Chris@8: 
Chris@8: module framer;
Chris@8: 
Chris@25: /**
Chris@25:  * Framer expresses a stream (or a file) as a lazy list of (possibly
Chris@25:  * overlapping) frames of mono data.
Chris@25:  */
Chris@25: 
Chris@11: vec = load fvector;
Chris@20: block = load block;
Chris@8: af = load audiofile;
Chris@8: 
Chris@32: blockList framesize stream =
Chris@14:     if stream.finished? then
Chris@14:        (stream.close (); [] );
Chris@13:     else
Chris@32:         block.resizedTo framesize (stream.readMono framesize)
Chris@32:             :. \(blockList framesize stream);
Chris@13:     fi;
Chris@13: 
Chris@32: overlappingBlockList size hop stream valid buffer
Chris@23:     is number -> number -> 'a -> number -> ~double[] -> 'b =
Chris@29:    (
Chris@29:     b = stream.readMono hop;
Chris@24:     obtained = block.length b;
Chris@23:     samples = block.unblock b;
Chris@23: 
Chris@32:     // Retain framesize - hop samples from old buffer, add hop samples
Chris@29:     // (zero-padded if necessary) just read
Chris@29:     buffer = vec.concat
Chris@35:        [vec.rangeOf buffer hop (size-hop),
Chris@35:         vec.resizedTo hop samples];
Chris@23: 
Chris@23:     // Number of "valid" elements (not tail-end zero-padding) left in buffer
Chris@24:     remaining = valid - (hop - obtained);
Chris@23: 
Chris@23:     if remaining <= 0 then
Chris@23:         stream.close ();
Chris@23:         [];
Chris@12:     else
Chris@29:         v = block.block buffer;
Chris@32:         v :. \(overlappingBlockList size hop stream remaining buffer);
Chris@23:     fi);
Chris@14: 
Chris@32: frames { framesize, hop } stream =
Chris@32:     if framesize == hop then
Chris@32:         blockList framesize stream
Chris@30:     else
Chris@32:         overlappingBlockList framesize hop stream 
Chris@32:             framesize (vec.zeros framesize);
Chris@30:     fi;
Chris@14: 
Chris@32: framesOfFile { framesize, hop } filename =
Chris@32:     if framesize == hop then
Chris@32:         blockList framesize (af.open filename)
Chris@30:     else
Chris@32:         overlappingBlockList framesize hop (af.open filename)
Chris@32:             framesize (vec.zeros framesize);
Chris@30:     fi;
Chris@23: 
Chris@11: { 
Chris@30:     frames,
Chris@30:     framesOfFile,
Chris@11: }
Chris@8: