mirror of
https://github.com/DarkflameUniverse/DarkflameServer.git
synced 2024-11-13 03:38:20 +00:00
59 lines
2.0 KiB
C++
59 lines
2.0 KiB
C++
#include "DataCompressor.h"
|
|
#include "DS_HuffmanEncodingTree.h"
|
|
#include <assert.h>
|
|
#include <string.h> // Use string.h rather than memory.h for a console
|
|
|
|
void DataCompressor::Compress( unsigned char *userData, unsigned sizeInBytes, RakNet::BitStream * output )
|
|
{
|
|
// Don't use this for small files as you will just make them bigger!
|
|
assert(sizeInBytes > 2048);
|
|
|
|
unsigned int frequencyTable[ 256 ];
|
|
unsigned int i;
|
|
memset(frequencyTable,0,256*sizeof(unsigned int));
|
|
for (i=0; i < sizeInBytes; i++)
|
|
++frequencyTable[userData[i]];
|
|
HuffmanEncodingTree tree;
|
|
BitSize_t writeOffset1, writeOffset2, bitsUsed1, bitsUsed2;
|
|
tree.GenerateFromFrequencyTable(frequencyTable);
|
|
output->WriteCompressed(sizeInBytes);
|
|
for (i=0; i < 256; i++)
|
|
output->WriteCompressed(frequencyTable[i]);
|
|
output->AlignWriteToByteBoundary();
|
|
writeOffset1=output->GetWriteOffset();
|
|
output->Write((unsigned int)0); // Dummy value
|
|
bitsUsed1=output->GetNumberOfBitsUsed();
|
|
tree.EncodeArray(userData, sizeInBytes, output);
|
|
bitsUsed2=output->GetNumberOfBitsUsed();
|
|
writeOffset2=output->GetWriteOffset();
|
|
output->SetWriteOffset(writeOffset1);
|
|
output->Write(bitsUsed2-bitsUsed1); // Go back and write how many bits were used for the encoding
|
|
output->SetWriteOffset(writeOffset2);
|
|
}
|
|
|
|
unsigned DataCompressor::DecompressAndAllocate( RakNet::BitStream * input, unsigned char **output )
|
|
{
|
|
HuffmanEncodingTree tree;
|
|
unsigned int bitsUsed, destinationSizeInBytes, decompressedBytes;
|
|
unsigned int frequencyTable[ 256 ];
|
|
unsigned i;
|
|
|
|
input->ReadCompressed(destinationSizeInBytes);
|
|
for (i=0; i < 256; i++)
|
|
input->ReadCompressed(frequencyTable[i]);
|
|
input->AlignReadToByteBoundary();
|
|
if (input->Read(bitsUsed)==false)
|
|
{
|
|
// Read error
|
|
#ifdef _DEBUG
|
|
assert(0);
|
|
#endif
|
|
return 0;
|
|
}
|
|
*output = (unsigned char*) rakMalloc(destinationSizeInBytes);
|
|
tree.GenerateFromFrequencyTable(frequencyTable);
|
|
decompressedBytes=tree.DecodeArray(input, bitsUsed, destinationSizeInBytes, *output );
|
|
assert(decompressedBytes==destinationSizeInBytes);
|
|
return destinationSizeInBytes;
|
|
}
|