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802 lines
24 KiB
802 lines
24 KiB
![]()
4 years ago
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// zdeflate.cpp - written and placed in the public domain by Wei Dai
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// Many of the algorithms and tables used here came from the deflate implementation
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// by Jean-loup Gailly, which was included in Crypto++ 4.0 and earlier. I completely
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// rewrote it in order to fix a bug that I could not figure out. This code
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// is less clever, but hopefully more understandable and maintainable.
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#include "pch.h"
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#include "zdeflate.h"
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#include <functional>
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#if _MSC_VER >= 1600
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// for make_unchecked_array_iterator
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#include <iterator>
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#endif
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NAMESPACE_BEGIN(CryptoPP)
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using namespace std;
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LowFirstBitWriter::LowFirstBitWriter(BufferedTransformation *attachment)
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: Filter(attachment), m_counting(false), m_buffer(0), m_bitsBuffered(0), m_bytesBuffered(0)
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{
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}
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void LowFirstBitWriter::StartCounting()
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{
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assert(!m_counting);
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m_counting = true;
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m_bitCount = 0;
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}
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unsigned long LowFirstBitWriter::FinishCounting()
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{
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assert(m_counting);
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m_counting = false;
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return m_bitCount;
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}
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void LowFirstBitWriter::PutBits(unsigned long value, unsigned int length)
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{
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if (m_counting)
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m_bitCount += length;
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else
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{
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m_buffer |= value << m_bitsBuffered;
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m_bitsBuffered += length;
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assert(m_bitsBuffered <= sizeof(unsigned long)*8);
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while (m_bitsBuffered >= 8)
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{
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m_outputBuffer[m_bytesBuffered++] = (byte)m_buffer;
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if (m_bytesBuffered == m_outputBuffer.size())
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{
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AttachedTransformation()->PutModifiable(m_outputBuffer, m_bytesBuffered);
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m_bytesBuffered = 0;
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}
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m_buffer >>= 8;
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m_bitsBuffered -= 8;
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}
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}
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}
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void LowFirstBitWriter::FlushBitBuffer()
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{
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if (m_counting)
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m_bitCount += 8*(m_bitsBuffered > 0);
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else
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{
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if (m_bytesBuffered > 0)
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{
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AttachedTransformation()->PutModifiable(m_outputBuffer, m_bytesBuffered);
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m_bytesBuffered = 0;
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}
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if (m_bitsBuffered > 0)
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{
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AttachedTransformation()->Put((byte)m_buffer);
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m_buffer = 0;
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m_bitsBuffered = 0;
