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/* -*- 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 

 */

#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;

}

#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);

	if (wc < 0x10000) {

	    str16[i++] = wc;

	} else {

	    str16[i++] = (wc - 0x10000) / 0x400 + 0xd800;

	    str16[i++] = (wc - 0x10000) % 0x400 + 0xdc00;

	}

	in = UTF8_NEXT_CHAR (in);

    }

    str16[i] = 0;

    *result = str16;

    if (items_written)

	*items_written = n16;

    return CAIRO_STATUS_SUCCESS;

}

#endif