/// <summary>
/// DecompressPacketData - given a compressed byte[], uncompress it to the outputBuffer
/// </summary>
/// <param name="input">compressed byte from the ISF stream</param>
/// <param name="outputBuffer">prealloc'd buffer to write to</param>
/// <returns></returns>
internal uint DecompressPacketData(byte[] input, int[] outputBuffer)
{
if (input == null)
{
throw new ArgumentNullException("input");
}
if (input.Length < 2)
{
throw new ArgumentException(StrokeCollectionSerializer.ISFDebugMessage("Input buffer passed was shorter than expected"));
}
if (outputBuffer == null)
{
throw new ArgumentNullException("outputBuffer");
}
if (outputBuffer.Length == 0)
{
throw new ArgumentException(StrokeCollectionSerializer.ISFDebugMessage("output buffer length was zero"));
}
byte compression = input[0];
uint totalBytesRead = 1; //we just read one
int inputIndex = 1;
switch (compression & 0xC0)
{
case 0x80: //IndexedHuffman
{
DataXform dtxf = this.HuffModule.FindDtXf(compression);
HuffCodec huffCodec = this.HuffModule.FindCodec(compression);
totalBytesRead += huffCodec.Uncompress(dtxf, input, inputIndex, outputBuffer);
return(totalBytesRead);
}
case 0x00: //NoCompression
{
int outputBufferIndex = 0;
DeltaDelta dtxf = null;
if ((compression & 0x20) != 0)
{
dtxf = this.DeltaDelta;
}
int bitCount = 0;
if ((compression & 0x1F) == 0)
{
bitCount = Native.BitsPerInt; //32
}
else
{
bitCount = (compression & 0x1F);
}
if (null != dtxf)
{
//must have at least two more bytes besides the
//initial algo byte
if (input.Length < 3)
{
throw new ArgumentException(StrokeCollectionSerializer.ISFDebugMessage("Input buffer was too short (must be at least 3 bytes)"));
}
//multibyteencode the first two values
int xfData = 0;
int xfExtra = 0;
dtxf.ResetState();
uint bytesRead =
this.MultiByteCodec.SignDecode(input, inputIndex, ref xfData);
//advance our index
inputIndex += (int)bytesRead;
totalBytesRead += bytesRead;
int result = dtxf.InverseTransform(xfData, xfExtra);
Debug.Assert(outputBufferIndex < outputBuffer.Length);
outputBuffer[outputBufferIndex++] = result;
bytesRead =
this.MultiByteCodec.SignDecode(input, inputIndex, ref xfData);
//advance our index
inputIndex += (int)bytesRead;
totalBytesRead += bytesRead;
result = dtxf.InverseTransform(xfData, xfExtra);
Debug.Assert(outputBufferIndex < outputBuffer.Length);
outputBuffer[outputBufferIndex++] = result;
}
totalBytesRead +=
this.GorillaCodec.Uncompress(bitCount, //the max count of bits required for each int
input, //the input array to uncompress
inputIndex, //the index to start uncompressing at
dtxf, //data transform to use when compressing, can be null
outputBuffer, //a ref to the output buffer to write to
outputBufferIndex); //the index of the output buffer to write to
return(totalBytesRead);
}
default:
{
throw new ArgumentException(StrokeCollectionSerializer.ISFDebugMessage("Invalid decompression algo byte"));
}
}
}
/// <summary>
/// Uncompress - uncompress a byte[] into an int[] of point data (x,x,x,x,x)
/// </summary>
/// <param name="bitCount">The number of bits each element uses in input</param>
/// <param name="input">compressed data</param>
/// <param name="inputIndex">index to begin decoding at</param>
/// <param name="dtxf">data xf, can be null</param>
/// <param name="outputBuffer">output buffer that is prealloc'd to write to</param>
/// <param name="outputBufferIndex">the index of the output buffer to write to</param>
internal uint Uncompress(int bitCount, byte[] input, int inputIndex, DeltaDelta dtxf, int[] outputBuffer, int outputBufferIndex)
{
if (null == input)
{
throw new ArgumentNullException("input");
}
if (inputIndex >= input.Length)
{
throw new ArgumentOutOfRangeException("inputIndex");
}
if (null == outputBuffer)
{
throw new ArgumentNullException("outputBuffer");
}
if (outputBufferIndex >= outputBuffer.Length)
{
throw new ArgumentOutOfRangeException("outputBufferIndex");
}
if (bitCount < 0)
{
throw new ArgumentOutOfRangeException("bitCount");
}
// Adjust bit count if 0 passed in
if (bitCount == 0)
{
//adjust if the bitcount is 0
//(this makes bitCount 32)
bitCount = (int)(Native.SizeOfInt << 3);
}
// Test whether the items are signed. For unsigned number, we don't need mask
// If we are trying to compress signed long values with bit count = 5
// The mask will be 1111 1111 1111 0000. The way it is done is, if the 5th
// bit is 1, the number is negative numbe, othrwise it's positive. Testing
// will be non-zero, ONLY if the 5th bit is 1, in which case we OR with the mask
// otherwise we leave the number as it is.
uint bitMask = (unchecked((uint)~0) << (bitCount - 1));
uint bitData = 0;
BitStreamReader reader = new BitStreamReader(input, inputIndex);
if(dtxf != null)
{
while (!reader.EndOfStream)
{
bitData = reader.ReadUInt32(bitCount);
// Construct the item
bitData = ((bitData & bitMask) != 0) ? bitMask | bitData : bitData;
int result = dtxf.InverseTransform((int)bitData, 0);
Debug.Assert(outputBufferIndex < outputBuffer.Length);
outputBuffer[outputBufferIndex++] = result;
if (outputBufferIndex == outputBuffer.Length)
{
//only write as much as the outputbuffer can hold
//this is assumed by calling code
break;
}
}
}
else
{
while (!reader.EndOfStream)
{
bitData = reader.ReadUInt32(bitCount);
// Construct the item
bitData = ((bitData & bitMask) != 0) ? bitMask | bitData : bitData;
Debug.Assert(outputBufferIndex < outputBuffer.Length);
outputBuffer[outputBufferIndex++] = (int)bitData;
if (outputBufferIndex == outputBuffer.Length)
{
//only write as much as the outputbuffer can hold
//this is assumed by calling code
break;
}
}
}
// Calculate how many bytes were read from input buffer
return (uint)((outputBuffer.Length * bitCount + 7) >> 3);
}
/// <summary>
/// Uncompress - uncompress a byte[] into an int[] of point data (x,x,x,x,x)
/// </summary>
/// <param name="bitCount">The number of bits each element uses in input</param>
/// <param name="input">compressed data</param>
/// <param name="inputIndex">index to begin decoding at</param>
/// <param name="dtxf">data xf, can be null</param>
/// <param name="outputBuffer">output buffer that is prealloc'd to write to</param>
/// <param name="outputBufferIndex">the index of the output buffer to write to</param>
internal uint Uncompress(int bitCount, byte[] input, int inputIndex, DeltaDelta dtxf, int[] outputBuffer, int outputBufferIndex)
{
if (null == input)
{
throw new ArgumentNullException("input");
}
if (inputIndex >= input.Length)
{
throw new ArgumentOutOfRangeException("inputIndex");
}
if (null == outputBuffer)
{
throw new ArgumentNullException("outputBuffer");
}
if (outputBufferIndex >= outputBuffer.Length)
{
throw new ArgumentOutOfRangeException("outputBufferIndex");
}
if (bitCount < 0)
{
throw new ArgumentOutOfRangeException("bitCount");
}
// Adjust bit count if 0 passed in
if (bitCount == 0)
{
//adjust if the bitcount is 0
//(this makes bitCount 32)
bitCount = (int)(Native.SizeOfInt << 3);
}
// Test whether the items are signed. For unsigned number, we don't need mask
// If we are trying to compress signed long values with bit count = 5
// The mask will be 1111 1111 1111 0000. The way it is done is, if the 5th
// bit is 1, the number is negative numbe, othrwise it's positive. Testing
// will be non-zero, ONLY if the 5th bit is 1, in which case we OR with the mask
// otherwise we leave the number as it is.
uint bitMask = (unchecked ((uint)~0) << (bitCount - 1));
uint bitData = 0;
BitStreamReader reader = new BitStreamReader(input, inputIndex);
if (dtxf != null)
{
while (!reader.EndOfStream)
{
bitData = reader.ReadUInt32(bitCount);
// Construct the item
bitData = ((bitData & bitMask) != 0) ? bitMask | bitData : bitData;
int result = dtxf.InverseTransform((int)bitData, 0);
Debug.Assert(outputBufferIndex < outputBuffer.Length);
outputBuffer[outputBufferIndex++] = result;
if (outputBufferIndex == outputBuffer.Length)
{
//only write as much as the outputbuffer can hold
//this is assumed by calling code
break;
}
}
}
else
{
while (!reader.EndOfStream)
{
bitData = reader.ReadUInt32(bitCount);
// Construct the item
bitData = ((bitData & bitMask) != 0) ? bitMask | bitData : bitData;
Debug.Assert(outputBufferIndex < outputBuffer.Length);
outputBuffer[outputBufferIndex++] = (int)bitData;
if (outputBufferIndex == outputBuffer.Length)
{
//only write as much as the outputbuffer can hold
//this is assumed by calling code
break;
}
}
}
// Calculate how many bytes were read from input buffer
return((uint)((outputBuffer.Length * bitCount + 7) >> 3));
}
