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     int c;
  79     char *q = buf;
  80
  81     if (buf_size <= 0)
  82         return;
  83
  84     for(;;) {
  85         c = *str++;
  86         if (c == 0 || q >= buf + buf_size - 1)
  87             break;
  88         *q++ = c;
  89     }
  90     *q = '\0';
  91 }
  92
  93 /* strcat and truncate. */
  94 char *pstrcat(char *buf, int buf_size, const char *s)
  95 {
  96     int len;
  97     len = strlen(buf);
  98     if (len < buf_size)
  99         pstrcpy(buf + len, buf_size - len, s);
 100     return buf;
 101 }
 102
 103 #endif
 104
 105 /* add one element to a dynamic array */
 106 void __dynarray_add(unsigned long **tab_ptr, int *nb_ptr, unsigned long elem)
 107 {
 108     int nb, nb_alloc;
 109     unsigned long *tab;
 110
 111     nb = *nb_ptr;
 112     tab = *tab_ptr;
 113     if ((nb & (nb - 1)) == 0) {
 114         if (nb == 0)
 115             nb_alloc = 1;
 116         else
 117             nb_alloc = nb * 2;
 118         tab = av_realloc(tab, nb_alloc * sizeof(unsigned long));
 119         *tab_ptr = tab;
 120     }
 121     tab[nb++] = elem;
 122     *nb_ptr = nb;
 123 }
 124
 125 time_t mktimegm(struct tm *tm)
 126 {
 127     time_t t;
 128
 129     int y = tm->tm_year + 1900, m = tm->tm_mon + 1, d = tm->tm_mday;
 130
 131     if (m < 3) {
 132         m += 12;
 133         y--;
 134     }
 135
 136     t = 86400 *
 137         (d + (153 * m - 457) / 5 + 365 * y + y / 4 - y / 100 + y / 400 - 719469);
 138
 139     t += 3600 * tm->tm_hour + 60 * tm->tm_min + tm->tm_sec;
 140
 141     return t;
 142 }
 143
 144 #define ISLEAP(y) (((y) % 4 == 0) && (((y) % 100) != 0 || ((y) % 400) == 0))
 145 #define LEAPS_COUNT(y) ((y)/4 - (y)/100 + (y)/400)
 146
 147 /* this is our own gmtime_r. it differs from its POSIX counterpart in a
 148    couple of places, though. */
 149 struct tm *brktimegm(time_t secs, struct tm *tm)
 150 {
 151     int days, y, ny, m;
 152     int md[] = { 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31 };
 153
 154     days = secs / 86400;
 155     secs %= 86400;
 156     tm->tm_hour = secs / 3600;
 157     tm->tm_min = (secs % 3600) / 60;
 158     tm->tm_sec =  secs % 60;
 159
 160     /* oh well, may be someone some day will invent a formula for this stuff */
 161     y = 1970; /* start "guessing" */
 162     while (days >= (ISLEAP(y)?366:365)) {
 163         ny = (y + days/366);
 164         days -= (ny - y) * 365 + LEAPS_COUNT(ny - 1) - LEAPS_COUNT(y - 1);
 165         y = ny;
 166     }
 167     md[1] = ISLEAP(y)?29:28;
 168     for (m=0; days >= md[m]; m++)
 169          days -= md[m];
 170
 171     tm->tm_year = y;  /* unlike gmtime_r we store complete year here */
 172     tm->tm_mon = m+1; /* unlike gmtime_r tm_mon is from 1 to 12 */
 173     tm->tm_mday = days+1;
 174
 175     return tm;
 176 }
 177
 178 /* get a positive number between n_min and n_max, for a maximum length
 179    of len_max. Return -1 if error. */
 180 static int date_get_num(const char **pp,
 181                         int n_min, int n_max, int len_max)
 182 {
 183     int i, val, c;
 184     const char *p;
 185
 186     p = *pp;
 187     val = 0;
 188     for(i = 0; i < len_max; i++) {
 189         c = *p;
 190         if (!isdigit(c))
 191             break;
 192         val = (val * 10) + c - '0';
 193         p++;
 194     }
 195     /* no number read ? */
 196     if (p == *pp)
 197         return -1;
 198     if (val < n_min || val > n_max)
 199         return -1;
 200     *pp = p;
 201     return val;
 202 }
 203
 204 /* small strptime for ffmpeg */
 205 const char *small_strptime(const char *p, const char *fmt,
 206                            struct tm *dt)
 207 {
 208     int c, val;
 209
 210     for(;;) {
 211         c = *fmt++;
 212         if (c == '\0') {
 213             return p;
 214         } else if (c == '%') {
 215             c = *fmt++;
 216             switch(c) {
 217             case 'H':
 218                 val = date_get_num(&p, 0, 23, 2);
 219                 if (val == -1)
 220                     return NULL;
 221                 dt->tm_hour = val;
 222                 break;
 223             case 'M':
 224                 val = date_get_num(&p, 0, 59, 2);
 225                 if (val == -1)
 226                     return NULL;
 227                 dt->tm_min = val;
 228                 break;
 229             case 'S':
 230                 val = date_get_num(&p, 0, 59, 2);
 231                 if (val == -1)
 232                     return NULL;
 233                 dt->tm_sec = val;
 234                 break;
 235             case 'Y':
 236                 val = date_get_num(&p, 0, 9999, 4);
 237                 if (val == -1)
 238                     return NULL;
 239                 dt->tm_year = val - 1900;
 240                 break;
 241             case 'm':
 242                 val = date_get_num(&p, 1, 12, 2);
 243                 if (val == -1)
 244                     return NULL;
 245                 dt->tm_mon = val - 1;
 246                 break;
 247             case 'd':
 248                 val = date_get_num(&p, 1, 31, 2);
 249                 if (val == -1)
 250                     return NULL;
 251                 dt->tm_mday = val;
 252                 break;
 253             case '%':
 254                 goto match;
 255             default:
 256                 return NULL;
 257             }
 258         } else {
 259         match:
 260             if (c != *p)
 261                 return NULL;
 262             p++;
 263         }
 264     }
 265     return p;
 266 }
 267