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wget/lib/mbrtowc.c

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/* Convert multibyte character to wide character.
Copyright (C) 1999-2002, 2005-2019 Free Software Foundation, Inc.
Written by Bruno Haible <bruno@clisp.org>, 2008.
This program is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 3 of the License, or
(at your option) any later version.
This program 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 General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program. If not, see <https://www.gnu.org/licenses/>. */
#include <config.h>
/* Specification. */
#include <wchar.h>
#if C_LOCALE_MAYBE_EILSEQ
# include "hard-locale.h"
# include <locale.h>
#endif
#if GNULIB_defined_mbstate_t
/* Implement mbrtowc() on top of mbtowc(). */
# include <errno.h>
# include <stdlib.h>
# include "localcharset.h"
# include "streq.h"
# include "verify.h"
# ifndef FALLTHROUGH
# if __GNUC__ < 7
# define FALLTHROUGH ((void) 0)
# else
# define FALLTHROUGH __attribute__ ((__fallthrough__))
# endif
# endif
/* Returns a classification of special values of the encoding of the current
locale. */
typedef enum {
enc_other, /* other */
enc_utf8, /* UTF-8 */
enc_eucjp, /* EUC-JP */
enc_94, /* EUC-KR, GB2312, BIG5 */
enc_euctw, /* EUC-TW */
enc_gb18030, /* GB18030 */
enc_sjis /* SJIS */
} enc_t;
static inline enc_t
locale_enc (void)
{
const char *encoding = locale_charset ();
if (STREQ_OPT (encoding, "UTF-8", 'U', 'T', 'F', '-', '8', 0, 0, 0, 0))
return enc_utf8;
if (STREQ_OPT (encoding, "EUC-JP", 'E', 'U', 'C', '-', 'J', 'P', 0, 0, 0))
return enc_eucjp;
if (STREQ_OPT (encoding, "EUC-KR", 'E', 'U', 'C', '-', 'K', 'R', 0, 0, 0)
|| STREQ_OPT (encoding, "GB2312", 'G', 'B', '2', '3', '1', '2', 0, 0, 0)
|| STREQ_OPT (encoding, "BIG5", 'B', 'I', 'G', '5', 0, 0, 0, 0, 0))
return enc_94;
if (STREQ_OPT (encoding, "EUC-TW", 'E', 'U', 'C', '-', 'T', 'W', 0, 0, 0))
return enc_euctw;
if (STREQ_OPT (encoding, "GB18030", 'G', 'B', '1', '8', '0', '3', '0', 0, 0))
return enc_gb18030;
if (STREQ_OPT (encoding, "SJIS", 'S', 'J', 'I', 'S', 0, 0, 0, 0, 0))
return enc_sjis;
return enc_other;
}
#if GNULIB_WCHAR_SINGLE
/* When we know that the locale does not change, provide a speedup by
caching the value of locale_enc. */
static int cached_locale_enc = -1;
static inline enc_t
locale_enc_cached (void)
{
if (cached_locale_enc < 0)
cached_locale_enc = locale_enc ();
return cached_locale_enc;
}
#else
/* By default, don't make assumptions, hence no caching. */
# define locale_enc_cached locale_enc
#endif
verify (sizeof (mbstate_t) >= 4);
static char internal_state[4];
size_t
mbrtowc (wchar_t *pwc, const char *s, size_t n, mbstate_t *ps)
{
char *pstate = (char *)ps;
if (s == NULL)
{
pwc = NULL;
s = "";
n = 1;
}
if (n == 0)
return (size_t)(-2);
/* Here n > 0. */
if (pstate == NULL)
pstate = internal_state;
{
size_t nstate = pstate[0];
char buf[4];
const char *p;
size_t m;
switch (nstate)
{
case 0:
p = s;
m = n;
break;
case 3:
buf[2] = pstate[3];
FALLTHROUGH;
case 2:
buf[1] = pstate[2];
FALLTHROUGH;
case 1:
buf[0] = pstate[1];
p = buf;
m = nstate;
buf[m++] = s[0];
if (n >= 2 && m < 4)
{
buf[m++] = s[1];
if (n >= 3 && m < 4)
buf[m++] = s[2];
}
break;
default:
errno = EINVAL;
return (size_t)(-1);
}
/* Here m > 0. */
# if __GLIBC__ || defined __UCLIBC__
/* Work around bug <https://sourceware.org/bugzilla/show_bug.cgi?id=9674> */
mbtowc (NULL, NULL, 0);
# endif
{
int res = mbtowc (pwc, p, m);
if (res >= 0)
{
if (pwc != NULL && ((*pwc == 0) != (res == 0)))
abort ();
if (nstate >= (res > 0 ? res : 1))
abort ();
res -= nstate;
pstate[0] = 0;
return res;
}
/* mbtowc does not distinguish between invalid and incomplete multibyte
sequences. But mbrtowc needs to make this distinction.
There are two possible approaches:
- Use iconv() and its return value.
- Use built-in knowledge about the possible encodings.
Given the low quality of implementation of iconv() on the systems that
lack mbrtowc(), we use the second approach.
The possible encodings are:
- 8-bit encodings,
- EUC-JP, EUC-KR, GB2312, EUC-TW, BIG5, GB18030, SJIS,
- UTF-8.
