closures.lisp

   1 ;;;
   2 ;;; Copyright (c) 2007 Zachary Beane, All Rights Reserved
   3 ;;;
   4 ;;; Redistribution and use in source and binary forms, with or without
   5 ;;; modification, are permitted provided that the following conditions
   6 ;;; are met:
   7 ;;;
   8 ;;;   * Redistributions of source code must retain the above copyright
   9 ;;;     notice, this list of conditions and the following disclaimer.
  10 ;;;
  11 ;;;   * Redistributions in binary form must reproduce the above
  12 ;;;     copyright notice, this list of conditions and the following
  13 ;;;     disclaimer in the documentation and/or other materials
  14 ;;;     provided with the distribution.
  15 ;;;
  16 ;;; THIS SOFTWARE IS PROVIDED BY THE AUTHOR 'AS IS' AND ANY EXPRESSED
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  28
  29 (in-package #:salza2)
  30
  31 (defun make-huffman-writer (huffman-codes bitstream)
  32   (let ((codes (codes huffman-codes))
  33         (sizes (sizes huffman-codes))
  34         (buffer (buffer bitstream))
  35         (callback (callback bitstream)))
  36     (lambda (value)
  37       (setf (bits bitstream)
  38             (merge-bits (aref codes value)
  39                         (aref sizes value)
  40                         buffer
  41                         (bits bitstream)
  42                         callback)))))