// Copy up to length of bytes from input directly.
// This is used for uncompressed block.
public int CopyFrom(InputBuffer input, int length)
{
length = Math.Min(Math.Min(length, WindowSize - _bytesUsed), input.AvailableBytes);
int copied;
// We might need wrap around to copy all bytes.
int tailLen = WindowSize - _end;
if (length > tailLen)
{
// copy the first part
copied = input.CopyTo(_window, _end, tailLen);
if (copied == tailLen)
{
// only try to copy the second part if we have enough bytes in input
copied += input.CopyTo(_window, 0, length - tailLen);
}
}
else
{
// only one copy is needed if there is no wrap around.
copied = input.CopyTo(_window, _end, length);
}
_end = (_end + copied) & WindowMask;
_bytesUsed += copied;
return copied;
}
public int GetNextSymbol(InputBuffer input)
{
uint num = input.TryLoad16Bits();
if (input.AvailableBits == 0) {
return -1;
}
int index = this.table[(int)((IntPtr)(num & this.tableMask))];
if (index < 0) {
uint num3 = ((uint)1) << this.tableBits;
do {
index = -index;
if ((num & num3) == 0) {
index = this.left[index];
}
else {
index = this.right[index];
}
num3 = num3 << 1;
}
while (index < 0);
}
if (this.codeLengthArray[index] > input.AvailableBits) {
return -1;
}
input.SkipBits(this.codeLengthArray[index]);
return index;
}
public Inflater(bool doGZip) {
this.using_gzip = doGZip;
this.output = new OutputWindow();
this.input = new InputBuffer();
this.gZipDecoder = new GZipDecoder(this.input);
this.codeList = new byte[320];
this.codeLengthTreeCodeLength = new byte[0x13];
this.Reset();
}
public int CopyFrom(InputBuffer input, int length) {
int num;
length = Math.Min(Math.Min(length, 0x8000 - this.bytesUsed), input.AvailableBytes);
int num2 = 0x8000 - this.end;
if (length > num2) {
num = input.CopyTo(this.window, this.end, num2);
if (num == num2) {
num += input.CopyTo(this.window, 0, length - num2);
}
}
else {
num = input.CopyTo(this.window, this.end, length);
}
this.end = (this.end + num) & 0x7fff;
this.bytesUsed += num;
return num;
}
public int CopyFrom(InputBuffer input, int length)
{
int num;
length = Math.Min(Math.Min(length, 0x8000 - this.bytesUsed), input.AvailableBytes);
int num2 = 0x8000 - this.end;
if (length > num2)
{
num = input.CopyTo(this.window, this.end, num2);
if (num == num2)
{
num += input.CopyTo(this.window, 0, length - num2);
}
}
else
{
num = input.CopyTo(this.window, this.end, length);
}
this.end = (this.end + num) & 0x7fff;
this.bytesUsed += num;
return(num);
}
public bool ReadFooter(InputBuffer input)
{
input.SkipToByteBoundary();
if (this.gzipFooterSubstate == GzipHeaderState.ReadingCRC)
{
while (this.loopCounter < 4)
{
int bits = input.GetBits(8);
if (bits < 0)
{
return(false);
}
this.expectedCrc32 |= (uint)(bits << (8 * this.loopCounter));
this.loopCounter++;
}
this.gzipFooterSubstate = GzipHeaderState.ReadingFileSize;
this.loopCounter = 0;
}
if (this.gzipFooterSubstate == GzipHeaderState.ReadingFileSize)
{
if (this.loopCounter == 0)
{
this.expectedOutputStreamSize = 0;
}
while (this.loopCounter < 4)
{
int num2 = input.GetBits(8);
if (num2 < 0)
{
return(false);
}
this.expectedOutputStreamSize |= (uint)(num2 << (8 * this.loopCounter));
this.loopCounter++;
}
}
return(true);
}
public bool ReadFooter(InputBuffer input)
{
input.SkipToByteBoundary();
if (this.gzipFooterSubstate == GzipHeaderState.ReadingCRC)
{
while (this.loopCounter < 4)
{
int bits = input.GetBits(8);
if (bits < 0)
{
return false;
}
this.expectedCrc32 |= (uint) (bits << (8 * this.loopCounter));
this.loopCounter++;
}
this.gzipFooterSubstate = GzipHeaderState.ReadingFileSize;
this.loopCounter = 0;
}
if (this.gzipFooterSubstate == GzipHeaderState.ReadingFileSize)
{
if (this.loopCounter == 0)
{
this.expectedOutputStreamSize = 0;
}
while (this.loopCounter < 4)
{
int num2 = input.GetBits(8);
if (num2 < 0)
{
return false;
}
this.expectedOutputStreamSize |= (uint) (num2 << (8 * this.loopCounter));
this.loopCounter++;
}
}
return true;
}
GZipDecoder gZipDecoder; // class to decode gzip header and footer
public Inflater(bool doGZip) {
using_gzip = doGZip;
output = new OutputWindow();
input = new InputBuffer();
gZipDecoder = new GZipDecoder(input);
codeList = new byte[HuffmanTree.MaxLiteralTreeElements + HuffmanTree.MaxDistTreeElements];
codeLengthTreeCodeLength = new byte[HuffmanTree.NumberOfCodeLengthTreeElements];
Reset();
}
public GZipDecoder(InputBuffer input)
{
this.input = input;
this.Reset();
}
//
// This function will try to get enough bits from input and
// try to decode the bits.
// If there are no enought bits in the input, this function will return -1.
//
public int GetNextSymbol(InputBuffer input)
{
// Try to load 16 bits into input buffer if possible and get the bitBuffer value.
// If there aren't 16 bits available we will return all we have in the
// input buffer.
uint bitBuffer = input.TryLoad16Bits();
if (input.AvailableBits == 0)
{ // running out of input.
return -1;
}
// decode an element
int symbol = _table[bitBuffer & _tableMask];
if (symbol < 0)
{ // this will be the start of the binary tree
// navigate the tree
uint mask = (uint)1 << _tableBits;
do
{
symbol = -symbol;
if ((bitBuffer & mask) == 0)
symbol = _left[symbol];
else
symbol = _right[symbol];
mask <<= 1;
} while (symbol < 0);
}
int codeLength = _codeLengthArray[symbol];
// huffman code lengths must be at least 1 bit long
if (codeLength <= 0)
{
throw new InvalidDataException(SR.InvalidHuffmanData);
}
//
// If this code is longer than the # bits we had in the bit buffer (i.e.
// we read only part of the code), we can hit the entry in the table or the tree
// for another symbol. However the length of another symbol will not match the
// available bits count.
if (codeLength > input.AvailableBits)
{
// We already tried to load 16 bits and maximum length is 15,
// so this means we are running out of input.
return -1;
}
input.SkipBits(codeLength);
return symbol;
}
public bool ReadHeader(InputBuffer input)
{
while (true)
{
int bits;
switch (gzipHeaderSubstate)
{
case GzipHeaderState.ReadingID1:
bits = input.GetBits(8);
if (bits < 0)
{
return(false);
}
if (bits != GZipConstants.ID1)
{
