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