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663 lines
18 KiB
663 lines
18 KiB
![]()
4 years ago
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// zinflate.cpp - originally written and placed in the public domain by Wei Dai
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// This is a complete reimplementation of the DEFLATE decompression algorithm.
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// It should not be affected by any security vulnerabilities in the zlib
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// compression library. In particular it is not affected by the double free bug
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// (http://www.kb.cert.org/vuls/id/368819).
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#include "pch.h"
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#include "zinflate.h"
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#include "secblock.h"
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#include "smartptr.h"
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NAMESPACE_BEGIN(CryptoPP)
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struct CodeLessThan
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{
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inline bool operator()(CryptoPP::HuffmanDecoder::code_t lhs, const CryptoPP::HuffmanDecoder::CodeInfo &rhs)
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{return lhs < rhs.code;}
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// needed for MSVC .NET 2005
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inline bool operator()(const CryptoPP::HuffmanDecoder::CodeInfo &lhs, const CryptoPP::HuffmanDecoder::CodeInfo &rhs)
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{return lhs.code < rhs.code;}
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};
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inline bool LowFirstBitReader::FillBuffer(unsigned int length)
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{
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while (m_bitsBuffered < length)
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{
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byte b;
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if (!m_store.Get(b))
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return false;
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m_buffer |= (unsigned long)b << m_bitsBuffered;
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m_bitsBuffered += 8;
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}
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CRYPTOPP_ASSERT(m_bitsBuffered <= sizeof(unsigned long)*8);
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return true;
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}
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inline unsigned long LowFirstBitReader::PeekBits(unsigned int length)
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{
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bool result = FillBuffer(length);
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CRYPTOPP_UNUSED(result); CRYPTOPP_ASSERT(result);
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return m_buffer & (((unsigned long)1 << length) - 1);
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}
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inline void LowFirstBitReader::SkipBits(unsigned int length)
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{
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CRYPTOPP_ASSERT(m_bitsBuffered >= length);
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m_buffer >>= length;
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m_bitsBuffered -= length;
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}
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inline unsigned long LowFirstBitReader::GetBits(unsigned int length)
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{
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unsigned long result = PeekBits(length);
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SkipBits(length);
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return result;
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}
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inline HuffmanDecoder::code_t HuffmanDecoder::NormalizeCode(HuffmanDecoder::code_t code, unsigned int codeBits)
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{
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return code << (MAX_CODE_BITS - codeBits);
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}
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void HuffmanDecoder::Initialize(const unsigned int *codeBits, unsigned int nCodes)
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{
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// the Huffman codes are represented in 3 ways in this code:
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//
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// 1. most significant code bit (i.e. top of code tree) in the least significant bit position
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// 2. most significant code bit (i.e. top of code tree) in the most significant bit position
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// 3. most significant code bit (i.e. top of code tree) in n-th least significant bit position,
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// where n is the maximum code length for this code tree
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//
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// (1) is the way the codes come in from the deflate stream
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// (2) is used to sort codes so they can be binary searched
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// (3) is used in this function to compute codes from code lengths
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//
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// a code in representation (2) is called "normalized" here
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// The BitReverse() function is used to convert between (1) and (2)
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// The NormalizeCode() function is used to convert from (3) to (2)
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if (nCodes == 0)
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throw Err("null code");
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m_maxCodeBits = *std::max_element(codeBits, codeBits+nCodes);
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if (m_maxCodeBits > MAX_CODE_BITS)
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throw Err("code length exceeds maximum");
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if (m_maxCodeBits == 0)
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throw Err("null code");
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// count number of codes of each length
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SecBlockWithHint<unsigned int, 15+1> blCount(m_maxCodeBits+1);
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std::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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// compute the starting code of each length
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code_t code = 0;
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SecBlockWithHint<code_t, 15+1> nextCode(m_maxCodeBits+1);
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nextCode[1] = 0;
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for (i=2; i<=m_maxCodeBits; i++)
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{
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// compute this while checking for overflow: code = (code + blCount[i-1]) << 1
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if (code > code + blCount[i-1])
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throw Err("codes oversubscribed");
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code += blCount[i-1];
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if (code > (code << 1))
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throw Err("codes oversubscribed");
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code <<= 1;
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nextCode[i] = code;
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}
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// MAX_CODE_BITS is 32, m_maxCodeBits may be smaller.
