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#import "OFKernelEventObserver.h"
#import "OFHuffmanTree.h"
#import "OFInvalidFormatException.h"
#import "OFNotOpenException.h"
enum state {
StateBlockHeader,
StateCodeLenCodesCount,
StateCodeLenTree,
StateCodeLenTreeSingle,
StateLitLenCodesCount,
StateLitLenTree,
StateLitLenTreeSingle,
StateDistCodesCount,
StateDistTree,
StateDistTreeSingle,
StateBlockLitLen,
StateBlockDistLength,
StateBlockDistLengthExtra,
StateBlockLenDistPair
enum State {
stateBlockHeader,
stateCodeLenCodesCount,
stateCodeLenTree,
stateCodeLenTreeSingle,
stateLitLenCodesCount,
stateLitLenTree,
stateLitLenTreeSingle,
stateDistCodesCount,
stateDistTree,
stateDistTreeSingle,
stateBlockLitLen,
stateBlockDistLength,
stateBlockDistLengthExtra,
stateBlockLenDistPair
};
@implementation OFLHADecompressingStream
@synthesize bytesConsumed = _bytesConsumed;
static OF_INLINE bool
tryReadBits(OFLHADecompressingStream *stream, uint16_t *bits, uint8_t count)
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uint16_t bits = 0, value = 0;
size_t bytesWritten = 0;
if (_stream == nil)
@throw [OFNotOpenException exceptionWithObject: self];
if (_stream.atEndOfStream && _bufferLength - _bufferIndex == 0 &&
_state == StateBlockHeader)
_state == stateBlockHeader)
return 0;
start:
switch ((enum state)_state) {
case StateBlockHeader:
switch ((enum State)_state) {
case stateBlockHeader:
if OF_UNLIKELY (!tryReadBits(self, &bits, 16))
return bytesWritten;
_symbolsLeft = bits;
_state = StateCodeLenCodesCount;
_state = stateCodeLenCodesCount;
goto start;
case StateCodeLenCodesCount:
case stateCodeLenCodesCount:
if OF_UNLIKELY (!tryReadBits(self, &bits, 5))
return bytesWritten;
if OF_UNLIKELY (bits > 20)
@throw [OFInvalidFormatException exception];
if OF_UNLIKELY (bits == 0) {
_state = StateCodeLenTreeSingle;
_state = stateCodeLenTreeSingle;
goto start;
}
_codesCount = bits;
_codesReceived = 0;
_codesLengths = OFAllocZeroedMemory(bits, 1);
_skip = true;
_state = StateCodeLenTree;
_state = stateCodeLenTree;
goto start;
case StateCodeLenTree:
case stateCodeLenTree:
while (_codesReceived < _codesCount) {
if OF_UNLIKELY (_currentIsExtendedLength) {
if OF_UNLIKELY (!tryReadBits(self, &bits, 1))
return bytesWritten;
if OF_UNLIKELY (bits == 0) {
_codesReceived++;
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_codesReceived++;
}
_codeLenTree = OFHuffmanTreeNew(_codesLengths, _codesCount);
OFFreeMemory(_codesLengths);
_codesLengths = NULL;
_state = StateLitLenCodesCount;
_state = stateLitLenCodesCount;
goto start;
case StateCodeLenTreeSingle:
case stateCodeLenTreeSingle:
if OF_UNLIKELY (!tryReadBits(self, &bits, 5))
return bytesWritten;
_codeLenTree = OFHuffmanTreeNewSingle(bits);
_state = StateLitLenCodesCount;
_state = stateLitLenCodesCount;
goto start;
case StateLitLenCodesCount:
case stateLitLenCodesCount:
if OF_UNLIKELY (!tryReadBits(self, &bits, 9))
return bytesWritten;
if OF_UNLIKELY (bits > 510)
@throw [OFInvalidFormatException exception];
if OF_UNLIKELY (bits == 0) {
OFHuffmanTreeFree(_codeLenTree);
_codeLenTree = NULL;
_state = StateLitLenTreeSingle;
_state = stateLitLenTreeSingle;
goto start;
}
_codesCount = bits;
_codesReceived = 0;
_codesLengths = OFAllocZeroedMemory(bits, 1);
_skip = false;
_treeIter = _codeLenTree;
_state = StateLitLenTree;
_state = stateLitLenTree;
goto start;
case StateLitLenTree:
case stateLitLenTree:
while (_codesReceived < _codesCount) {
if OF_UNLIKELY (_skip) {
uint16_t skipCount;
switch (_codesLengths[_codesReceived]) {
case 0:
skipCount = 1;
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_litLenTree = OFHuffmanTreeNew(_codesLengths, _codesCount);
