Further compression and png work.

src/compression/DeflateBlock.cpp

@@ -0,0 +1,262 @@
+#include "DeflateBlock.h"
+
+#include "ByteUtils.h"
+
+#include <algorithm>
+#include <iostream>
+
+DeflateBlock::DeflateBlock(BitStream* inputStream, BitStream* outputStream)
+    : mInputStream(inputStream),
+      mOutputStream(outputStream)
+{
+
+}
+
+bool DeflateBlock::readNextCodeLengthSymbol(unsigned char& final_symbol)
+{
+    unsigned working_index{0};
+    auto count = mCodeLengthMapping[working_index].first;
+    auto delta = count;
+
+    bool found{false};
+    unsigned char buffer{0};
+    unsigned char working_bits{0};
+    unsigned working_symbol{0};
+
+    while(!found)
+    {
+        auto valid = mInputStream->readNextNBits(delta, buffer);
+        working_bits = (working_bits << delta) | buffer;
+
+        for(const auto& entry : mCodeLengthMapping[working_index].second)
+        {
+            if (entry.first == working_bits)
+            {
+                found = true;
+                working_symbol = entry.second;
+                break;
+            }
+        }
+
+        if (!found)
+        {
+            working_index++;
+            if (working_index >= mCodeLengthMapping.size())
+            {
+                break;
+            }
+
+            auto new_count = mCodeLengthMapping[working_index].first;
+            delta = new_count - count;
+            count = new_count;
+        }
+    }
+
+    if (found)
+    {
+        final_symbol = working_symbol;
+        std::cout << "Found symbol " << working_symbol << " with bits " << ByteUtils::toString(working_bits) << std::endl;
+        std::cout << "At Byte offset " << mInputStream->getCurrentByteOffset() << " and bit offset " << mInputStream->getCurrentBitOffset() << std::endl;
+        return true;
+    }
+    else
+    {
+        std::cout << "SYMBOL NOT FOUND " << " with bits " << ByteUtils::toString(working_bits) << std::endl;
+        return false;
+    }
+}
+
+void DeflateBlock::setCodeLengthAlphabetLengths(const std::vector<unsigned char>& lengths)
+{
+    mCodeLengthAlphabetLengths = lengths;
+}
+
+void DeflateBlock::setCodeLengthLength(unsigned length)
+{
+    mHclen = length;
+}
+
+void DeflateBlock::setLiteralsTableLength(unsigned length)
+{
+    mHlit = length;
+}
+
+void DeflateBlock::setDistanceTableLength(unsigned length)
+{
+    mHdist = length;
+}
+
+void DeflateBlock::setIsFinalBlock(bool isFinal)
+{
+
+}
+
+void DeflateBlock::flushToStream()
+{
+
+}
+
+void DeflateBlock::readLiteralCodeLengths()
+{
+    std::vector<unsigned> lengths;
+    unsigned char symbol{0};
+
+    while(lengths.size() < mHlit)
+    {
+        bool valid = readNextCodeLengthSymbol(symbol);
+
+        if (!valid)
+        {
+            std::cout << "Hit unknown symbol - bailing out" << std::endl;
+            break;
+        }
+
+        if (symbol < 16)
+        {
+            lengths.push_back(symbol);
+        }
+        else if(symbol == 16)
+        {
+            unsigned char num_reps{0};
+            mInputStream->readNextNBits(2, num_reps);
+
+            auto last_val = lengths[lengths.size()-1];
+            std::cout << "Got val 16 doing " << 3 + num_reps << std::endl;
+            for(unsigned idx=0; idx< 3 + num_reps; idx++)
+            {
+                lengths.push_back(last_val);
+            }
+        }
+        else if(symbol == 17)
+        {
+            unsigned char num_reps{0};
+            mInputStream->readNextNBits(3, num_reps);
+
+            std::cout << "Got val 17 doing " << 3 + num_reps << std::endl;
+            for(unsigned idx=0; idx< 3 + num_reps; idx++)
+            {
+                lengths.push_back(0);