throw new InvalidDataException(SR.GetString(SR.CorruptedGZipHeader));
}
gzipHeaderSubstate = GzipHeaderState.ReadingID2;
goto case GzipHeaderState.ReadingID2;
case GzipHeaderState.ReadingID2:
bits = input.GetBits(8);
if (bits < 0)
{
return(false);
}
if (bits != GZipConstants.ID2)
{
throw new InvalidDataException(SR.GetString(SR.CorruptedGZipHeader));
}
gzipHeaderSubstate = GzipHeaderState.ReadingCM;
goto case GzipHeaderState.ReadingCM;
case GzipHeaderState.ReadingCM:
bits = input.GetBits(8);
if (bits < 0)
{
return(false);
}
if (bits != GZipConstants.Deflate) // compression mode must be 8 (deflate)
{
throw new InvalidDataException(SR.GetString(SR.UnknownCompressionMode));
}
gzipHeaderSubstate = GzipHeaderState.ReadingFLG;;
goto case GzipHeaderState.ReadingFLG;
case GzipHeaderState.ReadingFLG:
bits = input.GetBits(8);
if (bits < 0)
{
return(false);
}
gzip_header_flag = bits;
gzipHeaderSubstate = GzipHeaderState.ReadingMMTime;
loopCounter = 0; // 4 MMTIME bytes
goto case GzipHeaderState.ReadingMMTime;
case GzipHeaderState.ReadingMMTime:
bits = 0;
while (loopCounter < 4)
{
bits = input.GetBits(8);
if (bits < 0)
{
return(false);
}
loopCounter++;
}
gzipHeaderSubstate = GzipHeaderState.ReadingXFL;
loopCounter = 0;
goto case GzipHeaderState.ReadingXFL;
case GzipHeaderState.ReadingXFL: // ignore XFL
bits = input.GetBits(8);
if (bits < 0)
{
return(false);
}
gzipHeaderSubstate = GzipHeaderState.ReadingOS;
goto case GzipHeaderState.ReadingOS;
case GzipHeaderState.ReadingOS: // ignore OS
bits = input.GetBits(8);
if (bits < 0)
{
return(false);
}
gzipHeaderSubstate = GzipHeaderState.ReadingXLen1;
goto case GzipHeaderState.ReadingXLen1;
case GzipHeaderState.ReadingXLen1:
if ((gzip_header_flag & (int)GZipOptionalHeaderFlags.ExtraFieldsFlag) == 0)
{
goto case GzipHeaderState.ReadingFileName;
}
bits = input.GetBits(8);
if (bits < 0)
{
return(false);
}
gzip_header_xlen = bits;
gzipHeaderSubstate = GzipHeaderState.ReadingXLen2;
goto case GzipHeaderState.ReadingXLen2;
case GzipHeaderState.ReadingXLen2:
bits = input.GetBits(8);
if (bits < 0)
{
return(false);
}
gzip_header_xlen |= (bits << 8);
gzipHeaderSubstate = GzipHeaderState.ReadingXLenData;
loopCounter = 0; // 0 bytes of XLEN data read so far
goto case GzipHeaderState.ReadingXLenData;
case GzipHeaderState.ReadingXLenData:
bits = 0;
while (loopCounter < gzip_header_xlen)
{
bits = input.GetBits(8);
if (bits < 0)
{
return(false);
}
loopCounter++;
}
gzipHeaderSubstate = GzipHeaderState.ReadingFileName;
loopCounter = 0;
goto case GzipHeaderState.ReadingFileName;
case GzipHeaderState.ReadingFileName:
if ((gzip_header_flag & (int)GZipOptionalHeaderFlags.FileNameFlag) == 0)
{
gzipHeaderSubstate = GzipHeaderState.ReadingComment;
goto case GzipHeaderState.ReadingComment;
}
do
{
bits = input.GetBits(8);
if (bits < 0)
{
return(false);
}
if (bits == 0) // see '\0' in the file name string
{
break;
}
} while (true);
gzipHeaderSubstate = GzipHeaderState.ReadingComment;
goto case GzipHeaderState.ReadingComment;
case GzipHeaderState.ReadingComment:
if ((gzip_header_flag & (int)GZipOptionalHeaderFlags.CommentFlag) == 0)
