ObjFW  Artifact [9d59f54685]

Artifact 9d59f54685b2878ffb6cc8be67f98d611321a2a2c2e88d7f58057ce82e096ef0:

• File src/OFInflateStream.h — part of check-in [2e9336b1ef] at 2015-05-16 20:29:57 on branch trunk — Rename OFDeflateStream -> OFInflateStream

  It makes more sense to have one class for inflating and one for
  deflating instead of having one that does both, as having one that does
  both requires more memory per instance when only inflating or deflating
  is used. (user: js, size: 2905) [annotate] [blame] [check-ins using]

/*
 * Copyright (c) 2008, 2009, 2010, 2011, 2012, 2013, 2014, 2015
 *   Jonathan Schleifer <js@webkeks.org>
 *
 * 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"

#define OF_INFLATE_STREAM_BUFFER_SIZE 4096

/*!
 * @class OFInflateStream OFInflateStream.h ObjFW/OFInflateStream.h
 *
 * @brief A class that handles Deflate decompression transparently for an
 *	  underlying stream.
 */
@interface OFInflateStream: OFStream
{
#ifdef OF_INFLATE_STREAM_M
@public
#endif
	OFStream *_stream;
	uint8_t _buffer[OF_INFLATE_STREAM_BUFFER_SIZE];
	uint_fast16_t _bufferIndex, _bufferLength;
	uint8_t _byte;
	uint_fast8_t _bitIndex, _savedBitsLength;
	uint_fast16_t _savedBits;
@protected
	uint8_t *_slidingWindow;
	uint_fast16_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 {
			uint_fast8_t position;
			uint8_t length[4];
		} uncompressedHeader;
		struct {
			uint_fast16_t position, length;
		} uncompressed;
		struct {
			struct huffman_tree *litLenTree, *distTree;
			struct huffman_tree *codeLenTree, *treeIter;
			uint8_t *lengths;
			uint_fast16_t receivedCount;
			uint_fast8_t value, litLenCodesCount, distCodesCount;
			uint_fast8_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;
			uint_fast16_t value, length, distance;
			uint_fast16_t extraBits;
		} huffman;
	} _context;
	bool _inLastBlock, _atEndOfStream;
}

/*!
 * @brief Creates a new OFInflateStream 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 OFInflateStream
 */
+ (instancetype)streamWithStream: (OFStream*)stream;

/*!
 * @brief Initializes an already allocated OFInflateStream 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 OFInflateStream
 */
- initWithStream: (OFStream*)stream;
@end