Continue png writing.

src/compression/AbstractEncoder.h

@@ -1,5 +1,9 @@
 #pragma once
 
+#include "AbstractChecksumCalculator.h"
+
+#include <vector>
+
 class BitStream;
 
 class AbstractEncoder
@@ -14,10 +18,17 @@ public:
 
     virtual ~AbstractEncoder() = default;
 
+    void addChecksumCalculator(AbstractChecksumCalculator* calculator)
+    {
+        mChecksumCalculators.push_back(calculator);
+    }
+
     virtual bool encode() = 0;
     virtual bool decode() = 0;
 
 protected:
+
+    std::vector<AbstractChecksumCalculator*> mChecksumCalculators;
     BitStream* mInputStream{nullptr};
     BitStream* mOutputStream{nullptr};
 };

src/compression/Adler32Checksum.h

@@ -0,0 +1,29 @@
+#pragma once
+
+#include "AbstractChecksumCalculator.h"
+
+class Adler32Checksum : public AbstractChecksumCalculator
+{
+public:
+    void addValue(unsigned char val) override
+    {
+        mSum1 = (mSum1 + val) % MOD_ADLER32;
+        mSum2 = (mSum2 + mSum1) % MOD_ADLER32;
+    }
+
+    uint32_t getChecksum() const override
+    {
+        return (mSum2 << 16) | mSum1;
+    }
+
+    void reset() override
+    {
+        mSum1 = 1;
+        mSum2 = 0;
+    }
+
+private:
+    static constexpr unsigned MOD_ADLER32{65536};
+    uint32_t mSum1{1};
+    uint32_t mSum2{0};
+};

src/compression/CMakeLists.txt

@@ -3,10 +3,9 @@ list(APPEND compression_LIB_INCLUDES
     StreamCompressor.cpp
     HuffmanEncoder.cpp
     RunLengthEncoder.cpp
-    ZlibData.cpp
     ZlibEncoder.cpp
-    DeflateEncoder.cpp
+    deflate/DeflateEncoder.cpp
-    DeflateBlock.cpp
+    deflate/DeflateBlock.cpp
     Lz77Encoder.cpp
     CyclicRedundancyChecker.cpp
     )
@@ -14,7 +13,8 @@ list(APPEND compression_LIB_INCLUDES
 add_library(compression SHARED ${compression_LIB_INCLUDES})
 
 target_include_directories(compression PUBLIC
-                          "${CMAKE_CURRENT_SOURCE_DIR}"
+                          ${CMAKE_CURRENT_SOURCE_DIR}
+                          ${CMAKE_CURRENT_SOURCE_DIR}/deflate
                           )
                           
 target_link_libraries(compression PUBLIC core)

src/compression/DeflateEncoder.cpp

@@ -1,38 +0,0 @@
-#include "DeflateEncoder.h"
-
-#include "BitStream.h"
-#include "DeflateBlock.h"
-
-#include <iostream>
-
-DeflateEncoder::DeflateEncoder(BitStream* inputStream, BitStream* outputStream)
-    : AbstractEncoder(inputStream, outputStream)
-{
-
-}
-
-DeflateEncoder::~DeflateEncoder()
-{
-
-}
-
-bool DeflateEncoder::encode()
-{
-    return false;
-}
-
-bool DeflateEncoder::decode()
-{
-    auto working_block = std::make_unique<DeflateBlock>(mInputStream, mOutputStream);
-    working_block->readHeader();
-
-    DeflateBlock* raw_block = working_block.get();
-
-    while(!raw_block->isFinalBlock())
-    {
-        break;
-    }
-
-    return false;
-}
-

src/compression/ZlibData.h

@@ -1,107 +0,0 @@
-#pragma once
-
-#include "ByteUtils.h"
-#include "BitStream.h"
-
-#include <vector>
-#include <iostream>
-
-class ZlibData
-{
-public:
-    void setByte(unsigned idx, unsigned char data)
-    {
-        mBitStream.setByte(idx, data);
-    }
-
-    void setDataSize(std::size_t size)
-    {
-        mBitStream.setBufferSize(size);
-    }
-
-    void setCompressionMethod(unsigned char method)
-    {
-        std::cout << "Got compression input " << static_cast<int>(method) << std::endl;
-        mCmf = method;
-        mCompressionMethod = ByteUtils::getLowerNBits(method, 4);
-        mCompressionInfo = ByteUtils::getHigherNBits(method, 4);
-
-        std::cout << "Got compression method " << static_cast<int>(mCompressionMethod) << " and info " << static_cast<int>(mCompressionInfo) << std::endl;
-    }
-
-    void setExtraFlags(unsigned char extraFlags)
-    {
-        std::cout << "Got flags  " << static_cast<int>(extraFlags) << std::endl;
-
-        mFlg = extraFlags;
-        mFlagCheck = ByteUtils::getLowerNBits(extraFlags, 5);
-        mFlagDict = ByteUtils::getBitN(extraFlags, 5);
-        mFlagLevel = ByteUtils::getHigherNBits(extraFlags, 2);
-
-        std::cout << "Got flag check " << static_cast<int>(mFlagCheck) << " and dict " << static_cast<int>(mFlagDict) << " and level " << static_cast<int>(mFlagLevel) << std::endl;
-    }
-
-    void processData()
-    {
-        unsigned char NO_COMPRESSION = 0x00;
-        unsigned char FIXED_HUFFMAN = 0x01;
-        unsigned char DYNAMIC_HUFFMAN = 0x02;
-        unsigned char ERROR = 0x03;
-
-        bool in_final_block = false;
-        while(mBitStream.loadNextByte())
-        {
-            auto working_byte = mBitStream.getCurrentByte();
-            std::cout << "Into process data, byte is: " << static_cast<unsigned>(working_byte) << std::endl;
-
-            unsigned char final_block{0};
-            mBitStream.getNextNBits(1, final_block);
-            if (final_block)
-            {
-                std::cout << "Got final block" << std::endl;
-                in_final_block = true;
-            }
-
-            unsigned char compress_type{0};
-            mBitStream.getNextNBits(2, compress_type);
-            std::cout << "Compress type byte is: " << static_cast<unsigned>(compress_type) << std::endl;
-            if (compress_type == NO_COMPRESSION)
-            {
-                std::cout << "Got NO_COMPRESSION" << std::endl;
-            }
-            else if (compress_type == FIXED_HUFFMAN)
-            {
-                std::cout << "Got FIXED_HUFFMAN" << std::endl;
-            }
-            else if (compress_type == DYNAMIC_HUFFMAN)
-            {
-                std::cout << "Got DYNAMIC_HUFFMAN" << std::endl;
-
-                unsigned char h_list{0};
-                mBitStream.getNextNBits(5, h_list);
-                mHlist = h_list + 257;
-                std::cout << "Got HLIST " << mHlist << std::endl;
-
-            }
-            else if (compress_type == ERROR)
-            {
-                std::cout << "Got ERROR" << std::endl;
-            }
-            break;
-        }
-    }
-
-private:
-    BitStream mBitStream;
-
-    unsigned mHlist{0};
-
-    unsigned char mCmf{0};
-    unsigned char mFlg{0};
-    unsigned char mCompressionMethod{0};
-    unsigned char mCompressionInfo{0};
-    unsigned char mFlagCheck{0};
-    unsigned char mFlagDict{0};
-    unsigned char mFlagLevel{0};
-    unsigned char mCheckValue{0};
-};