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const word64 shiftedMaxCode = ((word64)1 << m_maxCodeBits);
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if (code > shiftedMaxCode - blCount[m_maxCodeBits])
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throw Err("codes oversubscribed");
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else if (m_maxCodeBits != 1 && code < shiftedMaxCode - blCount[m_maxCodeBits])
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throw Err("codes incomplete");
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// compute a vector of <code, length, value> triples sorted by code
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m_codeToValue.resize(nCodes - blCount[0]);
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unsigned int j=0;
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for (i=0; i<nCodes; i++)
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{
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unsigned int len = codeBits[i];
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if (len != 0)
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{
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CRYPTOPP_ASSERT(j < m_codeToValue.size());
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code = NormalizeCode(nextCode[len]++, len);
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m_codeToValue[j].code = code;
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m_codeToValue[j].len = len;
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m_codeToValue[j].value = i;
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j++;
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}
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}
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std::sort(m_codeToValue.begin(), m_codeToValue.end());
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// initialize the decoding cache
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m_cacheBits = STDMIN(9U, m_maxCodeBits);
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m_cacheMask = (1 << m_cacheBits) - 1;
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m_normalizedCacheMask = NormalizeCode(m_cacheMask, m_cacheBits);
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CRYPTOPP_ASSERT(m_normalizedCacheMask == BitReverse(m_cacheMask));
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const word64 shiftedCache = ((word64)1 << m_cacheBits);
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CRYPTOPP_ASSERT(shiftedCache <= SIZE_MAX);
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if (m_cache.size() != shiftedCache)
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m_cache.resize((size_t)shiftedCache);
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for (i=0; i<m_cache.size(); i++)
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m_cache[i].type = 0;
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}
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void HuffmanDecoder::FillCacheEntry(LookupEntry &entry, code_t normalizedCode) const
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{
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normalizedCode &= m_normalizedCacheMask;
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const CodeInfo &codeInfo = *(std::upper_bound(m_codeToValue.begin(), m_codeToValue.end(), normalizedCode, CodeLessThan())-1);
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if (codeInfo.len <= m_cacheBits)
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{
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entry.type = 1;
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entry.value = codeInfo.value;
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entry.len = codeInfo.len;
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}
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else
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{
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entry.begin = &codeInfo;
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const CodeInfo *last = & *(std::upper_bound(m_codeToValue.begin(), m_codeToValue.end(), normalizedCode + ~m_normalizedCacheMask, CodeLessThan())-1);
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if (codeInfo.len == last->len)
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{
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entry.type = 2;
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entry.len = codeInfo.len;
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}
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else
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{
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entry.type = 3;
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entry.end = last+1;
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}
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}
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}
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inline unsigned int HuffmanDecoder::Decode(code_t code, /* out */ value_t &value) const
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{
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CRYPTOPP_ASSERT(((int)(code & m_cacheMask)) < (int)m_cache.size());
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LookupEntry &entry = m_cache[code & m_cacheMask];
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code_t normalizedCode = 0;
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if (entry.type != 1)
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normalizedCode = BitReverse(code);
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if (entry.type == 0)
