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Some more simplifications of xan_unpack

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Originally committed as revision 18588 to svn://svn.ffmpeg.org/ffmpeg/trunk
This commit is contained in:
Reimar Döffinger 2009-04-17 19:03:43 +00:00
parent 455fdd2f8c
commit c644665f42
1 changed files with 6 additions and 16 deletions
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22
libavcodec/xan.c
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@ -35,6 +35,7 @@
#include "libavutil/intreadwrite.h"
#include "avcodec.h"
#include "bytestream.h"
// for av_memcpy_backptr
#include "libavutil/lzo.h"
@ -128,8 +129,6 @@ static void xan_unpack(unsigned char *dest, const unsigned char *src, int dest_l
{
unsigned char opcode;
int size;
int offset;
int byte1, byte2, byte3;
unsigned char *dest_end = dest + dest_len;
while (dest < dest_end) {
@ -139,33 +138,24 @@ static void xan_unpack(unsigned char *dest, const unsigned char *src, int dest_l
int size2, back;
if ( (opcode & 0x80) == 0 ) {
offset = *src++;
size = opcode & 3;
size2 = ((opcode & 0x1c) >> 2) + 3;
back = ((opcode & 0x60) << 3) + offset + 1;
back = ((opcode & 0x60) << 3) + *src++ + 1;
} else if ( (opcode & 0x40) == 0 ) {
byte1 = *src++;
byte2 = *src++;
size = byte1 >> 6;
size = *src >> 6;
size2 = (opcode & 0x3f) + 4;
back = ((byte1 & 0x3f) << 8) + byte2 + 1;
back = (bytestream_get_be16(&src) & 0x3fff) + 1;
} else {
byte1 = *src++;
byte2 = *src++;
byte3 = *src++;
size = opcode & 3;
size2 = byte3 + 5 + ((opcode & 0xc) << 6);
back = ((opcode & 0x10) << 12) + 1 + (byte1 << 8) + byte2;
back = ((opcode & 0x10) << 12) + 1 + bytestream_get_be16(&src);
size2 = *src++ + 5 + ((opcode & 0xc) << 6);
if (dest >= dest_end || size > dest_end - dest)
return;
}