{
gzipHeaderSubstate = GzipHeaderState.ReadingCRC16Part1;
goto case GzipHeaderState.ReadingCRC16Part1;
}
do
{
bits = input.GetBits(8);
if (bits < 0)
{
return(false);
}
if (bits == 0) // see '\0' in the file name string
{
break;
}
} while (true);
gzipHeaderSubstate = GzipHeaderState.ReadingCRC16Part1;
goto case GzipHeaderState.ReadingCRC16Part1;
case GzipHeaderState.ReadingCRC16Part1:
if ((gzip_header_flag & (int)GZipOptionalHeaderFlags.CRCFlag) == 0)
{
gzipHeaderSubstate = GzipHeaderState.Done;
goto case GzipHeaderState.Done;
}
bits = input.GetBits(8); // ignore crc
if (bits < 0)
{
return(false);
}
gzipHeaderSubstate = GzipHeaderState.ReadingCRC16Part2;
goto case GzipHeaderState.ReadingCRC16Part2;
case GzipHeaderState.ReadingCRC16Part2:
bits = input.GetBits(8); // ignore crc
if (bits < 0)
{
return(false);
}
gzipHeaderSubstate = GzipHeaderState.Done;
goto case GzipHeaderState.Done;
case GzipHeaderState.Done:
return(true);
default:
Debug.Assert(false, "We should not reach unknown state!");
throw new InvalidDataException(SR.GetString(SR.UnknownState));
}
}
}
public bool ReadHeader(InputBuffer input)
{
int bits;
switch (this.gzipHeaderSubstate)
{
case GzipHeaderState.ReadingID1:
bits = input.GetBits(8);
if (bits >= 0)
{
if (bits != 0x1f)
{
throw new InvalidDataException(SR.GetString("CorruptedGZipHeader"));
}
this.gzipHeaderSubstate = GzipHeaderState.ReadingID2;
break;
}
return false;
case GzipHeaderState.ReadingID2:
break;
case GzipHeaderState.ReadingCM:
goto Label_00A5;
case GzipHeaderState.ReadingFLG:
goto Label_00CE;
case GzipHeaderState.ReadingMMTime:
goto Label_00F1;
case GzipHeaderState.ReadingXFL:
goto Label_0128;
case GzipHeaderState.ReadingOS:
goto Label_013D;
case GzipHeaderState.ReadingXLen1:
goto Label_0152;
case GzipHeaderState.ReadingXLen2:
goto Label_017B;
case GzipHeaderState.ReadingXLenData:
goto Label_01A8;
case GzipHeaderState.ReadingFileName:
goto Label_01E5;
case GzipHeaderState.ReadingComment:
goto Label_0212;
case GzipHeaderState.ReadingCRC16Part1:
goto Label_0240;
case GzipHeaderState.ReadingCRC16Part2:
goto Label_026A;
case GzipHeaderState.Done:
goto Label_0280;
default:
throw new InvalidDataException(SR.GetString("UnknownState"));
}
bits = input.GetBits(8);
if (bits < 0)
{
return false;
}
if (bits != 0x8b)
{
throw new InvalidDataException(SR.GetString("CorruptedGZipHeader"));
}
this.gzipHeaderSubstate = GzipHeaderState.ReadingCM;
Label_00A5:
bits = input.GetBits(8);
if (bits < 0)
{
return false;
}
if (bits != 8)
{
throw new InvalidDataException(SR.GetString("UnknownCompressionMode"));
}
this.gzipHeaderSubstate = GzipHeaderState.ReadingFLG;
Label_00CE:
bits = input.GetBits(8);
if (bits < 0)
{
return false;
}
this.gzip_header_flag = bits;
this.gzipHeaderSubstate = GzipHeaderState.ReadingMMTime;
this.loopCounter = 0;
Label_00F1:
bits = 0;
while (this.loopCounter < 4)
{
if (input.GetBits(8) < 0)
{
return false;
}
this.loopCounter++;
}
this.gzipHeaderSubstate = GzipHeaderState.ReadingXFL;
this.loopCounter = 0;
Label_0128:
if (input.GetBits(8) < 0)
{
