--- /dev/null
+/* Convert multibyte character to wide character.
+ Copyright (C) 1999-2002, 2005-2008 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 <http://www.gnu.org/licenses/>. */
+
+#include <config.h>
+
+/* Specification. */
+#include <wchar.h>
+
+#include <errno.h>
+#include <stdlib.h>
+
+#include "localcharset.h"
+#include "streq.h"
+
+
+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 (pstate == NULL)
+ pstate = internal_state;
+
+ if (s == NULL)
+ {
+ pwc = NULL;
+ s = "";
+ n = 1;
+ }
+
+ if (n == 0)
+ return (size_t)(-2);
+
+ /* Here n > 0. */
+ {
+ 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 0 < m ≤ 4. */
+
+#if __GLIBC__
+ /* Work around bug <http://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, 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. */
+ {
+ const char *encoding = locale_charset ();
+
+ if (STREQ (encoding, "UTF-8", 'U', 'T', 'F', '-', '8', 0, 0, 0, 0))
+ {
+ /* 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. */
+
+ if (STREQ (encoding, "EUC-JP", 'E', 'U', 'C', '-', 'J', 'P', 0, 0, 0))
+ {
+ 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;
+ }
+ if (STREQ (encoding, "EUC-KR", 'E', 'U', 'C', '-', 'K', 'R', 0, 0, 0)
+ || STREQ (encoding, "GB2312", 'G', 'B', '2', '3', '1', '2', 0, 0, 0)
+ || STREQ (encoding, "BIG5", 'B', 'I', 'G', '5', 0, 0, 0, 0, 0))
+ {
+ if (m == 1)
+ {
+ unsigned char c = (unsigned char) p[0];
+
+ if (c >= 0xa1 && c < 0xff)
+ goto incomplete;
+ }
+ goto invalid;
+ }
+ if (STREQ (encoding, "EUC-TW", 'E', 'U', 'C', '-', 'T', 'W', 0, 0, 0))
+ {
+ 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;
+ }
+ if (STREQ (encoding, "SJIS", 'S', 'J', 'I', 'S', 0, 0, 0, 0, 0))
+ {
+ 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;
+ }
+
+ /* 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)
+ abort ();
+ }
+ pstate[0] = m;
+ return (size_t)(-2);
+
+ invalid:
+ errno = EILSEQ;
+ /* The conversion state is undefined, says POSIX. */
+ return (size_t)(-1);
+ }
+ }
+}
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