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}
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}
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}
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void LowFirstBitWriter::ClearBitBuffer()
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{
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m_buffer = 0;
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m_bytesBuffered = 0;
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m_bitsBuffered = 0;
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}
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HuffmanEncoder::HuffmanEncoder(const unsigned int *codeBits, unsigned int nCodes)
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{
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Initialize(codeBits, nCodes);
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}
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struct HuffmanNode
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{
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size_t symbol;
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union {size_t parent; unsigned depth, freq;};
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};
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struct FreqLessThan
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{
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inline bool operator()(unsigned int lhs, const HuffmanNode &rhs) {return lhs < rhs.freq;}
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inline bool operator()(const HuffmanNode &lhs, const HuffmanNode &rhs) const {return lhs.freq < rhs.freq;}
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// needed for MSVC .NET 2005
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inline bool operator()(const HuffmanNode &lhs, unsigned int rhs) {return lhs.freq < rhs;}
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};
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void HuffmanEncoder::GenerateCodeLengths(unsigned int *codeBits, unsigned int maxCodeBits, const unsigned int *codeCounts, size_t nCodes)
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{
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assert(nCodes > 0);
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assert(nCodes <= ((size_t)1 << maxCodeBits));
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size_t i;
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SecBlockWithHint<HuffmanNode, 2*286> tree(nCodes);
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for (i=0; i<nCodes; i++)
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{
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tree[i].symbol = i;
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tree[i].freq = codeCounts[i];
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}
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sort(tree.begin(), tree.end(), FreqLessThan());
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size_t treeBegin = upper_bound(tree.begin(), tree.end(), 0, FreqLessThan()) - tree.begin();
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if (treeBegin == nCodes)
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{ // special case for no codes
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fill(codeBits, codeBits+nCodes, 0);
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return;
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}
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tree.resize(nCodes + nCodes - treeBegin - 1);
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size_t leastLeaf = treeBegin, leastInterior = nCodes;
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for (i=nCodes; i<tree.size(); i++)
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{
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size_t least;
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least = (leastLeaf == nCodes || (leastInterior < i && tree[leastInterior].freq < tree[leastLeaf].freq)) ? leastInterior++ : leastLeaf++;
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tree[i].freq = tree[least].freq;
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tree[least].parent = i;
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least = (leastLeaf == nCodes || (leastInterior < i && tree[leastInterior].freq < tree[leastLeaf].freq)) ? leastInterior++ : leastLeaf++;
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tree[i].freq += tree[least].freq;
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tree[least].parent = i;
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}
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tree[tree.size()-1].depth = 0;
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if (tree.size() >= 2)
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for (i=tree.size()-2; i>=nCodes; i--)
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tree[i].depth = tree[tree[i].parent].depth + 1;
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unsigned int sum = 0;
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SecBlockWithHint<unsigned int, 15+1> blCount(maxCodeBits+1);
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fill(blCount.begin(), blCount.end(), 0);
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for (i=treeBegin; i<nCodes; i++)
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{
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size_t depth = STDMIN(maxCodeBits, tree[tree[i].parent].depth + 1);