src/compression/ZlibEncoder.cpp

@@ -3,13 +3,18 @@
 #include "ByteUtils.h"
 #include "DeflateEncoder.h"
 #include "FileLogger.h"
+#include "BitStream.h"
 
+#include "Adler32Checksum.h"
+
+#include <math.h>
 #include <iostream>
+#include <sstream>
 
 ZlibEncoder::ZlibEncoder(BitStream* inputStream, BitStream* outputStream)
 : AbstractEncoder(inputStream, outputStream)
 {
-
+    mChecksumCalculator = std::make_unique<Adler32Checksum>();
 }
 
 ZlibEncoder::~ZlibEncoder()
@@ -17,58 +22,132 @@ ZlibEncoder::~ZlibEncoder()
 
 }
 
-void ZlibEncoder::setCompressionMethod(unsigned char method)
+void ZlibEncoder::setWindowSize(unsigned size)
 {
-    std::cout << "Got compression input " << static_cast<int>(method) << std::endl;
+    mWindowSize = size;
-    mCmf = method;
-    mCompressionMethod = ByteUtils::getLowerNBits(method, 4);
-    mCompressionInfo = ByteUtils::getHigherNBits(method, 4);
-
-    std::cout << "Got compression method " << static_cast<int>(mCompressionMethod) << " and info " << static_cast<int>(mCompressionInfo) << std::endl;
 }
 
-void ZlibEncoder::setExtraFlags(unsigned char extraFlags)
+std::string ZlibEncoder::toString(CompressionLevel level) const
+{
+    switch(level)
+    {
+    case CompressionLevel::FASTEST:
+        return "FASTEST";
+    case CompressionLevel::FAST:
+        return "FAST";
+    case CompressionLevel::DEFAULT:
+        return "DEFAULT";
+    case CompressionLevel::MAX_COMPRESSION:
+        return "MAX_COMPRESSION";
+    default:
+        return "UNKNOWN";
+    }
+}
+
+std::string ZlibEncoder::toString(CompressionMethod method) const
+{
+    return method == CompressionMethod::DEFLATE ? "DEFLATE" : "UNKNOWN";
+}
+
+void ZlibEncoder::parseCompressionMethod(unsigned char method)
+{
+    std::cout << "Got compression input " << static_cast<int>(method) << std::endl;
+    mCompressionMethod = static_cast<CompressionMethod>(ByteUtils::getLowerNBits(method, 4));
+    auto compression_info = ByteUtils::getHigherNBits(method, 4);
+
+    if (mCompressionMethod == CompressionMethod::DEFLATE)
+    {
+        mWindowSize = pow(2, compression_info + 8);
+    }
+}
+
+void ZlibEncoder::parseExtraFlags(unsigned char extraFlags)
 {
     std::cout << "Got flags  " << static_cast<int>(extraFlags) << std::endl;
 
-    mFlg = extraFlags;
     mFlagCheck = ByteUtils::getLowerNBits(extraFlags, 5);
-    mFlagDict = ByteUtils::getBitN(extraFlags, 5);
+    mUseDictionary = bool(ByteUtils::getBitN(extraFlags, 5));
-    mFlagLevel = ByteUtils::getHigherNBits(extraFlags, 2);
+    mFlagLevel = static_cast<CompressionLevel>(ByteUtils::getHigherNBits(extraFlags, 2));
+}
+
+std::string ZlibEncoder::getData() const
+{
+    std::stringstream sstream;
+    sstream << "ZlibEncoder data \n";
+    sstream << "Compression method: " << toString(mCompressionMethod) << '\n';
+    sstream << "Window size: " << mWindowSize << '\n';
+    sstream << "Flag check: " << mFlagCheck << '\n';
+    sstream << "Use dictionary: " << mUseDictionary << '\n';
+    sstream << "Flag level: " << toString(mFlagLevel) << '\n';
+    return sstream.str();
 