+            }
+        }
+        else if(symbol == 18)
+        {
+            unsigned char num_reps{0};
+            mInputStream->readNextNBits(7, num_reps);
+
+            std::cout << "Got val 18 doing " << 11 + num_reps << std::endl;
+            for(unsigned idx=0; idx< 11 + num_reps; idx++)
+            {
+                lengths.push_back(0);
+            }
+        }
+    }
+}
+
+void DeflateBlock::buildCodeLengthMapping()
+{
+    for(unsigned idx=1; idx<8; idx++)
+    {
+        std::vector<unsigned> entries;
+        for(unsigned jdx=0; jdx<mCodeLengthAlphabetLengths.size(); jdx++)
+        {
+            if (mCodeLengthAlphabetLengths[jdx] == idx)
+            {
+                entries.push_back(jdx);
+            }
+        }
+
+        if (entries.empty())
+        {
+            continue;
+        }
+
+        CodeLengthCountEntry count_entry{idx, {}};
+        std::sort(entries.begin(), entries.end());
+
+        unsigned char offset = 0x01 << idx - 1;
+        unsigned char count{0};
+        for (auto entry : entries)
+        {
+            count_entry.second.push_back(CodeLengthEntry{offset + count, entry});
+            count++;
+        }
+        mCodeLengthMapping.push_back(count_entry);
+    }
+
+    for (const auto& map_data : mCodeLengthMapping)
+    {
+        std::cout << "Map entry " << map_data.first << " has vals: "  << std::endl;
+        for (const auto& entry : map_data.second)
+        {
+            std::cout << "Key " << ByteUtils::toString(entry.first) << " val: " << entry.second << std::endl;
+        }
+    }
+}
+
+void DeflateBlock::readDynamicHuffmanTable()
+{
+    unsigned char h_lit{0};
+    mInputStream->readNextNBits(5, h_lit);
+    mHlit = h_lit + 257;
+    std::cout << "Got HLIT " << mHlit << std::endl;
+
+    unsigned char h_dist{0};
+    mInputStream->readNextNBits(5, h_dist);
+    mHdist = h_dist + 1;
+    std::cout << "Got HDIST " << mHdist << std::endl;
+
+    unsigned char h_clen{0};
+    mInputStream->readNextNBits(4, h_clen);
+    mHclen = h_clen + 4;
+    std::cout << "Got HCLEN " << mHclen << std::endl;
+
+    mCodeLengthAlphabetLengths = std::vector<unsigned char>(19, 0);
+    unsigned char buffer{0};
+    for(unsigned idx = 0; idx< mHclen; idx++)
+    {
+        mInputStream->readNextNBits(3, buffer);
+        mCodeLengthAlphabetLengths[CODE_LENGTH_ALPHABET_PERMUTATION[idx]] = buffer;
+        std::cout << "Got code length for " << CODE_LENGTH_ALPHABET_PERMUTATION[idx] << " of " << static_cast<unsigned>(buffer) << std::endl;
+    }
+
+    buildCodeLengthMapping();
+
+    readLiteralCodeLengths();
+}
+
+void DeflateBlock::readHeader()
+{
+    auto working_byte = mInputStream->getCurrentByte();
+    std::cout << "Into process data "<< std::endl;
+    std::cout << mInputStream->logNextNBytes(9);
+
+    unsigned char final_block{0};
+    mInputStream->readNextNBits(1, final_block);
+    mInFinalBlock = bool(final_block);
+
+    if (mInFinalBlock)
+    {
+        std::cout << "Got final block" << std::endl;
+    }
+
+    mInputStream->readNextNBits(2, mCompressionType);
+    std::cout << "Compress type byte is: " << static_cast<unsigned>(mCompressionType) << std::endl;
+    if (mCompressionType == NO_COMPRESSION)
+    {
+        std::cout << "Got NO_COMPRESSION" << std::endl;
+    }
+    else if (mCompressionType == FIXED_HUFFMAN)
+    {
+        std::cout << "Got FIXED_HUFFMAN" << std::endl;
+    }
+    else if (mCompressionType == DYNAMIC_HUFFMAN)
+    {
+        std::cout << "Got DYNAMIC_HUFFMAN" << std::endl;
+        readDynamicHuffmanTable();
+    }
+    else if (mCompressionType == ERROR)
+    {
+        std::cout << "Got ERROR" << std::endl;
+    }
+
+}