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blCount[depth]++;
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sum += 1 << (maxCodeBits - depth);
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}
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unsigned int overflow = sum > (unsigned int)(1 << maxCodeBits) ? sum - (1 << maxCodeBits) : 0;
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while (overflow--)
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{
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unsigned int bits = maxCodeBits-1;
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while (blCount[bits] == 0)
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bits--;
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blCount[bits]--;
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blCount[bits+1] += 2;
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assert(blCount[maxCodeBits] > 0);
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blCount[maxCodeBits]--;
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}
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for (i=0; i<treeBegin; i++)
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codeBits[tree[i].symbol] = 0;
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unsigned int bits = maxCodeBits;
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for (i=treeBegin; i<nCodes; i++)
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{
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while (blCount[bits] == 0)
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bits--;
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codeBits[tree[i].symbol] = bits;
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blCount[bits]--;
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}
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assert(blCount[bits] == 0);
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}
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void HuffmanEncoder::Initialize(const unsigned int *codeBits, unsigned int nCodes)
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{
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assert(nCodes > 0);
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unsigned int maxCodeBits = *max_element(codeBits, codeBits+nCodes);
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if (maxCodeBits == 0)
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return; // assume this object won't be used
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SecBlockWithHint<unsigned int, 15+1> blCount(maxCodeBits+1);
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fill(blCount.begin(), blCount.end(), 0);
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unsigned int i;
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for (i=0; i<nCodes; i++)
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blCount[codeBits[i]]++;
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code_t code = 0;
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SecBlockWithHint<code_t, 15+1> nextCode(maxCodeBits+1);
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nextCode[1] = 0;
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for (i=2; i<=maxCodeBits; i++)
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{
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code = (code + blCount[i-1]) << 1;
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nextCode[i] = code;
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}
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assert(maxCodeBits == 1 || code == (1 << maxCodeBits) - blCount[maxCodeBits]);
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m_valueToCode.resize(nCodes);
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for (i=0; i<nCodes; i++)
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{
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unsigned int len = m_valueToCode[i].len = codeBits[i];
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if (len != 0)
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m_valueToCode[i].code = BitReverse(nextCode[len]++) >> (8*sizeof(code_t)-len);
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}
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}
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inline void HuffmanEncoder::Encode(LowFirstBitWriter &writer, value_t value) const
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{
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assert(m_valueToCode[value].len > 0);
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writer.PutBits(m_valueToCode[value].code, m_valueToCode[value].len);
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}
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Deflator::Deflator(BufferedTransformation *attachment, int deflateLevel, int log2WindowSize, bool detectUncompressible)
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: LowFirstBitWriter(attachment)
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, m_deflateLevel(-1)
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{
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InitializeStaticEncoders();
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IsolatedInitialize(MakeParameters("DeflateLevel", deflateLevel)("Log2WindowSize", log2WindowSize)("DetectUncompressible", detectUncompressible));
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}
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Deflator::Deflator(const NameValuePairs ¶meters, BufferedTransformation *attachment)
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: LowFirstBitWriter(attachment)
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, m_deflateLevel(-1)
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{
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InitializeStaticEncoders();
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IsolatedInitialize(parameters);
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}
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void Deflator::InitializeStaticEncoders()
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{
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unsigned int codeLengths[288];
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fill(codeLengths + 0, codeLengths + 144, 8);
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fill(codeLengths + 144, codeLengths + 256, 9);
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fill(codeLengths + 256, codeLengths + 280, 7);
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fill(codeLengths + 280, codeLengths + 288, 8);
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m_staticLiteralEncoder.Initialize(codeLengths, 288);
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fill(codeLengths + 0, codeLengths + 32, 5);
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m_staticDistanceEncoder.Initialize(codeLengths, 32);
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}
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void Deflator::IsolatedInitialize(const NameValuePairs ¶meters)
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{
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int log2WindowSize = parameters.GetIntValueWithDefault("Log2WindowSize", DEFAULT_LOG2_WINDOW_SIZE);
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if (!(MIN_LOG2_WINDOW_SIZE <= log2WindowSize && log2WindowSize <= MAX_LOG2_WINDOW_SIZE))
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throw InvalidArgument("Deflator: " + IntToString(log2WindowSize) + " is an invalid window size");
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m_log2WindowSize = log2WindowSize;
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DSIZE = 1 << m_log2WindowSize;
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DMASK = DSIZE - 1;
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HSIZE = 1 << m_log2WindowSize;
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HMASK = HSIZE - 1;
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m_byteBuffer.New(2*DSIZE);
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m_head.New(HSIZE);
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m_prev.New(DSIZE);
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m_matchBuffer.New(DSIZE/2);
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Reset(true);
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SetDeflateLevel(parameters.GetIntValueWithDefault("DeflateLevel", DEFAULT_DEFLATE_LEVEL));
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bool detectUncompressible = parameters.GetValueWithDefault("DetectUncompressible", true);
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m_compressibleDeflateLevel = detectUncompressible ? m_deflateLevel : 0;
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}
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void Deflator::Reset(bool forceReset)
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{
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if (forceReset)
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ClearBitBuffer();
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else
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assert(m_bitsBuffered == 0);
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m_headerWritten = false;
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m_matchAvailable = false;
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m_dictionaryEnd = 0;
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m_stringStart = 0;
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m_lookahead = 0;
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m_minLookahead = MAX_MATCH;
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m_matchBufferEnd = 0;
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m_blockStart = 0;
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m_blockLength = 0;
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m_detectCount = 1;
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m_detectSkip = 0;
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// m_prev will be initialized automaticly in InsertString
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fill(m_head.begin(), m_head.end(), 0);
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fill(m_literalCounts.begin(), m_literalCounts.end(), 0);
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fill(m_distanceCounts.begin(), m_distanceCounts.end(), 0);
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}
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void Deflator::SetDeflateLevel(int deflateLevel)
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{
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if (!(MIN_DEFLATE_LEVEL <= deflateLevel && deflateLevel <= MAX_DEFLATE_LEVEL))
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throw InvalidArgument("Deflator: " + IntToString(deflateLevel) + " is an invalid deflate level");
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if (deflateLevel == m_deflateLevel)
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return;
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EndBlock(false);
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static const unsigned int configurationTable[10][4] = {
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/* good lazy nice chain */
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/* 0 */ {0, 0, 0, 0}, /* store only */
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/* 1 */ {4, 3, 8, 4}, /* maximum speed, no lazy matches */
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/* 2 */ {4, 3, 16, 8},
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/* 3 */ {4, 3, 32, 32},
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/* 4 */ {4, 4, 16, 16}, /* lazy matches */
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/* 5 */ {8, 16, 32, 32},
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/* 6 */ {8, 16, 128, 128},
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/* 7 */ {8, 32, 128, 256},
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/* 8 */ {32, 128, 258, 1024},
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/* 9 */ {32, 258, 258, 4096}}; /* maximum compression */
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GOOD_MATCH = configurationTable[deflateLevel][0];
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MAX_LAZYLENGTH = configurationTable[deflateLevel][1];
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MAX_CHAIN_LENGTH = configurationTable[deflateLevel][3];
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m_deflateLevel = deflateLevel;
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}
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unsigned int Deflator::FillWindow(const byte *str, size_t length)
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{
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unsigned int maxBlockSize = (unsigned int)STDMIN(2UL*DSIZE, 0xffffUL);
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if (m_stringStart >= maxBlockSize - MAX_MATCH)
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{
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if (m_blockStart < DSIZE)
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EndBlock(false);
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memcpy(m_byteBuffer, m_byteBuffer + DSIZE, DSIZE);
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m_dictionaryEnd = m_dictionaryEnd < DSIZE ? 0 : m_dictionaryEnd-DSIZE;
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assert(m_stringStart >= DSIZE);
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m_stringStart -= DSIZE;
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assert(!m_matchAvailable || m_previousMatch >= DSIZE);
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m_previousMatch -= DSIZE;
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assert(m_blockStart >= DSIZE);
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m_blockStart -= DSIZE;
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unsigned int i;
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for (i=0; i<HSIZE; i++)
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m_head[i] = SaturatingSubtract(m_head[i], DSIZE);
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for (i=0; i<DSIZE; i++)
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m_prev[i] = SaturatingSubtract(m_prev[i], DSIZE);
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}
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assert(maxBlockSize > m_stringStart+m_lookahead);
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unsigned int accepted = UnsignedMin(maxBlockSize-(m_stringStart+m_lookahead), length);
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assert(accepted > 0);
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memcpy(m_byteBuffer + m_stringStart + m_lookahead, str, accepted);
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m_lookahead += accepted;
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return accepted;
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}
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inline unsigned int Deflator::ComputeHash(const byte *str) const
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{
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assert(str+3 <= m_byteBuffer + m_stringStart + m_lookahead);
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return ((str[0] << 10) ^ (str[1] << 5) ^ str[2]) & HMASK;
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}
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unsigned int Deflator::LongestMatch(unsigned int &bestMatch) const
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{
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assert(m_previousLength < MAX_MATCH);
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bestMatch = 0;
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unsigned int bestLength = STDMAX(m_previousLength, (unsigned int)MIN_MATCH-1);
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if (m_lookahead <= bestLength)
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return 0;
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const byte *scan = m_byteBuffer + m_stringStart, *scanEnd = scan + STDMIN((unsigned int)MAX_MATCH, m_lookahead);