OFFreeMemory(_codesLengths);
_codesLengths = NULL;
OFHuffmanTreeFree(_codeLenTree);
_codeLenTree = NULL;
_state = StateDistCodesCount;
_state = stateDistCodesCount;
goto start;
case StateLitLenTreeSingle:
case stateLitLenTreeSingle:
if OF_UNLIKELY (!tryReadBits(self, &bits, 9))
return bytesWritten;
_litLenTree = OFHuffmanTreeNewSingle(bits);
_state = StateDistCodesCount;
_state = stateDistCodesCount;
goto start;
case StateDistCodesCount:
case stateDistCodesCount:
if OF_UNLIKELY (!tryReadBits(self, &bits, _distanceBits))
return bytesWritten;
if OF_UNLIKELY (bits > _dictionaryBits)
@throw [OFInvalidFormatException exception];
if OF_UNLIKELY (bits == 0) {
_state = StateDistTreeSingle;
_state = stateDistTreeSingle;
goto start;
}
_codesCount = bits;
_codesReceived = 0;
_codesLengths = OFAllocZeroedMemory(bits, 1);
_treeIter = _codeLenTree;
_state = StateDistTree;
_state = stateDistTree;
goto start;
case StateDistTree:
case stateDistTree:
while (_codesReceived < _codesCount) {
if OF_UNLIKELY (_currentIsExtendedLength) {
if OF_UNLIKELY (!tryReadBits(self, &bits, 1))
return bytesWritten;
if OF_UNLIKELY (bits == 0) {
_codesReceived++;
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}
_distTree = OFHuffmanTreeNew(_codesLengths, _codesCount);
OFFreeMemory(_codesLengths);
_codesLengths = NULL;
_treeIter = _litLenTree;
_state = StateBlockLitLen;
_state = stateBlockLitLen;
goto start;
case StateDistTreeSingle:
case stateDistTreeSingle:
if OF_UNLIKELY (!tryReadBits(self, &bits, _distanceBits))
return bytesWritten;
_distTree = OFHuffmanTreeNewSingle(bits);
_treeIter = _litLenTree;
_state = StateBlockLitLen;
_state = stateBlockLitLen;
goto start;
case StateBlockLitLen:
case stateBlockLitLen:
if OF_UNLIKELY (_symbolsLeft == 0) {
OFHuffmanTreeFree(_litLenTree);
OFHuffmanTreeFree(_distTree);
_litLenTree = _distTree = NULL;
_state = StateBlockHeader;
_state = stateBlockHeader;
/*
* 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.
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_slidingWindowMask;
_symbolsLeft--;
_treeIter = _litLenTree;
} else {
_length = value - 253;
_treeIter = _distTree;
_state = StateBlockDistLength;
_state = stateBlockDistLength;
}
goto start;
case StateBlockDistLength:
case stateBlockDistLength:
if OF_UNLIKELY (!OFHuffmanTreeWalk(self, tryReadBits,
&_treeIter, &value))
return bytesWritten;
_distance = value;
_state = (value < 2
? StateBlockLenDistPair : StateBlockDistLengthExtra);
? stateBlockLenDistPair : stateBlockDistLengthExtra);
goto start;
case StateBlockDistLengthExtra:
case stateBlockDistLengthExtra:
if OF_UNLIKELY (!tryReadBits(self, &bits, _distance - 1))
return bytesWritten;
_distance = bits + (1u << (_distance - 1));
_state = StateBlockLenDistPair;
_state = stateBlockLenDistPair;
goto start;
case StateBlockLenDistPair:
case stateBlockLenDistPair:
for (uint_fast16_t i = 0; i < _length; i++) {
uint32_t idx;
if OF_UNLIKELY (length == 0) {
_length -= i;
return bytesWritten;
}
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_slidingWindowIndex = (_slidingWindowIndex + 1) &
_slidingWindowMask;
}
_symbolsLeft--;
_treeIter = _litLenTree;
_state = StateBlockLitLen;
_state = stateBlockLitLen;
goto start;
}
OF_UNREACHABLE
}
- (bool)lowlevelIsAtEndOfStream
{
if (_stream == nil)
@throw [OFNotOpenException exceptionWithObject: self];
return (_stream.atEndOfStream &&
_bufferLength - _bufferIndex == 0 && _state == StateBlockHeader);
_bufferLength - _bufferIndex == 0 && _state == stateBlockHeader);
}
- (int)fileDescriptorForReading
{
return ((id <OFReadyForReadingObserving>)_stream)
.fileDescriptorForReading;
}
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