ClickHouse/dbms/src/Compression/CompressionCodecMultiple.cpp
2018-12-24 17:10:37 +03:00

116 lines
3.7 KiB
C++

#include <Compression/CompressionCodecMultiple.h>
#include <Compression/CompressionInfo.h>
#include <common/unaligned.h>
#include <Compression/CompressionFactory.h>
#include <IO/ReadHelpers.h>
#include <IO/WriteHelpers.h>
#include <Common/hex.h>
namespace DB
{
namespace ErrorCodes
{
extern const int UNKNOWN_CODEC;
extern const int CORRUPTED_DATA;
}
CompressionCodecMultiple::CompressionCodecMultiple(Codecs codecs)
: codecs(codecs)
{
for (size_t idx = 0; idx < codecs.size(); idx++)
{
if (idx != 0)
codec_desc = codec_desc + ',';
const auto codec = codecs[idx];
codec_desc = codec_desc + codec->getCodecDesc();
}
}
UInt8 CompressionCodecMultiple::getMethodByte() const
{
return static_cast<UInt8>(CompressionMethodByte::Multiple);
}
String CompressionCodecMultiple::getCodecDesc() const
{
return codec_desc;
}
UInt32 CompressionCodecMultiple::getCompressedDataSize(UInt32 uncompressed_size) const
{
UInt32 compressed_size = uncompressed_size;
for (auto & codec : codecs)
compressed_size = codec->getCompressedReserveSize(compressed_size);
/// TotalCodecs ByteForEachCodec data
return sizeof(UInt8) + codecs.size() + compressed_size;
}
UInt32 CompressionCodecMultiple::doCompressData(const char * source, UInt32 source_size, char * dest) const
{
PODArray<char> compressed_buf;
PODArray<char> uncompressed_buf(source, source + source_size);
dest[0] = static_cast<UInt8>(codecs.size());
size_t codecs_byte_pos = 1;
for (size_t idx = 0; idx < codecs.size(); ++idx, ++codecs_byte_pos)
{
const auto codec = codecs[idx];
dest[codecs_byte_pos] = codec->getMethodByte();
compressed_buf.resize(codec->getCompressedReserveSize(source_size));
UInt32 size_compressed = codec->compress(uncompressed_buf.data(), source_size, compressed_buf.data());
uncompressed_buf.swap(compressed_buf);
source_size = size_compressed;
}
memcpy(&dest[1 + codecs.size()], uncompressed_buf.data(), source_size);
return 1 + codecs.size() + source_size;
}
void CompressionCodecMultiple::doDecompressData(const char * source, UInt32 source_size, char * dest, UInt32 decompressed_size) const
{
UInt8 compression_methods_size = source[0];
PODArray<char> compressed_buf(&source[compression_methods_size + 1], &source[source_size]);
PODArray<char> uncompressed_buf;
/// Insert all data into compressed buf
source_size -= (compression_methods_size + 1);
for (long idx = compression_methods_size - 1; idx >= 0; --idx)
{
UInt8 compression_method = source[idx + 1];
const auto codec = CompressionCodecFactory::instance().get(compression_method);
compressed_buf.resize(compressed_buf.size() + codec->getAdditionalSizeAtTheEndOfBuffer());
UInt32 uncompressed_size = ICompressionCodec::readDecompressedBlockSize(compressed_buf.data());
if (idx == 0 && uncompressed_size != decompressed_size)
throw Exception("Wrong final decompressed size in codec Multiple, got " + toString(uncompressed_size) + ", expected " + toString(decompressed_size), ErrorCodes::CORRUPTED_DATA);
uncompressed_buf.resize(uncompressed_size + codec->getAdditionalSizeAtTheEndOfBuffer());
codec->decompress(compressed_buf.data(), source_size, uncompressed_buf.data());
uncompressed_buf.swap(compressed_buf);
source_size = uncompressed_size;
}
memcpy(dest, compressed_buf.data(), decompressed_size);
}
void registerCodecMultiple(CompressionCodecFactory & factory)
{
factory.registerSimpleCompressionCodec("Multiple", static_cast<UInt8>(CompressionMethodByte::Multiple), [&] ()
{
return std::make_shared<CompressionCodecMultiple>();
});
}
}