Change license headers to say 'FFmpeg' instead of 'this program/this library'
[libav.git] / libavformat / cutils.c
1 /*
2 * Various simple utilities for ffmpeg system
3 * Copyright (c) 2000, 2001, 2002 Fabrice Bellard
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 #include "avformat.h"
22
23 #if !defined(CONFIG_NOCUTILS)
24 /**
25 * Return TRUE if val is a prefix of str. If it returns TRUE, ptr is
26 * set to the next character in 'str' after the prefix.
27 *
28 * @param str input string
29 * @param val prefix to test
30 * @param ptr updated after the prefix in str in there is a match
31 * @return TRUE if there is a match
32 */
33 int strstart(const char *str, const char *val, const char **ptr)
34 {
35 const char *p, *q;
36 p = str;
37 q = val;
38 while (*q != '\0') {
39 if (*p != *q)
40 return 0;
41 p++;
42 q++;
43 }
44 if (ptr)
45 *ptr = p;
46 return 1;
47 }
48
49 /**
50 * Return TRUE if val is a prefix of str (case independent). If it
51 * returns TRUE, ptr is set to the next character in 'str' after the
52 * prefix.
53 *
54 * @param str input string
55 * @param val prefix to test
56 * @param ptr updated after the prefix in str in there is a match
57 * @return TRUE if there is a match */
58 int stristart(const char *str, const char *val, const char **ptr)
59 {
60 const char *p, *q;
61 p = str;
62 q = val;
63 while (*q != '\0') {
64 if (toupper(*(const unsigned char *)p) != toupper(*(const unsigned char *)q))
65 return 0;
66 p++;
67 q++;
68 }
69 if (ptr)
70 *ptr = p;
71 return 1;
72 }
73
74 /**
75 * Copy the string str to buf. If str length is bigger than buf_size -
76 * 1 then it is clamped to buf_size - 1.
77 * NOTE: this function does what strncpy should have done to be
78 * useful. NEVER use strncpy.
79 *
80 * @param buf destination buffer
81 * @param buf_size size of destination buffer
82 * @param str source string
83 */
84 void pstrcpy(char *buf, int buf_size, const char *str)
85 {
86 int c;
87 char *q = buf;
88
89 if (buf_size <= 0)
90 return;
91
92 for(;;) {
93 c = *str++;
94 if (c == 0 || q >= buf + buf_size - 1)
95 break;
96 *q++ = c;
97 }
98 *q = '\0';
99 }
100
101 /* strcat and truncate. */
102 char *pstrcat(char *buf, int buf_size, const char *s)
103 {
104 int len;
105 len = strlen(buf);
106 if (len < buf_size)
107 pstrcpy(buf + len, buf_size - len, s);
108 return buf;
109 }
110
111 #endif
112
113 /* add one element to a dynamic array */
114 void __dynarray_add(unsigned long **tab_ptr, int *nb_ptr, unsigned long elem)
115 {
116 int nb, nb_alloc;
117 unsigned long *tab;
118
119 nb = *nb_ptr;
120 tab = *tab_ptr;
121 if ((nb & (nb - 1)) == 0) {
122 if (nb == 0)
123 nb_alloc = 1;
124 else
125 nb_alloc = nb * 2;
126 tab = av_realloc(tab, nb_alloc * sizeof(unsigned long));
127 *tab_ptr = tab;
128 }
129 tab[nb++] = elem;
130 *nb_ptr = nb;
131 }
132
133 time_t mktimegm(struct tm *tm)
134 {
135 time_t t;
136
137 int y = tm->tm_year + 1900, m = tm->tm_mon + 1, d = tm->tm_mday;
138
139 if (m < 3) {
140 m += 12;
141 y--;
142 }
143
144 t = 86400 *
