// zdeflate.cpp - written and placed in the public domain by Wei Dai
// Many of the algorithms and tables used here came from the deflate implementation
// by Jean-loup Gailly, which was included in Crypto++ 4.0 and earlier. I completely
// rewrote it in order to fix a bug that I could not figure out. This code
// is less clever, but hopefully more understandable and maintainable.
#include "pch.h"
#include "zdeflate.h"
#include <functional>
NAMESPACE_BEGIN(CryptoPP)
using namespace std;
LowFirstBitWriter::LowFirstBitWriter(BufferedTransformation *attachment)
: Filter(attachment), m_counting(false), m_buffer(0), m_bitsBuffered(0), m_bytesBuffered(0)
{
}
void LowFirstBitWriter::StartCounting()
{
assert(!m_counting);
m_counting = true;
m_bitCount = 0;
}
unsigned long LowFirstBitWriter::FinishCounting()
{
assert(m_counting);
m_counting = false;
return m_bitCount;
}
void LowFirstBitWriter::PutBits(unsigned long value, unsigned int length)
{
if (m_counting)
m_bitCount += length;
else
{
m_buffer |= value << m_bitsBuffered;
m_bitsBuffered += length;
assert(m_bitsBuffered <= sizeof(unsigned long)*8);
while (m_bitsBuffered >= 8)
{
m_outputBuffer[m_bytesBuffered++] = (byte)m_buffer;
if (m_bytesBuffered == m_outputBuffer.size())
{
AttachedTransformation()->PutModifiable(m_outputBuffer, m_bytesBuffered);
m_bytesBuffered = 0;
}
m_buffer >>= 8;
m_bitsBuffered -= 8;
}
}
}
void LowFirstBitWriter::FlushBitBuffer()
{
if (m_counting)
m_bitCount += 8*(m_bitsBuffered > 0);
else
{
if (m_bytesBuffered > 0)
{
AttachedTransformation()->PutModifiable(m_outputBuffer, m_bytesBuffered);
m_bytesBuffered = 0;
}
if (m_bitsBuffered > 0)
{
AttachedTransformation()->Put((byte)m_buffer);
m_buffer = 0;
m_bitsBuffered = 0;
}
}
}
void LowFirstBitWriter::ClearBitBuffer()
{
m_buffer = 0;
m_bytesBuffered = 0;
m_bitsBuffered = 0;
}
HuffmanEncoder::HuffmanEncoder(const unsigned int *codeBits, unsigned int nCodes)
{
Initialize(codeBits, nCodes);
}
struct HuffmanNode
{
size_t symbol;
union {size_t parent; unsigned depth, freq;};
};
struct FreqLessThan
{
inline bool operator()(unsigned int lhs, const HuffmanNode &rhs) {return lhs < rhs.freq;}
inline bool operator()(const HuffmanNode &lhs, const HuffmanNode &rhs) const {return lhs.freq < rhs.freq;}
// needed for MSVC .NET 2005
inline bool operator()(const HuffmanNode &lhs, unsigned int rhs) {return lhs.freq < rhs;}
};
void HuffmanEncoder::GenerateCodeLengths(unsigned int *codeBits, unsigned int maxCodeBits, const unsigned int *codeCounts, size_t nCodes)
{
assert(nCodes > 0);
assert(nCodes <= ((size_t)1 << maxCodeBits));
size_t i;
SecBlockWithHint<HuffmanNode, 2*286> tree(nCodes);
for (i=0; i<nCodes; i++)
{
tree[i].symbol = i;
tree[i].freq = codeCounts[i];
}
sort(tree.begin(), tree.end(), FreqLessThan());
size_t treeBegin = upper_bound(tree.begin(), tree.end(), 0, FreqLessThan()) - tree.begin();
if (treeBegin == nCodes)
{ // special case for no codes
fill(codeBits, codeBits+nCodes, 0);
return;
}
tree.resize(nCodes + nCodes - treeBegin - 1);
size_t leastLeaf = treeBegin, leastInterior = nCodes;
for (i=nCodes; i<tree.size(); i++)
{
size_t least;
least = (leastLeaf == nCodes || (leastInterior < i && tree[leastInterior].freq < tree[leastLeaf].freq)) ? leastInterior++ : leastLeaf++;
tree[i].freq = tree[least].freq;
tree[least].parent = i;
least = (leastLeaf == nCodes || (leastInterior < i && tree[leastInterior].freq < tree[leastLeaf].freq)) ? leastInterior++ : leastLeaf++;
tree[i].freq += tree[least].freq;
tree[least].parent = i;
}
tree[tree.size()-1].depth = 0;
if (tree.size() >= 2)
for (i=tree.size()-2; i>=nCodes; i--)
tree[i].depth = tree[tree[i].parent].depth + 1;
unsigned int sum = 0;
SecBlockWithHint<unsigned int, 15+1> blCount(maxCodeBits+1);
