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#pragma once
#include "sample.h"
#include <util/generic/bt_exception.h>
#include <util/generic/hash.h>
#include <util/generic/ptr.h>
#include <util/generic/singleton.h>
#include <util/stream/input.h>
#include <util/stream/output.h>
#include <util/string/cast.h>
#include <util/string/vector.h>
#include <util/system/tls.h>
#include <util/ysaveload.h>
namespace NCodecs {
class TCodecException: public TWithBackTrace<yexception> {};
class ICodec;
using TCodecPtr = TIntrusivePtr<ICodec>;
using TCodecConstPtr = TIntrusiveConstPtr<ICodec>;
struct TCodecTraits {
ui32 RecommendedSampleSize = 0;
ui16 SizeOfInputElement = 1;
ui8 SizeOnEncodeMultiplier = 1;
ui8 SizeOnEncodeAddition = 0;
ui8 SizeOnDecodeMultiplier = 1;
bool NeedsTraining = false;
bool PreservesPrefixGrouping = false;
bool Irreversible = false;
bool PaddingBit = 0;
bool AssumesStructuredInput = false;
size_t ApproximateSizeOnEncode(size_t sz) const {
return sz * SizeOnEncodeMultiplier + SizeOnEncodeAddition;
}
size_t ApproximateSizeOnDecode(size_t sz) const {
return sz * SizeOnDecodeMultiplier;
}
};
class ICodec: public TAtomicRefCount<ICodec> {
protected:
bool Trained = false;
TCodecTraits MyTraits;
public:
TCodecTraits Traits() const {
return MyTraits;
}
// the name of the codec (or its variant) to be used in the codec registry
virtual TString GetName() const = 0;
virtual ui8 /*free bits in last byte*/ Encode(TStringBuf, TBuffer&) const = 0;
virtual ui8 Encode(const TBuffer& input, TBuffer& output) const {
return Encode(TStringBuf(input.Data(), input.Data() + input.Size()), output);
}
virtual void Decode(TStringBuf, TBuffer&) const = 0;
virtual void Decode(const TBuffer& input, TBuffer& output) const {
Decode(TStringBuf(input.Data(), input.Data() + input.Size()), output);
}
virtual ~ICodec() = default;
virtual bool AlreadyTrained() const {
return !Traits().NeedsTraining || Trained;
}
virtual void SetTrained(bool t) {
Trained = t;
}
bool TryToLearn(ISequenceReader& r) {
Trained = DoTryToLearn(r);
return Trained;
}
void Learn(ISequenceReader& r) {
LearnX(r, 1);
}
template <class TIter>
void Learn(TIter beg, TIter end) {
Learn(beg, end, IterToStringBuf<TIter>);
}
template <class TIter, class TGetter>
void Learn(TIter beg, TIter end, TGetter getter) {
auto sample = GetSample(beg, end, Traits().RecommendedSampleSize, getter);
TSimpleSequenceReader<TBuffer> reader{sample};
Learn(reader);
}
static TCodecPtr GetInstance(TStringBuf name);
static TVector<TString> GetCodecsList();
static TString GetNameSafe(TCodecPtr p);
static void Store(IOutputStream* out, TCodecPtr p);
static TCodecPtr Restore(IInputStream* in);
static TCodecPtr RestoreFromString(TStringBuf);
protected:
virtual void DoLearn(ISequenceReader&) = 0;
virtual bool DoTryToLearn(ISequenceReader& r) {
DoLearn(r);
return true;
}
// so the pipeline codec will know to adjust the sample for the subcodecs
virtual void DoLearnX(ISequenceReader& r, double /*sampleSizeMultiplier*/) {
DoLearn(r);
}
virtual void Save(IOutputStream*) const {
}
virtual void Load(IInputStream*) {
}
friend class TPipelineCodec;
public:
// so the pipeline codec will know to adjust the sample for the subcodecs
void LearnX(ISequenceReader& r, double sampleSizeMult) {
DoLearnX(r, sampleSizeMult);
Trained = true;
}
template <class TIter>
void LearnX(TIter beg, TIter end, double sampleSizeMult) {
auto sample = GetSample(beg, end, Traits().RecommendedSampleSize * sampleSizeMult);
TSimpleSequenceReader<TBuffer> reader{sample};
LearnX(reader, sampleSizeMult);
}
};
class TBasicTrivialCodec: public ICodec {
public:
ui8 Encode(TStringBuf in, TBuffer& out) const override {
out.Assign(in.data(), in.size());
return 0;
}
void Decode(TStringBuf in, TBuffer& out) const override {
Encode(in, out);
}
protected:
void DoLearn(ISequenceReader&) override {
}
};
class TTrivialCodec: public TBasicTrivialCodec {
public:
TTrivialCodec() {
MyTraits.PreservesPrefixGrouping = true;
}
static TStringBuf MyName() {
return "trivial";
}
TString GetName() const override {
return ToString(MyName());
}
};
class TTrivialTrainableCodec: public TBasicTrivialCodec {
public:
TTrivialTrainableCodec() {
MyTraits.PreservesPrefixGrouping = true;
MyTraits.NeedsTraining = true;
}
static TStringBuf MyName() {
return "trivial-trainable";
}
TString GetName() const override {
return ToString(MyName());
}
};
class TNullCodec: public ICodec {
public:
TNullCodec() {
MyTraits.Irreversible = true;
MyTraits.SizeOnDecodeMultiplier = 0;
MyTraits.SizeOnEncodeMultiplier = 0;
}
TString GetName() const override {
return "null";
}
ui8 Encode(TStringBuf, TBuffer& out) const override {
out.Clear();
return 0;
}
void Decode(TStringBuf, TBuffer& out) const override {
out.Clear();
}
protected:
void DoLearn(ISequenceReader&) override {
}
};
class TPipelineCodec: public ICodec {
typedef TVector<TCodecPtr> TPipeline;
TPipeline Pipeline;
TString MyName;
public:
explicit TPipelineCodec(TCodecPtr c0 = nullptr, TCodecPtr c1 = nullptr, TCodecPtr c2 = nullptr, TCodecPtr c3 = nullptr) {
MyTraits.PreservesPrefixGrouping = true;
AddCodec(c0);
AddCodec(c1);
AddCodec(c2);
AddCodec(c3);
}
TString GetName() const override {
return MyName;
}
ui8 Encode(TStringBuf in, TBuffer& out) const override;
void Decode(TStringBuf in, TBuffer& out) const override;
public:
/*
* Add codecs in the following order:
* uncompressed -> codec0 | codec1 | ... | codecN -> compressed
*/
TPipelineCodec& AddCodec(TCodecPtr codec);
bool AlreadyTrained() const override;
void SetTrained(bool t) override;
protected:
void DoLearn(ISequenceReader& in) override {
DoLearnX(in, 1);
}
void DoLearnX(ISequenceReader& in, double sampleSizeMult) override;
void Save(IOutputStream* out) const override;
void Load(IInputStream* in) override;
};
}
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