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2ba45a60 DM |
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 FFmpeg. | |
6 | * | |
7 | * FFmpeg 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 | * FFmpeg 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 FFmpeg; 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 "compat/va_copy.h" | |
28 | #include "libavutil/error.h" | |
29 | ||
30 | #if defined(__MINGW32__) | |
31 | #define EOVERFLOW EFBIG | |
32 | #endif | |
33 | ||
34 | int avpriv_snprintf(char *s, size_t n, const char *fmt, ...) | |
35 | { | |
36 | va_list ap; | |
37 | int ret; | |
38 | ||
39 | va_start(ap, fmt); | |
40 | ret = avpriv_vsnprintf(s, n, fmt, ap); | |
41 | va_end(ap); | |
42 | ||
43 | return ret; | |
44 | } | |
45 | ||
46 | int avpriv_vsnprintf(char *s, size_t n, const char *fmt, | |
47 | va_list ap) | |
48 | { | |
49 | int ret; | |
50 | va_list ap_copy; | |
51 | ||
52 | if (n == 0) | |
53 | return _vscprintf(fmt, ap); | |
54 | else if (n > INT_MAX) | |
55 | return AVERROR(EOVERFLOW); | |
56 | ||
57 | /* we use n - 1 here because if the buffer is not big enough, the MS | |
58 | * runtime libraries don't add a terminating zero at the end. MSDN | |
59 | * recommends to provide _snprintf/_vsnprintf() a buffer size that | |
60 | * is one less than the actual buffer, and zero it before calling | |
61 | * _snprintf/_vsnprintf() to workaround this problem. | |
62 | * See http://msdn.microsoft.com/en-us/library/1kt27hek(v=vs.80).aspx */ | |
63 | memset(s, 0, n); | |
64 | va_copy(ap_copy, ap); | |
65 | ret = _vsnprintf(s, n - 1, fmt, ap_copy); | |
66 | va_end(ap_copy); | |
67 | if (ret == -1) | |
68 | ret = _vscprintf(fmt, ap); | |
69 | ||
70 | return ret; | |
71 | } |