glib/gutf8.c
Owen Taylor 37e7118821 Fix stray character
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.
2000-07-31 18:52:11 +00:00

490 lines
11 KiB
C

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