/*
* Copyright (c) 2008, 2009, 2010, 2011, 2012, 2013, 2014, 2015, 2016, 2017,
* 2018, 2019, 2020
* Jonathan Schleifer <js@nil.im>
*
* 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.
*/
#include "config.h"
#include <assert.h>
#import "OFLHADecompressingStream.h"
#import "OFKernelEventObserver.h"
#import "huffman_tree.h"
#import "OFInvalidFormatException.h"
#import "OFNotOpenException.h"
enum state {
STATE_BLOCK_HEADER,
STATE_CODE_LEN_CODES_COUNT,
STATE_CODE_LEN_TREE,
STATE_CODE_LEN_TREE_SINGLE,
STATE_LITLEN_CODES_COUNT,
STATE_LITLEN_TREE,
STATE_LITLEN_TREE_SINGLE,
STATE_DIST_CODES_COUNT,
STATE_DIST_TREE,
STATE_DIST_TREE_SINGLE,
STATE_BLOCK_LITLEN,
STATE_BLOCK_DIST_LENGTH,
STATE_BLOCK_DIST_LENGTH_EXTRA,
STATE_BLOCK_LEN_DIST_PAIR
};
@implementation OFLHADecompressingStream
@synthesize bytesConsumed = _bytesConsumed;
static OF_INLINE bool
tryReadBits(OFLHADecompressingStream *stream, uint16_t *bits, uint8_t count)
{
uint16_t ret = stream->_savedBits;
assert(stream->_savedBitsLength < count);
for (uint_fast8_t i = stream->_savedBitsLength; i < count; i++) {
if OF_UNLIKELY (stream->_bitIndex == 8) {
if OF_LIKELY (stream->_bufferIndex <
stream->_bufferLength)
stream->_byte =
stream->_buffer[stream->_bufferIndex++];
else {
const size_t bufferLength =
OF_LHA_DECOMPRESSING_STREAM_BUFFER_SIZE;
size_t length = [stream->_stream
readIntoBuffer: stream->_buffer
length: bufferLength];
stream->_bytesConsumed += (uint32_t)length;
if OF_UNLIKELY (length < 1) {
stream->_savedBits = ret;
stream->_savedBitsLength = i;
return false;
}
stream->_byte = stream->_buffer[0];
stream->_bufferIndex = 1;
stream->_bufferLength = (uint16_t)length;
}
stream->_bitIndex = 0;
}
ret = (ret << 1) |
((stream->_byte >> (7 - stream->_bitIndex++)) & 1);
}
stream->_savedBits = 0;
stream->_savedBitsLength = 0;
*bits = ret;
return true;
}
- (instancetype)of_initWithStream: (OFStream *)stream
distanceBits: (uint8_t)distanceBits
dictionaryBits: (uint8_t)dictionaryBits
{
self = [super init];
@try {
_stream = [stream retain];
/* 0-7 address the bit, 8 means fetch next byte */
_bitIndex = 8;
_distanceBits = distanceBits;
_dictionaryBits = dictionaryBits;
_slidingWindowMask = (1u << dictionaryBits) - 1;
_slidingWindow = of_alloc(_slidingWindowMask + 1, 1);
memset(_slidingWindow, ' ', _slidingWindowMask + 1);
} @catch (id e) {
[self release];
@throw e;
}
return self;
}
- (void)dealloc
{
if (_stream != nil)
[self close];
free(_slidingWindow);
if (_codeLenTree != NULL)
of_huffman_tree_release(_codeLenTree);
if (_litLenTree != NULL)
of_huffman_tree_release(_litLenTree);
if (_distTree != NULL)
of_huffman_tree_release(_distTree);
free(_codesLengths);
[super dealloc];
}
- (size_t)lowlevelReadIntoBuffer: (void *)buffer_
length: (size_t)length
{
unsigned char *buffer = buffer_;
uint16_t bits = 0, value = 0;
size_t bytesWritten = 0;
if (_stream == nil)
@throw [OFNotOpenException exceptionWithObject: self];
if (_stream.atEndOfStream && _bufferLength - _bufferIndex == 0 &&
_state == STATE_BLOCK_HEADER)
return 0;
start:
switch ((enum state)_state) {
case STATE_BLOCK_HEADER:
if OF_UNLIKELY (!tryReadBits(self, &bits, 16))
return bytesWritten;
_symbolsLeft = bits;
_state = STATE_CODE_LEN_CODES_COUNT;
goto start;
case STATE_CODE_LEN_CODES_COUNT:
if OF_UNLIKELY (!tryReadBits(self, &bits, 5))
return bytesWritten;
if OF_UNLIKELY (bits > 20)
@throw [OFInvalidFormatException exception];
if OF_UNLIKELY (bits == 0) {
_state = STATE_CODE_LEN_TREE_SINGLE;
goto start;
}
_codesCount = bits;
_codesReceived = 0;
_codesLengths = of_alloc_zeroed(bits, 1);
_skip = true;
_state = STATE_CODE_LEN_TREE;
goto start;
case STATE_CODE_LEN_TREE:
while (_codesReceived < _codesCount) {
if OF_UNLIKELY (_currentIsExtendedLength) {
if OF_UNLIKELY (!tryReadBits(self, &bits, 1))
return bytesWritten;
if OF_UNLIKELY (bits == 0) {
_codesReceived++;
_currentIsExtendedLength = false;
continue;
}
_codesLengths[_codesReceived]++;
continue;
}
if OF_UNLIKELY (_codesReceived == 3 && _skip) {
if OF_UNLIKELY (!tryReadBits(self, &bits, 2))
return bytesWritten;
if OF_UNLIKELY (_codesReceived + bits >
_codesCount)
@throw [OFInvalidFormatException
exception];
