/usr/share/common-lisp/source/chipz/decompress.lisp is in cl-chipz 20130128-1.
This file is owned by root:root, with mode 0o644.
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;;; We provide several convenience functions for decompression:
;;;
;;; * decompress a buffer to a newly-consed buffer;
;;; * decompress a stream to a newly-consed buffer;
;;; * decompress a pathane to a newly-consed buffer;
;;; * decompress a buffer to a user-specified buffer;
;;; * decompress a buffer to a stream;
;;; * decompress a stream to a stream.
;;; * decompress a pathname to another pathname;
;;; * decompress a pathname to a stream;
;;;
;;; We do not provide stream->buffer decompression, as we have no way of
;;; knowing how much to read from the stream to fill the buffer, no way
;;; of determining what to do with possible state left in the
;;; INFLATE-STATE that we used, etc. Application-specific logic will
;;; have to handle those bits.
(defgeneric decompress (output state input &key &allow-other-keys)
(:method (output format input &rest keys)
(%decompress output format input keys)))
(defun %decompress (output format input keys)
(let ((state (make-dstate format)))
(multiple-value-prog1 (apply #'decompress output state input keys)
(finish-dstate state))))
;;; SUBSEQ is specified to always make a copy. But we don't want an
;;; exact copy of a freshly-consed vector; that'd be wasteful.
(defun maybe-subseq (v end)
(if (= end (length v))
v
(subseq v 0 end)))
(defun decompress-fun-for-state (state)
(typecase state
(inflate-state #'%inflate)
(bzip2-state #'%bzip2-decompress)))
;; For convenience.
(defun %decompress-from-pathname (output state pathname buffer-size)
(with-open-file (stream pathname :element-type '(unsigned-byte 8)
:direction :input)
(decompress output state stream
:buffer-size (if (eq buffer-size :file-length)
(file-length stream)
buffer-size))))
(defmethod decompress ((output null) (state decompression-state) (input pathname)
&key)
(%decompress-from-pathname output state input :file-length))
(defmethod decompress ((output pathname) (state decompression-state) (input pathname)
&key buffer-size)
(check-type buffer-size (or null integer))
(with-open-file (stream output :element-type '(unsigned-byte 8)
:direction :output)
(%decompress-from-pathname stream state input buffer-size)))
(defmethod decompress ((output stream) (state decompression-state) (input pathname)
&key buffer-size)
(check-type buffer-size (or null integer))
(%decompress-from-pathname output state input buffer-size))
(defun %decompress/null-vector (state input fun
input-start input-end buffer-size)
(declare (type function fun))
(loop
with output = (make-array buffer-size :element-type '(unsigned-byte 8))
with output-start = 0
do (cond
((= output-start (length output))
;; Reallocate the output buffer.
(let ((new (make-array (* 2 (length output))
:element-type '(unsigned-byte 8))))
(setf output (replace new output))))
(t
(multiple-value-bind (consumed produced)
(funcall fun state input output
:input-start input-start :input-end input-end
:output-start output-start :output-end (length output))
(incf input-start consumed)
(incf output-start produced)
(when (or (dstate-done state)
(and (or (>= input-start input-end)
(zerop consumed))
(zerop produced)))
(return-from %decompress/null-vector (maybe-subseq output output-start))))))))
(defmethod decompress ((output null) (state decompression-state) (input vector)
&key (input-start 0) input-end buffer-size)
(%decompress/null-vector state input
(decompress-fun-for-state state)
input-start (or input-end (length input))
(or buffer-size +default-buffer-size+)))
(defun %decompress/null-stream (state input fun buffer-size)
(declare (type function fun))
(let ((input-buffer (make-array 8192 :element-type '(unsigned-byte 8))))
(declare (dynamic-extent input-buffer))
(loop
with input-start = 0
with input-end = 0
with output = (make-array buffer-size :element-type '(unsigned-byte 8))
with output-start = 0
initially (setf input-end (read-sequence input-buffer input))
do (cond
((= output-start (length output))
;; Reallocate the output buffer.
