ObjFW  Artifact [da155ca87d]

Artifact da155ca87d7c74cbe3d820e9fa1c589cd38695b69eac1748bc070ae4b0faf39a:

• File src/OFDeflateStream.h — part of check-in [134a1121c7] at 2016-05-29 13:02:05 on branch trunk — Rename OFInflateStream back to OFDeflateStream

  The reason for renaming to OFInflateStream was to have one stream for
  decompression and one for compression in order to reduce memory usage if
  only one of the two is needed, as the ivar layout will be smaller then.
  However, it is more consistent with other stream classes to have one
  stream that can handle both. The increased memory footprint of having
  ivars for compression and decompression can be solved by having a
  pointer to those instead. This will not incur any performance penalty,
  as the pointer will be dereferenced instead of the ivars, meaning the
  overhead is only getting the pointer from the ivars once. (user: js, size: 2902) [annotate] [blame] [check-ins using]

/*
 * Copyright (c) 2008, 2009, 2010, 2011, 2012, 2013, 2014, 2015, 2016
 *   Jonathan Schleifer <js@heap.zone>
 *
 * All rights reserved.
 *
 * This file is part of ObjFW. It may be distributed under the terms of the
 * Q Public License 1.0, which can be found in the file LICENSE.QPL included in
 * the packaging of this file.
 *
 * Alternatively, it may be distributed under the terms of the GNU General
 * Public License, either version 2 or 3, which can be found in the file
 * LICENSE.GPLv2 or LICENSE.GPLv3 respectively included in the packaging of this
 * file.
 */

#import "OFStream.h"

OF_ASSUME_NONNULL_BEGIN

#define OF_INFLATE_STREAM_BUFFER_SIZE 4096

/*!
 * @class OFDeflateStream OFDeflateStream.h ObjFW/OFDeflateStream.h
 *
 * @brief A class that handles Deflate decompression transparently for an
 *	  underlying stream.
 */
@interface OFDeflateStream: OFStream
{
#ifdef OF_INFLATE_STREAM_M
@public
#endif
	OFStream *_stream;
	uint8_t _buffer[OF_INFLATE_STREAM_BUFFER_SIZE];
	uint16_t _bufferIndex, _bufferLength;
	uint8_t _byte;
	uint8_t _bitIndex, _savedBitsLength;
	uint16_t _savedBits;
@protected
	uint8_t *_slidingWindow;
	uint16_t _slidingWindowIndex, _slidingWindowMask;
	enum {
		OF_INFLATE_STREAM_BLOCK_HEADER,
		OF_INFLATE_STREAM_UNCOMPRESSED_BLOCK_HEADER,
		OF_INFLATE_STREAM_UNCOMPRESSED_BLOCK,
		OF_INFLATE_STREAM_HUFFMAN_TREE,
		OF_INFLATE_STREAM_HUFFMAN_BLOCK
	} _state;
	union {
		struct {
			uint8_t position;
			uint8_t length[4];
		} uncompressedHeader;
		struct {
			uint16_t position, length;
		} uncompressed;
		struct {
			struct huffman_tree *litLenTree, *distTree;
			struct huffman_tree *codeLenTree, *treeIter;
			uint8_t *lengths;
			uint16_t receivedCount;
			uint8_t value, litLenCodesCount, distCodesCount;
			uint8_t codeLenCodesCount;
		} huffmanTree;
		struct {
			struct huffman_tree *litLenTree, *distTree, *treeIter;
			enum {
				OF_INFLATE_STREAM_WRITE_VALUE,
				OF_INFLATE_STREAM_AWAIT_CODE,
				OF_INFLATE_STREAM_AWAIT_LENGTH_EXTRA_BITS,
				OF_INFLATE_STREAM_AWAIT_DISTANCE,
				OF_INFLATE_STREAM_AWAIT_DISTANCE_EXTRA_BITS,
				OF_INFLATE_STREAM_PROCESS_PAIR
			} state;
			uint16_t value, length, distance;
			uint16_t extraBits;
		} huffman;
	} _context;
	bool _inLastBlock, _atEndOfStream;
}

/*!
 * @brief Creates a new OFDeflateStream with the specified underlying stream.
 *
 * @param stream The underlying stream to which compressed data is written or
 *		 from which compressed data is read
 * @return A new, autoreleased OFDeflateStream
 */
+ (instancetype)streamWithStream: (OFStream*)stream;

/*!
 * @brief Initializes an already allocated OFDeflateStream with the specified
 *	  underlying stream.
 *
 * @param stream The underlying stream to which compressed data is written or
 *		 from which compressed data is read
 * @return A initialized OFDeflateStream
 */
- initWithStream: (OFStream*)stream;
@end

OF_ASSUME_NONNULL_END