for (uint_fast8_t j = 0; j < bits; j++)
_codesLengths[_codesReceived++] = 0;
_skip = false;
continue;
}
if OF_UNLIKELY (!tryReadBits(self, &bits, 3))
return bytesWritten;
_codesLengths[_codesReceived] = bits;
if OF_UNLIKELY (bits == 7) {
_currentIsExtendedLength = true;
continue;
} else
_codesReceived++;
}
_codeLenTree = of_huffman_tree_construct(_codesLengths,
_codesCount);
free(_codesLengths);
_codesLengths = NULL;
_state = STATE_LITLEN_CODES_COUNT;
goto start;
case STATE_CODE_LEN_TREE_SINGLE:
if OF_UNLIKELY (!tryReadBits(self, &bits, 5))
return bytesWritten;
_codeLenTree = of_huffman_tree_construct_single(bits);
_state = STATE_LITLEN_CODES_COUNT;
goto start;
case STATE_LITLEN_CODES_COUNT:
if OF_UNLIKELY (!tryReadBits(self, &bits, 9))
return bytesWritten;
if OF_UNLIKELY (bits > 510)
@throw [OFInvalidFormatException exception];
if OF_UNLIKELY (bits == 0) {
of_huffman_tree_release(_codeLenTree);
_codeLenTree = NULL;
_state = STATE_LITLEN_TREE_SINGLE;
goto start;
}
_codesCount = bits;
_codesReceived = 0;
_codesLengths = of_alloc_zeroed(bits, 1);
_skip = false;
_treeIter = _codeLenTree;
_state = STATE_LITLEN_TREE;
goto start;
case STATE_LITLEN_TREE:
while (_codesReceived < _codesCount) {
if OF_UNLIKELY (_skip) {
uint16_t skipCount;
switch (_codesLengths[_codesReceived]) {
case 0:
skipCount = 1;
break;
case 1:
if OF_UNLIKELY (!tryReadBits(self,
&bits, 4))
return bytesWritten;
skipCount = bits + 3;
break;
case 2:
if OF_UNLIKELY (!tryReadBits(self,
&bits, 9))
return bytesWritten;
skipCount = bits + 20;
break;
default:
OF_ENSURE(0);
}
if OF_UNLIKELY (_codesReceived + skipCount >
_codesCount)
@throw [OFInvalidFormatException
exception];
for (uint_fast16_t j = 0; j < skipCount; j++)
_codesLengths[_codesReceived++] = 0;
_skip = false;
continue;
}
if (!of_huffman_tree_walk(self, tryReadBits,
&_treeIter, &value))
return bytesWritten;
_treeIter = _codeLenTree;
if (value < 3) {
_codesLengths[_codesReceived] = value;
_skip = true;
} else
_codesLengths[_codesReceived++] = value - 2;
}
_litLenTree = of_huffman_tree_construct(_codesLengths,
_codesCount);
free(_codesLengths);
_codesLengths = NULL;
of_huffman_tree_release(_codeLenTree);
_codeLenTree = NULL;
_state = STATE_DIST_CODES_COUNT;
goto start;
case STATE_LITLEN_TREE_SINGLE:
if OF_UNLIKELY (!tryReadBits(self, &bits, 9))
return bytesWritten;
_litLenTree = of_huffman_tree_construct_single(bits);
_state = STATE_DIST_CODES_COUNT;
goto start;
case STATE_DIST_CODES_COUNT:
if OF_UNLIKELY (!tryReadBits(self, &bits, _distanceBits))
return bytesWritten;
if OF_UNLIKELY (bits > _dictionaryBits)
@throw [OFInvalidFormatException exception];
if OF_UNLIKELY (bits == 0) {
_state = STATE_DIST_TREE_SINGLE;
goto start;
}
_codesCount = bits;
_codesReceived = 0;
_codesLengths = of_alloc_zeroed(bits, 1);
_treeIter = _codeLenTree;
_state = STATE_DIST_TREE;
goto start;
case STATE_DIST_TREE:
while (_codesReceived < _codesCount) {
if OF_UNLIKELY (_currentIsExtendedLength) {
if OF_UNLIKELY (!tryReadBits(self, &bits, 1))
return bytesWritten;
if OF_UNLIKELY (bits == 0) {
_codesReceived++;
_currentIsExtendedLength = false;
continue;
}
_codesLengths[_codesReceived]++;
continue;
}
if OF_UNLIKELY (!tryReadBits(self, &bits, 3))
return bytesWritten;
_codesLengths[_codesReceived] = bits;
if OF_UNLIKELY (bits == 7) {
_currentIsExtendedLength = true;
continue;
} else
_codesReceived++;
}
_distTree = of_huffman_tree_construct(_codesLengths,
_codesCount);
free(_codesLengths);
_codesLengths = NULL;
_treeIter = _litLenTree;
_state = STATE_BLOCK_LITLEN;
goto start;
case STATE_DIST_TREE_SINGLE:
if OF_UNLIKELY (!tryReadBits(self, &bits, _distanceBits))
return bytesWritten;
_distTree = of_huffman_tree_construct_single(bits);
_treeIter = _litLenTree;
_state = STATE_BLOCK_LITLEN;
goto start;
case STATE_BLOCK_LITLEN:
if OF_UNLIKELY (_symbolsLeft == 0) {
of_huffman_tree_release(_litLenTree);
of_huffman_tree_release(_distTree);
_litLenTree = _distTree = NULL;
_state = STATE_BLOCK_HEADER;
/*
* We must return here, as there is no indication
* whether this was the last block. Whoever called this
* method needs to check if everything has been read
* already and only call read again if that is not the
* case.
