It makes more sense to return 1 here in case of overflow.
[FFMpeg-mirror/DVCPRO-HD.git] / libavformat / cutils.c
blob42ef5996d996e57b59e147c3e0cc2b3d676d1e79
1 /*
2 * Various simple utilities for ffmpeg system
3 * Copyright (c) 2000, 2001, 2002 Fabrice Bellard
5 * This file is part of FFmpeg.
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.
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.
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
21 #include "avformat.h"
23 /* add one element to a dynamic array */
24 void ff_dynarray_add(unsigned long **tab_ptr, int *nb_ptr, unsigned long elem)
26 int nb, nb_alloc;
27 unsigned long *tab;
29 nb = *nb_ptr;
30 tab = *tab_ptr;
31 if ((nb & (nb - 1)) == 0) {
32 if (nb == 0)
33 nb_alloc = 1;
34 else
35 nb_alloc = nb * 2;
36 tab = av_realloc(tab, nb_alloc * sizeof(unsigned long));
37 *tab_ptr = tab;
39 tab[nb++] = elem;
40 *nb_ptr = nb;
43 time_t mktimegm(struct tm *tm)
45 time_t t;
47 int y = tm->tm_year + 1900, m = tm->tm_mon + 1, d = tm->tm_mday;
49 if (m < 3) {
50 m += 12;
51 y--;
54 t = 86400 *
55 (d + (153 * m - 457) / 5 + 365 * y + y / 4 - y / 100 + y / 400 - 719469);
57 t += 3600 * tm->tm_hour + 60 * tm->tm_min + tm->tm_sec;
59 return t;
62 #define ISLEAP(y) (((y) % 4 == 0) && (((y) % 100) != 0 || ((y) % 400) == 0))
63 #define LEAPS_COUNT(y) ((y)/4 - (y)/100 + (y)/400)
65 /* This is our own gmtime_r. It differs from its POSIX counterpart in a
66 couple of places, though. */
67 struct tm *brktimegm(time_t secs, struct tm *tm)
69 int days, y, ny, m;
70 int md[] = { 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31 };
72 days = secs / 86400;
73 secs %= 86400;
74 tm->tm_hour = secs / 3600;
75 tm->tm_min = (secs % 3600) / 60;
76 tm->tm_sec = secs % 60;
78 /* oh well, may be someone some day will invent a formula for this stuff */
79 y = 1970; /* start "guessing" */
80 while (days > 365) {
81 ny = (y + days/366);
82 days -= (ny - y) * 365 + LEAPS_COUNT(ny - 1) - LEAPS_COUNT(y - 1);
83 y = ny;
85 if (days==365 && !ISLEAP(y)) { days=0; y++; }
86 md[1] = ISLEAP(y)?29:28;
87 for (m=0; days >= md[m]; m++)
88 days -= md[m];
90 tm->tm_year = y; /* unlike gmtime_r we store complete year here */
91 tm->tm_mon = m+1; /* unlike gmtime_r tm_mon is from 1 to 12 */
92 tm->tm_mday = days+1;
94 return tm;
97 /* get a positive number between n_min and n_max, for a maximum length
98 of len_max. Return -1 if error. */
99 static int date_get_num(const char **pp,
100 int n_min, int n_max, int len_max)
102 int i, val, c;
103 const char *p;
105 p = *pp;
106 val = 0;
107 for(i = 0; i < len_max; i++) {
108 c = *p;
109 if (!isdigit(c))
110 break;
111 val = (val * 10) + c - '0';
112 p++;
114 /* no number read ? */
115 if (p == *pp)
116 return -1;
117 if (val < n_min || val > n_max)
118 return -1;
119 *pp = p;
120 return val;
123 /* small strptime for ffmpeg */
124 const char *small_strptime(const char *p, const char *fmt,
125 struct tm *dt)
127 int c, val;
129 for(;;) {
130 c = *fmt++;
131 if (c == '\0') {
132 return p;
133 } else if (c == '%') {
134 c = *fmt++;
135 switch(c) {
136 case 'H':
137 val = date_get_num(&p, 0, 23, 2);
138 if (val == -1)
139 return NULL;
140 dt->tm_hour = val;
141 break;
142 case 'M':
143 val = date_get_num(&p, 0, 59, 2);
144 if (val == -1)
145 return NULL;
146 dt->tm_min = val;
147 break;
148 case 'S':
149 val = date_get_num(&p, 0, 59, 2);
150 if (val == -1)
151 return NULL;
152 dt->tm_sec = val;
153 break;
154 case 'Y':
155 val = date_get_num(&p, 0, 9999, 4);
156 if (val == -1)
157 return NULL;
158 dt->tm_year = val - 1900;
159 break;
160 case 'm':
161 val = date_get_num(&p, 1, 12, 2);
162 if (val == -1)
163 return NULL;
164 dt->tm_mon = val - 1;
165 break;
166 case 'd':
167 val = date_get_num(&p, 1, 31, 2);
168 if (val == -1)
169 return NULL;
170 dt->tm_mday = val;
171 break;
172 case '%':
173 goto match;
174 default:
175 return NULL;
177 } else {
178 match:
179 if (c != *p)
180 return NULL;
181 p++;
184 return p;