-    std::cout << "Got flag check " << static_cast<int>(mFlagCheck) << " and dict " << static_cast<int>(mFlagDict) << " and level " << static_cast<int>(mFlagLevel) << std::endl;
 }
 
 bool ZlibEncoder::encode()
 {
+    DeflateEncoder* deflate_encoder{nullptr};
     if (!mWorkingEncoder)
     {
-        if (mCompressionMethod == 8)
+        if (mCompressionMethod == CompressionMethod::DEFLATE)
         {
-            mWorkingEncoder = std::make_unique<DeflateEncoder>(mInputStream, mOutputStream);
+            auto uq_deflate_encoder = std::make_unique<DeflateEncoder>(mInputStream, mOutputStream);
+            deflate_encoder = uq_deflate_encoder.get();
+            mWorkingEncoder = std::move(uq_deflate_encoder);
+            mWorkingEncoder->addChecksumCalculator(mChecksumCalculator.get());
         }
         else
         {
-            MLOG_ERROR("Zib requested decoder not recognized: " << mCompressionMethod << " aborting encode");
+            MLOG_ERROR("Zib requested decoder not recognized: " << static_cast<int>(mCompressionMethod) << " aborting encode");
             return false;
         }
     }
-    return mWorkingEncoder->encode();
+    deflate_encoder->setCompressionMethod(mDeflateCompressionMethod);
+
+    auto compression_info = static_cast<unsigned char>(log2(mWindowSize) - 8);
+    const unsigned char compression_byte = (compression_info << 4) | static_cast<unsigned char>(mCompressionMethod);
+
+    std::cout << "ZlibEncoder Writing compression byte " << static_cast<int>(compression_byte) << " with info " << static_cast<int>(compression_info) << std::endl;
+    mOutputStream->writeByte(compression_byte);
+
+    unsigned char flag_byte{0};
+    flag_byte |= (static_cast<unsigned char>(mUseDictionary) << 5);
+    flag_byte |= (static_cast<unsigned char>(mFlagLevel) << 6);
+
+    const auto mod = (unsigned(compression_byte)*256 + flag_byte) % 31;
+    flag_byte += (31 - mod);
+
+    std::cout << "ZlibEncoder Writing Flag byte " << static_cast<int>(flag_byte) << std::endl;
+    mOutputStream->writeByte(flag_byte);
+
+    if(!mWorkingEncoder->encode())
+    {
+        MLOG_ERROR("Sub-Encoder failed - aborting zlib encode");
+        //return false;
+    }
+
+    const auto checksum = mChecksumCalculator->getChecksum();
+    std::cout << "ZlibEncoder Writing Checksum " << checksum << std::endl;
+    mOutputStream->write(checksum);
+    return true;
 }
 
 bool ZlibEncoder::decode()
 {
+    parseCompressionMethod(*mInputStream->readNextByte());
+    parseExtraFlags(*mInputStream->readNextByte());
+
     if (!mWorkingEncoder)
     {
-        if (mCompressionMethod == 8)
+        if (mCompressionMethod == CompressionMethod::DEFLATE)
         {
             mWorkingEncoder = std::make_unique<DeflateEncoder>(mInputStream, mOutputStream);
         }
         else
         {
-            MLOG_ERROR("Zib requested decoder not recognized: " << mCompressionMethod << " aborting decode");
+            MLOG_ERROR("Zib requested decoder not recognized: " << static_cast<int>(mCompressionMethod) << " aborting decode");
             return false;
         }
     }
+
     return mWorkingEncoder->decode();
 }

src/compression/ZlibEncoder.h

@@ -2,33 +2,54 @@
 
 #include "AbstractEncoder.h"
 
+#include "DeflateElements.h"
+
 #include <memory>
 #include <vector>
 
+class AbstractChecksumCalculator;
+
 class ZlibEncoder : public AbstractEncoder
 {
-
 public:
+
+    enum class CompressionMethod : unsigned char
+    {
+        DEFLATE = 8,
+    };
+
+    enum class CompressionLevel : unsigned char
+    {
+        FASTEST,
+        FAST,
+        DEFAULT,
+        MAX_COMPRESSION
+    };
+
     ZlibEncoder(BitStream* inputStream, BitStream* outputStream);
     ~ZlibEncoder();
 
-    void setCompressionMethod(unsigned char method);
+    void setWindowSize(unsigned size);
-
-    void setExtraFlags(unsigned char extraFlags);
 
     bool encode() override;
-
     bool decode() override;
 
-private:
+    std::string getData() const;
-    unsigned char mCmf{0};
+    std::string toString(CompressionLevel level) const;
-    unsigned char mFlg{0};
+    std::string toString(CompressionMethod method) const;
-    unsigned char mCompressionMethod{8};
-    unsigned char mCompressionInfo{0};
-    unsigned char mFlagCheck{0};
-    unsigned char mFlagDict{0};
-    unsigned char mFlagLevel{0};
-    unsigned char mCheckValue{0};
 
+private:
+    void parseCompressionMethod(unsigned char method);
+    void parseExtraFlags(unsigned char extraFlags);
+
+    CompressionMethod mCompressionMethod{CompressionMethod::DEFLATE};
+    Deflate::CompressionMethod mDeflateCompressionMethod{Deflate::CompressionMethod::NONE};
+    unsigned mWindowSize{32768}; // Window size, n in 2^(n+8) bytes
+
+    unsigned char mFlagCheck{0};
+    bool mUseDictionary{false};
+    CompressionLevel mFlagLevel{CompressionLevel::DEFAULT};
+
+    std::unique_ptr<AbstractChecksumCalculator> mChecksumCalculator;
     std::unique_ptr<AbstractEncoder> mWorkingEncoder;
 };

src/compression/deflate/DeflateBlock.cpp

@@ -1,9 +1,11 @@
 #include "DeflateBlock.h"
 
 #include "ByteUtils.h"
+#include "AbstractChecksumCalculator.h"
 
