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37e7118821
Sun Jul 30 16:54:13 2000 Owen Taylor <otaylor@redhat.com>
* gunicode.h: Fix stray character
* gutf8.c (g_unichar_to_utf8): Allow outbuf to be NULL, in
which case we just compute the length.
490 lines
11 KiB
C
490 lines
11 KiB
C
/* gutf8.c - Operations on UTF-8 strings.
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*
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* Copyright (C) 1999 Tom Tromey
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* Copyright (C) 2000 Red Hat, Inc.
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*
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* This library is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Lesser General Public
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* License as published by the Free Software Foundation; either
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* version 2 of the License, or (at your option) any later version.
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*
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* This library is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public
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* License along with this library; if not, write to the
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* Free Software Foundation, Inc., 59 Temple Place - Suite 330,
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* Boston, MA 02111-1307, USA.
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*/
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#include <config.h>
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#include <stdlib.h>
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#ifdef HAVE_CODESET
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#include <langinfo.h>
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#endif
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#include <string.h>
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#include "glib.h"
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#define UTF8_COMPUTE(Char, Mask, Len) \
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if (Char < 128) \
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{ \
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Len = 1; \
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Mask = 0x7f; \
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} \
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else if ((Char & 0xe0) == 0xc0) \
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{ \
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Len = 2; \
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Mask = 0x1f; \
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} \
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else if ((Char & 0xf0) == 0xe0) \
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{ \
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Len = 3; \
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Mask = 0x0f; \
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} \
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else if ((Char & 0xf8) == 0xf0) \
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{ \
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Len = 4; \
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Mask = 0x07; \
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} \
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else if ((Char & 0xfc) == 0xf8) \
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{ \
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Len = 5; \
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Mask = 0x03; \
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} \
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else if ((Char & 0xfe) == 0xfc) \
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{ \
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Len = 6; \
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Mask = 0x01; \
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} \
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else \
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Len = -1;
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#define UTF8_GET(Result, Chars, Count, Mask, Len) \
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(Result) = (Chars)[0] & (Mask); \
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for ((Count) = 1; (Count) < (Len); ++(Count)) \
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{ \
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if (((Chars)[(Count)] & 0xc0) != 0x80) \
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{ \
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(Result) = -1; \
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break; \
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} \
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(Result) <<= 6; \
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(Result) |= ((Chars)[(Count)] & 0x3f); \
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}
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gchar g_utf8_skip[256] = {
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1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,
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1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,
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1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,
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1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,
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1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,
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1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,
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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,
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3,3,3,3,3,3,3,3,3,3,3,3,3,3,3,3,4,4,4,4,4,4,4,4,5,5,5,5,6,6,0,0
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};
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/**
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* g_utf8_find_prev_char:
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* @str: pointer to the beginning of a UTF-8 string
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* @p: pointer to some position within @str
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*
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* Given a position @p with a UTF-8 encoded string @str, find the start
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* of the previous UTF-8 character starting before @p. Returns %NULL if no
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* UTF-8 characters are present in @p before @str.
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*
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* @p does not have to be at the beginning of a UTF-8 chracter. No check
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* is made to see if the character found is actually valid other than
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* it starts with an appropriate byte.
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*
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* Return value: a pointer to the found character or %NULL.
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**/
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gchar *
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g_utf8_find_prev_char (const char *str,
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const char *p)
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{
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for (--p; p > str; --p)
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{
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if ((*p & 0xc0) != 0x80)
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return (gchar *)p;
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}
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return NULL;
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}
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/**
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* g_utf8_find_next_char:
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* @p: a pointer to a position within a UTF-8 encoded string
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* @end: a pointer to the end of the string, or %NULL to indicate
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* that the string is NULL terminated, in which case
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* the returned value will be
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*
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* Find the start of the next utf-8 character in the string after @p
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*
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* @p does not have to be at the beginning of a UTF-8 chracter. No check
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* is made to see if the character found is actually valid other than
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* it starts with an appropriate byte.
