generic-library/ffmpeg
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simplify

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Originally committed as revision 8509 to svn://svn.ffmpeg.org/ffmpeg/trunk
This commit is contained in:
Michael Niedermayer 2007-03-25 13:41:14 +00:00
parent b666151045
commit 62ef8925c5
1 changed files with 4 additions and 10 deletions
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14
libavcodec/lzw.c
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@ -55,7 +55,7 @@ struct LZWState {
int end_code; int end_code;
int newcodes; ///< First available code int newcodes; ///< First available code
int top_slot; ///< Highest code for current size int top_slot; ///< Highest code for current size
int top_slot2; ///< Highest possible code for current size (<=top_slot) int extra_slot;
int slot; ///< Last read code int slot; ///< Last read code
int fc, oc; int fc, oc;
uint8_t *sp; uint8_t *sp;
@ -158,10 +158,10 @@ int ff_lzw_decode_init(LZWState *p, int csize, uint8_t *buf, int buf_size, int m
s->mode = mode; s->mode = mode;
switch(s->mode){ switch(s->mode){
case FF_LZW_GIF: case FF_LZW_GIF:
s->top_slot2 = s->top_slot; s->extra_slot= 0;
break; break;
case FF_LZW_TIFF: case FF_LZW_TIFF:
s->top_slot2 = s->top_slot - 1; s->extra_slot= 1;
break; break;
default: default:
return -1; return -1;
@ -208,9 +208,6 @@ int ff_lzw_decode(LZWState *p, uint8_t *buf, int len){
s->curmask = mask[s->cursize]; s->curmask = mask[s->cursize];
s->slot = s->newcodes; s->slot = s->newcodes;
s->top_slot = 1 << s->cursize; s->top_slot = 1 << s->cursize;
s->top_slot2 = s->top_slot;
if(s->mode == FF_LZW_TIFF)
s->top_slot2--;
while ((c = lzw_get_code(s)) == s->clear_code); while ((c = lzw_get_code(s)) == s->clear_code);
if (c == s->end_code) { if (c == s->end_code) {
s->end_code = -1; s->end_code = -1;
@ -239,12 +236,9 @@ int ff_lzw_decode(LZWState *p, uint8_t *buf, int len){
s->prefix[s->slot++] = oc; s->prefix[s->slot++] = oc;
oc = c; oc = c;
} }
if (s->slot >= s->top_slot2) { if (s->slot >= s->top_slot - s->extra_slot) {
if (s->cursize < LZW_MAXBITS) { if (s->cursize < LZW_MAXBITS) {
s->top_slot <<= 1; s->top_slot <<= 1;
s->top_slot2 = s->top_slot;
if(s->mode == FF_LZW_TIFF)
s->top_slot2--;
s->curmask = mask[++s->cursize]; s->curmask = mask[++s->cursize];
} }
} }