137 lines
5.3 KiB
Racket
137 lines
5.3 KiB
Racket
(module flac-decoder racket/base
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(require ffi/unsafe
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"libflac-ffi.rkt"
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"flac-definitions.rkt"
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"../utils/utils.rkt")
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(provide flac-open
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flac-read
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flac-read-meta
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flac-stream-state
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flac-stop
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(all-from-out "flac-definitions.rkt")
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kinds
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last-buffer last-buf-len
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)
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;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
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;; Functions to do the good stuff
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;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
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(define (flac-open flac-file* cb-stream-info cb-audio)
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(let ((flac-file (if (path? flac-file*) (path->string flac-file*) flac-file*)))
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(if (file-exists? flac-file)
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(let ((handler (flac-ffi-decoder-handler)))
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(handler 'new)
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(handler 'init flac-file)
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(let ((h (make-flac-handle handler)))
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(set-flac-handle-cb-stream-info! h cb-stream-info)
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(set-flac-handle-cb-audio! h cb-audio)
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h))
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#f)))
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(define (flac-stream-state handle)
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((flac-handle-ffi-decoder-handler handle) 'state))
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(define kinds (make-hash))
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(define last-buffer #f)
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(define last-buf-len #f)
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(define (process-frame handle frame buffer)
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(let* ((h (flac-ffi-frame-header frame))
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(cb-audio (flac-handle-cb-audio handle))
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(ffi (flac-handle-ffi-decoder-handler handle))
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(type (hash-ref h 'number-type))
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(channels (hash-ref h 'channels))
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(block-size (hash-ref h 'blocksize)))
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(hash-set! h 'duration (flac-duration handle))
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(let ((buffers (ffi 'get-buffers buffer channels block-size)))
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(set! last-buffer buffers)
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(set! last-buf-len (hash-ref h 'blocksize))
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(hash-set! kinds type #t)
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(when (procedure? cb-audio)
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(cb-audio h buffers))
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))
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;(displayln "Processing frame"))
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#t
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)
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(define (process-meta handle meta)
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(let ((type (FLAC__StreamMetadata-type meta)))
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(display (format " Got metadata type: ~a\n" type))
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(cond
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([eq? type 'streaminfo]
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(let ((mh (flac-ffi-meta meta)))
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(let ((si (make-flac-stream-info
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(hash-ref mh 'min-blocksize) (hash-ref mh 'max-blocksize)
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(hash-ref mh 'min-framesize) (hash-ref mh 'max-framesize)
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(hash-ref mh 'sample-rate)
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(hash-ref mh 'channels)
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(hash-ref mh 'bits-per-sample)
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(hash-ref mh 'total-samples))))
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(set-flac-handle-stream-info! handle si)
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(let ((cb (flac-handle-cb-stream-info handle)))
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(when (procedure? cb)
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(cb si))))))
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)
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))
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(define (flac-read handle)
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(let* ((ffi-handler (flac-handle-ffi-decoder-handler handle))
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(state (ffi-handler 'state)))
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(set-flac-handle-stop-reading! handle #f)
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(letrec ((reader (lambda (frame-nr)
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(let* ((st (ffi-handler 'state)))
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(ffi-handler 'process-single)
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(unless (eq? state st)
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(set! state st)
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(displayln
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(format "Now in state ~a (frame-nr = ~a) (int-state = ~a)"
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st frame-nr (ffi-handler 'int-state)))
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)
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(when (flac-handle-stop-reading handle)
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'stopped-reading)
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(when (ffi-handler 'has-errno?)
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(displayln
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(format "Error in stream: ~a" (ffi-handler 'errno)))
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)
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(when (ffi-handler 'has-meta-data?)
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(ffi-handler 'process-meta-data
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(lambda (meta) (process-meta handle meta)))
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)
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(when (ffi-handler 'has-write-data?)
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(ffi-handler 'process-write-data
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(lambda (frame buffer)
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(process-frame handle frame buffer)))
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)
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(if (eq? st 'end-of-stream)
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'end-of-stream
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(reader (+ frame-nr 1)))))
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))
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(reader 0))))
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(define (flac-read-meta handle)
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(let* ((ffi-handler (flac-handle-ffi-decoder-handler handle))
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(state (ffi-handler 'state)))
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(while (not (or (eq? state 'read-metadata)
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(eq? state 'end-of-stream)
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(eq? state 'aborted)
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(eq? state 'memory-allocation-error)
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(eq? state 'uninitialized)))
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(ffi-handler 'process-single)
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(set! state (ffi-handler 'state))
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state)
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(if (eq? state 'read-metadata)
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(begin
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(ffi-handler 'process-meta-data
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(lambda (meta) (process-meta handle meta)))
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(flac-handle-stream-info handle))
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#f)))
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(define (flac-stop handle)
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(set-flac-handle-stop-reading! handle #t))
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); end of module
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