 #include <algorithm>
 #include <iostream>
+#include <sstream>
 
 DeflateBlock::DeflateBlock(BitStream* inputStream, BitStream* outputStream)
     : mInputStream(inputStream),
@@ -88,7 +90,7 @@ void DeflateBlock::setDistanceTableLength(unsigned length)
 
 void DeflateBlock::setIsFinalBlock(bool isFinal)
 {
-
+    mInFinalBlock = isFinal;
 }
 
 void DeflateBlock::flushToStream()
@@ -224,6 +226,22 @@ void DeflateBlock::readDynamicHuffmanTable()
     readLiteralCodeLengths();
 }
 
+std::string DeflateBlock::getMetaData() const
+{
+    std::stringstream sstr;
+    sstr << "DeflateBlock Metadata \n";
+
+    sstr << "Final block: " << mInFinalBlock << '\n';
+    sstr << "Compression method: " << Deflate::toString(mCompressionMethod) << '\n';
+
+    return sstr.str();
+}
+
+bool DeflateBlock::isFinalBlock() const
+{
+    return mInFinalBlock;
+}
+
 void DeflateBlock::readHeader()
 {
     auto working_byte = mInputStream->getCurrentByte();
@@ -234,29 +252,33 @@ void DeflateBlock::readHeader()
     mInputStream->readNextNBits(1, final_block);
     mInFinalBlock = bool(final_block);
 
-    if (mInFinalBlock)
+    unsigned char compression_type{0};
-    {
+    mInputStream->readNextNBits(2, compression_type);
-        std::cout << "Got final block" << std::endl;
+    mCompressionMethod = static_cast<Deflate::CompressionMethod>(compression_type);
 }
 
-    mInputStream->readNextNBits(2, mCompressionType);
+void DeflateBlock::write(uint16_t datalength)
-    std::cout << "Compress type byte is: " << static_cast<unsigned>(mCompressionType) << std::endl;
-    if (mCompressionType == NO_COMPRESSION)
 {
-        std::cout << "Got NO_COMPRESSION" << std::endl;
+    unsigned char working_block{0};
-    }
+    working_block |= static_cast<unsigned char>(mInFinalBlock);
-    else if (mCompressionType == FIXED_HUFFMAN)
+    working_block |= static_cast<unsigned char>(mCompressionMethod) << 1;
-    {
-        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;
-    }
 
+    if (mCompressionMethod == Deflate::CompressionMethod::NONE)
+    {
+        std::cout << "Writing compression block header " << static_cast<int>(working_block) << std::endl;
+        mOutputStream->writeByte(working_block);
+
+        std::cout << "Writing data length " << datalength << " " << ByteUtils::toString(datalength) << std::endl;
+        mOutputStream->writeWord(datalength);
+
+        std::cout << "Writing iverse data length " << ~datalength << " " << ByteUtils::toString(~datalength) << std::endl;
+        mOutputStream->writeWord(static_cast<uint16_t>(~datalength));
+
+        for(unsigned idx=0; idx<datalength;idx++)
+        {
+            auto byte = *mInputStream->readNextByte();
+            std::cout << "Writing next byte " << static_cast<int>(byte) << std::endl;
+            mOutputStream->writeByte(byte);
+        }
+    }
 }

src/compression/deflate/DeflateBlock.h

@@ -1,27 +1,32 @@
 #pragma once
 
+#include "DeflateElements.h"
+
 #include "BitStream.h"
 
+class AbstractChecksumCalculator;
+
 class DeflateBlock
 {
 public:
     DeflateBlock(BitStream* inputStream, BitStream* outputStream);
 
+    void buildCodeLengthMapping();
+
+    std::string getMetaData() const;
+
+    void flushToStream();
+
+    bool isFinalBlock() const;
+
     void readHeader();
 
     void readDynamicHuffmanTable();
 
-    void buildCodeLengthMapping();
-
     void readLiteralCodeLengths();
 
     bool readNextCodeLengthSymbol(unsigned char& buffer);
 
-    bool isFinalBlock() const
-    {
-        return mInFinalBlock;
-    }
-
     void setCodeLengthAlphabetLengths(const std::vector<unsigned char>& lengths);
 
     void setCodeLengthLength(unsigned length);
@@ -32,7 +37,7 @@ public:
 
     void setIsFinalBlock(bool isFinal);
 
-    void flushToStream();
+    void write(uint16_t datalength);
 
 private:
     BitStream* mInputStream;
@@ -49,12 +54,6 @@ private:
     std::vector<unsigned char> mCodeLengthAlphabetLengths;
     static constexpr unsigned CODE_LENGTH_ALPHABET_PERMUTATION[19]{16, 17, 18, 0, 8, 7, 9, 6, 10, 5, 11, 4, 12, 3, 13, 2, 14, 1, 15};
 
-    unsigned char mCompressionType{0};
-
     bool mInFinalBlock{false};
-
+    Deflate::CompressionMethod mCompressionMethod{Deflate::CompressionMethod::NONE};
-    static constexpr unsigned char NO_COMPRESSION = 0x00;
-    static constexpr unsigned char FIXED_HUFFMAN = 0x01;
-    static constexpr unsigned char DYNAMIC_HUFFMAN = 0x02;
-    static constexpr unsigned char ERROR = 0x03;
 };

src/compression/deflate/DeflateElements.h

@@ -0,0 +1,33 @@
+#pragma once
+
+#include <string>
+
+namespace Deflate
+{
+    enum class CompressionMethod
+    {
+        NONE,
+        FIXED_HUFFMAN,
+        DYNAMIC_HUFFMAN,
+        ERROR
+    };
+
+    inline std::string toString(CompressionMethod method)
+    {
+        switch (method)
+        {
+        case CompressionMethod::NONE:
+                return "NONE";
+        case CompressionMethod::FIXED_HUFFMAN:
+                return "FIXED_HUFFMAN";
+        case CompressionMethod::DYNAMIC_HUFFMAN:
+                return "DYNAMIC_HUFFMAN";
+        case CompressionMethod::ERROR:
+                return "ERROR";
+        default:
+            return "UNKNOWN";
+        }
+    }
+
+
+}

