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 <ctype.h>
19#include <dlfcn.h>
20#include <gconv.h>
21#include <stdio.h>
22#include <string.h>
23#include <wchar.h>
24#include <wcsmbsload.h>
25#include <limits.h>
26
27#include <pointer_guard.h>
28
29
30wint_t
31__btowc (int c)
32{
33 const struct gconv_fcts *fcts;
34
35 /* If the parameter does not fit into one byte or it is the EOF value
36 we can give the answer now. */
37 if (c < SCHAR_MIN || c > UCHAR_MAX || c == EOF)
38 return WEOF;
39
40 /* We know that only ASCII compatible encodings are used for the
41 locale and that the wide character encoding is ISO 10646. */
42 if (isascii (c))
43 return (wint_t) c;
44
45 /* Get the conversion functions. */
46 fcts = get_gconv_fcts (_NL_CURRENT_DATA (LC_CTYPE));
47 __gconv_btowc_fct btowc_fct = fcts->towc->__btowc_fct;
48 if (fcts->towc->__shlib_handle != NULL)
49 PTR_DEMANGLE (btowc_fct);
50
51 if (__builtin_expect (fcts->towc_nsteps == 1, 1)
52 && __builtin_expect (btowc_fct != NULL, 1))
53 {
54 /* Use the shortcut function. */
55 return DL_CALL_FCT (btowc_fct, (fcts->towc, (unsigned char) c));
56 }
57 else
58 {
59 /* Fall back to the slow but generic method. */
60 wchar_t result;
61 struct __gconv_step_data data;
62 unsigned char inbuf[1];
63 const unsigned char *inptr = inbuf;
64 size_t dummy;
65 int status;
66
67 /* Tell where we want the result. */
68 data.__outbuf = (unsigned char *) &result;
69 data.__outbufend = data.__outbuf + sizeof (wchar_t);
70 data.__invocation_counter = 0;
71 data.__internal_use = 1;
72 data.__flags = __GCONV_IS_LAST;
73 data.__statep = &data.__state;
74
75 /* Make sure we start in the initial state. */
76 memset (&data.__state, '\0', sizeof (mbstate_t));
77
78 /* Create the input string. */
79 inbuf[0] = c;
80
81 __gconv_fct fct = fcts->towc->__fct;
82 if (fcts->towc->__shlib_handle != NULL)
83 PTR_DEMANGLE (fct);
84 status = DL_CALL_FCT (fct, (fcts->towc, &data, &inptr, inptr + 1,
85 NULL, &dummy, 0, 1));
86
87 if (status != __GCONV_OK && status != __GCONV_FULL_OUTPUT
88 && status != __GCONV_EMPTY_INPUT)
89 /* The conversion failed. */
90 result = WEOF;
91
92 return result;
93 }
94}
95weak_alias (__btowc, btowc)
96