ++i) {

  uint32_t ch = ((unsigned char *)p)[i];

  if ((ch & 0xc0) != 0x80) {

      if (ch)

    return (uint32_t)-1;

      else

    return (uint32_t)-2;

  }

  wc <<= 6;

  wc |= (ch & 0x3f);

    }

    if (UTF8_LENGTH(wc) != len)

  return (uint32_t)-1;

    return wc;

}

/**

 * _cairo_utf8_get_char_validated:

 * @p: a UTF-8 string

 * @unicode: location to store one Unicode character

 *

 * Decodes the first character of a valid UTF-8 string, and returns

 * the number of bytes consumed.

 *

 * Note that the string should be valid.  Do not use this without

 * validating the string first.

 *

 * Returns: the number of bytes forming the character returned.

 **/

int

_cairo_utf8_get_char_validated (const char *p,

        uint32_t   *unicode)

{

    int i, mask = 0, len;

    uint32_t result;

    unsigned char c = (unsigned char) *p;

    UTF8_COMPUTE (c, mask, len);

    if (len == -1) {

  if (unicode)

      *unicode = (uint32_t)-1;

  return 1;

    }

    UTF8_GET (result, p, i, mask, len);

    if (unicode)

  *unicode = result;

    return len;

}

/**

 * _cairo_utf8_to_ucs4:

 * @str: an UTF-8 string

 * @len: length of @str in bytes, or -1 if it is nul-terminated.

 *   If @len is supplied and the string has an embedded nul

 *   byte, only the portion before the nul byte is converted.

 * @result: location to store a pointer to a newly allocated UTF-32

 *   string (always native endian), or %NULL. Free with free(). A 0

 *   word will be written after the last character.

 * @items_written: location to store number of 32-bit words

 *   written. (Not including the trailing 0)

 *

 * Converts a UTF-8 string to UCS-4. UCS-4 is an encoding of Unicode

 * with 1 32-bit word per character. The string is validated to

 * consist entirely of valid Unicode characters.

 *

 * Return value: %CAIRO_STATUS_SUCCESS if the entire string was

 *   successfully converted. %CAIRO_STATUS_INVALID_STRING if an

 *   invalid sequence was found.

 **/

cairo_status_t

_cairo_utf8_to_ucs4 (const char *str,

         int   len,

         uint32_t  **result,

         int  *items_written)

{

    uint32_t *str32 = NULL;

    int n_chars, i;

    const unsigned char *in;

    const unsigned char * const ustr = (const unsigned char *) str;

    in = ustr;

    n_chars = 0;

    while ((len < 0 || ustr + len - in > 0) && *in)

    {

  uint32_t wc = _utf8_get_char_extended (in, ustr + len - in);

  if (wc & 0x80000000 || !UNICODE_VALID (wc))

      return _cairo_error (CAIRO_STATUS_INVALID_STRING);

  n_chars++;

  if (n_chars == INT_MAX)

      return _cairo_error (CAIRO_STATUS_INVALID_STRING);

  in = UTF8_NEXT_CHAR (in);

    }

    if (result) {

  str32 = _cairo_malloc_ab (n_chars + 1, sizeof (uint32_t));

  if (!str32)

      return _cairo_error (CAIRO_STATUS_NO_MEMORY);

  in = ustr;

  for (i=0; i < n_chars; i++) {

      str32[i] = _utf8_get_char (in);

      in = UTF8_NEXT_CHAR (in);

  }

  str32[i] = 0;

  *result = str32;

    }

    if (items_written)

  *items_written = n_chars;

    return CAIRO_STATUS_SUCCESS;

}

/**

 * _cairo_ucs4_to_utf8:

 * @unicode: a UCS-4 character

 * @utf8: buffer to write utf8 string into. Must have at least 4 bytes

 * space available. Or %NULL.

 *

 * This space left intentionally blank.