fill(blCount.begin(), blCount.end(), 0);
for (i=treeBegin; i<nCodes; i++)
{
size_t depth = STDMIN(maxCodeBits, tree[tree[i].parent].depth + 1);
blCount[depth]++;
sum += 1 << (maxCodeBits - depth);
}
unsigned int overflow = sum > (unsigned int)(1 << maxCodeBits) ? sum - (1 << maxCodeBits) : 0;
while (overflow--)
{
unsigned int bits = maxCodeBits-1;
while (blCount[bits] == 0)
bits--;
blCount[bits]--;
blCount[bits+1] += 2;
assert(blCount[maxCodeBits] > 0);
blCount[maxCodeBits]--;
}
for (i=0; i<treeBegin; i++)
codeBits[tree[i].symbol] = 0;
unsigned int bits = maxCodeBits;
for (i=treeBegin; i<nCodes; i++)
{
while (blCount[bits] == 0)
bits--;
codeBits[tree[i].symbol] = bits;
blCount[bits]--;
}
assert(blCount[bits] == 0);
}
void HuffmanEncoder::Initialize(const unsigned int *codeBits, unsigned int nCodes)
{
assert(nCodes > 0);
unsigned int maxCodeBits = *max_element(codeBits, codeBits+nCodes);
if (maxCodeBits == 0)
return; // assume this object won't be used
SecBlockWithHint<unsigned int, 15+1> blCount(maxCodeBits+1);
fill(blCount.begin(), blCount.end(), 0);
unsigned int i;
for (i=0; i<nCodes; i++)
blCount[codeBits[i]]++;
code_t code = 0;
SecBlockWithHint<code_t, 15+1> nextCode(maxCodeBits+1);
nextCode[1] = 0;
for (i=2; i<=maxCodeBits; i++)
{
code = (code + blCount[i-1]) << 1;
nextCode[i] = code;
}
assert(maxCodeBits == 1 || code == (1 << maxCodeBits) - blCount[maxCodeBits]);
m_valueToCode.resize(nCodes);
for (i=0; i<nCodes; i++)
{
unsigned int len = m_valueToCode[i].len = codeBits[i];
if (len != 0)
m_valueToCode[i].code = BitReverse(nextCode[len]++) >> (8*sizeof(code_t)-len);
}
}
inline void HuffmanEncoder::Encode(LowFirstBitWriter &writer, value_t value) const
{
assert(m_valueToCode[value].len > 0);
writer.PutBits(m_valueToCode[value].code, m_valueToCode[value].len);
}
Deflator::Deflator(BufferedTransformation *attachment, int deflateLevel, int log2WindowSize, bool detectUncompressible)
: LowFirstBitWriter(attachment)
{
InitializeStaticEncoders();
IsolatedInitialize(MakeParameters("DeflateLevel", deflateLevel)("Log2WindowSize", log2WindowSize)("DetectUncompressible", detectUncompressible));
}
Deflator::Deflator(const NameValuePairs ¶meters, BufferedTransformation *attachment)
: LowFirstBitWriter(attachment)
{
InitializeStaticEncoders();
IsolatedInitialize(parameters);
}
void Deflator::InitializeStaticEncoders()
{
unsigned int codeLengths[288];
fill(codeLengths + 0, codeLengths + 144, 8);
fill(codeLengths + 144, codeLengths + 256, 9);
fill(codeLengths + 256, codeLengths + 280, 7);
fill(codeLengths + 280, codeLengths + 288, 8);
m_staticLiteralEncoder.Initialize(codeLengths, 288);
fill(codeLengths + 0, codeLengths + 32, 5);
m_staticDistanceEncoder.Initialize(codeLengths, 32);
}
void Deflator::IsolatedInitialize(const NameValuePairs ¶meters)
{
int log2WindowSize = parameters.GetIntValueWithDefault("Log2WindowSize", DEFAULT_LOG2_WINDOW_SIZE);
if (!(MIN_LOG2_WINDOW_SIZE <= log2WindowSize && log2WindowSize <= MAX_LOG2_WINDOW_SIZE))
throw InvalidArgument("Deflator: " + IntToString(log2WindowSize) + " is an invalid window size");
m_log2WindowSize = log2WindowSize;
DSIZE = 1 << m_log2WindowSize;
DMASK = DSIZE - 1;
HSIZE = 1 << m_log2WindowSize;
HMASK = HSIZE - 1;
m_byteBuffer.New(2*DSIZE);
m_head.New(HSIZE);
m_prev.New(DSIZE);
m_matchBuffer.New(DSIZE/2);
Reset(true);
SetDeflateLevel(parameters.GetIntValueWithDefault("DeflateLevel", DEFAULT_DEFLATE_LEVEL));
bool detectUncompressible = parameters.GetValueWithDefault("DetectUncompressible", true);
m_compressibleDeflateLevel = detectUncompressible ? m_deflateLevel : 0;
}
void Deflator::Reset(bool forceReset)
{
if (forceReset)
ClearBitBuffer();
else
assert(m_bitsBuffered == 0);
m_headerWritten = false;
m_matchAvailable = false;
m_dictionaryEnd = 0;
