From 705e12445cf54de9d1a4fab8fe2a69eabcac976f Mon Sep 17 00:00:00 2001
From: Joe Groff <arcata@gmail.com>
Date: Tue, 28 Apr 2009 22:43:43 -0500
Subject: [PATCH] wav file parser

---
 extra/audio/audio.factor   | 23 ++++++++++++
 extra/audio/wav/wav.factor | 74 ++++++++++++++++++++++++++++++++++++++
 2 files changed, 97 insertions(+)
 create mode 100644 extra/audio/audio.factor
 create mode 100644 extra/audio/wav/wav.factor

diff --git a/extra/audio/audio.factor b/extra/audio/audio.factor
new file mode 100644
index 0000000000..04df36ebd6
--- /dev/null
+++ b/extra/audio/audio.factor
@@ -0,0 +1,23 @@
+USING: accessors alien arrays combinators kernel math openal ;
+IN: audio
+
+TUPLE: audio
+    { channels integer }
+    { sample-bits integer }
+    { sample-rate integer }
+    { size integer }
+    { data c-ptr } ;
+
+C: <audio> audio
+
+ERROR: format-unsupported-by-openal audio ;
+
+: openal-format ( audio -- format )
+    dup [ channels>> ] [ sample-bits>> ] bi 2array {
+        { { 1  8 } [ drop AL_FORMAT_MONO8    ] }
+        { { 1 16 } [ drop AL_FORMAT_MONO16   ] }
+        { { 2  8 } [ drop AL_FORMAT_STEREO8  ] }
+        { { 2 16 } [ drop AL_FORMAT_STEREO16 ] }
+        [ drop format-unsupported-by-openal ]
+    } case ;
+
diff --git a/extra/audio/wav/wav.factor b/extra/audio/wav/wav.factor
new file mode 100644
index 0000000000..6f8ee49395
--- /dev/null
+++ b/extra/audio/wav/wav.factor
@@ -0,0 +1,74 @@
+USING: alien.c-types alien.syntax audio combinators
+combinators.short-circuit io io.binary io.encodings.binary
+io.files io.streams.memory kernel locals sequences ;
+IN: audio.wav
+
+CONSTANT: RIFF-MAGIC "RIFF"
+CONSTANT: WAVE-MAGIC "WAVE"
+CONSTANT: FMT-MAGIC  "fmt "
+CONSTANT: DATA-MAGIC "data"
+
+C-STRUCT: riff-chunk-header
+    { "char[4]" "id" }
+    { "uchar[4]" "size" }
+    ;
+
+C-STRUCT: riff-chunk
+    { "riff-chunk-header" "header" }
+    { "char[4]" "format" }
+    { "uchar[0]" "body" }
+    ;
+
+C-STRUCT: wav-fmt-chunk
+    { "riff-chunk-header" "header" }
+    { "uchar[2]" "audio-format" }
+    { "uchar[2]" "num-channels" }
+    { "uchar[4]" "sample-rate" }
+    { "uchar[4]" "byte-rate" }
+    { "uchar[2]" "block-align" }
+    { "uchar[2]" "bits-per-sample" }
+    ;
+
+C-STRUCT: wav-data-chunk
+    { "riff-chunk-header" "header" }
+    { "uchar[0]" "body" }
+    ;
+
+: read-chunk ( -- byte-array/f )
+    4 read [ 4 read le> [ <uint> ] [ read ] bi 3append ] [ f ] if* ;
+
+: id= ( chunk id -- ? )
+    [ 4 memory>byte-array ] dip sequence= ;
+
+:: read-wav-chunks ( -- fmt data )
+    f :> fmt! f :> data!
+    [ { [ fmt data and not ] [ read-chunk ] } 0&& dup ]
+    [ {
+        { [ dup FMT-MAGIC  id= ] [ fmt!  ] }
+        { [ dup DATA-MAGIC id= ] [ data! ] }
+    } cond ] while drop
+    fmt data ;
+
+ERROR: invalid-wav-file ;
+
+: verify-wav ( chunk -- )
+    { [ RIFF-MAGIC id= ] [ riff-chunk-format WAVE-MAGIC id= ] } 1&&
+    [ invalid-wav-file ] unless ;
+
+: (read-wav) ( -- audio )
+    read-wav-chunks 
+    [
+        [ wav-fmt-chunk-num-channels    2 memory>byte-array le> ]
+        [ wav-fmt-chunk-bits-per-sample 2 memory>byte-array le> ]
+        [ wav-fmt-chunk-sample-rate     4 memory>byte-array le> ] tri
+    ] [
+        [ riff-chunk-header-size 4 memory>byte-array le> dup ]
+        [ wav-data-chunk-body ] bi swap memory>byte-array
+    ] bi* <audio> ;
+
+: read-wav ( filename -- audio )
+    binary [
+        read-chunk
+        [ verify-wav ]
+        [ riff-chunk-body <memory-stream> [ (read-wav) ] with-input-stream* ] bi
+    ] with-file-reader ;