1/* Copyright (C) 2011-2023 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 <uchar.h>
23#include <wcsmbsload.h>
24
25#include <pointer_guard.h>
26
27#ifndef EILSEQ
28# define EILSEQ EINVAL
29#endif
30
31
32/* This is the private state used if PS is NULL. */
33static mbstate_t state;
34
35size_t
36mbrtoc16 (char16_t *pc16, const char *s, size_t n, mbstate_t *ps)
37{
38 if (ps == NULL)
39 ps = &state;
40
41 /* The standard text does not say that S being NULL means the state
42 is reset even if the second half of a surrogate still have to be
43 returned. In fact, the error code description indicates
44 otherwise. Therefore always first try to return a second
45 half. */
46 if (ps->__count & 0x80000000)
47 {
48 /* We have to return the second word for a surrogate. */
49 ps->__count &= 0x7fffffff;
50 *pc16 = ps->__value.__wch;
51 ps->__value.__wch = L'\0';
52 return (size_t) -3;
53 }
54
55 wchar_t wc;
56 struct __gconv_step_data data;
57 int status;
58 size_t result;
59 size_t dummy;
60 const unsigned char *inbuf, *endbuf;
61 unsigned char *outbuf = (unsigned char *) &wc;
62 const struct gconv_fcts *fcts;
63
64 /* Set information for this step. */
65 data.__invocation_counter = 0;
66 data.__internal_use = 1;
67 data.__flags = __GCONV_IS_LAST;
68 data.__statep = ps;
69
70 /* A first special case is if S is NULL. This means put PS in the
71 initial state. */
72 if (s == NULL)
73 {
74 pc16 = NULL;
75 s = "";
76 n = 1;
77 }
78
79 if (n == 0)
80 return (size_t) -2;
81
82 /* Tell where we want the result. */
83 data.__outbuf = outbuf;
84 data.__outbufend = outbuf + sizeof (wchar_t);
85
86 /* Get the conversion functions. */
87 fcts = get_gconv_fcts (_NL_CURRENT_DATA (LC_CTYPE));
88
89 /* Do a normal conversion. */
90 inbuf = (const unsigned char *) s;
91 endbuf = inbuf + n;
92 if (__glibc_unlikely (endbuf < inbuf))
93 {
94 endbuf = (const unsigned char *) ~(uintptr_t) 0;
95 if (endbuf == inbuf)
96 goto ilseq;
97 }
98 __gconv_fct fct = fcts->towc->__fct;
99 if (fcts->towc->__shlib_handle != NULL)
100 PTR_DEMANGLE (fct);
101
102 status = DL_CALL_FCT (fct, (fcts->towc, &data, &inbuf, endbuf,
103 NULL, &dummy, 0, 1));
104
105 /* There must not be any problems with the conversion but illegal input
106 characters. The output buffer must be large enough, otherwise the
107 definition of MB_CUR_MAX is not correct. All the other possible
108 errors also must not happen. */
109 assert (status == __GCONV_OK || status == __GCONV_EMPTY_INPUT
110 || status == __GCONV_ILLEGAL_INPUT
111 || status == __GCONV_INCOMPLETE_INPUT
112 || status == __GCONV_FULL_OUTPUT);
113
114 if (status == __GCONV_OK || status == __GCONV_EMPTY_INPUT
115 || status == __GCONV_FULL_OUTPUT)
116 {
117 result = inbuf - (const unsigned char *) s;
118
119 if (wc < 0x10000)
120 {
121 if (pc16 != NULL)
122 *pc16 = wc;
123
124 if (data.__outbuf != outbuf && wc == L'\0')
125 {
126 /* The converted character is the NUL character. */
127 assert (__mbsinit (data.__statep));
128 result = 0;
129 }
130 }
131 else
132 {
133 /* This is a surrogate. */
134 if (pc16 != NULL)
135 *pc16 = 0xd7c0 + (wc >> 10);
136
137 ps->__count |= 0x80000000;
138 ps->__value.__wch = 0xdc00 + (wc & 0x3ff);
139 }
140 }
141 else if (status == __GCONV_INCOMPLETE_INPUT)
142 result = (size_t) -2;
143 else
144 {
145 ilseq:
146 result = (size_t) -1;
147 __set_errno (EILSEQ);
148 }
149
150 return result;
151}
152