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