AudioBuffer_from_aiff   xtlang

(bind-func AudioBuffer_from_aiff
  (lambda (filepath)
    (let ((filedata (sys_slurp_file filepath)))
      (if (null? filedata)
          (begin (println "aiff file error: could not open file")
                 null)
          (let ((common (iffchunk_find_dumb filedata "COMM"))
                (sounddata (iffchunk_find_dumb filedata "SSND")))
            ;; pull the data out of the common chunk
            (let ((nchan (i16toi64 (swapi16 (pref (cast (pref-ptr common IFF_CHUNK_HEADER_SIZE) i16*) 0))))
                  (nframes (i32toi64 (swapi32 (pref (cast (pref-ptr common (+ IFF_CHUNK_HEADER_SIZE 2)) i32*) 0))))
                  (bitdepth (i16toi64 (swapi16 (pref (cast (pref-ptr common (+ IFF_CHUNK_HEADER_SIZE 6)) i16*) 0))))
                  (samplerate (begin
                                (swap_bytes_inplace (pref-ptr common (+ IFF_CHUNK_HEADER_SIZE 8)) 10)
                                (fp80ptrtod (pref-ptr common (+ IFF_CHUNK_HEADER_SIZE 8)))))
                  (ab (AudioBuffer nframes nchan samplerate))
                  (abres (AudioBuffer_set_filepath ab (Str filepath)))
                  (res (audiofile_copy_samples (pref-ptr sounddata (+ IFF_CHUNK_HEADER_SIZE 8))
                                               (AudioBuffer_data ab)
                                               (* nchan nframes)
                                               bitdepth
                                               WAVE_FORMAT_PCM ;; AIFF is always PCM
                                               #f)))
              (free filedata) ;; why does this cause a crash?
              (if res ab null)))))))