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*
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* Return value: a pointer to the found character or %NULL
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**/
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gchar *
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g_utf8_find_next_char (const gchar *p,
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const gchar *end)
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{
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if (*p)
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{
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if (end)
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for (++p; p < end && (*p & 0xc0) == 0x80; ++p)
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;
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else
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for (++p; (*p & 0xc0) == 0x80; ++p)
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;
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}
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return (p == end) ? NULL : (gchar *)p;
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}
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/**
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* g_utf8_prev_char:
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* @p: a pointer to a position within a UTF-8 encoded string
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*
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* Find the previous UTF-8 character in the string before @p
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*
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* @p does not have to be at the beginning of a UTF-8 character. No check
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* is made to see if the character found is actually valid other than
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* it starts with an appropriate byte. If @p might be the first
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* character of the string, you must use g_utf8_find_prev_char instead.
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*
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* Return value: a pointer to the found character.
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**/
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gchar *
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g_utf8_prev_char (const gchar *p)
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{
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while (TRUE)
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{
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p--;
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if ((*p & 0xc0) != 0x80)
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return (gchar *)p;
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}
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}
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/**
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* g_utf8_strlen:
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* @p: pointer to the start of a UTF-8 string.
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* @max: the maximum number of bytes to examine. If @max
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* is less than 0, then the string is assumed to be
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* nul-terminated.
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*
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* Return value: the length of the string in characters
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*/
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gint
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g_utf8_strlen (const gchar *p, gint max)
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{
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int len = 0;
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const gchar *start = p;
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/* special case for the empty string */
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if (!*p)
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return 0;
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/* Note that the test here and the test in the loop differ subtly.
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In the loop we want to see if we've passed the maximum limit --
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for instance if the buffer ends mid-character. Here at the top
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of the loop we want to see if we've just reached the last byte. */
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while (max < 0 || p - start < max)
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{
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p = g_utf8_next_char (p);
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++len;
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if (! *p || (max > 0 && p - start > max))
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break;
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}
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return len;
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}
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/**
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* g_utf8_get_char:
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* @p: a pointer to unicode character encoded as UTF-8
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*
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* Convert a sequence of bytes encoded as UTF-8 to a unicode character.
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*
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* Return value: the resulting character or (gunichar)-1 if @p does
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* not point to a valid UTF-8 encoded unicode character
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**/
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gunichar
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g_utf8_get_char (const gchar *p)
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{
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int i, mask = 0, len;
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gunichar result;
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unsigned char c = (unsigned char) *p;
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UTF8_COMPUTE (c, mask, len);
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if (len == -1)
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return (gunichar)-1;
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UTF8_GET (result, p, i, mask, len);
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return result;
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}
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/**
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* g_utf8_offset_to_pointer:
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* @str: a UTF-8 encoded string
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* @offset: a character offset within the string.
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*
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* Converts from an integer character offset to a pointer to a position
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* within the string.
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*
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* Return value: the resulting pointer
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**/
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gchar *
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g_utf8_offset_to_pointer (const gchar *str,
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gint offset)
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{
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const gchar *s = str;
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while (offset--)
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s = g_utf8_next_char (s);
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return (gchar *)s;
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}
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/**
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* g_utf8_pointer_to_offset:
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* @str: a UTF-8 encoded string
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* @pos: a pointer to a position within @str
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*
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* Converts from a pointer to position within a string to a integer
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* character offset
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*
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* Return value: the resulting character offset
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**/
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gint
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g_utf8_pointer_to_offset (const gchar *str,
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const gchar *pos)
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{
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const gchar *s = str;
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gint offset = 0;
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while (s < pos)
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{
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s = g_utf8_next_char (s);
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offset++;
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}
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return offset;
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}
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gchar *
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g_utf8_strncpy (gchar *dest, const gchar *src, size_t n)
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{
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const gchar *s = src;
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while (n && *s)
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{
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s = g_utf8_next_char(s);
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n--;
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}
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strncpy(dest, src, s - src);
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dest[s - src] = 0;
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return dest;
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}
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static gboolean
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g_utf8_get_charset_internal (char **a)
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{
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char *charset = getenv("CHARSET");
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if (charset && a && ! *a)
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*a = charset;
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if (charset && strstr (charset, "UTF-8"))
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return TRUE;
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#ifdef HAVE_CODESET
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charset = nl_langinfo(CODESET);
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if (charset)
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{
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if (a && ! *a)
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*a = charset;
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if (strcmp (charset, "UTF-8") == 0)
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return TRUE;
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}
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#endif
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#if 0 /* #ifdef _NL_CTYPE_CODESET_NAME */
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charset = nl_langinfo (_NL_CTYPE_CODESET_NAME);
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if (charset)
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{
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if (a && ! *a)
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*a = charset;
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if (strcmp (charset, "UTF-8") == 0)
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return TRUE;
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}
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#endif
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if (a && ! *a)
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*a = "US-ASCII";
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/* Assume this for compatibility at present. */
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return FALSE;
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}
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static int utf8_locale_cache = -1;
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static char *utf8_charset_cache = NULL;
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gboolean
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g_get_charset (char **charset)
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{
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if (utf8_locale_cache != -1)
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{
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if (charset)
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*charset = utf8_charset_cache;
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return utf8_locale_cache;
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}
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utf8_locale_cache = g_utf8_get_charset_internal (&utf8_charset_cache);
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if (charset)
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*charset = utf8_charset_cache;
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return utf8_locale_cache;
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}
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/* unicode_strchr */
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/**
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* g_unichar_to_utf8:
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* @ch: a ISO10646 character code
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* @out: output buffer, must have at least 6 bytes of space.
