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[libav.git] / libavformat / cutils.c
1 /*
2 * Various simple utilities for ffmpeg system
3 * Copyright (c) 2000, 2001, 2002 Fabrice Bellard
4 *
5 * This library is free software; you can redistribute it and/or
6 * modify it under the terms of the GNU Lesser General Public
7 * License as published by the Free Software Foundation; either
8 * version 2 of the License, or (at your option) any later version.
9 *
10 * This library is distributed in the hope that it will be useful,
11 * but WITHOUT ANY WARRANTY; without even the implied warranty of
12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13 * Lesser General Public License for more details.
14 *
15 * You should have received a copy of the GNU Lesser General Public
16 * License along with this library; if not, write to the Free Software
17 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
18 */
19 #include "avformat.h"
20
21 #if !defined(CONFIG_NOCUTILS)
22 /**
23 * Return TRUE if val is a prefix of str. If it returns TRUE, ptr is
24 * set to the next character in 'str' after the prefix.
25 *
26 * @param str input string
27 * @param val prefix to test
28 * @param ptr updated after the prefix in str in there is a match
29 * @return TRUE if there is a match
30 */
31 int strstart(const char *str, const char *val, const char **ptr)
32 {
33 const char *p, *q;
34 p = str;
35 q = val;
36 while (*q != '\0') {
37 if (*p != *q)
38 return 0;
39 p++;
40 q++;
41 }
42 if (ptr)
43 *ptr = p;
44 return 1;
45 }
46
47 /**
48 * Return TRUE if val is a prefix of str (case independent). If it
49 * returns TRUE, ptr is set to the next character in 'str' after the
50 * prefix.
51 *
52 * @param str input string
53 * @param val prefix to test
54 * @param ptr updated after the prefix in str in there is a match
55 * @return TRUE if there is a match */
56 int stristart(const char *str, const char *val, const char **ptr)
57 {
58 const char *p, *q;
59 p = str;
60 q = val;
61 while (*q != '\0') {
62 if (toupper(*(const unsigned char *)p) != toupper(*(const unsigned char *)q))
63 return 0;
64 p++;
65 q++;
66 }
67 if (ptr)
68 *ptr = p;
69 return 1;
70 }
71
72 /**
73 * Copy the string str to buf. If str length is bigger than buf_size -
74 * 1 then it is clamped to buf_size - 1.
75 * NOTE: this function does what strncpy should have done to be
76 * useful. NEVER use strncpy.
77 *
78 * @param buf destination buffer
79 * @param buf_size size of destination buffer
80 * @param str source string
81 */
82 void pstrcpy(char *buf, int buf_size, const char *str)
83 {
84 int c;
85 char *q = buf;
86
87 if (buf_size <= 0)
88 return;
89
90 for(;;) {
91 c = *str++;
92 if (c == 0 || q >= buf + buf_size - 1)
93 break;
94 *q++ = c;
95 }
96 *q = '\0';
97 }
98
99 /* strcat and truncate. */
100 char *pstrcat(char *buf, int buf_size, const char *s)
101 {
102 int len;
103 len = strlen(buf);
104 if (len < buf_size)
105 pstrcpy(buf + len, buf_size - len, s);
106 return buf;
107 }
108
109 #endif
110
111 /* add one element to a dynamic array */
112 void __dynarray_add(unsigned long **tab_ptr, int *nb_ptr, unsigned long elem)
113 {
114 int nb, nb_alloc;
115 unsigned long *tab;
116
117 nb = *nb_ptr;
118 tab = *tab_ptr;
119 if ((nb & (nb - 1)) == 0) {
120 if (nb == 0)
121 nb_alloc = 1;
122 else
123 nb_alloc = nb * 2;
