zlib.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
  17 ;;; OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
  18 ;;; WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  19 ;;; ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
  20 ;;; DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  21 ;;; DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE
  22 ;;; GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
  23 ;;; INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
  24 ;;; WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
  25 ;;; NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
  26 ;;; SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  27 ;;;
  28
  29 (in-package #:salza2)
  30
  31 (defclass zlib-compressor (deflate-compressor)
  32   ((adler32
  33     :initarg :adler32
  34     :accessor adler32))
  35   (:default-initargs
  36    :adler32 (make-instance 'adler32-checksum)))
  37
  38 (defmethod start-data-format :before ((compressor zlib-compressor))
  39   ;; FIXME: Replace these naked constants with symbolic constants.
  40   (write-octet #x78 compressor)
  41   (write-octet #x9C compressor))
  42
  43 (defmethod process-input :after ((compressor zlib-compressor) input start count)
  44   (let ((checksum (adler32 compressor)))
  45     (update checksum input start count)))
  46
  47 (defmethod finish-data-format :after ((compressor zlib-compressor))
  48   (dolist (octet (result-octets (adler32 compressor)))
  49     (write-octet octet compressor)))
  50
  51 (defmethod reset :after ((compressor zlib-compressor))
  52   (reset (adler32 compressor)))