internal int Inflate(FlushType flush)
{
int b;
if (_codec.InputBuffer == null)
throw new ZlibException("InputBuffer is null. ");
// int f = (flush == FlushType.Finish)
// ? ZlibConstants.Z_BUF_ERROR
// : ZlibConstants.Z_OK;
// workitem 8870
int f = ZlibConstants.Z_OK;
int r = ZlibConstants.Z_BUF_ERROR;
while (true)
{
switch (mode)
{
case InflateManagerMode.METHOD:
if (_codec.AvailableBytesIn == 0) return r;
r = f;
_codec.AvailableBytesIn--;
_codec.TotalBytesIn++;
if (((method = _codec.InputBuffer[_codec.NextIn++]) & 0xf) != Z_DEFLATED)
{
mode = InflateManagerMode.BAD;
_codec.Message = String.Format("unknown compression method (0x{0:X2})", method);
marker = 5; // can't try inflateSync
break;
}
if ((method >> 4) + 8 > wbits)
{
mode = InflateManagerMode.BAD;
_codec.Message = String.Format("invalid window size ({0})", (method >> 4) + 8);
marker = 5; // can't try inflateSync
break;
}
mode = InflateManagerMode.FLAG;
break;
case InflateManagerMode.FLAG:
if (_codec.AvailableBytesIn == 0) return r;
r = f;
_codec.AvailableBytesIn--;
_codec.TotalBytesIn++;
b = (_codec.InputBuffer[_codec.NextIn++]) & 0xff;
if ((((method << 8) + b) % 31) != 0)
{
mode = InflateManagerMode.BAD;
_codec.Message = "incorrect header check";
marker = 5; // can't try inflateSync
break;
}
mode = ((b & PRESET_DICT) == 0)
? InflateManagerMode.BLOCKS
: InflateManagerMode.DICT4;
break;
case InflateManagerMode.DICT4:
if (_codec.AvailableBytesIn == 0) return r;
r = f;
_codec.AvailableBytesIn--;
_codec.TotalBytesIn++;
expectedCheck = (uint)((_codec.InputBuffer[_codec.NextIn++] << 24) & 0xff000000);
mode = InflateManagerMode.DICT3;
break;
case InflateManagerMode.DICT3:
if (_codec.AvailableBytesIn == 0) return r;
r = f;
_codec.AvailableBytesIn--;
_codec.TotalBytesIn++;
expectedCheck += (uint)((_codec.InputBuffer[_codec.NextIn++] << 16) & 0x00ff0000);
mode = InflateManagerMode.DICT2;
break;
case InflateManagerMode.DICT2:
if (_codec.AvailableBytesIn == 0) return r;
r = f;
_codec.AvailableBytesIn--;
_codec.TotalBytesIn++;
expectedCheck += (uint)((_codec.InputBuffer[_codec.NextIn++] << 8) & 0x0000ff00);
mode = InflateManagerMode.DICT1;
break;
case InflateManagerMode.DICT1:
if (_codec.AvailableBytesIn == 0) return r;
r = f;
_codec.AvailableBytesIn--; _codec.TotalBytesIn++;
expectedCheck += (uint)(_codec.InputBuffer[_codec.NextIn++] & 0x000000ff);
_codec._Adler32 = expectedCheck;
mode = InflateManagerMode.DICT0;
return ZlibConstants.Z_NEED_DICT;
case InflateManagerMode.DICT0:
mode = InflateManagerMode.BAD;
_codec.Message = "need dictionary";
marker = 0; // can try inflateSync
return ZlibConstants.Z_STREAM_ERROR;
case InflateManagerMode.BLOCKS:
r = blocks.Process(r);
if (r == ZlibConstants.Z_DATA_ERROR)
{
mode = InflateManagerMode.BAD;
marker = 0; // can try inflateSync
break;
}
if (r == ZlibConstants.Z_OK) r = f;
if (r != ZlibConstants.Z_STREAM_END)
return r;
r = f;
computedCheck = blocks.Reset();
if (!HandleRfc1950HeaderBytes)
{
mode = InflateManagerMode.DONE;
return ZlibConstants.Z_STREAM_END;
}
mode = InflateManagerMode.CHECK4;
break;
case InflateManagerMode.CHECK4:
if (_codec.AvailableBytesIn == 0) return r;
r = f;
_codec.AvailableBytesIn--;
_codec.TotalBytesIn++;
expectedCheck = (uint)((_codec.InputBuffer[_codec.NextIn++] << 24) & 0xff000000);
mode = InflateManagerMode.CHECK3;
break;
case InflateManagerMode.CHECK3:
if (_codec.AvailableBytesIn == 0) return r;
r = f;
_codec.AvailableBytesIn--; _codec.TotalBytesIn++;
expectedCheck += (uint)((_codec.InputBuffer[_codec.NextIn++] << 16) & 0x00ff0000);
mode = InflateManagerMode.CHECK2;
break;
case InflateManagerMode.CHECK2:
if (_codec.AvailableBytesIn == 0) return r;
r = f;
_codec.AvailableBytesIn--;
_codec.TotalBytesIn++;
expectedCheck += (uint)((_codec.InputBuffer[_codec.NextIn++] << 8) & 0x0000ff00);
mode = InflateManagerMode.CHECK1;
break;
case InflateManagerMode.CHECK1:
if (_codec.AvailableBytesIn == 0) return r;
r = f;
_codec.AvailableBytesIn--; _codec.TotalBytesIn++;
expectedCheck += (uint)(_codec.InputBuffer[_codec.NextIn++] & 0x000000ff);
if (computedCheck != expectedCheck)
{
mode = InflateManagerMode.BAD;
_codec.Message = "incorrect data check";
marker = 5; // can't try inflateSync
break;
}
mode = InflateManagerMode.DONE;
return ZlibConstants.Z_STREAM_END;
case InflateManagerMode.DONE:
return ZlibConstants.Z_STREAM_END;
case InflateManagerMode.BAD:
throw new ZlibException(String.Format("Bad state ({0})", _codec.Message));
default:
throw new ZlibException("Stream error.");
}
}
}