src/compression/deflate/DeflateEncoder.cpp

@@ -0,0 +1,78 @@
+#include "DeflateEncoder.h"
+
+#include "BitStream.h"
+#include "DeflateBlock.h"
+#include "BufferBitStream.h"
+
+#include <iostream>
+
+DeflateEncoder::DeflateEncoder(BitStream* inputStream, BitStream* outputStream)
+    : AbstractEncoder(inputStream, outputStream)
+{
+
+}
+
+DeflateEncoder::~DeflateEncoder()
+{
+
+}
+
+bool DeflateEncoder::encode()
+{
+    uint16_t count = 0;
+    BufferBitStream stream;
+    std::unique_ptr<DeflateBlock> working_block = std::make_unique<DeflateBlock>(&stream, mOutputStream);
+
+    AbstractChecksumCalculator* checksum_calc;
+    if (mChecksumCalculators.size() > 0)
+    {
+       std::cout << "Setting checksum calculator " << std::endl;
+       mOutputStream->setChecksumCalculator(mChecksumCalculators[0]);
+    }
+
+    while(true)
+    {
+        if (count == mMaxBlockSize)
+        {
+            std::cout << working_block->getMetaData();
+            working_block->write(count);
+
+            working_block = std::make_unique<DeflateBlock>(&stream, mOutputStream);
+            stream.reset();
+        }
+
+        if (auto byte = mInputStream->readNextByte())
+        {
+            stream.writeByte(*byte);
+        }
+        else
+        {
+            stream.resetOffsets();
+            working_block->setIsFinalBlock(true);
+
+            std::cout << working_block->getMetaData();
+            working_block->write(count);
+            break;
+        }
+        count++;
+    }
+
+    mOutputStream->clearChecksumCalculator();
+    return true;
+}
+
+bool DeflateEncoder::decode()
+{
+    auto working_block = std::make_unique<DeflateBlock>(mInputStream, mOutputStream);
+    working_block->readHeader();
+
+    DeflateBlock* raw_block = working_block.get();
+
+    while(!raw_block->isFinalBlock())
+    {
+        break;
+    }
+
+    return false;
+}
+

src/compression/deflate/DeflateEncoder.h

@@ -1,6 +1,7 @@
 #pragma once
 
 #include "AbstractEncoder.h"
+#include "DeflateElements.h"
 
 #include <vector>
 #include <memory>
@@ -18,8 +19,15 @@ public:
 
     bool decode() override;
 
+    void setCompressionMethod(Deflate::CompressionMethod method)
+    {
+        mCompressionMethod = method;
+    }
+
 private:
-    std::vector<std::unique_ptr<DeflateBlock > > mBlocks;
+    uint16_t mMaxBlockSize{65535};
+    Deflate::CompressionMethod mCompressionMethod{Deflate::CompressionMethod::NONE};
+    std::unique_ptr<DeflateBlock > mLastBlock;
 };
 
 

src/core/streams/AbstractChecksumCalculator.h

@@ -0,0 +1,16 @@
+#pragma once
+
+#include "stdint.h"
+
+class AbstractChecksumCalculator
+{
+public:
+    virtual ~AbstractChecksumCalculator() = default;
+
+    virtual void addValue(unsigned char val) = 0;
+    virtual uint32_t getChecksum() const = 0;
+
+    virtual void reset()
+    {
+    }
+};

src/core/streams/BitStream.cpp

@@ -28,6 +28,15 @@ void BitStream::write(uint32_t data)
     }
 }
 
+void BitStream::writeWord(uint16_t data)
+{
+    unsigned num_bytes = sizeof(uint16_t);
+    for(unsigned idx=0; idx<num_bytes;idx++)
+    {
+        writeByte(ByteUtils::getByteN(data, idx));
+    }
+}
+
 int BitStream::getCurrentByteOffset() const
 {
     return mByteOffset;

src/core/streams/BitStream.h

@@ -1,5 +1,7 @@
 #pragma once
 
+#include "AbstractChecksumCalculator.h"
+
 #include <vector>
 #include <string>
 #include <optional>
@@ -29,11 +31,39 @@ public:
 
     void write(uint32_t data);
 
+    void writeWord(uint16_t data);
+
     virtual void writeBytes(const std::vector<unsigned char> data) = 0;
 
+    void resetOffsets()
+    {
+        mByteOffset = -1;
+        mBitOffset = 0;
+    }
+
+    virtual void reset()
+    {
+        resetOffsets();
+        mCurrentByte = 0;
+    }
+
+    void setChecksumCalculator(AbstractChecksumCalculator* calc)
+    {
+        mChecksumCalculator = calc;
+    }
+
+    void clearChecksumCalculator()
+    {
+        mChecksumCalculator = nullptr;
+    }
+
+    //unsigned getSize() = 0;
+
 protected:
-    int mByteOffset{0};
+    int mByteOffset{-1};
     unsigned mBitOffset{0};
 
     unsigned char mCurrentByte{0};
+
+    AbstractChecksumCalculator* mChecksumCalculator{nullptr};
 };

src/core/streams/BufferBitStream.cpp

@@ -1,8 +1,10 @@
 #include "BufferBitStream.h"
 