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unsigned int limit = m_stringStart > (DSIZE-MAX_MATCH) ? m_stringStart - (DSIZE-MAX_MATCH) : 0;
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unsigned int current = m_head[ComputeHash(scan)];
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unsigned int chainLength = MAX_CHAIN_LENGTH;
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if (m_previousLength >= GOOD_MATCH)
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chainLength >>= 2;
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while (current > limit && --chainLength > 0)
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{
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const byte *match = m_byteBuffer + current;
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assert(scan + bestLength < m_byteBuffer + m_stringStart + m_lookahead);
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if (scan[bestLength-1] == match[bestLength-1] && scan[bestLength] == match[bestLength] && scan[0] == match[0] && scan[1] == match[1])
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{
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assert(scan[2] == match[2]);
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unsigned int len = (unsigned int)(
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#if defined(_STDEXT_BEGIN) && !(defined(_MSC_VER) && (_MSC_VER < 1400 || _MSC_VER >= 1600)) && !defined(_STLPORT_VERSION)
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stdext::unchecked_mismatch
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#else
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std::mismatch
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#endif
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#if _MSC_VER >= 1600
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(stdext::make_unchecked_array_iterator(scan)+3, stdext::make_unchecked_array_iterator(scanEnd), stdext::make_unchecked_array_iterator(match)+3).first - stdext::make_unchecked_array_iterator(scan));
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#else
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(scan+3, scanEnd, match+3).first - scan);
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#endif
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assert(len != bestLength);
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if (len > bestLength)
|
||
|
{
|
||
|
bestLength = len;
|
||
|
bestMatch = current;
|
||
|
if (len == (scanEnd - scan))
|
||
|
break;
|
||
|
}
|
||
|
}
|
||
|
current = m_prev[current & DMASK];
|
||
|
}
|
||
|
return (bestMatch > 0) ? bestLength : 0;
|
||
|
}
|
||
|
|
||
|
inline void Deflator::InsertString(unsigned int start)
|
||
|
{
|
||
|
unsigned int hash = ComputeHash(m_byteBuffer + start);
|
||
|
m_prev[start & DMASK] = m_head[hash];
|
||
|
m_head[hash] = start;
|
||
|
}
|
||
|
|
||
|
void Deflator::ProcessBuffer()
|
||
|
{
|
||
|
if (!m_headerWritten)
|
||
|
{
|
||
|
WritePrestreamHeader();
|
||
|
m_headerWritten = true;
|
||
|
}
|
||
|
|
||
|
if (m_deflateLevel == 0)
|
||
|
{
|
||
|
m_stringStart += m_lookahead;
|
||
|
m_lookahead = 0;
|
||
|
m_blockLength = m_stringStart - m_blockStart;
|
||
|
m_matchAvailable = false;
|
||
|
return;
|
||
|
}
|
||
|
|
||
|
while (m_lookahead > m_minLookahead)
|
||
|
{
|
||
|
while (m_dictionaryEnd < m_stringStart && m_dictionaryEnd+3 <= m_stringStart+m_lookahead)
|
||
|
InsertString(m_dictionaryEnd++);
|
||
|
|
||
|
if (m_matchAvailable)
|
||
|
{
|
||
|
unsigned int matchPosition, matchLength;
|
||
|
bool usePreviousMatch;
|
||
|
if (m_previousLength >= MAX_LAZYLENGTH)
|
||
|
usePreviousMatch = true;
|
||
|
else
|
||
|
{
|
||
|
matchLength = LongestMatch(matchPosition);
|
||
|
usePreviousMatch = (matchLength == 0);
|
||
|
}
|
||
|
if (usePreviousMatch)
|
||
|
{
|
||
|
MatchFound(m_stringStart-1-m_previousMatch, m_previousLength);
|
||
|
m_stringStart += m_previousLength-1;
|
||
|
m_lookahead -= m_previousLength-1;
|
||
|
m_matchAvailable = false;
|
||
|
}
|
||
|
else
|
||
|
{
|
||
|
m_previousLength = matchLength;
|
||
|
m_previousMatch = matchPosition;
|
||
|
LiteralByte(m_byteBuffer[m_stringStart-1]);
|
||
|
m_stringStart++;
|
||
|
m_lookahead--;
|
||
|
}
|
||
|
}
|
||
|
else
|
||
|
{
|
||
|
m_previousLength = 0;
|
||
|
m_previousLength = LongestMatch(m_previousMatch);
|
||
|
if (m_previousLength)
|
||
|
m_matchAvailable = true;
|
||
|
else
|
||
|
LiteralByte(m_byteBuffer[m_stringStart]);
|
||
|
m_stringStart++;
|
||
|
m_lookahead--;
|
||
|
}
|
||
|
|
||
|
assert(m_stringStart - (m_blockStart+m_blockLength) == (unsigned int)m_matchAvailable);
|
||
|
}
|
||
|
|
||
|
if (m_minLookahead == 0 && m_matchAvailable)
|
||
|
{
|
||
|
LiteralByte(m_byteBuffer[m_stringStart-1]);
|
||
|
m_matchAvailable = false;
|
||
|
}
|
||
|
}
|
||
|
|
||
|
size_t Deflator::Put2(const byte *str, size_t length, int messageEnd, bool blocking)
|
||
|
{
|
||
|
if (!blocking)
|
||
|
throw BlockingInputOnly("Deflator");
|
||
|
|
||
|
size_t accepted = 0;
|
||
|
while (accepted < length)
|
||
|
{
|
||
|
unsigned int newAccepted = FillWindow(str+accepted, length-accepted);
|
||
|
ProcessBuffer();
|
||
|
// call ProcessUncompressedData() after WritePrestreamHeader()
|
||
|
ProcessUncompressedData(str+accepted, newAccepted);
|
||
|
accepted += newAccepted;
|
||
|
}
|
||
|
assert(accepted == length);
|
||
|
|
||
|
if (messageEnd)
|
||
|
{
|
||
|
m_minLookahead = 0;
|
||
|
ProcessBuffer();
|
||
|
EndBlock(true);
|
||
|
FlushBitBuffer();
|
||
|
WritePoststreamTail();
|
||
|
Reset();
