[FFmpeg-devel] [PATCH] Decoding of raw UTF-8 text from Ogg streams

[Michael Niedermayer]

On Sun, Aug 16, 2009 at 04:02:25PM +0100, ogg.k.ogg.k at googlemail.com wrote:
> > So I can't see how what you said would make any sense at all
> 
> After thinking some more about the code and your comment, I now
> see why it all falls down into place without needing the extra check.
> Patch attached again :)

[...]
> +static void find_timing(const AVPacket *avpkt, const AVRational *time_base,
> +                        uint32_t *start, uint32_t *end)
> +{
> +    unsigned int hour0, min0, sec0, hsec0;
> +    unsigned int hour1, min1, sec1, hsec1;
> +    uint32_t start_ms, end_ms, pts_ms;
> +    char *copy;
> +
> +    *start = 0;
> +    *end   = 0;
> +
> +    copy = av_malloc(avpkt->size+1);
> +    if (!copy)
> +        return;

this silent error handling seems bad to me


> +    memcpy(copy, avpkt->data, avpkt->size);
> +    copy[avpkt->size] = 0;
> +
> +    if (sscanf(copy, "%*[^,],%u:%u:%u%*c%u,%u:%u:%u%*c%u",
> +        &hour0, &min0, &sec0, &hsec0, &hour1, &min1, &sec1, &hsec1) != 8) {
> +        goto end;
> +    }
> +
> +#define CHK(val, mx) if ((val) >= (mx)) goto end;
> +    CHK(hour0, ((unsigned int)INT_MAX)+1);
> +    CHK(hour1, ((unsigned int)INT_MAX)+1);
> +    CHK(min0,  60);
> +    CHK(min1,  60);
> +    CHK(sec0,  60);
> +    CHK(sec1,  60);
> +    CHK(hsec0, 100);
> +    CHK(hsec1, 100);
> +#undef CHK
> +
> +    /* 1197 hours or so */
> +    start_ms = hour0 * 60*60*1000 + min0 * 60*1000 + sec0 * 1000 + hsec0 * 10;
> +    end_ms   = hour1 * 60*60*1000 + min1 * 60*1000 + sec1 * 1000 + hsec1 * 10;
> +    pts_ms   = 1000 * avpkt->pts * time_base->num / time_base->den;
> +
> +    if (start_ms < pts_ms || end_ms < start_ms)
> +        goto end;
> +
> +    /* assumes the packet pts is set to the start data from the string */

> +    *start = 0;

if start is always 0 it doesnt need to be passed into the function to begin with


[...]
-- 
Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

If you really think that XML is the answer, then you definitly missunderstood
the question -- Attila Kinali
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