145 (d + (153 * m - 457) / 5 + 365 * y + y / 4 - y / 100 + y / 400 - 719469);
146
147 t += 3600 * tm->tm_hour + 60 * tm->tm_min + tm->tm_sec;
148
149 return t;
150 }
151
152 #define ISLEAP(y) (((y) % 4 == 0) && (((y) % 100) != 0 || ((y) % 400) == 0))
153 #define LEAPS_COUNT(y) ((y)/4 - (y)/100 + (y)/400)
154
155 /* this is our own gmtime_r. it differs from its POSIX counterpart in a
156 couple of places, though. */
157 struct tm *brktimegm(time_t secs, struct tm *tm)
158 {
159 int days, y, ny, m;
160 int md[] = { 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31 };
161
162 days = secs / 86400;
163 secs %= 86400;
164 tm->tm_hour = secs / 3600;
165 tm->tm_min = (secs % 3600) / 60;
166 tm->tm_sec = secs % 60;
167
168 /* oh well, may be someone some day will invent a formula for this stuff */
169 y = 1970; /* start "guessing" */
170 while (days >= (ISLEAP(y)?366:365)) {
171 ny = (y + days/366);
172 days -= (ny - y) * 365 + LEAPS_COUNT(ny - 1) - LEAPS_COUNT(y - 1);
173 y = ny;
174 }
175 md[1] = ISLEAP(y)?29:28;
176 for (m=0; days >= md[m]; m++)
177 days -= md[m];
178
179 tm->tm_year = y; /* unlike gmtime_r we store complete year here */
180 tm->tm_mon = m+1; /* unlike gmtime_r tm_mon is from 1 to 12 */
181 tm->tm_mday = days+1;
182
183 return tm;
184 }
185
186 /* get a positive number between n_min and n_max, for a maximum length
187 of len_max. Return -1 if error. */
188 static int date_get_num(const char **pp,
189 int n_min, int n_max, int len_max)
190 {
191 int i, val, c;
192 const char *p;
193
194 p = *pp;
195 val = 0;
196 for(i = 0; i < len_max; i++) {
197 c = *p;
198 if (!isdigit(c))
199 break;
200 val = (val * 10) + c - '0';
201 p++;
202 }
203 /* no number read ? */
204 if (p == *pp)
205 return -1;
206 if (val < n_min || val > n_max)
207 return -1;
208 *pp = p;
209 return val;
210 }
211
212 /* small strptime for ffmpeg */
213 const char *small_strptime(const char *p, const char *fmt,
214 struct tm *dt)
215 {
216 int c, val;
217
218 for(;;) {
219 c = *fmt++;
220 if (c == '\0') {
221 return p;
222 } else if (c == '%') {
223 c = *fmt++;
224 switch(c) {
225 case 'H':
226 val = date_get_num(&p, 0, 23, 2);
227 if (val == -1)
228 return NULL;
229 dt->tm_hour = val;
230 break;
231 case 'M':
232 val = date_get_num(&p, 0, 59, 2);
233 if (val == -1)
234 return NULL;
235 dt->tm_min = val;
236 break;
237 case 'S':
238 val = date_get_num(&p, 0, 59, 2);
239 if (val == -1)
240 return NULL;
241 dt->tm_sec = val;
242 break;
243 case 'Y':
244 val = date_get_num(&p, 0, 9999, 4);
245 if (val == -1)
246 return NULL;
247 dt->tm_year = val - 1900;
248 break;
249 case 'm':
250 val = date_get_num(&p, 1, 12, 2);
251 if (val == -1)
252 return NULL;
253 dt->tm_mon = val - 1;
254 break;
255 case 'd':
256 val = date_get_num(&p, 1, 31, 2);
257 if (val == -1)
258 return NULL;
259 dt->tm_mday = val;
260 break;
261 case '%':
262 goto match;
263 default:
264 return NULL;
265 }
266 } else {
267 match:
268 if (c != *p)
269 return NULL;
270 p++;
271 }
272 }
273 return p;
274 }
275