m_stringStart = 0;
m_lookahead = 0;
m_minLookahead = MAX_MATCH;
m_matchBufferEnd = 0;
m_blockStart = 0;
m_blockLength = 0;
m_detectCount = 1;
m_detectSkip = 0;
// m_prev will be initialized automaticly in InsertString
fill(m_head.begin(), m_head.end(), 0);
fill(m_literalCounts.begin(), m_literalCounts.end(), 0);
fill(m_distanceCounts.begin(), m_distanceCounts.end(), 0);
}
void Deflator::SetDeflateLevel(int deflateLevel)
{
if (!(MIN_DEFLATE_LEVEL <= deflateLevel && deflateLevel <= MAX_DEFLATE_LEVEL))
throw InvalidArgument("Deflator: " + IntToString(deflateLevel) + " is an invalid deflate level");
if (deflateLevel == m_deflateLevel)
return;
EndBlock(false);
static const unsigned int configurationTable[10][4] = {
/* good lazy nice chain */
/* 0 */ {0, 0, 0, 0}, /* store only */
/* 1 */ {4, 3, 8, 4}, /* maximum speed, no lazy matches */
/* 2 */ {4, 3, 16, 8},
/* 3 */ {4, 3, 32, 32},
/* 4 */ {4, 4, 16, 16}, /* lazy matches */
/* 5 */ {8, 16, 32, 32},
/* 6 */ {8, 16, 128, 128},
/* 7 */ {8, 32, 128, 256},
/* 8 */ {32, 128, 258, 1024},
/* 9 */ {32, 258, 258, 4096}}; /* maximum compression */
GOOD_MATCH = configurationTable[deflateLevel][0];
MAX_LAZYLENGTH = configurationTable[deflateLevel][1];
MAX_CHAIN_LENGTH = configurationTable[deflateLevel][3];
m_deflateLevel = deflateLevel;
}
unsigned int Deflator::FillWindow(const byte *str, size_t length)
{
unsigned int maxBlockSize = (unsigned int)STDMIN(2UL*DSIZE, 0xffffUL);
if (m_stringStart >= maxBlockSize - MAX_MATCH)
{
if (m_blockStart < DSIZE)
EndBlock(false);
memcpy(m_byteBuffer, m_byteBuffer + DSIZE, DSIZE);
m_dictionaryEnd = m_dictionaryEnd < DSIZE ? 0 : m_dictionaryEnd-DSIZE;
assert(m_stringStart >= DSIZE);
m_stringStart -= DSIZE;
assert(!m_matchAvailable || m_previousMatch >= DSIZE);
m_previousMatch -= DSIZE;
assert(m_blockStart >= DSIZE);
m_blockStart -= DSIZE;
unsigned int i;
for (i=0; i<HSIZE; i++)
m_head[i] = SaturatingSubtract(m_head[i], DSIZE);
for (i=0; i<DSIZE; i++)
m_prev[i] = SaturatingSubtract(m_prev[i], DSIZE);
}
assert(maxBlockSize > m_stringStart+m_lookahead);
unsigned int accepted = UnsignedMin(maxBlockSize-(m_stringStart+m_lookahead), length);
assert(accepted > 0);
memcpy(m_byteBuffer + m_stringStart + m_lookahead, str, accepted);
m_lookahead += accepted;
return accepted;
}
inline unsigned int Deflator::ComputeHash(const byte *str) const
{
assert(str+3 <= m_byteBuffer + m_stringStart + m_lookahead);
return ((str[0] << 10) ^ (str[1] << 5) ^ str[2]) & HMASK;
}
unsigned int Deflator::LongestMatch(unsigned int &bestMatch) const
{
assert(m_previousLength < MAX_MATCH);
bestMatch = 0;
unsigned int bestLength = STDMAX(m_previousLength, (unsigned int)MIN_MATCH-1);
if (m_lookahead <= bestLength)
return 0;
const byte *scan = m_byteBuffer + m_stringStart, *scanEnd = scan + STDMIN((unsigned int)MAX_MATCH, m_lookahead);
unsigned int limit = m_stringStart > (DSIZE-MAX_MATCH) ? m_stringStart - (DSIZE-MAX_MATCH) : 0;
unsigned int current = m_head[ComputeHash(scan)];
unsigned int chainLength = MAX_CHAIN_LENGTH;
if (m_previousLength >= GOOD_MATCH)
chainLength >>= 2;
while (current > limit && --chainLength > 0)
{
const byte *match = m_byteBuffer + current;
assert(scan + bestLength < m_byteBuffer + m_stringStart + m_lookahead);
if (scan[bestLength-1] == match[bestLength-1] && scan[bestLength] == match[bestLength] && scan[0] == match[0] && scan[1] == match[1])
{
assert(scan[2] == match[2]);
unsigned int len = (unsigned int)(
#if defined(_STDEXT_BEGIN) && !(defined(_MSC_VER) && _MSC_VER < 1400)
stdext::unchecked_mismatch
#else
std::mismatch
#endif
(scan+3, scanEnd, match+3).first - scan);
assert(len != bestLength);
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
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