more defensive constructs with early-return & let-assert

libflac-ffi.rkt

@@ -108,21 +108,6 @@
            undefined
            )))
 
-
-;typedef enum {
-;    FLAC__STREAM_DECODER_SEARCH_FOR_METADATA = 0,
-;    FLAC__STREAM_DECODER_READ_METADATA,
-;    FLAC__STREAM_DECODER_SEARCH_FOR_FRAME_SYNC,
-;    FLAC__STREAM_DECODER_READ_FRAME,
-;    FLAC__STREAM_DECODER_END_OF_STREAM,
-;    FLAC__STREAM_DECODER_OGG_ERROR,
-;    FLAC__STREAM_DECODER_SEEK_ERROR,
-;    FLAC__STREAM_DECODER_ABORTED,
-;    FLAC__STREAM_DECODER_MEMORY_ALLOCATION_ERROR,
-;    FLAC__STREAM_DECODER_UNINITIALIZED,
-;    FLAC__STREAM_DECODER_END_OF_LINK
-;} FLAC__StreamDecoderState;
-
 (define _FLAC_StreamDecoderState
   (_enum '(search-for-metadata = 0
            read-metadata
@@ -247,23 +232,6 @@
 ;; FLAC Metadata 
 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
 
-;typedef struct FLAC__StreamMetadata {
-;    FLAC__MetadataType type;
-;    FLAC__bool is_last;
-;    uint32_t length;
-;    union {
-;        FLAC__StreamMetadata_StreamInfo stream_info;
-;        FLAC__StreamMetadata_Padding padding;
-;        FLAC__StreamMetadata_Application application;
-;        FLAC__StreamMetadata_SeekTable seek_table;
-;        FLAC__StreamMetadata_VorbisComment vorbis_comment;
-;        FLAC__StreamMetadata_CueSheet cue_sheet;
-;        FLAC__StreamMetadata_Picture picture;
-;        FLAC__StreamMetadata_Unknown unknown;
-;    } data;
-;} FLAC__StreamMetadata;
-
-
 (define-cstruct _FLAC__StreamMetadata_StreamInfo
   (
    [min_blocksize _uint32_t]
@@ -498,6 +466,52 @@
 ;; Our interface for decoding to racket
 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
 
+(define (endian-little? e)
+  (cond [(eq? e 'little-endian) #t]
+        [(eq? e 'big-endian) #f]
+        [(eq? e 'native-endian) (not (system-big-endian?))]
+        [else (error (format "unknown endian value: ~a" e))]))
+
+(define (flac-channels->interleaved-buffer buffer block-size channels bits endianness)
+  ;; buffer    = FLAC__int32 * const buffer[]
+  ;; block-size = samples per channel
+
+  (let* ([bytes    (quotient bits 8)]
+         [big?     (not (endian-little? endianness))]
+         [buf-size (* block-size channels bytes)]
+         [bs       (make-bytes buf-size)]
+         ;[out      (malloc buf-size 'atomic-interior)]
+         [out-pos  0])
+
+    (for ([k (in-range block-size)])
+      (for ([channel (in-range channels)])
+        (let* ([chan   (ptr-ref buffer _pointer channel)]
+               [sample (ptr-ref chan _int32 k)])
+          (integer->int-bytes sample bytes #t big? bs out-pos)
+          (set! out-pos (+ out-pos bytes)))))
+
+    ;(memcpy out bs buf-size)
+    ;(list out buf-size)
+    (list bs buf-size)
+    ))
+  
+(define (copy-flac-frame frame buffer)
+  (let* ((h          (flac-ffi-frame-header frame))
+         (channels   (hash-ref h 'channels))
+         (block-size (hash-ref h 'blocksize))
+         (bits       (hash-ref h 'bits-per-sample))
+         (endianness 'native-endian)
+         (result     (flac-channels->interleaved-buffer
+                      buffer block-size channels bits endianness))
+         (bs         (car result))
+         (buf-size   (cadr result)))
+    (hash-set! h 'type 'interleaved)
+    (hash-set! h 'endianness endianness)
+    (hash-set! h 'bits-per-sample bits)
+    (hash-set! h 'sample (hash-ref h 'number))
+    (cons h bs)))
+  
+
 (define (flac-ffi-decoder-handler)
   (define write-data '())
   (define meta-data '())
@@ -506,14 +520,21 @@
   (define flac-file #f)
   (define client-data #f)
   
+  ;(define (write-callback fl frame buffer client-data)
+  ;  (set! write-data (append write-data (list (cons frame buffer))))
+  ;  0)
   (define (write-callback fl frame buffer client-data)
-    (set! write-data (append write-data (list (cons frame buffer))))
+  (set! write-data (cons (copy-flac-frame frame buffer) write-data))
     0)
 
+  ;(define (meta-callback fl meta client-data)
+  ;  (let ((meta-clone (FLAC__metadata_object_clone meta)))
+  ;    (unless (eq? meta-clone #f)
+  ;      (set! meta-data (append meta-data (list meta-clone))))))
   (define (meta-callback fl meta client-data)
     (let ((meta-clone (FLAC__metadata_object_clone meta)))
       (unless (eq? meta-clone #f)
-        (set! meta-data (append meta-data (list meta-clone))))))
+        (set! meta-data (cons meta-clone meta-data)))))
 
   (define (error-callback fl errno client-data)
     (set! error-no errno)
@@ -557,16 +578,16 @@
     (decoder-state (int-state)))
 
   (define (process-meta-data cb)
-    (for-each (λ (meta-entry)
+    (for-each (lambda (meta-entry)
                 (cb meta-entry)
                 (FLAC__metadata_object_delete meta-entry))
-              meta-data)
+              (reverse meta-data))
     (set! meta-data '()))
 
   (define (process-write-data cb)
-    (for-each (lambda (d)
-                (cb (car d) (cdr d)))
-              write-data)
+  (for-each (lambda (d)
+              (cb (car d) (cdr d)))
+            (reverse write-data))
     (set! write-data '()))
 
   (define (buffer->vectorlist buffer channels size)
@@ -618,4 +639,5 @@
       ))
   )
 
-); end of module
+); end of module
+