Use specialized code for each. */
if (m >= 4 || m >= MB_CUR_MAX)
goto invalid;
/* Here MB_CUR_MAX > 1 and 0 < m < 4. */
switch (locale_enc_cached ())
{
case enc_utf8: /* UTF-8 */
{
/* Cf. unistr/u8-mblen.c. */
unsigned char c = (unsigned char) p[0];
if (c >= 0xc2)
{
if (c < 0xe0)
{
if (m == 1)
goto incomplete;
}
else if (c < 0xf0)
{
if (m == 1)
goto incomplete;
if (m == 2)
{
unsigned char c2 = (unsigned char) p[1];
if ((c2 ^ 0x80) < 0x40
&& (c >= 0xe1 || c2 >= 0xa0)
&& (c != 0xed || c2 < 0xa0))
goto incomplete;
}
}
else if (c <= 0xf4)
{
if (m == 1)
goto incomplete;
else /* m == 2 || m == 3 */
{
unsigned char c2 = (unsigned char) p[1];
if ((c2 ^ 0x80) < 0x40
&& (c >= 0xf1 || c2 >= 0x90)
&& (c < 0xf4 || (c == 0xf4 && c2 < 0x90)))
{
if (m == 2)
goto incomplete;
else /* m == 3 */
{
unsigned char c3 = (unsigned char) p[2];
if ((c3 ^ 0x80) < 0x40)
goto incomplete;
}
}
}
}
}
goto invalid;
}
/* As a reference for this code, you can use the GNU libiconv
implementation. Look for uses of the RET_TOOFEW macro. */
case enc_eucjp: /* EUC-JP */
{
if (m == 1)
{
unsigned char c = (unsigned char) p[0];
if ((c >= 0xa1 && c < 0xff) || c == 0x8e || c == 0x8f)
goto incomplete;
}
if (m == 2)
{
unsigned char c = (unsigned char) p[0];
if (c == 0x8f)
{
unsigned char c2 = (unsigned char) p[1];
if (c2 >= 0xa1 && c2 < 0xff)
goto incomplete;
}
}
goto invalid;
}
case enc_94: /* EUC-KR, GB2312, BIG5 */
{
if (m == 1)
{
unsigned char c = (unsigned char) p[0];
if (c >= 0xa1 && c < 0xff)
goto incomplete;
}
goto invalid;
}
case enc_euctw: /* EUC-TW */
{
if (m == 1)
{
unsigned char c = (unsigned char) p[0];
if ((c >= 0xa1 && c < 0xff) || c == 0x8e)
goto incomplete;
}
else /* m == 2 || m == 3 */
{
unsigned char c = (unsigned char) p[0];
if (c == 0x8e)
goto incomplete;
}
goto invalid;
}
case enc_gb18030: /* GB18030 */
{
if (m == 1)
{
unsigned char c = (unsigned char) p[0];
if ((c >= 0x90 && c <= 0xe3) || (c >= 0xf8 && c <= 0xfe))
goto incomplete;
}
else /* m == 2 || m == 3 */
{
unsigned char c = (unsigned char) p[0];
if (c >= 0x90 && c <= 0xe3)
{
unsigned char c2 = (unsigned char) p[1];
if (c2 >= 0x30 && c2 <= 0x39)
{
if (m == 2)
goto incomplete;
else /* m == 3 */
{
unsigned char c3 = (unsigned char) p[2];
if (c3 >= 0x81 && c3 <= 0xfe)
goto incomplete;
}
}
}
}
goto invalid;
}
case enc_sjis: /* SJIS */
{
if (m == 1)
{
unsigned char c = (unsigned char) p[0];
if ((c >= 0x81 && c <= 0x9f) || (c >= 0xe0 && c <= 0xea)
|| (c >= 0xf0 && c <= 0xf9))
goto incomplete;
}
goto invalid;
}
default:
/* An unknown multibyte encoding. */
goto incomplete;
}
incomplete:
{
size_t k = nstate;
/* Here 0 <= k < m < 4. */
pstate[++k] = s[0];
if (k < m)
{
pstate[++k] = s[1];
if (k < m)
pstate[++k] = s[2];
}
if (k != m)
abort ();
}
pstate[0] = m;
return (size_t)(-2);
invalid:
errno = EILSEQ;
/* The conversion state is undefined, says POSIX. */
return (size_t)(-1);
}
}
}
#else
/* Override the system's mbrtowc() function. */
# undef mbrtowc
size_t
rpl_mbrtowc (wchar_t *pwc, const char *s, size_t n, mbstate_t *ps)
{
size_t ret;
wchar_t wc;
# if MBRTOWC_NULL_ARG2_BUG || MBRTOWC_RETVAL_BUG || MBRTOWC_EMPTY_INPUT_BUG
if (s == NULL)
{
pwc = NULL;
s = "";
n = 1;
}
# endif
# if MBRTOWC_EMPTY_INPUT_BUG
if (n == 0)
return (size_t) -2;
# endif
if (! pwc)
pwc = &wc;
# if MBRTOWC_RETVAL_BUG
{
static mbstate_t internal_state;
/* Override mbrtowc's internal state. We cannot call mbsinit() on the
hidden internal state, but we can call it on our variable. */
if (ps == NULL)
ps = &internal_state;
if (!mbsinit (ps))
{
/* Parse the rest of the multibyte character byte for byte. */
size_t count = 0;
for (; n > 0; s++, n--)
{
ret = mbrtowc (&wc, s, 1, ps);
if (ret == (size_t)(-1))
return (size_t)(-1);
count++;
if (ret != (size_t)(-2))
{
/* The multibyte character has been completed. */
*pwc = wc;
return (wc == 0 ? 0 : count);
}
}
return (size_t)(-2);
}
}
# endif
ret = mbrtowc (pwc, s, n, ps);
# if MBRTOWC_NUL_RETVAL_BUG
if (ret < (size_t) -2 && !*pwc)
return 0;
# endif
# if C_LOCALE_MAYBE_EILSEQ
if ((size_t) -2 <= ret && n != 0 && ! hard_locale (LC_CTYPE))
{
unsigned char uc = *s;
*pwc = uc;
return 1;
}
# endif
return ret;
}
#endif
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