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[glibc.git] / wcsmbs / mbrtowc.c
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1 /* Copyright (C) 1996, 1997, 1998, 1999, 2000, 2002, 2004
2 Free Software Foundation, Inc.
3 This file is part of the GNU C Library.
4 Contributed by Ulrich Drepper <drepper@gnu.org>, 1996.
6 The GNU C Library is free software; you can redistribute it and/or
7 modify it under the terms of the GNU Lesser General Public
8 License as published by the Free Software Foundation; either
9 version 2.1 of the License, or (at your option) any later version.
11 The GNU C Library is distributed in the hope that it will be useful,
12 but WITHOUT ANY WARRANTY; without even the implied warranty of
13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
14 Lesser General Public License for more details.
16 You should have received a copy of the GNU Lesser General Public
17 License along with the GNU C Library; if not, write to the Free
18 Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
19 02111-1307 USA. */
21 #include <dlfcn.h>
22 #include <errno.h>
23 #include <gconv.h>
24 #include <wchar.h>
25 #include <wcsmbsload.h>
27 #include <assert.h>
29 #ifndef EILSEQ
30 # define EILSEQ EINVAL
31 #endif
33 /* This is the private state used if PS is NULL. */
34 static mbstate_t state;
36 size_t
37 __mbrtowc (wchar_t *pwc, const char *s, size_t n, mbstate_t *ps)
39 wchar_t buf[1];
40 struct __gconv_step_data data;
41 int status;
42 size_t result;
43 size_t dummy;
44 const unsigned char *inbuf, *endbuf;
45 char *outbuf = (char *) (pwc ?: buf);
46 const struct gconv_fcts *fcts;
48 /* Set information for this step. */
49 data.__invocation_counter = 0;
50 data.__internal_use = 1;
51 data.__flags = __GCONV_IS_LAST;
52 data.__statep = ps ?: &state;
53 data.__trans = NULL;
55 /* A first special case is if S is NULL. This means put PS in the
56 initial state. */
57 if (s == NULL)
59 outbuf = (char *) buf;
60 s = "";
61 n = 1;
64 /* Tell where we want the result. */
65 data.__outbuf = outbuf;
66 data.__outbufend = outbuf + sizeof (wchar_t);
68 /* Get the conversion functions. */
69 fcts = get_gconv_fcts (_NL_CURRENT_DATA (LC_CTYPE));
71 /* Do a normal conversion. */
72 inbuf = (const unsigned char *) s;
73 endbuf = inbuf + n;
74 if (__builtin_expect (endbuf < inbuf, 0))
75 endbuf = (const unsigned char *) ~(uintptr_t) 0;
76 status = DL_CALL_FCT (fcts->towc->__fct,
77 (fcts->towc, &data, &inbuf, endbuf,
78 NULL, &dummy, 0, 1));
80 /* There must not be any problems with the conversion but illegal input
81 characters. The output buffer must be large enough, otherwise the
82 definition of MB_CUR_MAX is not correct. All the other possible
83 errors also must not happen. */
84 assert (status == __GCONV_OK || status == __GCONV_EMPTY_INPUT
85 || status == __GCONV_ILLEGAL_INPUT
86 || status == __GCONV_INCOMPLETE_INPUT
87 || status == __GCONV_FULL_OUTPUT);
89 if (status == __GCONV_OK || status == __GCONV_EMPTY_INPUT
90 || status == __GCONV_FULL_OUTPUT)
92 if (data.__outbuf != (unsigned char *) outbuf
93 && *(wchar_t *) outbuf == L'\0')
95 /* The converted character is the NUL character. */
96 assert (__mbsinit (data.__statep));
97 result = 0;
99 else
100 result = inbuf - (const unsigned char *) s;
102 else if (status == __GCONV_INCOMPLETE_INPUT)
103 result = (size_t) -2;
104 else
106 result = (size_t) -1;
107 __set_errno (EILSEQ);
110 return result;
112 libc_hidden_def (__mbrtowc)
113 weak_alias (__mbrtowc, mbrtowc)
114 libc_hidden_weak (mbrtowc)