utils.c

    /* Now we have all the fields that we can get */
    if (!q) {
        if (duration)
            return 0;
        else
            return now * INT64_C(1000000);
    }

    if (duration) {
        t = dt.tm_hour * 3600 + dt.tm_min * 60 + dt.tm_sec;
    } else {
        dt.tm_isdst = -1;       /* unknown */
        if (is_utc) {
            t = mktimegm(&dt);
        } else {
            t = mktime(&dt);
        }
    }

    t *= 1000000;

    if (*q == '.') {
        int val, n;
        q++;
        for (val = 0, n = 100000; n >= 1; n /= 10, q++) {
            if (!isdigit(*q)) 
                break;
            val += n * (*q - '0');
        }
        t += val;
    }
    return t;
}

/* syntax: '?tag1=val1&tag2=val2...'. Little URL decoding is done. Return
   1 if found */
int find_info_tag(char *arg, int arg_size, const char *tag1, const char *info)
{
    const char *p;
    char tag[128], *q;

    p = info;
    if (*p == '?')
        p++;
    for(;;) {
        q = tag;
        while (*p != '\0' && *p != '=' && *p != '&') {
            if ((q - tag) < sizeof(tag) - 1)
                *q++ = *p;
            p++;
        }
        *q = '\0';
        q = arg;
        if (*p == '=') {
            p++;
            while (*p != '&' && *p != '\0') {
                if ((q - arg) < arg_size - 1) {
                    if (*p == '+')
                        *q++ = ' ';
                    else
                        *q++ = *p;
                }
                p++;
            }
            *q = '\0';
        }
        if (!strcmp(tag, tag1)) 
            return 1;
        if (*p != '&')
            break;
        p++;
    }
    return 0;
}

/* Return in 'buf' the path with '%d' replaced by number. Also handles
   the '%0nd' format where 'n' is the total number of digits and
   '%%'. Return 0 if OK, and -1 if format error */
int get_frame_filename(char *buf, int buf_size,
                       const char *path, int number)
{
    const char *p;
    char *q, buf1[20];
    int nd, len, c, percentd_found;

    q = buf;
    p = path;
    percentd_found = 0;
    for(;;) {
        c = *p++;
        if (c == '\0')
            break;
        if (c == '%') {
            do {
                nd = 0;
                while (isdigit(*p)) {
                    nd = nd * 10 + *p++ - '0';
                }
                c = *p++;
                if (c == '*' && nd > 0) {
                    // The nd field is actually the modulus
                    number = number % nd;
                    c = *p++;
                    nd = 0;
                }
            } while (isdigit(c));

            switch(c) {
            case '%':
                goto addchar;
            case 'd':
                if (percentd_found)
                    goto fail;
                percentd_found = 1;
                snprintf(buf1, sizeof(buf1), "%0*d", nd, number);
                len = strlen(buf1);
                if ((q - buf + len) > buf_size - 1)
                    goto fail;
                memcpy(q, buf1, len);
                q += len;
                break;
            default:
                goto fail;
            }
        } else {
        addchar:
            if ((q - buf) < buf_size - 1)
                *q++ = c;
        }
    }
    if (!percentd_found)
        goto fail;
    *q = '\0';
    return 0;
 fail:
    *q = '\0';
    return -1;
}

/**
 *
 * Print on stdout a nice hexa dump of a buffer
 * @param buf buffer
 * @param size buffer size
 */
void av_hex_dump(UINT8 *buf, int size)
{
    int len, i, j, c;

    for(i=0;i<size;i+=16) {
        len = size - i;
        if (len > 16)
            len = 16;
        printf("%08x ", i);
        for(j=0;j<16;j++) {
            if (j < len)
                printf(" %02x", buf[i+j]);
            else
                printf("   ");
        }
        printf(" ");
        for(j=0;j<len;j++) {
            c = buf[i+j];
            if (c < ' ' || c > '~')
                c = '.';
            printf("%c", c);
        }
        printf("\n");
    }
}

void url_split(char *proto, int proto_size,
               char *hostname, int hostname_size,
               int *port_ptr,
               char *path, int path_size,
               const char *url)
{
    const char *p;
    char *q;
    int port;

    port = -1;

    p = url;
    q = proto;
    while (*p != ':' && *p != '\0') {
        if ((q - proto) < proto_size - 1)
            *q++ = *p;
        p++;
    }
    if (proto_size > 0)
        *q = '\0';
    if (*p == '\0') {
        if (proto_size > 0)
            proto[0] = '\0';
        if (hostname_size > 0)
            hostname[0] = '\0';
        p = url;
    } else {
        p++;
        if (*p == '/')
            p++;
        if (*p == '/')
            p++;
        q = hostname;
        while (*p != ':' && *p != '/' && *p != '?' && *p != '\0') {
            if ((q - hostname) < hostname_size - 1)
                *q++ = *p;
            p++;
        }
        if (hostname_size > 0)
            *q = '\0';
        if (*p == ':') {
            p++;
            port = strtoul(p, (char **)&p, 10);
        }
    }
    if (port_ptr)
        *port_ptr = port;
    pstrcpy(path, path_size, p);
}

/**
 * Set the pts for a given stream
 * @param s stream 
 * @param pts_wrap_bits number of bits effectively used by the pts
 *        (used for wrap control, 33 is the value for MPEG) 
 * @param pts_num numerator to convert to seconds (MPEG: 1) 
 * @param pts_den denominator to convert to seconds (MPEG: 90000)
 */
void av_set_pts_info(AVFormatContext *s, int pts_wrap_bits,
                     int pts_num, int pts_den)
{
    s->pts_wrap_bits = pts_wrap_bits;
    s->pts_num = pts_num;
    s->pts_den = pts_den;
}

/* fraction handling */

/**
 * f = val + (num / den) + 0.5. 'num' is normalized so that it is such
 * as 0 <= num < den.
 *
 * @param f fractional number
 * @param val integer value
 * @param num must be >= 0
 * @param den must be >= 1 
 */
void av_frac_init(AVFrac *f, INT64 val, INT64 num, INT64 den)
{
    num += (den >> 1);
    if (num >= den) {
        val += num / den;
        num = num % den;
    }
    f->val = val;
    f->num = num;
    f->den = den;
}

/* set f to (val + 0.5) */
void av_frac_set(AVFrac *f, INT64 val)
{
    f->val = val;
    f->num = f->den >> 1;
}

/**
 * Fractionnal addition to f: f = f + (incr / f->den)
 *
 * @param f fractional number
 * @param incr increment, can be positive or negative
 */
void av_frac_add(AVFrac *f, INT64 incr)
{
    INT64 num, den;

    num = f->num + incr;
    den = f->den;
    if (num < 0) {
        f->val += num / den;
        num = num % den;
        if (num < 0) {
            num += den;
            f->val--;
        }
    } else if (num >= den) {
        f->val += num / den;
        num = num % den;
    }
    f->num = num;
}