return false;
}
this.gzipHeaderSubstate = GzipHeaderState.ReadingOS;
Label_013D:
if (input.GetBits(8) < 0)
{
return false;
}
this.gzipHeaderSubstate = GzipHeaderState.ReadingXLen1;
Label_0152:
if ((this.gzip_header_flag & 4) == 0)
{
goto Label_01E5;
}
bits = input.GetBits(8);
if (bits < 0)
{
return false;
}
this.gzip_header_xlen = bits;
this.gzipHeaderSubstate = GzipHeaderState.ReadingXLen2;
Label_017B:
bits = input.GetBits(8);
if (bits < 0)
{
return false;
}
this.gzip_header_xlen |= bits << 8;
this.gzipHeaderSubstate = GzipHeaderState.ReadingXLenData;
this.loopCounter = 0;
Label_01A8:
bits = 0;
while (this.loopCounter < this.gzip_header_xlen)
{
if (input.GetBits(8) < 0)
{
return false;
}
this.loopCounter++;
}
this.gzipHeaderSubstate = GzipHeaderState.ReadingFileName;
this.loopCounter = 0;
Label_01E5:
if ((this.gzip_header_flag & 8) == 0)
{
this.gzipHeaderSubstate = GzipHeaderState.ReadingComment;
}
else
{
do
{
bits = input.GetBits(8);
if (bits < 0)
{
return false;
}
}
while (bits != 0);
this.gzipHeaderSubstate = GzipHeaderState.ReadingComment;
}
Label_0212:
if ((this.gzip_header_flag & 0x10) == 0)
{
this.gzipHeaderSubstate = GzipHeaderState.ReadingCRC16Part1;
}
else
{
do
{
bits = input.GetBits(8);
if (bits < 0)
{
return false;
}
}
while (bits != 0);
this.gzipHeaderSubstate = GzipHeaderState.ReadingCRC16Part1;
}
Label_0240:
if ((this.gzip_header_flag & 2) == 0)
{
this.gzipHeaderSubstate = GzipHeaderState.Done;
goto Label_0280;
}
if (input.GetBits(8) < 0)
{
return false;
}
this.gzipHeaderSubstate = GzipHeaderState.ReadingCRC16Part2;
Label_026A:
if (input.GetBits(8) < 0)
{
return false;
}
this.gzipHeaderSubstate = GzipHeaderState.Done;
Label_0280:
return true;
}
public bool ReadFooter(InputBuffer input) {
input.SkipToByteBoundary();
if (gzipFooterSubstate == GzipHeaderState.ReadingCRC) {
while (loopCounter < 4) {
int bits = input.GetBits(8);
if (bits < 0) {
return false;
}
expectedCrc32 |= ((uint)bits << (8 * loopCounter));
loopCounter++;
}
gzipFooterSubstate = GzipHeaderState.ReadingFileSize;
loopCounter = 0;
}
if (gzipFooterSubstate == GzipHeaderState.ReadingFileSize) {
if (loopCounter == 0)
expectedOutputStreamSizeModulo = 0;
while (loopCounter < 4) {
int bits = input.GetBits(8);
if (bits < 0) {
return false;
}
expectedOutputStreamSizeModulo |= ((uint) bits << (8 * loopCounter));
loopCounter++;
}
}
return true;
}
public bool ReadHeader(InputBuffer input)
{
int bits;
switch (this.gzipHeaderSubstate)
{
case GzipHeaderState.ReadingID1:
bits = input.GetBits(8);
if (bits >= 0)
{
if (bits != 0x1f)
{
throw new InvalidDataException(SR.GetString("CorruptedGZipHeader"));
}
this.gzipHeaderSubstate = GzipHeaderState.ReadingID2;
break;
}
return(false);
case GzipHeaderState.ReadingID2:
break;
case GzipHeaderState.ReadingCM:
goto Label_00A5;
case GzipHeaderState.ReadingFLG:
goto Label_00CE;
case GzipHeaderState.ReadingMMTime:
goto Label_00F1;
case GzipHeaderState.ReadingXFL:
goto Label_0128;
case GzipHeaderState.ReadingOS:
goto Label_013D;
case GzipHeaderState.ReadingXLen1:
goto Label_0152;
case GzipHeaderState.ReadingXLen2:
