86 lines
2.4 KiB
Factor
86 lines
2.4 KiB
Factor
USING: alien.c-types alien.syntax audio combinators
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combinators.short-circuit io io.binary io.encodings.binary
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io.files io.streams.byte-array kernel locals math
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sequences ;
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IN: audio.wav
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CONSTANT: RIFF-MAGIC "RIFF"
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CONSTANT: WAVE-MAGIC "WAVE"
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CONSTANT: FMT-MAGIC "fmt "
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CONSTANT: DATA-MAGIC "data"
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C-STRUCT: riff-chunk-header
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{ "char[4]" "id" }
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{ "uchar[4]" "size" }
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;
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C-STRUCT: riff-chunk
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{ "riff-chunk-header" "header" }
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{ "char[4]" "format" }
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;
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C-STRUCT: wav-fmt-chunk
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{ "riff-chunk-header" "header" }
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{ "uchar[2]" "audio-format" }
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{ "uchar[2]" "num-channels" }
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{ "uchar[4]" "sample-rate" }
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{ "uchar[4]" "byte-rate" }
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{ "uchar[2]" "block-align" }
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{ "uchar[2]" "bits-per-sample" }
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;
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C-STRUCT: wav-data-chunk
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{ "riff-chunk-header" "header" }
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{ "uchar[0]" "body" }
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;
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ERROR: invalid-wav-file ;
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: ensured-read ( count -- output/f )
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[ read ] keep over length = [ drop f ] unless ;
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: ensured-read* ( count -- output )
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ensured-read [ invalid-wav-file ] unless* ;
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: read-chunk ( -- byte-array/f )
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4 ensured-read [ 4 ensured-read* dup le> ensured-read* 3append ] [ f ] if* ;
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: read-riff-chunk ( -- byte-array/f )
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"riff-chunk" heap-size ensured-read* ;
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: id= ( chunk id -- ? )
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[ 4 head ] dip sequence= ;
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: check-chunk ( chunk id min-size -- ? )
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[ id= ] [ [ length ] dip >= ] bi-curry* bi and ;
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:: read-wav-chunks ( -- fmt data )
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f :> fmt! f :> data!
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[ { [ fmt data and not ] [ read-chunk ] } 0&& dup ]
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[ {
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{ [ dup FMT-MAGIC "wav-fmt-chunk" heap-size check-chunk ] [ fmt! ] }
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{ [ dup DATA-MAGIC "wav-data-chunk" heap-size check-chunk ] [ data! ] }
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} cond ] while drop
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fmt data 2dup and [ invalid-wav-file ] unless ;
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: verify-wav ( chunk -- )
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{
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[ RIFF-MAGIC id= ]
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[ riff-chunk-format 4 memory>byte-array WAVE-MAGIC id= ]
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} 1&&
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[ invalid-wav-file ] unless ;
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: (read-wav) ( -- audio )
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read-wav-chunks
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[
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[ wav-fmt-chunk-num-channels 2 memory>byte-array le> ]
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[ wav-fmt-chunk-bits-per-sample 2 memory>byte-array le> ]
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[ wav-fmt-chunk-sample-rate 4 memory>byte-array le> ] tri
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] [
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[ riff-chunk-header-size 4 memory>byte-array le> dup ]
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[ wav-data-chunk-body ] bi swap memory>byte-array
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] bi* <audio> ;
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: read-wav ( filename -- audio )
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binary [
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read-riff-chunk verify-wav (read-wav)
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] with-file-reader ;
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