(let ((new (make-array (* 2 (length output))
:element-type '(unsigned-byte 8))))
(setf output (replace new output))))
(t
(multiple-value-bind (consumed produced)
(funcall fun state input-buffer output
:input-start input-start :input-end input-end
:output-start output-start)
(incf input-start consumed)
(incf output-start produced)
(let ((input-consumed-p (>= input-start input-end)))
;; Get more input if possible.
(when input-consumed-p
(setf input-start 0
input-end (read-sequence input-buffer input)))
(when (or (dstate-done state)
(and (or (and input-consumed-p (zerop input-end))
(zerop consumed))
(zerop produced)))
(return-from %decompress/null-stream (maybe-subseq output output-start))))))))))
(defmethod decompress ((output null) (state decompression-state) (input stream)
&key buffer-size)
(%decompress/null-stream state input
(decompress-fun-for-state state)
(or buffer-size +default-buffer-size+)))
(defun %decompress/vector-vector (output state input fun
input-start input-end
output-start output-end)
(declare (type simple-octet-vector input output))
(declare (type function fun))
(loop
with n-bytes-consumed = 0 and n-bytes-produced = 0
do (multiple-value-bind (consumed produced)
(funcall fun state input output
:input-start input-start :input-end input-end
:output-start output-start :output-end output-end)
(incf input-start consumed)
(incf output-start produced)
(incf n-bytes-consumed consumed)
(incf n-bytes-produced produced)
(when (and (or (>= input-start input-end)
(zerop consumed))
(or (>= output-start output-end)
(zerop produced)))
(return-from %decompress/vector-vector
(values n-bytes-consumed n-bytes-produced))))))
(defmethod decompress ((output vector) (state decompression-state) (input vector)
&key (input-start 0) input-end
(output-start 0) output-end)
(%decompress/vector-vector output state input
(decompress-fun-for-state state)
input-start (or input-end (length input))
output-start (or output-end (length output))))
(defun %decompress/stream-vector (output state input fun input-start input-end)
(declare (type function fun))
(let ((buffer (make-array 8192 :element-type '(unsigned-byte 8))))
(declare (dynamic-extent buffer))
(loop (multiple-value-bind (consumed produced)
(funcall fun state input buffer
:input-start input-start :input-end input-end)
(incf input-start consumed)
(write-sequence buffer output :end produced)
(when (or (dstate-done state)
(and (or (>= input-start input-end)
(zerop consumed))
(zerop produced)))
(return-from %decompress/stream-vector output))))))
(defmethod decompress ((output stream) (state decompression-state) (input vector)
&key (input-start 0) input-end)
(%decompress/stream-vector output state input
(decompress-fun-for-state state)
input-start (or input-end (length input))))
(defun %decompress/stream-stream (output state input fun)
(declare (type function fun))
(let ((input-buffer (make-array 8192 :element-type '(unsigned-byte 8)))
(output-buffer (make-array 8192 :element-type '(unsigned-byte 8))))
(declare (dynamic-extent input-buffer output-buffer))
(loop
with input-start = 0
with input-end = 0
initially (setf input-end (read-sequence input-buffer input))
do (multiple-value-bind (consumed produced)
(funcall fun state input-buffer output-buffer
:input-start input-start :input-end input-end)
(incf input-start consumed)
(write-sequence output-buffer output :end produced)
(let ((input-consumed-p (>= input-start input-end)))
(when input-consumed-p
(setf input-start 0
input-end (read-sequence input-buffer input)))
(when (or (dstate-done state)
(and (or (and input-consumed-p (zerop input-end))
(zerop consumed))
(zerop produced)))
(return-from %decompress/stream-stream output)))))))
(defmethod decompress ((output stream) (state decompression-state) (input stream)
&key)
(%decompress/stream-stream output state input
(decompress-fun-for-state state)))
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