| 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 | } |