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#include "zstd.h"
#include <util/generic/buffer.h>
#include <util/generic/yexception.h>
#define ZSTD_STATIC_LINKING_ONLY
#include <contrib/libs/zstd/include/zstd.h>
namespace {
inline void CheckError(const char* op, size_t code) {
if (::ZSTD_isError(code)) {
ythrow yexception() << op << TStringBuf(" zstd error: ") << ::ZSTD_getErrorName(code);
}
}
struct DestroyZCStream {
static void Destroy(::ZSTD_CStream* p) noexcept {
::ZSTD_freeCStream(p);
}
};
struct DestroyZDStream {
static void Destroy(::ZSTD_DStream* p) noexcept {
::ZSTD_freeDStream(p);
}
};
}
class TZstdCompress::TImpl {
public:
TImpl(IOutputStream* slave, int quality)
: Slave_(slave)
, ZCtx_(::ZSTD_createCStream())
, Buffer_(::ZSTD_CStreamOutSize()) // do reserve
{
Y_ENSURE(nullptr != ZCtx_.Get(), "Failed to allocate ZSTD_CStream");
Y_ENSURE(0 != Buffer_.Capacity(), "ZSTD_CStreamOutSize was too small");
CheckError("init", ZSTD_initCStream(ZCtx_.Get(), quality));
}
void Write(const void* buffer, size_t size) {
::ZSTD_inBuffer zIn{buffer, size, 0};
auto zOut = OutBuffer();
while (0 != zIn.size) {
CheckError("compress", ::ZSTD_compressStream(ZCtx_.Get(), &zOut, &zIn));
DoWrite(zOut);
// forget about the data we already compressed
zIn.src = static_cast<const unsigned char*>(zIn.src) + zIn.pos;
zIn.size -= zIn.pos;
zIn.pos = 0;
}
}
void Flush() {
auto zOut = OutBuffer();
CheckError("flush", ::ZSTD_flushStream(ZCtx_.Get(), &zOut));
DoWrite(zOut);
}
void Finish() {
auto zOut = OutBuffer();
size_t returnCode;
do {
returnCode = ::ZSTD_endStream(ZCtx_.Get(), &zOut);
CheckError("finish", returnCode);
DoWrite(zOut);
} while (0 != returnCode); // zero means there is no more bytes to flush
}
private:
::ZSTD_outBuffer OutBuffer() {
return {Buffer_.Data(), Buffer_.Capacity(), 0};
}
void DoWrite(::ZSTD_outBuffer& buffer) {
Slave_->Write(buffer.dst, buffer.pos);
buffer.pos = 0;
}
private:
IOutputStream* Slave_;
THolder<::ZSTD_CStream, DestroyZCStream> ZCtx_;
TBuffer Buffer_;
};
TZstdCompress::TZstdCompress(IOutputStream* slave, int quality)
: Impl_(new TImpl(slave, quality)) {
}
TZstdCompress::~TZstdCompress() {
try {
Finish();
} catch (...) {
}
}
void TZstdCompress::DoWrite(const void* buffer, size_t size) {
Y_ENSURE(Impl_, "Cannot use stream after finish.");
Impl_->Write(buffer, size);
}
void TZstdCompress::DoFlush() {
Y_ENSURE(Impl_, "Cannot use stream after finish.");
Impl_->Flush();
}
void TZstdCompress::DoFinish() {
// Finish should be idempotent
if (Impl_) {
auto impl = std::move(Impl_);
impl->Finish();
}
}
////////////////////////////////////////////////////////////////////////////////
class TZstdDecompress::TImpl {
public:
TImpl(IInputStream* slave, size_t bufferSize)
: Slave_(slave)
, ZCtx_(::ZSTD_createDStream())
, Buffer_(bufferSize) // do reserve
, Offset_(0)
{
Y_ENSURE(nullptr != ZCtx_.Get(), "Failed to allocate ZSTD_DStream");
Y_ENSURE(0 != Buffer_.Capacity(), "Buffer size was too small");
}
size_t Read(void* buffer, size_t size) {
Y_ASSERT(size > 0);
::ZSTD_outBuffer zOut{buffer, size, 0};
::ZSTD_inBuffer zIn{Buffer_.Data(), Buffer_.Size(), Offset_};
size_t returnCode = 0;
while (zOut.pos != zOut.size) {
if (zIn.pos == zIn.size) {
zIn.size = Slave_->Read(Buffer_.Data(), Buffer_.Capacity());
Buffer_.Resize(zIn.size);
zIn.pos = Offset_ = 0;
if (0 == zIn.size) {
// end of stream, need to check that there is no uncompleted blocks
Y_ENSURE(0 == returnCode, "Incomplete block");
break;
}
}
returnCode = ::ZSTD_decompressStream(ZCtx_.Get(), &zOut, &zIn);
CheckError("decompress", returnCode);
if (0 == returnCode) {
// The frame is over, prepare to (maybe) start a new frame
ZSTD_initDStream(ZCtx_.Get());
}
}
Offset_ = zIn.pos;
return zOut.pos;
}
private:
IInputStream* Slave_;
THolder<::ZSTD_DStream, DestroyZDStream> ZCtx_;
TBuffer Buffer_;
size_t Offset_;
};
TZstdDecompress::TZstdDecompress(IInputStream* slave, size_t bufferSize)
: Impl_(new TImpl(slave, bufferSize)) {
}
TZstdDecompress::~TZstdDecompress() = default;
size_t TZstdDecompress::DoRead(void* buffer, size_t size) {
return Impl_->Read(buffer, size);
}
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