|
||
|
}
|
||
|
|
||
|
Output(0, NULL, 0, messageEnd, blocking);
|
||
|
return 0;
|
||
|
}
|
||
|
|
||
|
bool Deflator::IsolatedFlush(bool hardFlush, bool blocking)
|
||
|
{
|
||
|
if (!blocking)
|
||
|
throw BlockingInputOnly("Deflator");
|
||
|
|
||
|
m_minLookahead = 0;
|
||
|
ProcessBuffer();
|
||
|
m_minLookahead = MAX_MATCH;
|
||
|
EndBlock(false);
|
||
|
if (hardFlush)
|
||
|
EncodeBlock(false, STORED);
|
||
|
return false;
|
||
|
}
|
||
|
|
||
|
void Deflator::LiteralByte(byte b)
|
||
|
{
|
||
|
if (m_matchBufferEnd == m_matchBuffer.size())
|
||
|
EndBlock(false);
|
||
|
|
||
|
m_matchBuffer[m_matchBufferEnd++].literalCode = b;
|
||
|
m_literalCounts[b]++;
|
||
|
m_blockLength++;
|
||
|
}
|
||
|
|
||
|
void Deflator::MatchFound(unsigned int distance, unsigned int length)
|
||
|
{
|
||
|
if (m_matchBufferEnd == m_matchBuffer.size())
|
||
|
EndBlock(false);
|
||
|
|
||
|
static const unsigned int lengthCodes[] = {
|
||
|
257, 258, 259, 260, 261, 262, 263, 264, 265, 265, 266, 266, 267, 267, 268, 268,
|
||
|
269, 269, 269, 269, 270, 270, 270, 270, 271, 271, 271, 271, 272, 272, 272, 272,
|
||
|
273, 273, 273, 273, 273, 273, 273, 273, 274, 274, 274, 274, 274, 274, 274, 274,
|
||
|
275, 275, 275, 275, 275, 275, 275, 275, 276, 276, 276, 276, 276, 276, 276, 276,
|
||
|
277, 277, 277, 277, 277, 277, 277, 277, 277, 277, 277, 277, 277, 277, 277, 277,
|
||
|
278, 278, 278, 278, 278, 278, 278, 278, 278, 278, 278, 278, 278, 278, 278, 278,
|
||
|
279, 279, 279, 279, 279, 279, 279, 279, 279, 279, 279, 279, 279, 279, 279, 279,
|
||
|
280, 280, 280, 280, 280, 280, 280, 280, 280, 280, 280, 280, 280, 280, 280, 280,
|
||
|
281, 281, 281, 281, 281, 281, 281, 281, 281, 281, 281, 281, 281, 281, 281, 281,
|
||
|
281, 281, 281, 281, 281, 281, 281, 281, 281, 281, 281, 281, 281, 281, 281, 281,
|
||
|
282, 282, 282, 282, 282, 282, 282, 282, 282, 282, 282, 282, 282, 282, 282, 282,
|
||
|
282, 282, 282, 282, 282, 282, 282, 282, 282, 282, 282, 282, 282, 282, 282, 282,
|
||
|
283, 283, 283, 283, 283, 283, 283, 283, 283, 283, 283, 283, 283, 283, 283, 283,
|
||
|
283, 283, 283, 283, 283, 283, 283, 283, 283, 283, 283, 283, 283, 283, 283, 283,
|
||
|
284, 284, 284, 284, 284, 284, 284, 284, 284, 284, 284, 284, 284, 284, 284, 284,
|
||
|
284, 284, 284, 284, 284, 284, 284, 284, 284, 284, 284, 284, 284, 284, 284, 285};
|
||
|
static const unsigned int lengthBases[] = {3,4,5,6,7,8,9,10,11,13,15,17,19,23,27,31,35,43,51,59,67,83,99,115,131,163,195,227,258};
|
||
|
static const unsigned int distanceBases[30] =
|
||
|
{1,2,3,4,5,7,9,13,17,25,33,49,65,97,129,193,257,385,513,769,1025,1537,2049,3073,4097,6145,8193,12289,16385,24577};
|
||
|
|
||
|
EncodedMatch &m = m_matchBuffer[m_matchBufferEnd++];
|
||
|
assert(length >= 3);
|
||
|
unsigned int lengthCode = lengthCodes[length-3];
|
||
|
m.literalCode = lengthCode;
|
||
|
m.literalExtra = length - lengthBases[lengthCode-257];
|
||
|
unsigned int distanceCode = (unsigned int)(upper_bound(distanceBases, distanceBases+30, distance) - distanceBases - 1);
|
||
|
m.distanceCode = distanceCode;
|
||
|
m.distanceExtra = distance - distanceBases[distanceCode];
|
||
|
|
||
|
m_literalCounts[lengthCode]++;
|
||
|
m_distanceCounts[distanceCode]++;
|
||
|
m_blockLength += length;
|
||
|
}
|
||
|
|
||
|
inline unsigned int CodeLengthEncode(const unsigned int *begin,
|
||
|
const unsigned int *end,
|
||
|
const unsigned int *& p,
|
||
|
unsigned int &extraBits,
|
||
|
unsigned int &extraBitsLength)
|
||
|
{
|
||
|
unsigned int v = *p;
|
||
|
if ((end-p) >= 3)
|
||
|
{
|
||
|
const unsigned int *oldp = p;
|
||
|
if (v==0 && p[1]==0 && p[2]==0)
|
||
|
{
|
||
|
for (p=p+3; p!=end && *p==0 && p!=oldp+138; p++) {}
|
||
|
unsigned int repeat = (unsigned int)(p - oldp);
|
||
|
if (repeat <= 10)
|
||
|
{
|
||
|
extraBits = repeat-3;
|
||
|
extraBitsLength = 3;
|
||
|
return 17;
|
||
|
}
|
||
|
else
|
||
|
{
|
||
|
extraBits = repeat-11;
|
||
|
extraBitsLength = 7;
|
||
|
return 18;
|
||
|
}
|
||
|
}
|
||
|
else if (p!=begin && v==p[-1] && v==p[1] && v==p[2])
|
||
|
{
|
||
|
for (p=p+3; p!=end && *p==v && p!=oldp+6; p++) {}
|
||
|
unsigned int repeat = (unsigned int)(p - oldp);
|
||
|
extraBits = repeat-3;
|
||
|
extraBitsLength = 2;
|
||
|
return 16;
|
||
|
}
|
||
|
}
|
||
|
p++;
|
||
|
extraBits = 0;
|
||
|
extraBitsLength = 0;
|
||
|
return v;
|
||
|
}
|
||
|
|
||
|
void Deflator::EncodeBlock(bool eof, unsigned int blockType)
|
||
|
{
|
||
|
PutBits(eof, 1);
|
||
|
PutBits(blockType, 2);
|
||
|
|
||
|
if (blockType == STORED)
|
||
|
{
|
||
|
assert(m_blockStart + m_blockLength <= m_byteBuffer.size());
|
||
|
assert(m_blockLength <= 0xffff);
|
||
|
FlushBitBuffer();
|
||
|
AttachedTransformation()->PutWord16(m_blockLength, LITTLE_ENDIAN_ORDER);
|
||
|
AttachedTransformation()->PutWord16(~m_blockLength, LITTLE_ENDIAN_ORDER);
|
||
|
AttachedTransformation()->Put(m_byteBuffer + m_blockStart, m_blockLength);
|
||
|
}
|
||
|
else
|
||
|
{
|
||
|
if (blockType == DYNAMIC)
|
||
|
{
|
||
|
#if defined(_MSC_VER) && !defined(__MWERKS__) && (_MSC_VER <= 1300)
|
||
|
// VC60 and VC7 workaround: built-in reverse_iterator has two template parameters, Dinkumware only has one
|
||
|
typedef reverse_bidirectional_iterator<unsigned int *, unsigned int> RevIt;
|
||
|
#elif defined(_RWSTD_NO_CLASS_PARTIAL_SPEC)
|
||
|
typedef reverse_iterator<unsigned int *, random_access_iterator_tag, unsigned int> RevIt;
|
||
|
#else
|
||
|
typedef reverse_iterator<unsigned int *> RevIt;
|
||
|
#endif
|
||
|
|
||
|
FixedSizeSecBlock<unsigned int, 286> literalCodeLengths;
