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[glibc.git] / wcsmbs / mbsnrtowcs.c
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1 /* Copyright (C) 1996, 1997, 1998 Free Software Foundation, Inc.
2 This file is part of the GNU C Library.
3 Contributed by Ulrich Drepper <drepper@gnu.ai.mit.edu>, 1996.
5 The GNU C Library is free software; you can redistribute it and/or
6 modify it under the terms of the GNU Library General Public License as
7 published by the Free Software Foundation; either version 2 of the
8 License, or (at your option) any later version.
10 The GNU C Library is distributed in the hope that it will be useful,
11 but WITHOUT ANY WARRANTY; without even the implied warranty of
12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13 Library General Public License for more details.
15 You should have received a copy of the GNU Library General Public
16 License along with the GNU C Library; see the file COPYING.LIB. If not,
17 write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
18 Boston, MA 02111-1307, USA. */
20 #include <errno.h>
21 #include <gconv.h>
22 #include <string.h>
23 #include <wchar.h>
24 #include <wcsmbsload.h>
26 #include <assert.h>
28 #ifndef EILSEQ
29 # define EILSEQ EINVAL
30 #endif
33 /* This is the private state used if PS is NULL. */
34 static mbstate_t state;
36 /* This is a non-standard function but it is very useful in the
37 implementation of stdio because we have to deal with unterminated
38 buffers. At most NMC bytes will be converted. */
39 size_t
40 __mbsnrtowcs (dst, src, nmc, len, ps)
41 wchar_t *dst;
42 const char **src;
43 size_t nmc;
44 size_t len;
45 mbstate_t *ps;
47 const char *srcend;
48 struct gconv_step_data data;
49 size_t result = 0;
50 int status;
52 /* Tell where we want the result. */
53 data.invocation_counter = 0;
54 data.internal_use = 1;
55 data.is_last = 1;
56 data.statep = ps ?: &state;
58 if (nmc == 0)
59 return 0;
60 srcend = *src + __strnlen (*src, nmc - 1) + 1;
62 /* Make sure we use the correct function. */
63 update_conversion_ptrs ();
65 /* We have to handle DST == NULL special. */
66 if (dst == NULL)
68 wchar_t buf[64]; /* Just an arbitrary size. */
69 const char *inbuf = *src;
71 data.outbufend = data.outbuf + sizeof (buf);
74 data.outbuf = (char *) buf;
76 status = (*__wcsmbs_gconv_fcts.towc->fct) (__wcsmbs_gconv_fcts.towc,
77 &data, &inbuf, srcend,
78 &result, 0);
80 while (status == GCONV_FULL_OUTPUT);
82 if ((status == GCONV_OK || status == GCONV_EMPTY_INPUT)
83 && ((wchar_t *) data.outbuf)[-1] == L'\0')
84 /* Don't count the NUL character in. */
85 --result;
87 else
89 /* This code is based on the safe assumption that all internal
90 multi-byte encodings use the NUL byte only to mark the end
91 of the string. */
92 data.outbuf = (char *) dst;
93 data.outbufend = data.outbuf + len * sizeof (wchar_t);
95 status = (*__wcsmbs_gconv_fcts.towc->fct) (__wcsmbs_gconv_fcts.towc,
96 &data, src, srcend,
97 &result, 0);
99 /* We have to determine whether the last character converted
100 is the NUL character. */
101 if ((status == GCONV_OK || status == GCONV_EMPTY_INPUT)
102 && ((wchar_t *) dst)[result - 1] == L'\0')
104 assert (result > 0);
105 assert (__mbsinit (data.statep));
106 *src = NULL;
107 --result;
111 /* There must not be any problems with the conversion but illegal input
112 characters. */
113 assert (status == GCONV_OK || status != GCONV_EMPTY_INPUT
114 || status == GCONV_ILLEGAL_INPUT
115 || status == GCONV_INCOMPLETE_INPUT || status == GCONV_FULL_OUTPUT);
117 if (status != GCONV_OK && status != GCONV_FULL_OUTPUT
118 && status != GCONV_EMPTY_INPUT)
120 result = (size_t) -1;
121 __set_errno (EILSEQ);
124 return result;
126 weak_alias (__mbsnrtowcs, mbsnrtowcs)