*
* We must also unread the buffer, in case this was the
* last block and something else follows, e.g. another
* LHA header.
*/
[_stream unreadFromBuffer: _buffer + _bufferIndex
length: _bufferLength -
_bufferIndex];
_bytesConsumed -= _bufferLength - _bufferIndex;
_bufferIndex = _bufferLength = 0;
return bytesWritten;
}
if OF_UNLIKELY (length == 0)
return bytesWritten;
if OF_UNLIKELY (!of_huffman_tree_walk(self, tryReadBits,
&_treeIter, &value))
return bytesWritten;
if OF_LIKELY (value < 256) {
buffer[bytesWritten++] = value;
length--;
_slidingWindow[_slidingWindowIndex] = value;
_slidingWindowIndex = (_slidingWindowIndex + 1) &
_slidingWindowMask;
_symbolsLeft--;
_treeIter = _litLenTree;
} else {
_length = value - 253;
_treeIter = _distTree;
_state = STATE_BLOCK_DIST_LENGTH;
}
goto start;
case STATE_BLOCK_DIST_LENGTH:
if OF_UNLIKELY (!of_huffman_tree_walk(self, tryReadBits,
&_treeIter, &value))
return bytesWritten;
_distance = value;
_state = (value < 2
? STATE_BLOCK_LEN_DIST_PAIR
: STATE_BLOCK_DIST_LENGTH_EXTRA);
goto start;
case STATE_BLOCK_DIST_LENGTH_EXTRA:
if OF_UNLIKELY (!tryReadBits(self, &bits, _distance - 1))
return bytesWritten;
_distance = bits + (1u << (_distance - 1));
_state = STATE_BLOCK_LEN_DIST_PAIR;
goto start;
case STATE_BLOCK_LEN_DIST_PAIR:
for (uint_fast16_t i = 0; i < _length; i++) {
uint32_t idx;
if OF_UNLIKELY (length == 0) {
_length -= i;
return bytesWritten;
}
idx = (_slidingWindowIndex - _distance - 1) &
_slidingWindowMask;
value = _slidingWindow[idx];
buffer[bytesWritten++] = value;
length--;
_slidingWindow[_slidingWindowIndex] = value;
_slidingWindowIndex = (_slidingWindowIndex + 1) &
_slidingWindowMask;
}
_symbolsLeft--;
_treeIter = _litLenTree;
_state = STATE_BLOCK_LITLEN;
goto start;
}
OF_UNREACHABLE
}
- (bool)lowlevelIsAtEndOfStream
{
if (_stream == nil)
@throw [OFNotOpenException exceptionWithObject: self];
return (_stream.atEndOfStream &&
_bufferLength - _bufferIndex == 0 && _state == STATE_BLOCK_HEADER);
}
- (int)fileDescriptorForReading
{
return ((id <OFReadyForReadingObserving>)_stream)
.fileDescriptorForReading;
}
- (bool)hasDataInReadBuffer
{
return (super.hasDataInReadBuffer || _stream.hasDataInReadBuffer ||
_bufferLength - _bufferIndex > 0);
}
- (void)close
{
if (_stream == nil)
@throw [OFNotOpenException exceptionWithObject: self];
/* Give back our buffer to the stream, in case it's shared */
[_stream unreadFromBuffer: _buffer + _bufferIndex
length: _bufferLength - _bufferIndex];
_bytesConsumed -= _bufferLength - _bufferIndex;
_bufferIndex = _bufferLength = 0;
[_stream release];
_stream = nil;
[super close];
}
@end