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* If %NULL, the length will be computed and returned
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* and nothing will be written to @out.
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*
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* Convert a single character to utf8
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*
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* Return value: number of bytes written
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**/
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int
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g_unichar_to_utf8 (gunichar c, gchar *outbuf)
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{
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size_t len = 0;
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int first;
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int i;
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if (c < 0x80)
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{
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first = 0;
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len = 1;
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}
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else if (c < 0x800)
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{
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first = 0xc0;
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len = 2;
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}
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else if (c < 0x10000)
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{
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first = 0xe0;
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len = 3;
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}
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else if (c < 0x200000)
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{
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first = 0xf0;
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len = 4;
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}
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else if (c < 0x4000000)
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{
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first = 0xf8;
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len = 5;
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}
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else
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{
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first = 0xfc;
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len = 6;
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}
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if (outbuf)
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{
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for (i = len - 1; i > 0; --i)
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{
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outbuf[i] = (c & 0x3f) | 0x80;
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c >>= 6;
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}
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outbuf[0] = c | first;
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}
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return len;
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}
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/**
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* g_utf8_strchr:
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* @p: a nul-terminated utf-8 string
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* @c: a iso-10646 character/
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*
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* Find the leftmost occurence of the given iso-10646 character
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* in a UTF-8 string.
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*
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* Return value: NULL if the string does not contain the character, otherwise, a
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* a pointer to the start of the leftmost of the character in the string.
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**/
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gchar *
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g_utf8_strchr (const char *p, gunichar c)
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{
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gchar ch[10];
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gint len = g_unichar_to_utf8 (c, ch);
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ch[len] = '\0';
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return strstr(p, ch);
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}
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#if 0
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/**
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* g_utf8_strrchr:
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* @p: a nul-terminated utf-8 string
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* @c: a iso-10646 character/
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*
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* Find the rightmost occurence of the given iso-10646 character
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* in a UTF-8 string.
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*
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* Return value: NULL if the string does not contain the character, otherwise, a
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* a pointer to the start of the rightmost of the character in the string.
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**/
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/* This is ifdefed out atm as there is no strrstr function in libc.
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*/
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gchar *
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unicode_strrchr (const char *p, gunichar c)
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{
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gchar ch[10];
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len = g_unichar_to_utf8 (c, ch);
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ch[len] = '\0';
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return strrstr(p, ch);
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}
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#endif
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/**
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* g_utf8_to_ucs4:
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* @str: a UTF-8 encoded strnig
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* @len: the length of @
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*
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* Convert a string from UTF-8 to a 32-bit fixed width
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* representation as UCS-4.
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*
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* Return value: a pointer to a newly allocated UCS-4 string.
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* This value must be freed with g_free()
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**/
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gunichar *
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g_utf8_to_ucs4 (const char *str, int len)
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{
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gunichar *result;
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gint n_chars, i;
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const gchar *p;
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n_chars = g_utf8_strlen (str, len);
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result = g_new (gunichar, n_chars);
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p = str;
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for (i=0; i < n_chars; i++)
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{
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result[i] = g_utf8_get_char (p);
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p = g_utf8_next_char (p);
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}
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return result;
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}
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