goto Label_017B;
case GzipHeaderState.ReadingXLenData:
goto Label_01A8;
case GzipHeaderState.ReadingFileName:
goto Label_01E5;
case GzipHeaderState.ReadingComment:
goto Label_0212;
case GzipHeaderState.ReadingCRC16Part1:
goto Label_0240;
case GzipHeaderState.ReadingCRC16Part2:
goto Label_026A;
case GzipHeaderState.Done:
goto Label_0280;
default:
throw new InvalidDataException(SR.GetString("UnknownState"));
}
bits = input.GetBits(8);
if (bits < 0)
{
return(false);
}
if (bits != 0x8b)
{
throw new InvalidDataException(SR.GetString("CorruptedGZipHeader"));
}
this.gzipHeaderSubstate = GzipHeaderState.ReadingCM;
Label_00A5:
bits = input.GetBits(8);
if (bits < 0)
{
return(false);
}
if (bits != 8)
{
throw new InvalidDataException(SR.GetString("UnknownCompressionMode"));
}
this.gzipHeaderSubstate = GzipHeaderState.ReadingFLG;
Label_00CE:
bits = input.GetBits(8);
if (bits < 0)
{
return(false);
}
this.gzip_header_flag = bits;
this.gzipHeaderSubstate = GzipHeaderState.ReadingMMTime;
this.loopCounter = 0;
Label_00F1:
bits = 0;
while (this.loopCounter < 4)
{
if (input.GetBits(8) < 0)
{
return(false);
}
this.loopCounter++;
}
this.gzipHeaderSubstate = GzipHeaderState.ReadingXFL;
this.loopCounter = 0;
Label_0128:
if (input.GetBits(8) < 0)
{
return(false);
}
this.gzipHeaderSubstate = GzipHeaderState.ReadingOS;
Label_013D:
if (input.GetBits(8) < 0)
{
return(false);
}
this.gzipHeaderSubstate = GzipHeaderState.ReadingXLen1;
Label_0152:
if ((this.gzip_header_flag & 4) == 0)
{
goto Label_01E5;
}
bits = input.GetBits(8);
if (bits < 0)
{
return(false);
}
this.gzip_header_xlen = bits;
this.gzipHeaderSubstate = GzipHeaderState.ReadingXLen2;
Label_017B:
bits = input.GetBits(8);
if (bits < 0)
{
return(false);
}
this.gzip_header_xlen |= bits << 8;
this.gzipHeaderSubstate = GzipHeaderState.ReadingXLenData;
this.loopCounter = 0;
Label_01A8:
bits = 0;
while (this.loopCounter < this.gzip_header_xlen)
{
if (input.GetBits(8) < 0)
{
return(false);
}
this.loopCounter++;
}
this.gzipHeaderSubstate = GzipHeaderState.ReadingFileName;
this.loopCounter = 0;
Label_01E5:
if ((this.gzip_header_flag & 8) == 0)
{
this.gzipHeaderSubstate = GzipHeaderState.ReadingComment;
}
else
{
do
{
bits = input.GetBits(8);
if (bits < 0)
{
return(false);
}
}while (bits != 0);
this.gzipHeaderSubstate = GzipHeaderState.ReadingComment;
}
Label_0212:
if ((this.gzip_header_flag & 0x10) == 0)
{
this.gzipHeaderSubstate = GzipHeaderState.ReadingCRC16Part1;
}
else
{
do
{
bits = input.GetBits(8);
if (bits < 0)
{
return(false);
}
}while (bits != 0);
this.gzipHeaderSubstate = GzipHeaderState.ReadingCRC16Part1;
}
Label_0240:
if ((this.gzip_header_flag & 2) == 0)
{
this.gzipHeaderSubstate = GzipHeaderState.Done;
goto Label_0280;
}
if (input.GetBits(8) < 0)
{
return(false);
}
this.gzipHeaderSubstate = GzipHeaderState.ReadingCRC16Part2;
Label_026A:
if (input.GetBits(8) < 0)
{
return(false);
}
this.gzipHeaderSubstate = GzipHeaderState.Done;
Label_0280:
return(true);
}
IFileFormatReader formatReader; // class to decode header and footer (e.g. gzip)
public Inflater() {
