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#define MAX_BITS 15
struct huffman_tree {
struct huffman_tree *leafs[2];
uint16_t value;
};
static const uint_fast8_t numDistanceCodes = 30;
static const uint8_t lengthCodes[29] = {
/* indices are -257, values -3 */
0, 1, 2, 3, 4, 5, 6, 7, 8, 10, 12, 14, 16, 20, 24, 28, 32, 40, 48, 56,
64, 80, 96, 112, 128, 160, 192, 224, 255
};
static const uint8_t lengthExtraBits[29] = {
0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 1, 1, 2, 2, 2, 2, 3, 3, 3, 3, 4, 4, 4, 4,
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- initWithStream: (OFStream*)stream
{
self = [super init];
_stream = [stream retain];
_bitIndex = 8; /* 0-7 address the bit, 8 means fetch next byte */
_slidingWindowMask = 0x7FFF;
_codes.numDistanceCodes = numDistanceCodes;
_codes.lengthCodes = lengthCodes;
_codes.lengthExtraBits = lengthExtraBits;
_codes.distanceCodes = distanceCodes;
_codes.distanceExtraBits = distanceExtraBits;
return self;
}
- (void)dealloc
{
[_stream release];
[super dealloc];
}
- (size_t)lowlevelReadIntoBuffer: (void*)buffer_
length: (size_t)length
{
uint8_t *buffer = buffer_;
uint_fast16_t bits;
uint16_t value;
size_t i, tmp, bytesWritten = 0;
char *slidingWindow;
uint8_t *slidingWindow;
uint_fast16_t slidingWindowIndex;
if (_atEndOfStream)
@throw [OFReadFailedException exceptionWithStream: self
requestedLength: length];
start:
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tmp = (length < CTX.length - CTX.position
? length : CTX.length - CTX.position);
tmp = [_stream readIntoBuffer: buffer + bytesWritten
length: tmp];
if OF_UNLIKELY (_slidingWindow == NULL) {
_slidingWindow = [self allocMemoryWithSize: 0x8000];
_slidingWindow =
[self allocMemoryWithSize: _slidingWindowMask + 1];
/* Avoid leaking data */
memset(_slidingWindow, 0, 0x8000);
memset(_slidingWindow, 0, _slidingWindowMask + 1);
}
slidingWindow = _slidingWindow;
slidingWindowIndex = _slidingWindowIndex;
for (i = 0; i < tmp; i++) {
slidingWindow[slidingWindowIndex] =
buffer[bytesWritten + i];
slidingWindowIndex = (slidingWindowIndex + 1) & 0x7FFF;
slidingWindowIndex = (slidingWindowIndex + 1) &
_slidingWindowMask;
}
_slidingWindowIndex = slidingWindowIndex;
length -= tmp;
bytesWritten += tmp;
CTX.position += tmp;
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return bytesWritten;
buffer[bytesWritten++] = CTX.value;
length--;
if (_slidingWindow == NULL) {
_slidingWindow = [self
allocMemoryWithSize: 0x8000];
allocMemoryWithSize:
_slidingWindowMask + 1];
/* Avoid leaking data */
memset(_slidingWindow, 0, 0x8000);
memset(_slidingWindow, 0,
_slidingWindowMask + 1);
}
_slidingWindow[_slidingWindowIndex] = CTX.value;
_slidingWindowIndex =
(_slidingWindowIndex + 1) & 0x7FFF;
(_slidingWindowIndex + 1) &
_slidingWindowMask;
CTX.state = AWAIT_CODE;
CTX.treeIter = CTX.litLenTree;
}
if OF_UNLIKELY (CTX.state == AWAIT_LENGTH_EXTRA_BITS) {
if OF_UNLIKELY (!tryReadBits(self, &bits,
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/* Distance of length distance pair */
if (CTX.state == AWAIT_DISTANCE) {
if OF_UNLIKELY (!walkTree(self, &CTX.treeIter,
&value))
return bytesWritten;
if OF_UNLIKELY (value > 29)
if OF_UNLIKELY (value >=
_codes.numDistanceCodes)
@throw [OFInvalidFormatException
exception];
CTX.distance = distanceCodes[value];
extraBits = distanceExtraBits[value];
CTX.distance = _codes.distanceCodes[value];
extraBits = _codes.distanceExtraBits[value];
if (extraBits > 0) {
if OF_UNLIKELY (!tryReadBits(self,
&bits, extraBits)) {
CTX.state =
AWAIT_DISTANCE_EXTRA_BITS;
CTX.extraBits = extraBits;
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if OF_UNLIKELY (length == 0) {
CTX.length -= j;
return bytesWritten;
}
index = (_slidingWindowIndex -
CTX.distance) & 0x7FFF;
CTX.distance) & _slidingWindowMask;
value = _slidingWindow[index];
buffer[bytesWritten++] = value;
length--;
_slidingWindow[_slidingWindowIndex] =
value;
_slidingWindowIndex =
(_slidingWindowIndex + 1) & 0x7FFF;
(_slidingWindowIndex + 1) &
_slidingWindowMask;
}
CTX.state = AWAIT_CODE;
CTX.treeIter = CTX.litLenTree;
}
if OF_UNLIKELY (!walkTree(self, &CTX.treeIter, &value))
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}
buffer[bytesWritten++] = value;
length--;
if (_slidingWindow == NULL) {
_slidingWindow = [self
allocMemoryWithSize: 0x8000];
allocMemoryWithSize:
_slidingWindowMask + 1];
/* Avoid leaking data */
memset(_slidingWindow, 0, 0x8000);
memset(_slidingWindow, 0,
_slidingWindowMask + 1);
}
_slidingWindow[_slidingWindowIndex] = value;
_slidingWindowIndex =
(_slidingWindowIndex + 1) & 0x7FFF;
(_slidingWindowIndex + 1) &
_slidingWindowMask;
CTX.treeIter = CTX.litLenTree;
continue;
}
if OF_UNLIKELY (value > 285)
@throw [OFInvalidFormatException exception];
/* Length of length distance pair */
lengthCodeIndex = value - 257;
CTX.length = lengthCodes[lengthCodeIndex] + 3;
extraBits = lengthExtraBits[lengthCodeIndex];
CTX.length = _codes.lengthCodes[lengthCodeIndex] + 3;
extraBits = _codes.lengthExtraBits[lengthCodeIndex];
if (extraBits > 0) {
if OF_UNLIKELY (!tryReadBits(self, &bits,
extraBits)) {
CTX.extraBits = extraBits;
CTX.state = AWAIT_LENGTH_EXTRA_BITS;
return bytesWritten;
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