 *

 * Return value: Number of bytes in the utf8 string or 0 if an invalid

 * unicode character

 **/

int

_cairo_ucs4_to_utf8 (uint32_t  unicode,

         char     *utf8)

{

    int bytes;

    char *p;

    if (unicode < 0x80) {

  if (utf8)

      *utf8 = unicode;

  return 1;

    } else if (unicode < 0x800) {

  bytes = 2;

    } else if (unicode < 0x10000) {

  bytes = 3;

    } else if (unicode < 0x200000) {

  bytes = 4;

    } else {

  return 0;

    }

    if (!utf8)

  return bytes;

    p = utf8 + bytes;

    while (p > utf8) {

  *--p = 0x80 | (unicode & 0x3f);

  unicode >>= 6;

    }

    *p |= 0xf0 << (4 - bytes);

    return bytes;

}

/**

 * _cairo_ucs4_to_utf16:

 * @unicode: a UCS-4 character

 * @utf16: buffer to write utf16 string into. Must have at least 2

 * elements. Or %NULL.

 *

 * This space left intentionally blank.

 *

 * Return value: Number of elements in the utf16 string or 0 if an

 * invalid unicode character

 **/

int

_cairo_ucs4_to_utf16 (uint32_t  unicode,

          uint16_t *utf16)

{

    if (unicode < 0x10000) {

  if (utf16)

      utf16[0] = unicode;

  return 1;

    } else if (unicode < 0x110000) {

  if (utf16) {

      utf16[0] = (unicode - 0x10000) / 0x400 + 0xd800;

      utf16[1] = (unicode - 0x10000) % 0x400 + 0xdc00;

  }

  return 2;

    } else {

  return 0;

    }

}

#if CAIRO_HAS_UTF8_TO_UTF16

/**

 * _cairo_utf8_to_utf16:

 * @str: an UTF-8 string

 * @len: length of @str in bytes, or -1 if it is nul-terminated.

 *   If @len is supplied and the string has an embedded nul

 *   byte, only the portion before the nul byte is converted.

 * @result: location to store a pointer to a newly allocated UTF-16

 *   string (always native endian). Free with free(). A 0

 *   word will be written after the last character.

 * @items_written: location to store number of 16-bit words

 *   written. (Not including the trailing 0)

 *

 * Converts a UTF-8 string to UTF-16. UTF-16 is an encoding of Unicode

 * where characters are represented either as a single 16-bit word, or

 * as a pair of 16-bit "surrogates". The string is validated to

 * consist entirely of valid Unicode characters.

 *

 * Return value: %CAIRO_STATUS_SUCCESS if the entire string was

 *   successfully converted. %CAIRO_STATUS_INVALID_STRING if an

 *   an invalid sequence was found.

 **/

cairo_status_t

_cairo_utf8_to_utf16 (const char *str,

          int   len,

          uint16_t **result,

          int *items_written)

{

    uint16_t *str16 = NULL;

    int n16, i;

    const unsigned char *in;

    const unsigned char * const ustr = (const unsigned char *) str;

    in = ustr;

    n16 = 0;

    while ((len < 0 || ustr + len - in > 0) && *in) {

  uint32_t wc = _utf8_get_char_extended (in, ustr + len - in);

  if (wc & 0x80000000 || !UNICODE_VALID (wc))

      return _cairo_error (CAIRO_STATUS_INVALID_STRING);

  if (wc < 0x10000)

      n16 += 1;

  else

      n16 += 2;

  if (n16 == INT_MAX - 1 || n16 == INT_MAX)

      return _cairo_error (CAIRO_STATUS_INVALID_STRING);

  in = UTF8_NEXT_CHAR (in);

    }

    str16 = _cairo_malloc_ab (n16 + 1, sizeof (uint16_t));

    if (!str16)

  return _cairo_error (CAIRO_STATUS_NO_MEMORY);

    in = ustr;

    for (i = 0; i < n16;) {

  uint32_t wc = _utf8_get_char (in);

  i += _cairo_ucs4_to_utf16 (wc, str16 + i);

  in = UTF8_NEXT_CHAR (in);

    }

    str16[i] = 0;

    *result = str16;

    if (items_written)

  *items_written = n16;

    return CAIRO_STATUS_SUCCESS;

}

#endif