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compression.lzw: fix for gif89a decoding - maximum code size is 12 bits.

db4
John Benediktsson 2011-01-26 21:06:43 -08:00
parent 1defecf279
commit 0b6dae0a93
1 changed files with 9 additions and 4 deletions
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13
basis/compression/lzw/lzw.factor
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@ -1,7 +1,7 @@
! Copyright (C) 2009 Doug Coleman.
! See http://factorcode.org/license.txt for BSD license.
USING: accessors combinators io kernel math namespaces
sequences vectors ;
USING: accessors combinators io kernel math math.order
namespaces sequences vectors ;
QUALIFIED-WITH: bitstreams bs
IN: compression.lzw
@ -62,8 +62,13 @@ GENERIC: code-space-full? ( lzw -- ? )
M: tiff-lzw code-space-full? size-and-limit 1 - = ;
M: gif-lzw code-space-full? size-and-limit = ;
GENERIC: increment-code-size ( lzw -- lzw )
M: lzw increment-code-size [ 1 + ] change-code-size ;
M: gif-lzw increment-code-size [ 1 + 12 min ] change-code-size ;
: maybe-increment-code-size ( lzw -- lzw )
dup code-space-full? [ [ 1 + ] change-code-size ] when ;
dup code-space-full? [ increment-code-size ] when ;
: add-to-table ( seq lzw -- )
[ table>> push ]
@ -108,7 +113,7 @@ DEFER: lzw-uncompress-char
[ output>> push-all ] [ add-to-table ] 2bi
] [ code>old-code ] bi
] if ;
: lzw-uncompress-char ( lzw -- )
[ >>code handle-uncompress-code lzw-uncompress-char ]
lzw-process-next-code ;