+#include <iostream>
+
 bool BufferBitStream::isFinished() const
 {
-    return mByteOffset == mBuffer.size();
+    return mByteOffset == mBuffer.size() - 1;
 }
 
 std::vector<unsigned char> BufferBitStream::peekNextNBytes(unsigned n) const
@@ -43,6 +45,10 @@ void BufferBitStream::setBuffer(const std::vector<unsigned char>& data)
 
 void BufferBitStream::writeByte(unsigned char data)
 {
+    if (mChecksumCalculator)
+    {
+        mChecksumCalculator->addValue(data);
+    }
     mBuffer.push_back(data);
 }
 

src/core/streams/BufferBitStream.h

@@ -27,12 +27,13 @@ public:
         return mBuffer;
     }
 
-    void resetOffsets()
+    void reset() override
     {
-        mByteOffset = 0;
+        BitStream::reset();
-        mBitOffset = 0;
+        mBuffer.clear();
     }
 
 private:
+    unsigned mBufferSize{0};
     std::vector<unsigned char> mBuffer;
 };

src/image/CMakeLists.txt

@@ -8,6 +8,7 @@ list(APPEND image_LIB_INCLUDES
     png/PngWriter.cpp
     png/PngReader.cpp
     png/PngHeader.cpp
+    png/PngInfo.cpp
     ImageBitStream.cpp
     )
 

src/image/ImageBitStream.cpp

@@ -9,7 +9,7 @@ ImageBitStream::ImageBitStream(Image<unsigned char>* image)
 
 bool ImageBitStream::isFinished() const
 {
-    return true;
+    return mByteOffset == mImage->getDataRef().size();
 }
 
 std::vector<unsigned char> ImageBitStream::peekNextNBytes(unsigned n) const
@@ -18,9 +18,16 @@ std::vector<unsigned char> ImageBitStream::peekNextNBytes(unsigned n) const
 }
 
 std::optional<unsigned char> ImageBitStream::readNextByte()
+{
+    mByteOffset++;
+
+    if (isFinished() )
     {
         return std::nullopt;
     }
+    const auto val = mImage->getDataRef()[mByteOffset];
+    return val;
+}
 
 void ImageBitStream::writeByte(unsigned char data)
 {

src/image/ImageBitStream.h

@@ -22,6 +22,11 @@ public:
 
     }
 
+    unsigned getBytesPerScanline() const
+    {
+        return mImage->getBytesPerRow();
+    }
+
 private:
     Image<unsigned char>* mImage{nullptr};
 };

src/image/png/PngFilter.h

@@ -0,0 +1,73 @@
+#pragma once
+
+#include "ImageBitStream.h"
+#include "BitStream.h"
+
+#include "FileLogger.h"
+
+#include <iostream>
+
+class PngFilter
+{
+public:
+    enum class FilterType : unsigned char
+    {
+        NONE,
+        SUB,
+        UP,
+        AVERAGE,
+        PAETH
+    };
+
+    PngFilter(BitStream* inputStream, BitStream* outputStream)
+        : mInputStream(inputStream),
+          mOutputStream(outputStream)
+
+    {
+
+    }
+
+    void encode()
+    {
+        auto image_stream = dynamic_cast<ImageBitStream*>(mInputStream);
+        if (!image_stream)
+        {
+            MLOG_ERROR("Expected ImageStream in PngFilter encode - aborting.");
+            return;
+        }
+
+        const auto bytes_per_scanline = image_stream->getBytesPerScanline();
+        unsigned count{0};
+        if (mFilterType == FilterType::NONE)
+        {
+            while(true)
+            {
+                if (const auto byte = image_stream->readNextByte())
+                {
+                    if (count % bytes_per_scanline == 0)
+                    {
+                        mOutputStream->writeByte(0);
+                    }
+
+                    mOutputStream->writeByte(*byte);
+                }
+                else
+                {
+                    break;
+                }
+                count++;
+            }
+        }
+    }
+
+    void decode()
+    {
+
+    }
+
+private:
+
+    FilterType mFilterType{FilterType::NONE};
+    BitStream* mInputStream{nullptr};
+    BitStream* mOutputStream{nullptr};
+};

src/image/png/PngHeader.cpp

@@ -37,7 +37,7 @@ std::string PngHeader::getFileName() const
 
 const std::string& PngHeader::getChunkName() const
 {
-    return "IHDR";
+    return mName;
 }
 
 const std::vector<unsigned char>& PngHeader::getData() const
@@ -61,9 +61,9 @@ void PngHeader::updateData()
     }
     mData.push_back(mBitDepth);
     mData.push_back(static_cast<unsigned char>(mPngInfo.mColorType));
-    mData.push_back(mPngInfo.mCompressionMethod);
+    mData.push_back(static_cast<unsigned char>(mPngInfo.mCompressionMethod));
-    mData.push_back(mPngInfo.mFilterMethod);
+    mData.push_back(static_cast<unsigned char>(mPngInfo.mFilterMethod));
-    mData.push_back(mPngInfo.mInterlaceMethod);
+    mData.push_back(static_cast<unsigned char>(mPngInfo.mInterlaceMethod));
 }
 
