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// Compression/HuffmanEncoder.h
#ifndef __COMPRESSION_HUFFMANENCODER_H
#define __COMPRESSION_HUFFMANENCODER_H
#include "../../../Common/Types.h"
namespace NCompression {
namespace NHuffman {
const int kNumBitsInLongestCode = 20;
struct CItem
{
UInt32 Freq;
UInt32 Code;
UInt32 Dad;
UInt32 Len;
};
class CEncoder
{
public:
UInt32 m_NumSymbols; // number of symbols in adwSymbol
CItem *m_Items;
UInt32 *m_Heap;
UInt32 m_HeapSize;
Byte *m_Depth;
const Byte *m_ExtraBits;
UInt32 m_ExtraBase;
UInt32 m_MaxLength;
UInt32 m_HeapLength;
UInt32 m_BitLenCounters[kNumBitsInLongestCode + 1];
UInt32 RemoveSmallest();
bool Smaller(int n, int m);
void DownHeap(UInt32 k);
void GenerateBitLen(UInt32 maxCode, UInt32 heapMax);
void GenerateCodes(UInt32 maxCode);
UInt32 m_BlockBitLength;
void Free();
public:
CEncoder();
~CEncoder();
bool Create(UInt32 numSymbols, const Byte *extraBits,
UInt32 extraBase, UInt32 maxLength);
void StartNewBlock();
void AddSymbol(UInt32 symbol) { m_Items[symbol].Freq++; }
void SetFreqs(const UInt32 *freqs);
UInt32 GetPrice(const Byte *length) const
{
UInt32 price = 0;
for (UInt32 i = 0; i < m_NumSymbols; i++)
{
price += length[i] * m_Items[i].Freq;
if (m_ExtraBits && i >= m_ExtraBase)
price += m_ExtraBits[i - m_ExtraBase] * m_Items[i].Freq;
}
return price;
};
void SetFreq(UInt32 symbol, UInt32 value) { m_Items[symbol].Freq = value; };
void BuildTree(Byte *levels);
UInt32 GetBlockBitLength() const { return m_BlockBitLength; }
template <class TBitEncoder>
void CodeOneValue(TBitEncoder *bitEncoder, UInt32 symbol)
{ bitEncoder->WriteBits(m_Items[symbol].Code, m_Items[symbol].Len); }
void ReverseBits();
};
}}
#endif
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