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#include "solar_codec.h"

#include <library/cpp/codecs/greedy_dict/gd_builder.h>

#include <library/cpp/containers/comptrie/comptrie_builder.h>
#include <library/cpp/string_utils/relaxed_escaper/relaxed_escaper.h>
#include <util/stream/length.h>
#include <util/string/printf.h>
#include <util/ysaveload.h>

namespace NCodecs {
    static inline ui32 Append(TBuffer& pool, TStringBuf data) { 
        pool.Append(data.data(), data.size());
        return pool.Size(); 
    } 

    void TSolarCodec::DoLearn(ISequenceReader& r) { 
        using namespace NGreedyDict; 

        Decoder.clear(); 
        Pool.Clear(); 

        THolder<TEntrySet> set; 

        { 
            TMemoryPool pool(8112, TMemoryPool::TLinearGrow::Instance()); 
            TStringBufs bufs; 

            TStringBuf m; 
            while (r.NextRegion(m)) { 
                bufs.push_back(pool.AppendString(m)); 
            } 

            { 
                TDictBuilder b(Settings); 
                b.SetInput(bufs); 
                b.Build(MaxEntries, MaxIterations); 
 
                set = b.ReleaseEntrySet(); 
            } 
        }

        set->SetScores(ES_LEN_COUNT); 
 
        {
            TVector<std::pair<float, TStringBuf>> tmp; 
            tmp.reserve(set->size()); 

            for (const auto& it : *set) { 
                tmp.push_back(std::make_pair(-it.Score, TStringBuf(it.Str).Trunc(Max<ui32>() / Max<ui32>(MaxEntries, 1)))); 
            } 

            Sort(tmp.begin(), tmp.end()); 

            Decoder.reserve(tmp.size() + 1); 
            Decoder.push_back(0); 

            for (const auto& it : tmp) { 
                Y_ENSURE(Decoder.back() == Pool.Size(), "learning invariant failed"); 
                ui32 endoff = Append(Pool, it.second); 
                Decoder.push_back(endoff); 
            } 
        }

        Pool.ShrinkToFit(); 
        Decoder.shrink_to_fit(); 

        TBufferOutput bout; 

        { 
            TVector<std::pair<TStringBuf, ui32>> tmp2; 
            tmp2.reserve(Decoder.size()); 

            for (ui32 i = 1, sz = Decoder.size(); i < sz; ++i) { 
                TStringBuf s = DoDecode(i); 
                tmp2.push_back(std::make_pair(s, i - 1)); 
                Y_ENSURE(s.size() == (Decoder[i] - Decoder[i - 1]), "learning invariant failed");
            } 

            Sort(tmp2.begin(), tmp2.end()); 

            { 
                TEncoder::TBuilder builder(CTBF_PREFIX_GROUPED); 
                for (const auto& it : tmp2) { 
                    builder.Add(it.first.data(), it.first.size(), it.second);
                } 

                builder.Save(bout); 
            }
        }

        Encoder.Init(TBlob::FromBuffer(bout.Buffer())); 
    }

    void TSolarCodec::Save(IOutputStream* out) const { 
        TBlob b = Encoder.Data(); 
        ::Save(out, (ui32)b.Size()); 
        out->Write(b.Data(), b.Size()); 
    } 

    void TSolarCodec::Load(IInputStream* in) { 
        ui32 sz; 
        ::Load(in, sz); 
        TLengthLimitedInput lin(in, sz); 
        Encoder.Init(TBlob::FromStream(lin)); 
        Pool.Clear(); 
        Decoder.clear(); 

        TVector<std::pair<ui32, TString>> tmp; 

        ui32 poolsz = 0; 
        for (TEncoder::TConstIterator it = Encoder.Begin(); it != Encoder.End(); ++it) { 
            const TString& s = it.GetKey(); 
            tmp.push_back(std::make_pair(it.GetValue(), !s ? TString("\0", 1) : s)); 
            poolsz += Max<ui32>(s.size(), 1);
        } 

        Sort(tmp.begin(), tmp.end()); 

        Pool.Reserve(poolsz); 
        Decoder.reserve(tmp.size() + 1); 
        Decoder.push_back(0); 

        for (ui32 i = 0, sz2 = tmp.size(); i < sz2; ++i) { 
            Y_ENSURE(i == tmp[i].first, "oops! " << i << " " << tmp[i].first); 
            Decoder.push_back(Append(Pool, tmp[i].second)); 
        } 

        Pool.ShrinkToFit(); 
        Decoder.shrink_to_fit(); 
    }

}