1/* Copyright (C) 1996-2023 Free Software Foundation, Inc.
2 This file is part of the GNU C Library.
3
4 The GNU C Library is free software; you can redistribute it and/or
5 modify it under the terms of the GNU Lesser General Public
6 License as published by the Free Software Foundation; either
7 version 2.1 of the License, or (at your option) any later version.
8
9 The GNU C Library is distributed in the hope that it will be useful,
10 but WITHOUT ANY WARRANTY; without even the implied warranty of
11 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
12 Lesser General Public License for more details.
13
14 You should have received a copy of the GNU Lesser General Public
15 License along with the GNU C Library; if not, see
16 <https://www.gnu.org/licenses/>. */
17
18#include <assert.h>
19#include <dlfcn.h>
20#include <errno.h>
21#include <gconv.h>
22#include <wchar.h>
23#include <wcsmbsload.h>
24
25#include <pointer_guard.h>
26
27#ifndef EILSEQ
28# define EILSEQ EINVAL
29#endif
30
31/* This is the private state used if PS is NULL. */
32static mbstate_t state;
33
34size_t
35__mbrtowc (wchar_t *pwc, const char *s, size_t n, mbstate_t *ps)
36{
37 wchar_t buf[1];
38 struct __gconv_step_data data;
39 int status;
40 size_t result;
41 size_t dummy;
42 const unsigned char *inbuf, *endbuf;
43 unsigned char *outbuf = (unsigned char *) (pwc ?: buf);
44 const struct gconv_fcts *fcts;
45
46 /* Set information for this step. */
47 data.__invocation_counter = 0;
48 data.__internal_use = 1;
49 data.__flags = __GCONV_IS_LAST;
50 data.__statep = ps ?: &state;
51
52 /* A first special case is if S is NULL. This means put PS in the
53 initial state. */
54 if (s == NULL)
55 {
56 outbuf = (unsigned char *) buf;
57 s = "";
58 n = 1;
59 }
60
61 if (n == 0)
62 return (size_t) -2;
63
64 /* Tell where we want the result. */
65 data.__outbuf = outbuf;
66 data.__outbufend = outbuf + sizeof (wchar_t);
67
68 /* Get the conversion functions. */
69 fcts = get_gconv_fcts (_NL_CURRENT_DATA (LC_CTYPE));
70
71 /* Do a normal conversion. */
72 inbuf = (const unsigned char *) s;
73 endbuf = inbuf + n;
74 if (__glibc_unlikely (endbuf < inbuf))
75 {
76 endbuf = (const unsigned char *) ~(uintptr_t) 0;
77 if (endbuf == inbuf)
78 goto ilseq;
79 }
80 __gconv_fct fct = fcts->towc->__fct;
81 if (fcts->towc->__shlib_handle != NULL)
82 PTR_DEMANGLE (fct);
83 status = DL_CALL_FCT (fct, (fcts->towc, &data, &inbuf, endbuf,
84 NULL, &dummy, 0, 1));
85
86 /* There must not be any problems with the conversion but illegal input
87 characters. The output buffer must be large enough, otherwise the
88 definition of MB_CUR_MAX is not correct. All the other possible
89 errors also must not happen. */
90 assert (status == __GCONV_OK || status == __GCONV_EMPTY_INPUT
91 || status == __GCONV_ILLEGAL_INPUT
92 || status == __GCONV_INCOMPLETE_INPUT
93 || status == __GCONV_FULL_OUTPUT);
94
95 if (status == __GCONV_OK || status == __GCONV_EMPTY_INPUT
96 || status == __GCONV_FULL_OUTPUT)
97 {
98 if (data.__outbuf != (unsigned char *) outbuf
99 && *(wchar_t *) outbuf == L'\0')
100 {
101 /* The converted character is the NUL character. */
102 assert (__mbsinit (data.__statep));
103 result = 0;
104 }
105 else
106 result = inbuf - (const unsigned char *) s;
107 }
108 else if (status == __GCONV_INCOMPLETE_INPUT)
109 result = (size_t) -2;
110 else
111 {
112 ilseq:
113 result = (size_t) -1;
114 __set_errno (EILSEQ);
115 }
116
117 return result;
118}
119libc_hidden_def (__mbrtowc)
120weak_alias (__mbrtowc, mbrtowc)
121libc_hidden_weak (mbrtowc)
122