 uint32_t PngHeader::getCrc() const

src/image/png/PngInfo.cpp

@@ -0,0 +1,95 @@
+#include "PngInfo.h"
+
+std::string PngInfo::toString(ColorType colorType) const
+{
+    switch(colorType)
+    {
+        case ColorType::GREYSCALE:
+            return "GREYSCALE";
+        case ColorType::RGB:
+            return "RGB";
+        case ColorType::PALETTE:
+            return "PALETTE";
+        case ColorType::GREYSCALE_ALPHA:
+            return "GREYSCALE_ALPHA";
+        case ColorType::RGB_ALPHA:
+            return "RGB_ALPHA";
+        default:
+            return "UNKNOWN";
+    }
+}
+
+std::string PngInfo::toString(CompressionMethod method) const
+{
+    switch(method)
+    {
+        case CompressionMethod::DEFLATE:
+            return "DEFLATE";
+        default:
+            return "UNKNOWN";
+    }
+}
+
+std::string PngInfo::toString(FilterMethod method) const
+{
+    switch(method)
+    {
+        case FilterMethod::ADAPTIVE:
+            return "ADAPTIVE";
+        default:
+            return "UNKNOWN";
+    }
+}
+
+std::string PngInfo::toString(InterlaceMethod method) const
+{
+    switch(method)
+    {
+        case InterlaceMethod::NONE:
+            return "NONE";
+        case InterlaceMethod::ADAM7:
+            return "ADAM7";
+        default:
+            return "UNKNOWN";
+    }
+}
+
+bool PngInfo::bitDepthIsValid(ColorType colorType, unsigned char bitDepth) const
+{
+    switch(colorType)
+    {
+        case ColorType::GREYSCALE:
+            return (bitDepth == 1) || (bitDepth == 2) || (bitDepth == 4) || (bitDepth == 8) || (bitDepth == 16) ;
+        case ColorType::RGB:
+            return (bitDepth == 8) || (bitDepth == 16);
+        case ColorType::PALETTE:
+            return (bitDepth == 1) || (bitDepth == 2) || (bitDepth == 4) || (bitDepth == 8);
+        case ColorType::GREYSCALE_ALPHA:
+            return (bitDepth == 8) || (bitDepth == 16);
+        case ColorType::RGB_ALPHA:
+            return (bitDepth == 8) || (bitDepth == 16);
+        default:
+            return false;
+    }
+}
+
+bool PngInfo::compressionMethodIsValid(unsigned char method)
+{
+    return method == 0;
+}
+
+bool PngInfo::filterMethodIsValid(unsigned char method)
+{
+    return method == 0;
+}
+
+std::string PngInfo::toString() const
+{
+    std::stringstream sstr;
+    sstr << "PngInfo" << "\n";
+    sstr << "colorType: " << toString(mColorType) << "\n";
+    sstr << "compressionMethod: " << toString(mCompressionMethod) << "\n";
+    sstr << "filterMethod: " << toString(mFilterMethod) << "\n";
+    sstr << "interlaceMethod: " << toString(mInterlaceMethod) << "\n";
+    return sstr.str();
+}

src/image/png/PngInfo.h

@@ -12,43 +12,45 @@ public:
         RGB = 2,
         PALETTE = 3,
         GREYSCALE_ALPHA = 4,
-        RGB_ALPHA = 6,
+        RGB_ALPHA = 6
     };
 
-    std::string toString(ColorType colorType) const
+    enum class CompressionMethod : unsigned char
     {
-        switch(colorType)
+        DEFLATE = 0
-        {
+    };
-            case ColorType::GREYSCALE:
-                return "GREYSCALE";
-            case ColorType::RGB:
-                return "RGB";
-            case ColorType::PALETTE:
-                return "PALETTE";
-            case ColorType::GREYSCALE_ALPHA:
-                return "GREYSCALE_ALPHA";
-            case ColorType::RGB_ALPHA:
-                return "RGB_ALPHA";
-            default:
-                return "UNKNOWN";
-        }
-    }
 
-    std::string toString() const
+    enum class FilterMethod : unsigned char
     {
-        std::stringstream sstr;
+        ADAPTIVE = 0
-        sstr << "PngInfo" << "\n";
+    };
-        sstr << "colorType: " << toString(mColorType) << "\n";
+
-        sstr << "compressionMethod: " << (int)mCompressionMethod << "\n";
+    enum class InterlaceMethod : unsigned char
-        sstr << "filterMethod: " << (int)mFilterMethod << "\n";
+    {
-        sstr << "interlaceMethod: " << (int)mInterlaceMethod << "\n";
+        NONE = 0,
-        return sstr.str();
+        ADAM7 = 1
-    }
+    };
+
+    std::string toString(ColorType colorType) const;
+
+    std::string toString(CompressionMethod method) const;
+
+    std::string toString(FilterMethod method) const;
+
+    std::string toString(InterlaceMethod method) const;
+
+    bool bitDepthIsValid(ColorType colorType, unsigned char bitDepth) const;
+
+    bool compressionMethodIsValid(unsigned char method);
+
+    bool filterMethodIsValid(unsigned char method);
+
+    std::string toString() const;
 
     ColorType mColorType{ColorType::RGB};
-    unsigned char mCompressionMethod{0};
+    CompressionMethod mCompressionMethod{CompressionMethod::DEFLATE};
-    unsigned char mFilterMethod{0};
+    FilterMethod mFilterMethod{FilterMethod::ADAPTIVE};
-    unsigned char mInterlaceMethod{0};
+    InterlaceMethod mInterlaceMethod{InterlaceMethod::NONE};
 };
 
 

src/image/png/PngReader.cpp

@@ -85,25 +85,12 @@ bool PngReader::readChunk()
 }
 
 void PngReader::readIDATChunk(unsigned length)
-{
-    if (mAwaitingDataBlock)
-    {
-        mEncoder->setCompressionMethod(*mFile->readNextByte());
-        mEncoder->setExtraFlags(*mFile->readNextByte());
-        for(unsigned idx=0; idx<length-2; idx++)
-        {
-            mInputStream->writeByte(*mFile->readNextByte());
-        }
-        mAwaitingDataBlock = false;
-    }
-    else
 {
     for(unsigned idx=0; idx<length; idx++)
     {
         mInputStream->writeByte(*mFile->readNextByte());
     }
 }
-}
 
 void PngReader::readHeaderChunk()
 {
@@ -114,11 +101,10 @@ void PngReader::readHeaderChunk()
     mHeader.setImageData(width, height, bitDepth);
 
