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1/***
2*mbtowc.c - Convert multibyte char to wide char.
3*
4* Copyright (c) Microsoft Corporation. All rights reserved.
5*
6*Purpose:
7* Convert a multibyte character into the equivalent wide character.
8*
9*******************************************************************************/
10#include <corecrt_internal_mbstring.h>
11#include <corecrt_internal_ptd_propagation.h>
12#include <locale.h>
13#include <stdlib.h>
14#include <wchar.h>
15
16using namespace __crt_mbstring;
17
18/***
19*int mbtowc() - Convert multibyte char to wide character.
20*
21*Purpose:
22* Convert a multi-byte character into the equivalent wide character,
23* according to the LC_CTYPE category of the current locale.
24* [ANSI].
25*
26* NOTE: Currently, the C libraries support the "C" locale only.
27* Non-C locale support now available under _INTL switch.
28*Entry:
29* wchar_t *pwc = pointer to destination wide character
30* const char *s = pointer to multibyte character
31* size_t n = maximum length of multibyte character to consider
32*
33*Exit:
34* If s = nullptr, returns 0, indicating we only use state-independent
35* character encodings.
36* If s != nullptr, returns: 0 (if *s = null char)
37* -1 (if the next n or fewer bytes not valid mbc)
38* number of bytes comprising converted mbc
39*
40*Exceptions:
41* If errors are encountered, -1 is returned and errno is set to EILSEQ.
42*
43*******************************************************************************/
44
45extern "C" int __cdecl _mbtowc_internal(
46 wchar_t * pwc,
47 const char * s,
48 size_t n,
49 __crt_cached_ptd_host& ptd
50 )
51{
52 static mbstate_t internal_state{};
53 if (!s || n == 0)
54 {
55 /* indicate do not have state-dependent encodings,
56 handle zero length string */
57 internal_state = {};
58 return 0;
59 }
60
61 if (!*s)
62 {
63 /* handle NULL char */
64 if (pwc)
65 {
66 *pwc = 0;
67 }
68 return 0;
69 }
70
71 const _locale_t locale = ptd.get_locale();
72
73 if (locale->locinfo->_public._locale_lc_codepage == CP_UTF8)
74 {
75 int result = static_cast<int>(__mbrtowc_utf8(pwc, s, n, &internal_state, ptd));
76 if (result < 0)
77 result = -1;
78 return result;
79 }
80
81 _ASSERTE(locale->locinfo->_public._locale_mb_cur_max == 1 ||
82 locale->locinfo->_public._locale_mb_cur_max == 2);
83
84 if (locale->locinfo->locale_name[LC_CTYPE] == nullptr)
85 {
86 if (pwc)
87 {
88 *pwc = (wchar_t) (unsigned char) *s;
89 }
90 return sizeof(char);
91 }
92
93 if (_isleadbyte_fast_internal((unsigned char) *s, locale))
94 {
95 _ASSERTE(locale->locinfo->_public._locale_lc_codepage != CP_UTF8 && L"UTF-8 isn't supported in this _mbtowc_l function yet!!!");
96
97 /* multi-byte char */
98 // If this is a lead byte, then the codepage better be a multibyte codepage
99 _ASSERTE(locale->locinfo->_public._locale_mb_cur_max > 1);
100
101 if ((locale->locinfo->_public._locale_mb_cur_max <= 1) || ((int) n < locale->locinfo->_public._locale_mb_cur_max) ||
102 (__acrt_MultiByteToWideChar(locale->locinfo->_public._locale_lc_codepage,
103 MB_PRECOMPOSED | MB_ERR_INVALID_CHARS,
104 s,
105 locale->locinfo->_public._locale_mb_cur_max,
106 pwc,
107 (pwc) ? 1 : 0) == 0))
108 {
109 /* validate high byte of mbcs char */
110 if ((n < (size_t) locale->locinfo->_public._locale_mb_cur_max) || (!*(s + 1)))
111 {
112 ptd.get_errno().set(EILSEQ);
113 return -1;
114 }
115 }
116 return locale->locinfo->_public._locale_mb_cur_max;
117 }
118 else {
119 /* single byte char */
120 if (__acrt_MultiByteToWideChar(locale->locinfo->_public._locale_lc_codepage,
121 MB_PRECOMPOSED | MB_ERR_INVALID_CHARS,
122 s,
123 1,
124 pwc,
125 (pwc) ? 1 : 0) == 0)
126 {
127 ptd.get_errno().set(EILSEQ);
128 return -1;
129 }
130 return sizeof(char);
131 }
132}
133
134extern "C" int __cdecl _mbtowc_l(
135 wchar_t *pwc,
136 const char *s,
137 size_t n,
138 _locale_t plocinfo
139 )
140{
141 __crt_cached_ptd_host ptd(plocinfo);
142 return _mbtowc_internal(pwc, s, n, ptd);
143}
144
145extern "C" int __cdecl mbtowc(
146 wchar_t *pwc,
147 const char *s,
148 size_t n
149 )
150{
151 __crt_cached_ptd_host ptd;
152 return _mbtowc_internal(pwc, s, n, ptd);
153}