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FillCacheEntry(entry, normalizedCode);
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if (entry.type == 1)
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{
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value = entry.value;
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return entry.len;
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}
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else
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{
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const CodeInfo &codeInfo = (entry.type == 2)
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? entry.begin[(normalizedCode << m_cacheBits) >> (MAX_CODE_BITS - (entry.len - m_cacheBits))]
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: *(std::upper_bound(entry.begin, entry.end, normalizedCode, CodeLessThan())-1);
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value = codeInfo.value;
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return codeInfo.len;
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}
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}
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bool HuffmanDecoder::Decode(LowFirstBitReader &reader, value_t &value) const
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{
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bool result = reader.FillBuffer(m_maxCodeBits);
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CRYPTOPP_UNUSED(result); // CRYPTOPP_ASSERT(result);
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unsigned int codeBits = Decode(reader.PeekBuffer(), value);
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if (codeBits > reader.BitsBuffered())
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return false;
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reader.SkipBits(codeBits);
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return true;
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}
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// *************************************************************
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Inflator::Inflator(BufferedTransformation *attachment, bool repeat, int propagation)
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: AutoSignaling<Filter>(propagation)
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, m_state(PRE_STREAM), m_repeat(repeat), m_eof(0), m_wrappedAround(0)
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, m_blockType(0xff), m_storedLen(0xffff), m_nextDecode(), m_literal(0)
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, m_distance(0), m_reader(m_inQueue), m_current(0), m_lastFlush(0)
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{
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Detach(attachment);
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}
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void Inflator::IsolatedInitialize(const NameValuePairs ¶meters)
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{
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m_state = PRE_STREAM;
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parameters.GetValue("Repeat", m_repeat);
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m_inQueue.Clear();
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m_reader.SkipBits(m_reader.BitsBuffered());
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}
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void Inflator::OutputByte(byte b)
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{
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m_window[m_current++] = b;
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if (m_current == m_window.size())
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{
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ProcessDecompressedData(m_window + m_lastFlush, m_window.size() - m_lastFlush);
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m_lastFlush = 0;
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m_current = 0;
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m_wrappedAround = true;
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}
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}
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void Inflator::OutputString(const byte *string, size_t length)
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{
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while (length)
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{
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size_t len = UnsignedMin(length, m_window.size() - m_current);
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memcpy(m_window + m_current, string, len);
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m_current += len;
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if (m_current == m_window.size())
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{
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ProcessDecompressedData(m_window + m_lastFlush, m_window.size() - m_lastFlush);
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m_lastFlush = 0;
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m_current = 0;
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m_wrappedAround = true;
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}
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string += len;
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length -= len;
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}
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}
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void Inflator::OutputPast(unsigned int length, unsigned int distance)
