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Optimize/simplify ebml_read_num. 

Originally committed as revision 25026 to svn://svn.ffmpeg.org/ffmpeg/trunk
This commit is contained in:
Reimar Döffinger 2010-09-02 19:17:46 +00:00
parent 69a9c80bed
commit ff6a5fc1f0
1 changed files with 4 additions and 7 deletions
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11
libavformat/matroskadec.c
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@ -538,8 +538,8 @@ static int ebml_level_end(MatroskaDemuxContext *matroska)
static int ebml_read_num(MatroskaDemuxContext *matroska, ByteIOContext *pb,
int max_size, uint64_t *number)
{
int len_mask = 0x80, read = 1, n = 1;
int64_t total = 0;
int read = 1, n = 1;
uint64_t total = 0;
/* The first byte tells us the length in bytes - get_byte() can normally
* return 0, but since that's not a valid first ebmlID byte, we can
@ -556,10 +556,7 @@ static int ebml_read_num(MatroskaDemuxContext *matroska, ByteIOContext *pb,
}
/* get the length of the EBML number */
while (read <= max_size && !(total & len_mask)) {
read++;
len_mask >>= 1;
}
read = 8 - ff_log2_tab[total];
if (read > max_size) {
int64_t pos = url_ftell(pb) - 1;
av_log(matroska->ctx, AV_LOG_ERROR,
@ -569,7 +566,7 @@ static int ebml_read_num(MatroskaDemuxContext *matroska, ByteIOContext *pb,
}
/* read out length */
total &= ~len_mask;
total ^= 1 << ff_log2_tab[total];
while (n++ < read)
total = (total << 8) | get_byte(pb);