/*
* Copyright (c) 2008-2024 Jonathan Schleifer <js@nil.im>
*
* All rights reserved.
*
* This program is free software: you can redistribute it and/or modify it
* under the terms of the GNU Lesser General Public License version 3.0 only,
* as published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License
* version 3.0 for more details.
*
* You should have received a copy of the GNU Lesser General Public License
* version 3.0 along with this program. If not, see
* <https://www.gnu.org/licenses/>.
*/
#import "OFStream.h"
#import "OFKernelEventObserver.h"
OF_ASSUME_NONNULL_BEGIN
#define OFInflateStreamBufferSize 4096
/**
* @class OFInflateStream OFInflateStream.h ObjFW/OFInflateStream.h
*
* @note This class only conforms to OFReadyForReadingObserving if the
* underlying stream does so, too.
*
* @brief A class that handles Deflate decompression transparently for an
* underlying stream.
*/
OF_SUBCLASSING_RESTRICTED
@interface OFInflateStream: OFStream <OFReadyForReadingObserving>
{
OFStream *_stream;
unsigned char _buffer[OFInflateStreamBufferSize];
uint16_t _bufferIndex, _bufferLength;
uint8_t _byte;
uint8_t _bitIndex, _savedBitsLength;
uint16_t _savedBits;
unsigned char *_Nullable _slidingWindow;
uint16_t _slidingWindowIndex, _slidingWindowMask;
int _state;
union {
struct {
uint8_t position;
uint8_t length[4];
} uncompressedHeader;
struct {
uint16_t position, length;
} uncompressed;
struct {
struct _OFHuffmanTree *_Nullable litLenTree;
struct _OFHuffmanTree *_Nullable distTree;
struct _OFHuffmanTree *_Nullable codeLenTree;
struct _OFHuffmanTree *_Nullable treeIter;
uint8_t *_Nullable lengths;
uint16_t receivedCount;
uint8_t value, litLenCodesCount, distCodesCount;
uint8_t codeLenCodesCount;
} huffmanTree;
struct {
struct _OFHuffmanTree *_Nullable litLenTree;
struct _OFHuffmanTree *_Nullable distTree;
struct _OFHuffmanTree *_Nullable treeIter;
int state;
uint16_t value, length, distance, extraBits;
} huffman;
} _context;
bool _inLastBlock, _atEndOfStream;
}
/**
* @brief The underlying stream of the inflate stream.
*
* Setting this can be useful if the the data to be inflated is coming from
* multiple streams, such as split across multiple files.
*/
@property (retain, nonatomic) OFStream *underlyingStream;
/**
* @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;
- (instancetype)init OF_UNAVAILABLE;
/**
* @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
*/
- (instancetype)initWithStream: (OFStream *)stream OF_DESIGNATED_INITIALIZER;
@end
OF_ASSUME_NONNULL_END