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{
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size_t start;
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if (distance <= m_current)
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start = m_current - distance;
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else if (m_wrappedAround && distance <= m_window.size())
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start = m_current + m_window.size() - distance;
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else
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throw BadBlockErr();
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if (start + length > m_window.size())
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{
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for (; start < m_window.size(); start++, length--)
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OutputByte(m_window[start]);
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start = 0;
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}
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if (start + length > m_current || m_current + length >= m_window.size())
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{
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while (length--)
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OutputByte(m_window[start++]);
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}
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else
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{
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memcpy(m_window + m_current, m_window + start, length);
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m_current += length;
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}
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}
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size_t Inflator::Put2(const byte *inString, size_t length, int messageEnd, bool blocking)
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{
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if (!blocking)
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throw BlockingInputOnly("Inflator");
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LazyPutter lp(m_inQueue, inString, length);
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ProcessInput(messageEnd != 0);
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if (messageEnd)
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if (!(m_state == PRE_STREAM || m_state == AFTER_END))
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throw UnexpectedEndErr();
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Output(0, NULLPTR, 0, messageEnd, blocking);
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return 0;
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}
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bool Inflator::IsolatedFlush(bool hardFlush, bool blocking)
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{
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if (!blocking)
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throw BlockingInputOnly("Inflator");
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if (hardFlush)
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ProcessInput(true);
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FlushOutput();
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return false;
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}
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void Inflator::ProcessInput(bool flush)
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{
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while (true)
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{
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switch (m_state)
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{
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case PRE_STREAM:
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if (!flush && m_inQueue.CurrentSize() < MaxPrestreamHeaderSize())
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return;
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ProcessPrestreamHeader();
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m_state = WAIT_HEADER;
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m_wrappedAround = false;
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m_current = 0;
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m_lastFlush = 0;
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m_window.New(((size_t) 1) << GetLog2WindowSize());
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break;
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case WAIT_HEADER:
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{
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// maximum number of bytes before actual compressed data starts
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const size_t MAX_HEADER_SIZE = BitsToBytes(3+5+5+4+19*7+286*15+19*15);
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if (m_inQueue.CurrentSize() < (flush ? 1 : MAX_HEADER_SIZE))
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return;
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DecodeHeader();
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break;
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}
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case DECODING_BODY:
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if (!DecodeBody())
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return;
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break;
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case POST_STREAM:
