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#include "dxpcconf.h"
#include <string.h>
#include "X-headers.H"
#include "ClientChannel.H"
#include "EncodeBuffer.H"
#include "DecodeBuffer.H"
#include "util.H"
#include <assert.h>
#include <limits.h>
#include "Compresser.H"
typedef struct cEntry
{
int cLevel;
lzo_compress_t cFnc;
lzo_uint cWorkMem;
lzo_decompress_t dFnc;
} cEntry;
// The table including all supported LZO algorithms.
// lzo1x is the recommeded algortihm, but only comes
// with two compression levels: 1 & 999. lzo1c is used to fill
// in the gaps.
static cEntry _knownAlgorithms[] = {
{1, lzo1x_1_compress, LZO1X_MEM_COMPRESS, lzo1x_decompress},
{2, lzo1c_2_compress, LZO1C_MEM_COMPRESS, lzo1c_decompress},
{3, lzo1c_3_compress, LZO1C_MEM_COMPRESS, lzo1c_decompress},
{4, lzo1c_4_compress, LZO1C_MEM_COMPRESS, lzo1c_decompress},
{5, lzo1c_5_compress, LZO1C_MEM_COMPRESS, lzo1c_decompress},
{6, lzo1c_6_compress, LZO1C_MEM_COMPRESS, lzo1c_decompress},
{7, lzo1c_7_compress, LZO1C_MEM_COMPRESS, lzo1c_decompress},
{8, lzo1c_8_compress, LZO1C_MEM_COMPRESS, lzo1c_decompress},
{9, lzo1c_9_compress, LZO1C_MEM_COMPRESS, lzo1c_decompress},
{99, lzo1c_99_compress, LZO1C_99_MEM_COMPRESS, lzo1c_decompress},
{999, lzo1x_999_compress, LZO1X_999_MEM_COMPRESS, lzo1x_decompress},
{0, 0, 0}
};
Compresser::Compresser(int compressionLevel) :
lzoCompressionWorkspace(0),
lzoCompressionBuffer(0),
lzoCompressionBufferSize(0),
compressionFnc(0)
{
cEntry *alg = getCEntry(compressionLevel);
if (alg)
{
lzoCompressionWorkspace = new lzo_byte[alg->cWorkMem];
if (lzoCompressionWorkspace)
{
// memset here supresses valgrind warning in the bowels
// of lzo.
memset(lzoCompressionWorkspace, 0, alg->cWorkMem);
compressionFnc = alg->cFnc;
}
else
{
*logofs << "Insufficient memory for image compression level "
<< compressionLevel << "\n";
}
}
else
{
*logofs << "Unknown image compression level " << compressionLevel
<< "\n";
}
}
Compresser::~Compresser()
{
if (lzoCompressionWorkspace)
{
delete[]lzoCompressionWorkspace;
lzoCompressionWorkspace = 0;
}
if (lzoCompressionBuffer)
{
delete[]lzoCompressionBuffer;
lzoCompressionBuffer = 0;
lzoCompressionBufferSize = 0;
}
}
CompressionType
Compresser::compressBuffer(const unsigned char *buffer,
const unsigned int size,
EncodeBuffer & encodeBuffer)
{
if (!compressionFnc || !lzoCompressionWorkspace || size < 64)
{
return NO_STREAM_COMPRESSION;
}
// Algorithm stolen from LZO FAQ.
unsigned int max_compressed_size = size + (size / 64) + 16 + 3;
if (max_compressed_size > lzoCompressionBufferSize)
{
if (lzoCompressionBuffer)
{
delete[]lzoCompressionBuffer;
}
lzoCompressionBuffer = new lzo_byte[max_compressed_size];
if (lzoCompressionBuffer)
{
lzoCompressionBufferSize = max_compressed_size;
}
else
{
lzoCompressionBufferSize = 0;
}
}
if (!lzoCompressionBuffer)
{
return NO_STREAM_COMPRESSION;
}
lzo_uint compressedSize = max_compressed_size;
lzo_byte *compressedImage = lzoCompressionBuffer;
if (compressionFnc(buffer, size,
compressedImage, &compressedSize,
lzoCompressionWorkspace) == LZO_E_OK)
{
assert(compressedSize <= max_compressed_size);
assert(compressedSize <= UINT_MAX);
encodeBuffer.encodeValue(LZO_COMPRESSION, COMPRESSION_TYPE_BITS);
encodeBuffer.encodeValue((unsigned)compressedSize, sizeof(unsigned) * 8);
encodeBuffer.encodeValue(size, sizeof(unsigned) * 8);
encodeBuffer.encodeRawMem(compressedImage, compressedSize);
return LZO_COMPRESSION;
}
return NO_STREAM_COMPRESSION;
}
int Compresser::isValidCompressionLevel(int compressionLevel)
{
return getCEntry(compressionLevel) != 0;
}
cEntry *Compresser::getCEntry(int compressionLevel)
{
cEntry *alg = _knownAlgorithms;
while (alg->cLevel && alg->cLevel != compressionLevel)
{
alg++;
}
if (alg->cLevel)
{
return alg;
}
return 0;
}
lzo_decompress_t Compresser::getDecompresser(int compressionLevel)
{
cEntry *alg;
alg = getCEntry(compressionLevel);
if (alg)
{
return alg->dFnc;
}
return 0;
}
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