output = new OutputWindow();
input = new InputBuffer();
codeList = new byte[HuffmanTree.MaxLiteralTreeElements + HuffmanTree.MaxDistTreeElements];
codeLengthTreeCodeLength = new byte[HuffmanTree.NumberOfCodeLengthTreeElements];
Reset();
}
internal InflaterManaged(IFileFormatReader reader, bool deflate64)
{
_output = new OutputWindow();
_input = new InputBuffer();
_codeList = new byte[HuffmanTree.MaxLiteralTreeElements + HuffmanTree.MaxDistTreeElements];
_codeLengthTreeCodeLength = new byte[HuffmanTree.NumberOfCodeLengthTreeElements];
_deflate64 = deflate64;
if (reader != null)
{
_formatReader = reader;
_hasFormatReader = true;
}
Reset();
}
private IFileFormatReader _formatReader; // class to decode header and footer (e.g. gzip)
public InflaterManaged(bool deflate64)
{
_output = new OutputWindow();
_input = new InputBuffer();
_codeList = new byte[HuffmanTree.MaxLiteralTreeElements + HuffmanTree.MaxDistTreeElements];
_codeLengthTreeCodeLength = new byte[HuffmanTree.NumberOfCodeLengthTreeElements];
_deflate64 = deflate64;
Reset();
}
public int GetNextSymbol(InputBuffer input)
{
uint num = input.TryLoad16Bits();
if (input.AvailableBits == 0)
{
return -1;
}
int index = this.table[(int) ((IntPtr) (num & this.tableMask))];
if (index < 0)
{
uint num3 = ((uint) 1) << this.tableBits;
do
{
index = -index;
if ((num & num3) == 0)
{
index = this.left[index];
}
else
{
index = this.right[index];
}
num3 = num3 << 1;
}
while (index < 0);
}
int n = this.codeLengthArray[index];
if (n <= 0)
{
throw new InvalidDataException(SR.GetString("InvalidHuffmanData"));
}
if (n > input.AvailableBits)
{
return -1;
}
input.SkipBits(n);
return index;
}
public bool ReadHeader(InputBuffer input) {
while (true) {
int bits;
switch (gzipHeaderSubstate) {
case GzipHeaderState.ReadingID1:
bits = input.GetBits(8);
if (bits < 0) {
return false;
}
if (bits != GZipConstants.ID1) {
throw new InvalidDataException(SR.GetString(SR.CorruptedGZipHeader));
}
gzipHeaderSubstate = GzipHeaderState.ReadingID2;
goto case GzipHeaderState.ReadingID2;
case GzipHeaderState.ReadingID2:
bits = input.GetBits(8);
if (bits < 0) {
return false;
}
if (bits != GZipConstants.ID2) {
throw new InvalidDataException(SR.GetString(SR.CorruptedGZipHeader));
}
gzipHeaderSubstate = GzipHeaderState.ReadingCM;
goto case GzipHeaderState.ReadingCM;
case GzipHeaderState.ReadingCM:
bits = input.GetBits(8);
if (bits < 0) {
return false;
}
if (bits != GZipConstants.Deflate) { // compression mode must be 8 (deflate)
throw new InvalidDataException(SR.GetString(SR.UnknownCompressionMode));
}
gzipHeaderSubstate = GzipHeaderState.ReadingFLG; ;
goto case GzipHeaderState.ReadingFLG;
case GzipHeaderState.ReadingFLG:
bits = input.GetBits(8);
if (bits < 0) {
return false;
}
gzip_header_flag = bits;
gzipHeaderSubstate = GzipHeaderState.ReadingMMTime;
loopCounter = 0; // 4 MMTIME bytes
goto case GzipHeaderState.ReadingMMTime;
case GzipHeaderState.ReadingMMTime:
bits = 0;
while (loopCounter < 4) {
bits = input.GetBits(8);
if (bits < 0) {
return false;
}
loopCounter++;
}