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if (!flush && m_inQueue.CurrentSize() < MaxPoststreamTailSize())
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return;
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ProcessPoststreamTail();
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m_state = m_repeat ? PRE_STREAM : AFTER_END;
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Output(0, NULLPTR, 0, GetAutoSignalPropagation(), true); // TODO: non-blocking
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if (m_inQueue.IsEmpty())
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return;
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break;
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case AFTER_END:
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m_inQueue.TransferTo(*AttachedTransformation());
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return;
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}
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}
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}
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void Inflator::DecodeHeader()
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{
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if (!m_reader.FillBuffer(3))
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throw UnexpectedEndErr();
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m_eof = m_reader.GetBits(1) != 0;
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m_blockType = (byte)m_reader.GetBits(2);
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switch (m_blockType)
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{
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case 0: // stored
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{
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m_reader.SkipBits(m_reader.BitsBuffered() % 8);
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if (!m_reader.FillBuffer(32))
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throw UnexpectedEndErr();
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m_storedLen = (word16)m_reader.GetBits(16);
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word16 nlen = (word16)m_reader.GetBits(16);
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if (nlen != (word16)~m_storedLen)
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throw BadBlockErr();
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break;
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}
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case 1: // fixed codes
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m_nextDecode = LITERAL;
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break;
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case 2: // dynamic codes
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{
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if (!m_reader.FillBuffer(5+5+4))
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throw UnexpectedEndErr();
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unsigned int hlit = m_reader.GetBits(5);
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unsigned int hdist = m_reader.GetBits(5);
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unsigned int hclen = m_reader.GetBits(4);
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unsigned int i = 0;
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FixedSizeSecBlock<unsigned int, 286+32> codeLengths;
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static const unsigned int border[] = { // Order of the bit length code lengths
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16, 17, 18, 0, 8, 7, 9, 6, 10, 5, 11, 4, 12, 3, 13, 2, 14, 1, 15};
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std::fill(codeLengths.begin(), codeLengths+19, 0);
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for (i=0; i<hclen+4; ++i)
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{
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CRYPTOPP_ASSERT(border[i] < codeLengths.size());
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codeLengths[border[i]] = m_reader.GetBits(3);
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}
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try
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{
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bool result = false;
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unsigned int k=0, count=0, repeater=0;
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HuffmanDecoder codeLengthDecoder(codeLengths, 19);
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for (i=0; i < hlit+257+hdist+1; )
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{
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k = 0, count = 0, repeater = 0;
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result = codeLengthDecoder.Decode(m_reader, k);
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||
|
if (!result)
|
||
|
throw UnexpectedEndErr();
|
||
|
if (k <= 15)
|
||
|
{
|
||
|
count = 1;
|
||
|
repeater = k;
|
||
|
}
|
||
|
else switch (k)
|
||
|
{
|
||
|
case 16:
|
||
|
if (!m_reader.FillBuffer(2))
|
||
|
throw UnexpectedEndErr();
|
||
|
count = 3 + m_reader.GetBits(2);
|
||
|
if (i == 0)
|
||
|
throw BadBlockErr();
|
||
|
repeater = codeLengths[i-1];
|
||
|
break;
|
||
|
case 17:
|
||
|
if (!m_reader.FillBuffer(3))
|
||
|
throw UnexpectedEndErr();
|
||
|
count = 3 + m_reader.GetBits(3);
|
||
|
repeater = 0;
|
||
|
break;
|
||
|
case 18:
|
||
|
if (!m_reader.FillBuffer(7))
|
||
|
throw UnexpectedEndErr();
|
||
|
count = 11 + m_reader.GetBits(7);
|
||
|
repeater = 0;
|
||
|
break;
|
||
|
}
|
||
|
if (i + count > hlit+257+hdist+1)