|
||
|
FixedSizeSecBlock<unsigned int, 30> distanceCodeLengths;
|
||
|
|
||
|
m_literalCounts[256] = 1;
|
||
|
HuffmanEncoder::GenerateCodeLengths(literalCodeLengths, 15, m_literalCounts, 286);
|
||
|
m_dynamicLiteralEncoder.Initialize(literalCodeLengths, 286);
|
||
|
unsigned int hlit = (unsigned int)(find_if(RevIt(literalCodeLengths.end()), RevIt(literalCodeLengths.begin()+257), bind2nd(not_equal_to<unsigned int>(), 0)).base() - (literalCodeLengths.begin()+257));
|
||
|
|
||
|
HuffmanEncoder::GenerateCodeLengths(distanceCodeLengths, 15, m_distanceCounts, 30);
|
||
|
m_dynamicDistanceEncoder.Initialize(distanceCodeLengths, 30);
|
||
|
unsigned int hdist = (unsigned int)(find_if(RevIt(distanceCodeLengths.end()), RevIt(distanceCodeLengths.begin()+1), bind2nd(not_equal_to<unsigned int>(), 0)).base() - (distanceCodeLengths.begin()+1));
|
||
|
|
||
|
SecBlockWithHint<unsigned int, 286+30> combinedLengths(hlit+257+hdist+1);
|
||
|
memcpy(combinedLengths, literalCodeLengths, (hlit+257)*sizeof(unsigned int));
|
||
|
memcpy(combinedLengths+hlit+257, distanceCodeLengths, (hdist+1)*sizeof(unsigned int));
|
||
|
|
||
|
FixedSizeSecBlock<unsigned int, 19> codeLengthCodeCounts, codeLengthCodeLengths;
|
||
|
fill(codeLengthCodeCounts.begin(), codeLengthCodeCounts.end(), 0);
|
||
|
const unsigned int *p = combinedLengths.begin(), *begin = combinedLengths.begin(), *end = combinedLengths.end();
|
||
|
while (p != end)
|
||
|
{
|
||
|
unsigned int code, extraBits, extraBitsLength;
|
||
|
code = CodeLengthEncode(begin, end, p, extraBits, extraBitsLength);
|
||
|
codeLengthCodeCounts[code]++;
|
||
|
}
|
||
|
HuffmanEncoder::GenerateCodeLengths(codeLengthCodeLengths, 7, codeLengthCodeCounts, 19);
|
||
|
HuffmanEncoder codeLengthEncoder(codeLengthCodeLengths, 19);
|
||
|
static const unsigned int border[] = { // Order of the bit length code lengths
|
||
|
16, 17, 18, 0, 8, 7, 9, 6, 10, 5, 11, 4, 12, 3, 13, 2, 14, 1, 15};
|
||
|
unsigned int hclen = 19;
|
||
|
while (hclen > 4 && codeLengthCodeLengths[border[hclen-1]] == 0)
|
||
|
hclen--;
|
||
|
hclen -= 4;
|
||
|
|
||
|
PutBits(hlit, 5);
|
||
|
PutBits(hdist, 5);
|
||
|
PutBits(hclen, 4);
|
||
|
|
||
|
for (unsigned int i=0; i<hclen+4; i++)
|
||
|
PutBits(codeLengthCodeLengths[border[i]], 3);
|
||
|
|
||
|
p = combinedLengths.begin();
|
||
|
while (p != end)
|
||
|
{
|
||
|
unsigned int code, extraBits, extraBitsLength;
|
||
|
code = CodeLengthEncode(begin, end, p, extraBits, extraBitsLength);
|
||
|
codeLengthEncoder.Encode(*this, code);
|
||
|
PutBits(extraBits, extraBitsLength);
|
||
|
}
|
||
|
}
|
||
|
|
||
|
static const unsigned int lengthExtraBits[] = {
|
||
|
0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 1, 1, 2, 2, 2, 2,
|
||
|
3, 3, 3, 3, 4, 4, 4, 4, 5, 5, 5, 5, 0};
|
||
|
static const unsigned int distanceExtraBits[] = {
|
||
|
0, 0, 0, 0, 1, 1, 2, 2, 3, 3, 4, 4, 5, 5, 6, 6,
|
||
|
7, 7, 8, 8, 9, 9, 10, 10, 11, 11,
|
||
|
12, 12, 13, 13};
|
||
|
|
||
|
const HuffmanEncoder &literalEncoder = (blockType == STATIC) ? m_staticLiteralEncoder : m_dynamicLiteralEncoder;
|
||
|
const HuffmanEncoder &distanceEncoder = (blockType == STATIC) ? m_staticDistanceEncoder : m_dynamicDistanceEncoder;
|
||
|
|
||
|
for (unsigned int i=0; i<m_matchBufferEnd; i++)
|
||
|
{
|
||
|
unsigned int literalCode = m_matchBuffer[i].literalCode;
|
||
|
literalEncoder.Encode(*this, literalCode);
|
||
|
if (literalCode >= 257)
|
||
|
{
|
||
|
assert(literalCode <= 285);
|
||
|
PutBits(m_matchBuffer[i].literalExtra, lengthExtraBits[literalCode-257]);
|
||
|
unsigned int distanceCode = m_matchBuffer[i].distanceCode;
|
||
|
distanceEncoder.Encode(*this, distanceCode);
|
||
|
PutBits(m_matchBuffer[i].distanceExtra, distanceExtraBits[distanceCode]);
|
||
|
}
|
||
|
}
|
||
|
literalEncoder.Encode(*this, 256); // end of block
|
||
|
}
|
||
|
}
|
||
|
|
||
|
void Deflator::EndBlock(bool eof)
|
||
|
{
|
||
|
if (m_blockLength == 0 && !eof)
|
||
|
return;
|
||
|
|
||
|
if (m_deflateLevel == 0)
|
||
|
{
|
||
|
EncodeBlock(eof, STORED);
|
||
|
|
||
|
if (m_compressibleDeflateLevel > 0 && ++m_detectCount == m_detectSkip)
|
||
|
{
|
||
|
m_deflateLevel = m_compressibleDeflateLevel;
|
||
|
m_detectCount = 1;
|
||
|
}
|
||
|
}
|
||
|
else
|
||
|
{
|
||
|
unsigned long storedLen = 8*((unsigned long)m_blockLength+4) + RoundUpToMultipleOf(m_bitsBuffered+3, 8U)-m_bitsBuffered;
|
||
|
|
||
|
StartCounting();
|
||
|
EncodeBlock(eof, STATIC);
|
||
|
unsigned long staticLen = FinishCounting();
|
||
|
|
||
|
unsigned long dynamicLen;
|
||
|
if (m_blockLength < 128 && m_deflateLevel < 8)
|
||
|
dynamicLen = ULONG_MAX;
|
||
|
else
|
||
|
{
|
||
|
StartCounting();
|
||
|
EncodeBlock(eof, DYNAMIC);
|
||
|
dynamicLen = FinishCounting();
|
||
|
}
|
||
|
|
||
|
if (storedLen <= staticLen && storedLen <= dynamicLen)
|
||
|
{
|
||
|
EncodeBlock(eof, STORED);
|
||
|
|
||
|
if (m_compressibleDeflateLevel > 0)
|
||
|
{
|
||
|
if (m_detectSkip)
|
||
|
m_deflateLevel = 0;
|
||
|
m_detectSkip = m_detectSkip ? STDMIN(2*m_detectSkip, 128U) : 1;
|
||
|
}
|
||
|
}
|
||
|
else
|
||
|
{
|
||
|
if (staticLen <= dynamicLen)
|
||
|
EncodeBlock(eof, STATIC);
|
||
|
else
|
||
|
EncodeBlock(eof, DYNAMIC);
|
||
|
|
||
|
if (m_compressibleDeflateLevel > 0)
|
||
|
m_detectSkip = 0;
|
||
|
}
|
||
|
}
|
||
|
|
||
|
m_matchBufferEnd = 0;
|
||
|
m_blockStart += m_blockLength;
|
||
|
m_blockLength = 0;
|
||
|
fill(m_literalCounts.begin(), m_literalCounts.end(), 0);
|
||
|
fill(m_distanceCounts.begin(), m_distanceCounts.end(), 0);
|
||
|
}
|
||
|
|
||
|
NAMESPACE_END
|