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ffmpeg / libavformat / cutils.c @ 9a2cb05f

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/*
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 * Various simple utilities for ffmpeg system
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 * Copyright (c) 2000, 2001, 2002 Fabrice Bellard
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 *
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 * This file is part of FFmpeg.
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 *
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 * FFmpeg is free software; you can redistribute it and/or
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 * modify it under the terms of the GNU Lesser General Public
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 * License as published by the Free Software Foundation; either
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 * version 2.1 of the License, or (at your option) any later version.
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 *
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 * FFmpeg is distributed in the hope that it will be useful,
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 * but WITHOUT ANY WARRANTY; without even the implied warranty of
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 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
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 * Lesser General Public License for more details.
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 *
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 * You should have received a copy of the GNU Lesser General Public
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 * License along with FFmpeg; if not, write to the Free Software
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 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
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 */
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#include "avformat.h"
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#include "internal.h"
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/* add one element to a dynamic array */
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void ff_dynarray_add(intptr_t **tab_ptr, int *nb_ptr, intptr_t elem)
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{
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    int nb, nb_alloc;
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    intptr_t *tab;
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    nb = *nb_ptr;
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    tab = *tab_ptr;
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    if ((nb & (nb - 1)) == 0) {
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        if (nb == 0)
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            nb_alloc = 1;
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        else
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            nb_alloc = nb * 2;
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        tab = av_realloc(tab, nb_alloc * sizeof(intptr_t));
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        *tab_ptr = tab;
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    }
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    tab[nb++] = elem;
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    *nb_ptr = nb;
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}
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time_t mktimegm(struct tm *tm)
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{
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    time_t t;
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    int y = tm->tm_year + 1900, m = tm->tm_mon + 1, d = tm->tm_mday;
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    if (m < 3) {
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        m += 12;
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        y--;
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    }
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    t = 86400 *
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        (d + (153 * m - 457) / 5 + 365 * y + y / 4 - y / 100 + y / 400 - 719469);
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    t += 3600 * tm->tm_hour + 60 * tm->tm_min + tm->tm_sec;
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    return t;
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}
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#define ISLEAP(y) (((y) % 4 == 0) && (((y) % 100) != 0 || ((y) % 400) == 0))
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#define LEAPS_COUNT(y) ((y)/4 - (y)/100 + (y)/400)
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/* This is our own gmtime_r. It differs from its POSIX counterpart in a
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   couple of places, though. */
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struct tm *brktimegm(time_t secs, struct tm *tm)
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{
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    int days, y, ny, m;
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    int md[] = { 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31 };
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    days = secs / 86400;
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    secs %= 86400;
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    tm->tm_hour = secs / 3600;
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    tm->tm_min = (secs % 3600) / 60;
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    tm->tm_sec =  secs % 60;
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    /* oh well, may be someone some day will invent a formula for this stuff */
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    y = 1970; /* start "guessing" */
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    while (days > 365) {
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        ny = (y + days/366);
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        days -= (ny - y) * 365 + LEAPS_COUNT(ny - 1) - LEAPS_COUNT(y - 1);
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        y = ny;
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    }
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    if (days==365 && !ISLEAP(y)) { days=0; y++; }
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    md[1] = ISLEAP(y)?29:28;
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    for (m=0; days >= md[m]; m++)
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         days -= md[m];
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    tm->tm_year = y;  /* unlike gmtime_r we store complete year here */
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    tm->tm_mon = m+1; /* unlike gmtime_r tm_mon is from 1 to 12 */
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    tm->tm_mday = days+1;
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    return tm;
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}
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/* get a positive number between n_min and n_max, for a maximum length
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   of len_max. Return -1 if error. */
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static int date_get_num(const char **pp,
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                        int n_min, int n_max, int len_max)
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{
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    int i, val, c;
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    const char *p;
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    p = *pp;
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    val = 0;
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    for(i = 0; i < len_max; i++) {
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        c = *p;
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        if (!isdigit(c))
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            break;
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        val = (val * 10) + c - '0';
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        p++;
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    }
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    /* no number read ? */
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    if (p == *pp)
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        return -1;
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    if (val < n_min || val > n_max)
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        return -1;
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    *pp = p;
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    return val;
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}
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/* small strptime for ffmpeg */
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const char *small_strptime(const char *p, const char *fmt,
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                           struct tm *dt)
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{
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    int c, val;
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    for(;;) {
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        c = *fmt++;
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        if (c == '\0') {
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            return p;
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        } else if (c == '%') {
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            c = *fmt++;
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            switch(c) {
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            case 'H':
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                val = date_get_num(&p, 0, 23, 2);
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                if (val == -1)
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                    return NULL;
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                dt->tm_hour = val;
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                break;
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            case 'M':
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                val = date_get_num(&p, 0, 59, 2);
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                if (val == -1)
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                    return NULL;
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                dt->tm_min = val;
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                break;
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            case 'S':
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                val = date_get_num(&p, 0, 59, 2);
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                if (val == -1)
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                    return NULL;
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                dt->tm_sec = val;
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                break;
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            case 'Y':
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                val = date_get_num(&p, 0, 9999, 4);
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                if (val == -1)
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                    return NULL;
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                dt->tm_year = val - 1900;
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                break;
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            case 'm':
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                val = date_get_num(&p, 1, 12, 2);
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                if (val == -1)
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                    return NULL;
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                dt->tm_mon = val - 1;
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                break;
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            case 'd':
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                val = date_get_num(&p, 1, 31, 2);
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                if (val == -1)
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                    return NULL;
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                dt->tm_mday = val;
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                break;
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            case '%':
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                goto match;
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            default:
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                return NULL;
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            }
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        } else {
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        match:
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            if (c != *p)
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                return NULL;
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            p++;
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        }
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    }
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    return p;
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}
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