|
||
|
throw BadBlockErr();
|
||
|
std::fill(codeLengths + i, codeLengths + i + count, repeater);
|
||
|
i += count;
|
||
|
}
|
||
|
m_dynamicLiteralDecoder.Initialize(codeLengths, hlit+257);
|
||
|
if (hdist == 0 && codeLengths[hlit+257] == 0)
|
||
|
{
|
||
|
if (hlit != 0) // a single zero distance code length means all literals
|
||
|
throw BadBlockErr();
|
||
|
}
|
||
|
else
|
||
|
m_dynamicDistanceDecoder.Initialize(codeLengths+hlit+257, hdist+1);
|
||
|
m_nextDecode = LITERAL;
|
||
|
}
|
||
|
catch (HuffmanDecoder::Err &)
|
||
|
{
|
||
|
throw BadBlockErr();
|
||
|
}
|
||
|
break;
|
||
|
}
|
||
|
default:
|
||
|
throw BadBlockErr(); // reserved block type
|
||
|
}
|
||
|
m_state = DECODING_BODY;
|
||
|
}
|
||
|
|
||
|
bool Inflator::DecodeBody()
|
||
|
{
|
||
|
bool blockEnd = false;
|
||
|
switch (m_blockType)
|
||
|
{
|
||
|
case 0: // stored
|
||
|
CRYPTOPP_ASSERT(m_reader.BitsBuffered() == 0);
|
||
|
while (!m_inQueue.IsEmpty() && !blockEnd)
|
||
|
{
|
||
|
size_t size;
|
||
|
const byte *block = m_inQueue.Spy(size);
|
||
|
size = UnsignedMin(m_storedLen, size);
|
||
|
CRYPTOPP_ASSERT(size <= 0xffff);
|
||
|
|
||
|
OutputString(block, size);
|
||
|
m_inQueue.Skip(size);
|
||
|
m_storedLen = m_storedLen - (word16)size;
|
||
|
if (m_storedLen == 0)
|
||
|
blockEnd = true;
|
||
|
}
|
||
|
break;
|
||
|
case 1: // fixed codes
|
||
|
case 2: // dynamic codes
|
||
|
static const unsigned int lengthStarts[] = {
|
||
|
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 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 distanceStarts[] = {
|
||
|
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};
|
||
|
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 HuffmanDecoder& literalDecoder = GetLiteralDecoder();
|
||
|
const HuffmanDecoder& distanceDecoder = GetDistanceDecoder();
|
||
|
|
||
|
switch (m_nextDecode)
|
||
|
{
|
||
|
case LITERAL:
|
||
|
while (true)
|
||
|
{
|
||
|
if (!literalDecoder.Decode(m_reader, m_literal))
|
||
|
{
|
||
|
m_nextDecode = LITERAL;
|
||
|
break;
|
||
|
}
|
||
|
if (m_literal < 256)
|
||
|
OutputByte((byte)m_literal);
|
||
|
else if (m_literal == 256) // end of block
|
||
|
{
|
||
|
blockEnd = true;
|
||
|
break;
|
||
|
}
|
||
|
else
|
||
|
{
|
||
|
if (m_literal > 285)
|
||
|
throw BadBlockErr();
|
||
|
unsigned int bits;
|
||
|
case LENGTH_BITS:
|
||
|
CRYPTOPP_ASSERT(m_literal-257 < COUNTOF(lengthExtraBits));
|
||
|
bits = lengthExtraBits[m_literal-257];
|
||
|
if (!m_reader.FillBuffer(bits))
|
||
|
{
|
||
|
m_nextDecode = LENGTH_BITS;
|
||
|
break;
|
||
|
}
|
||
|
CRYPTOPP_ASSERT(m_literal-257 < COUNTOF(lengthStarts));
|
||
|
m_literal = m_reader.GetBits(bits) + lengthStarts[m_literal-257];
|
||
|
case DISTANCE:
|
||
|
if (!distanceDecoder.Decode(m_reader, m_distance))
|
||
|
{
|
||
|
m_nextDecode = DISTANCE;
|
||
|
break;
|
||
|
}
|
||
|
case DISTANCE_BITS:
|
||
|
CRYPTOPP_ASSERT(m_distance < COUNTOF(distanceExtraBits));
|
||
|
if (m_distance >= COUNTOF(distanceExtraBits))
|
||
|
throw BadDistanceErr();
|
||
|
bits = distanceExtraBits[m_distance];
|
||
|
if (!m_reader.FillBuffer(bits))
|
||
|
{
|
||
|
m_nextDecode = DISTANCE_BITS;
|
||
|
break;
|
||
|
}
|
||
|
CRYPTOPP_ASSERT(m_distance < COUNTOF(distanceStarts));
|
||
|
if (m_distance >= COUNTOF(distanceStarts))
|
||
|
throw BadDistanceErr();
|
||
|
m_distance = m_reader.GetBits(bits) + distanceStarts[m_distance];
|
||
|
OutputPast(m_literal, m_distance);
|
||
|
}
|
||
|
}
|
||
|
break;
|
||
|
default:
|
||
|
CRYPTOPP_ASSERT(0);
|
||
|
}
|
||
|
}
|
||
|
if (blockEnd)
|
||
|
{
|
||
|
if (m_eof)
|
||
|
{
|
||
|
FlushOutput();
|
||
|
m_reader.SkipBits(m_reader.BitsBuffered()%8);
|
||
|
if (m_reader.BitsBuffered())
|
||
|
{
|
||
|
// undo too much lookahead
|
||
|
SecBlockWithHint<byte, 4> buffer(m_reader.BitsBuffered() / 8);
|
||
|
for (unsigned int i=0; i<buffer.size(); i++)
|
||
|
buffer[i] = (byte)m_reader.GetBits(8);
|
||
|
m_inQueue.Unget(buffer, buffer.size());
|
||
|
}
|
||
|
m_state = POST_STREAM;
|
||
|
}
|
||
|
else
|
||
|
m_state = WAIT_HEADER;
|
||
|
}
|
||
|
return blockEnd;
|
||
|
}
|
||
|
|
||
|
void Inflator::FlushOutput()
|
||
|
{
|
||
|
if (m_state != PRE_STREAM)
|
||
|
{
|
||
|
CRYPTOPP_ASSERT(m_current >= m_lastFlush);
|
||
|
ProcessDecompressedData(m_window + m_lastFlush, m_current - m_lastFlush);
|
||
|
m_lastFlush = m_current;
|
||
|
}
|
||
|
}
|
||
|
|
||
|
void Inflator::CreateFixedLiteralDecoder()
|
||
|
{
|
||
|
unsigned int codeLengths[288];
|
||
|
std::fill(codeLengths + 0, codeLengths + 144, 8);
|
||
|
std::fill(codeLengths + 144, codeLengths + 256, 9);
|
||
|
std::fill(codeLengths + 256, codeLengths + 280, 7);
|
||
|
std::fill(codeLengths + 280, codeLengths + 288, 8);
|
||
|
m_fixedLiteralDecoder.reset(new HuffmanDecoder);
|
||
|
m_fixedLiteralDecoder->Initialize(codeLengths, 288);
|
||
|
}
|
||
|
|
||
|
void Inflator::CreateFixedDistanceDecoder()
|
||
|
{
|
||
|
unsigned int codeLengths[32];
|
||
|
std::fill(codeLengths + 0, codeLengths + 32, 5);
|
||
|
m_fixedDistanceDecoder.reset(new HuffmanDecoder);
|
||
|
m_fixedDistanceDecoder->Initialize(codeLengths, 32);
|
||
|
}
|
||
|
|
||
|
const HuffmanDecoder& Inflator::GetLiteralDecoder()
|
||
|
{
|
||
|
if (m_blockType == 1)
|
||
|
{
|
||
|
if (m_fixedLiteralDecoder.get() == NULLPTR)
|
||
|
CreateFixedLiteralDecoder();
|
||
|
return *m_fixedLiteralDecoder;
|
||
|
}
|
||
|
else
|
||
|
{
|
||
|
return m_dynamicLiteralDecoder;
|
||
|
}
|
||
|
}
|
||
|
|
||
|
const HuffmanDecoder& Inflator::GetDistanceDecoder()
|
||
|
{
|
||
|
if (m_blockType == 1)
|
||
|
{
|
||
|
if (m_fixedDistanceDecoder.get() == NULLPTR)
|
||
|
CreateFixedDistanceDecoder();
|
||
|
return *m_fixedDistanceDecoder;
|
||
|
}
|
||
|
else
|
||
|
{
|
||
|
return m_dynamicDistanceDecoder;
|
||
|
}
|
||
|
}
|
||
|
|
||
|
NAMESPACE_END
|