gzipHeaderSubstate = GzipHeaderState.ReadingXFL;
loopCounter = 0;
goto case GzipHeaderState.ReadingXFL;
case GzipHeaderState.ReadingXFL: // ignore XFL
bits = input.GetBits(8);
if (bits < 0) {
return false;
}
gzipHeaderSubstate = GzipHeaderState.ReadingOS;
goto case GzipHeaderState.ReadingOS;
case GzipHeaderState.ReadingOS: // ignore OS
bits = input.GetBits(8);
if (bits < 0) {
return false;
}
gzipHeaderSubstate = GzipHeaderState.ReadingXLen1;
goto case GzipHeaderState.ReadingXLen1;
case GzipHeaderState.ReadingXLen1:
if ((gzip_header_flag & (int)GZipOptionalHeaderFlags.ExtraFieldsFlag) == 0) {
goto case GzipHeaderState.ReadingFileName;
}
bits = input.GetBits(8);
if (bits < 0) {
return false;
}
gzip_header_xlen = bits;
gzipHeaderSubstate = GzipHeaderState.ReadingXLen2;
goto case GzipHeaderState.ReadingXLen2;
case GzipHeaderState.ReadingXLen2:
bits = input.GetBits(8);
if (bits < 0) {
return false;
}
gzip_header_xlen |= (bits << 8);
gzipHeaderSubstate = GzipHeaderState.ReadingXLenData;
loopCounter = 0; // 0 bytes of XLEN data read so far
goto case GzipHeaderState.ReadingXLenData;
case GzipHeaderState.ReadingXLenData:
bits = 0;
while (loopCounter < gzip_header_xlen) {
bits = input.GetBits(8);
if (bits < 0) {
return false;
}
loopCounter++;
}
gzipHeaderSubstate = GzipHeaderState.ReadingFileName;
loopCounter = 0;
goto case GzipHeaderState.ReadingFileName;
case GzipHeaderState.ReadingFileName:
if ((gzip_header_flag & (int)GZipOptionalHeaderFlags.FileNameFlag) == 0) {
gzipHeaderSubstate = GzipHeaderState.ReadingComment;
goto case GzipHeaderState.ReadingComment;
}
do {
bits = input.GetBits(8);
if (bits < 0) {
return false;
}
if (bits == 0) { // see '\0' in the file name string
break;
}
} while (true);
gzipHeaderSubstate = GzipHeaderState.ReadingComment;
goto case GzipHeaderState.ReadingComment;
case GzipHeaderState.ReadingComment:
if ((gzip_header_flag & (int)GZipOptionalHeaderFlags.CommentFlag) == 0) {
gzipHeaderSubstate = GzipHeaderState.ReadingCRC16Part1;
goto case GzipHeaderState.ReadingCRC16Part1;
}
do {
bits = input.GetBits(8);
if (bits < 0) {
return false;
}
if (bits == 0) { // see '\0' in the file name string
break;
}
} while (true);
gzipHeaderSubstate = GzipHeaderState.ReadingCRC16Part1;
goto case GzipHeaderState.ReadingCRC16Part1;
case GzipHeaderState.ReadingCRC16Part1:
if ((gzip_header_flag & (int)GZipOptionalHeaderFlags.CRCFlag) == 0) {
gzipHeaderSubstate = GzipHeaderState.Done;
goto case GzipHeaderState.Done;
}
bits = input.GetBits(8); // ignore crc
if (bits < 0) {
return false;
}
gzipHeaderSubstate = GzipHeaderState.ReadingCRC16Part2;
goto case GzipHeaderState.ReadingCRC16Part2;
case GzipHeaderState.ReadingCRC16Part2:
bits = input.GetBits(8); // ignore crc
if (bits < 0) {
return false;
}
gzipHeaderSubstate = GzipHeaderState.Done;
goto case GzipHeaderState.Done;
case GzipHeaderState.Done:
return true;
default:
Debug.Assert(false, "We should not reach unknown state!");
throw new InvalidDataException(SR.GetString(SR.UnknownState));
}
}
}
public GZipDecoder(InputBuffer input)
{
this.input = input;
this.Reset();
}
