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