124 tab = av_realloc(tab, nb_alloc * sizeof(unsigned long));
125 *tab_ptr = tab;
126 }
127 tab[nb++] = elem;
128 *nb_ptr = nb;
129 }
130
131 time_t mktimegm(struct tm *tm)
132 {
133 time_t t;
134
135 int y = tm->tm_year + 1900, m = tm->tm_mon + 1, d = tm->tm_mday;
136
137 if (m < 3) {
138 m += 12;
139 y--;
140 }
141
142 t = 86400 *
143 (d + (153 * m - 457) / 5 + 365 * y + y / 4 - y / 100 + y / 400 - 719469);
144
145 t += 3600 * tm->tm_hour + 60 * tm->tm_min + tm->tm_sec;
146
147 return t;
148 }
149
150 #define ISLEAP(y) (((y) % 4 == 0) && (((y) % 100) != 0 || ((y) % 400) == 0))
151 #define LEAPS_COUNT(y) ((y)/4 - (y)/100 + (y)/400)
152
153 /* this is our own gmtime_r. it differs from its POSIX counterpart in a
154 couple of places, though. */
155 struct tm *brktimegm(time_t secs, struct tm *tm)
156 {
157 int days, y, ny, m;
158 int md[] = { 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31 };
159
160 days = secs / 86400;
161 secs %= 86400;
162 tm->tm_hour = secs / 3600;
163 tm->tm_min = (secs % 3600) / 60;
164 tm->tm_sec = secs % 60;
165
166 /* oh well, may be someone some day will invent a formula for this stuff */
167 y = 1970; /* start "guessing" */
168 while (days >= (ISLEAP(y)?366:365)) {
169 ny = (y + days/366);
170 days -= (ny - y) * 365 + LEAPS_COUNT(ny - 1) - LEAPS_COUNT(y - 1);
171 y = ny;
172 }
173 md[1] = ISLEAP(y)?29:28;
174 for (m=0; days >= md[m]; m++)
175 days -= md[m];
176
177 tm->tm_year = y; /* unlike gmtime_r we store complete year here */
178 tm->tm_mon = m+1; /* unlike gmtime_r tm_mon is from 1 to 12 */
179 tm->tm_mday = days+1;
180
181 return tm;
182 }
183
184 /* get a positive number between n_min and n_max, for a maximum length
185 of len_max. Return -1 if error. */
186 static int date_get_num(const char **pp,
187 int n_min, int n_max, int len_max)
188 {
189 int i, val, c;
190 const char *p;
191
192 p = *pp;
193 val = 0;
194 for(i = 0; i < len_max; i++) {
195 c = *p;
196 if (!isdigit(c))
197 break;
198 val = (val * 10) + c - '0';
199 p++;
200 }
201 /* no number read ? */
202 if (p == *pp)
203 return -1;
204 if (val < n_min || val > n_max)
205 return -1;
206 *pp = p;
207 return val;
208 }
209
210 /* small strptime for ffmpeg */
211 const char *small_strptime(const char *p, const char *fmt,
212 struct tm *dt)
213 {
214 int c, val;
215
216 for(;;) {
217 c = *fmt++;
218 if (c == '\0') {
219 return p;
220 } else if (c == '%') {
221 c = *fmt++;
222 switch(c) {
223 case 'H':
224 val = date_get_num(&p, 0, 23, 2);
225 if (val == -1)
226 return NULL;
227 dt->tm_hour = val;
228 break;
229 case 'M':
230 val = date_get_num(&p, 0, 59, 2);
231 if (val == -1)
232 return NULL;
233 dt->tm_min = val;
234 break;
235 case 'S':
236 val = date_get_num(&p, 0, 59, 2);
237 if (val == -1)
238 return NULL;
239 dt->tm_sec = val;
240 break;
241 case 'Y':
242 val = date_get_num(&p, 0, 9999, 4);
243 if (val == -1)
244 return NULL;
245 dt->tm_year = val - 1900;
246 break;
247 case 'm':
248 val = date_get_num(&p, 1, 12, 2);
249 if (val == -1)
250 return NULL;
251 dt->tm_mon = val - 1;
252 break;
253 case 'd':
254 val = date_get_num(&p, 1, 31, 2);
255 if (val == -1)
256 return NULL;
257 dt->tm_mday = val;
258 break;
259 case '%':
260 goto match;
261 default:
262 return NULL;
263 }
264 } else {
265 match:
266 if (c != *p)
267 return NULL;
268 p++;
269 }
270 }
271 return p;
272 }
273