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#include <IO/LZMADeflatingWriteBuffer.h>
namespace DB
{
namespace ErrorCodes
{
extern const int LZMA_STREAM_ENCODER_FAILED;
}
LZMADeflatingWriteBuffer::LZMADeflatingWriteBuffer(
std::unique_ptr<WriteBuffer> out_, int compression_level, size_t buf_size, char * existing_memory, size_t alignment)
: WriteBufferWithOwnMemoryDecorator(std::move(out_), buf_size, existing_memory, alignment)
{
lstr = LZMA_STREAM_INIT;
lstr.allocator = nullptr;
lstr.next_in = nullptr;
lstr.avail_in = 0;
lstr.next_out = nullptr;
lstr.avail_out = 0;
// options for further compression
lzma_options_lzma opt_lzma2;
if (lzma_lzma_preset(&opt_lzma2, compression_level))
throw Exception(ErrorCodes::LZMA_STREAM_ENCODER_FAILED, "lzma preset failed: lzma version: {}", LZMA_VERSION_STRING);
// LZMA_FILTER_X86 -
// LZMA2 - codec for *.xz files compression; LZMA is not suitable for this purpose
// VLI - variable length integer (in *.xz most integers encoded as VLI)
// LZMA_VLI_UNKNOWN (UINT64_MAX) - VLI value to denote that the value is unknown
lzma_filter filters[] = {
{.id = LZMA_FILTER_X86, .options = nullptr},
{.id = LZMA_FILTER_LZMA2, .options = &opt_lzma2},
{.id = LZMA_VLI_UNKNOWN, .options = nullptr},
};
lzma_ret ret = lzma_stream_encoder(&lstr, filters, LZMA_CHECK_CRC64);
if (ret != LZMA_OK)
throw Exception(
ErrorCodes::LZMA_STREAM_ENCODER_FAILED,
"lzma stream encoder init failed: error code: {} lzma version: {}",
ret,
LZMA_VERSION_STRING);
}
LZMADeflatingWriteBuffer::~LZMADeflatingWriteBuffer() = default;
void LZMADeflatingWriteBuffer::nextImpl()
{
if (!offset())
return;
lstr.next_in = reinterpret_cast<unsigned char *>(working_buffer.begin());
lstr.avail_in = offset();
try
{
lzma_action action = LZMA_RUN;
do
{
out->nextIfAtEnd();
lstr.next_out = reinterpret_cast<unsigned char *>(out->position());
lstr.avail_out = out->buffer().end() - out->position();
lzma_ret ret = lzma_code(&lstr, action);
out->position() = out->buffer().end() - lstr.avail_out;
if (ret == LZMA_STREAM_END)
return;
if (ret != LZMA_OK)
throw Exception(
ErrorCodes::LZMA_STREAM_ENCODER_FAILED,
"lzma stream encoding failed: error code: {}; lzma_version: {}",
ret,
LZMA_VERSION_STRING);
} while (lstr.avail_in > 0 || lstr.avail_out == 0);
}
catch (...)
{
/// Do not try to write next time after exception.
out->position() = out->buffer().begin();
throw;
}
}
void LZMADeflatingWriteBuffer::finalizeBefore()
{
next();
do
{
out->nextIfAtEnd();
lstr.next_out = reinterpret_cast<unsigned char *>(out->position());
lstr.avail_out = out->buffer().end() - out->position();
lzma_ret ret = lzma_code(&lstr, LZMA_FINISH);
out->position() = out->buffer().end() - lstr.avail_out;
if (ret == LZMA_STREAM_END)
{
return;
}
if (ret != LZMA_OK)
throw Exception(
ErrorCodes::LZMA_STREAM_ENCODER_FAILED,
"lzma stream encoding failed: error code: {}; lzma version: {}",
ret,
LZMA_VERSION_STRING);
} while (lstr.avail_out == 0);
}
void LZMADeflatingWriteBuffer::finalizeAfter()
{
lzma_end(&lstr);
}
}
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