lavu: add snprintf(), vsnprint() and strtod() replacements for MS runtime.
[libav.git] / compat / msvcrt / snprintf.c
1 /*
2 * C99-compatible snprintf() and vsnprintf() implementations
3 * Copyright (c) 2012 Ronald S. Bultje <rsbultje@gmail.com>
4 *
5 * This file is part of Libav.
6 *
7 * Libav is free software; you can redistribute it and/or
8 * modify it under the terms of the GNU Lesser General Public
9 * License as published by the Free Software Foundation; either
10 * version 2.1 of the License, or (at your option) any later version.
11 *
12 * Libav is distributed in the hope that it will be useful,
13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
15 * Lesser General Public License for more details.
16 *
17 * You should have received a copy of the GNU Lesser General Public
18 * License along with Libav; if not, write to the Free Software
19 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
20 */
21
22 #include <stdio.h>
23 #include <stdarg.h>
24 #include <limits.h>
25 #include <string.h>
26
27 #include "libavutil/error.h"
28
29 int avpriv_snprintf(char *s, size_t n, const char *fmt, ...)
30 {
31 va_list ap;
32 int ret;
33
34 va_start(ap, fmt);
35 ret = avpriv_vsnprintf(s, n, fmt, ap);
36 va_end(ap);
37
38 return ret;
39 }
40
41 int avpriv_vsnprintf(char *s, size_t n, const char *fmt,
42 va_list ap)
43 {
44 int ret;
45
46 if (n == 0)
47 return 0;
48 else if (n > INT_MAX)
49 return AVERROR(EOVERFLOW);
50
51 /* we use n - 1 here because if the buffer is not big enough, the MS
52 * runtime libraries don't add a terminating zero at the end. MSDN
53 * recommends to provide _snprintf/_vsnprintf() a buffer size that
54 * is one less than the actual buffer, and zero it before calling
55 * _snprintf/_vsnprintf() to workaround this problem.
56 * See http://msdn.microsoft.com/en-us/library/1kt27hek(v=vs.80).aspx */
57 memset(s, 0, n);
58 ret = _vsnprintf(s, n - 1, fmt, ap);
59 if (ret == -1)
60 ret = n;
61
62 return ret;
63 }