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gif: preparing for LZW re-integration with TIFF

db4
Keith Lazuka 2009-09-25 11:12:40 -04:00
parent c0a8334d98
commit e006b62962
3 changed files with 17 additions and 14 deletions
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19
extra/compression/lzw-gif/lzw-gif.factor
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@ -13,8 +13,6 @@ SYMBOL: end-of-information
TUPLE: lzw input output table code old-code initial-code-size code-size ; TUPLE: lzw input output table code old-code initial-code-size code-size ;
SYMBOL: table-full
: initial-uncompress-table ( -- seq ) : initial-uncompress-table ( -- seq )
end-of-information get 1 + iota [ 1vector ] V{ } map-as ; end-of-information get 1 + iota [ 1vector ] V{ } map-as ;
@ -22,11 +20,11 @@ SYMBOL: table-full
initial-uncompress-table >>table initial-uncompress-table >>table
dup initial-code-size>> >>code-size ; dup initial-code-size>> >>code-size ;
: <lzw-uncompress> ( code-size input -- obj ) : <lzw-uncompress> ( input code-size -- obj )
lzw new lzw new
swap >>input
swap >>initial-code-size swap >>initial-code-size
dup initial-code-size>> >>code-size dup initial-code-size>> >>code-size
swap >>input
BV{ } clone >>output BV{ } clone >>output
reset-lzw-uncompress ; reset-lzw-uncompress ;
@ -103,14 +101,19 @@ DEFER: lzw-uncompress-char
drop drop
] if* ; ] if* ;
: register-special-codes ( first-code-size -- ) : register-special-codes ( first-code-size -- first-code-size )
[ [
1 - 2^ dup clear-code set 1 - 2^ dup clear-code set
1 + end-of-information set 1 + end-of-information set
] keep ; ] keep ;
: lzw-uncompress ( code-size seq -- byte-array ) : lzw-uncompress ( bitstream code-size -- byte-array )
[ register-special-codes ] dip register-special-codes
bs:<lsb0-bit-reader>
<lzw-uncompress> <lzw-uncompress>
[ lzw-uncompress-char ] [ output>> ] bi ; [ lzw-uncompress-char ] [ output>> ] bi ;
: lzw-uncompress-msb0 ( seq code-size -- byte-array )
[ bs:<msb0-bit-reader> ] dip lzw-uncompress ;
: lzw-uncompress-lsb0 ( seq code-size -- byte-array )
[ bs:<lsb0-bit-reader> ] dip lzw-uncompress ;

6
extra/images/gif/gif-tests.factor
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@ -47,9 +47,9 @@ IN: images.gif.tests
[ 2 ] [ gif-example3 declared-num-colors ] unit-test [ 2 ] [ gif-example3 declared-num-colors ] unit-test
: >index-stream ( gif -- seq ) : >index-stream ( gif -- seq )
[ image-descriptor>> first-code-size>> ] [ compressed-bytes>> ]
[ compressed-bytes>> ] bi [ image-descriptor>> first-code-size>> ] bi
lzw-uncompress ; lzw-uncompress-lsb0 ;
[ [
BV{ BV{

6
extra/images/gif/gif.factor
View File

@ -225,9 +225,9 @@ ERROR: unhandled-data byte ;
] with-input-stream ; ] with-input-stream ;
: decompress ( loading-gif -- indexes ) : decompress ( loading-gif -- indexes )
[ image-descriptor>> first-code-size>> ] [ compressed-bytes>> ]
[ compressed-bytes>> ] bi [ image-descriptor>> first-code-size>> ] bi
lzw-uncompress ; lzw-uncompress-lsb0 ;
: colorize ( index palette transparent-index/f -- seq ) : colorize ( index palette transparent-index/f -- seq )
pick = [ 2drop B{ 0 0 0 0 } ] [ nth 255 suffix ] if ; pick = [ 2drop B{ 0 0 0 0 } ] [ nth 255 suffix ] if ;