     PngInfo info;
-
     info.mColorType = static_cast<PngInfo::ColorType>(mFile->GetInHandle()->get());
-    info.mCompressionMethod = mFile->GetInHandle()->get();
+    info.mCompressionMethod = static_cast<PngInfo::CompressionMethod>(mFile->GetInHandle()->get());
-    info.mFilterMethod = mFile->GetInHandle()->get();
+    info.mFilterMethod = static_cast<PngInfo::FilterMethod>(mFile->GetInHandle()->get());
-    info.mInterlaceMethod = mFile->GetInHandle()->get();
+    info.mInterlaceMethod = static_cast<PngInfo::InterlaceMethod>(mFile->GetInHandle()->get());
     mHeader.setPngInfo(info);
 
     mCurrentOffset += 13;
@@ -152,6 +138,8 @@ std::unique_ptr<Image<unsigned char> > PngReader::read()
     {
 
     }
+
+    std::cout << mEncoder->getData() << std::endl;
     mEncoder->decode();
     return std::move(image);
 }

src/image/png/PngWriter.cpp

@@ -6,13 +6,14 @@
 #include "OutputBitStream.h"
 #include "ImageBitStream.h"
 
+#include "PngFilter.h"
 #include "Lz77Encoder.h"
 #include "ZlibEncoder.h"
 #include "CyclicRedundancyChecker.h"
 
 #include "ByteUtils.h"
 
-#include <stdio.h>
+#include <iostream>
 
 PngWriter::PngWriter()
 {
@@ -82,6 +83,8 @@ void PngWriter::writeHeader()
     mPngHeader.updateData();
     mOutStream->writeBytes(mPngHeader.getData());
 
+    std::cout << "Writing header " << mPngHeader.toString() << std::endl;
+
     auto crc = mPngHeader.getCrc();
     mOutStream->write(crc);
 }
@@ -92,17 +95,24 @@ void PngWriter::writeEndChunk()
     mOutStream->write(length);
 
     mOutStream->writeBytes(StringUtils::toBytes("IEND"));
+    std::vector<unsigned char> char_data = StringUtils::toBytes("IEND");
 
     CyclicRedundancyChecker crc_check;
-    auto crc = crc_check.doCrc(nullptr, 0);
+    auto crc = crc_check.doCrc(char_data.data(), char_data.size());
     mOutStream->write(crc);
+
+    std::cout << "Writing end chunk" << std::endl;
 }
 
 void PngWriter::writeDataChunks(const BufferBitStream& buffer)
 {
     auto num_bytes = buffer.getBuffer().size();
     auto max_bytes{32000};
-    std::vector<unsigned char> crc_buffer(max_bytes, 0);
+    std::vector<unsigned char> crc_buffer(num_bytes + 4, 0);
+    crc_buffer[0] = 'I';
+    crc_buffer[1] = 'D';
+    crc_buffer[2] = 'A';
+    crc_buffer[3] = 'T';
 
     unsigned num_dat_chunks = num_bytes/max_bytes + 1;
     unsigned offset = 0;
@@ -114,19 +124,22 @@ void PngWriter::writeDataChunks(const BufferBitStream& buffer)
             length = num_bytes - num_dat_chunks*num_bytes;
         }
 
-        mOutStream->write(length);
+        std::cout << "Writing idat length " << num_bytes << std::endl;
+        mOutStream->write(num_bytes);
 
         mOutStream->writeBytes(StringUtils::toBytes("IDAT"));
 
-        for(unsigned jdx=0; jdx<length; jdx++)
+        for(unsigned jdx=0; jdx<num_bytes; jdx++)
         {
             auto val = buffer.getBuffer()[idx*max_bytes + jdx];
-            crc_buffer[jdx] = val;
+            crc_buffer[jdx + 4] = val;
             mOutStream->writeByte(val);
         }
 
         CyclicRedundancyChecker crc_check;
         auto crc = crc_check.doCrc(crc_buffer.data(), crc_buffer.size());
+
+        std::cout << "Writing idat crc" << crc << std::endl;
         mOutStream->write(crc);
     }
 }
@@ -146,18 +159,41 @@ void PngWriter::write(const std::unique_ptr<Image<unsigned char> >& image)
     }
 
     mWorkingImage = image.get();
-    mInStream = std::make_unique<ImageBitStream>(image.get());
+
+    auto image_bit_stream = std::make_unique<ImageBitStream>(image.get());
+    auto raw_image_stream = image_bit_stream.get();
+
+    mInStream = std::move(image_bit_stream);
 
     writeHeader();
 
-    BufferBitStream lz77_out_stream;
+    auto filter_out_stream = std::make_unique<BufferBitStream>();
-    Lz77Encoder lz77_encoder(mInStream.get(), &lz77_out_stream);
+    PngFilter filter(raw_image_stream, filter_out_stream.get());
+    filter.encode();
+    //while(!filter_out_stream->isFinished())
+    //{
+        //std::cout << "Got pix " << static_cast<int>(*filter_out_stream->readNextByte()) << std::endl;
+    //}
+
+    filter_out_stream->resetOffsets();
+
+    std::unique_ptr<BufferBitStream> lz77_out_stream;
+
+    if (mCompressionMethod == Deflate::CompressionMethod::NONE)
+    {
+        lz77_out_stream = std::move(filter_out_stream);
+    }
+    else
+    {
+        lz77_out_stream = std::make_unique<BufferBitStream>();
+        Lz77Encoder lz77_encoder(filter_out_stream.get(), lz77_out_stream.get());
 
         lz77_encoder.encode();
-    lz77_out_stream.resetOffsets();
+        lz77_out_stream->resetOffsets();
+    }
 
     BufferBitStream zlib_out_stream;
-    ZlibEncoder zlib_encoder(&lz77_out_stream, &zlib_out_stream);
+    ZlibEncoder zlib_encoder(lz77_out_stream.get(), &zlib_out_stream);
     zlib_encoder.encode();
     zlib_out_stream.resetOffsets();
 

src/image/png/PngWriter.h

@@ -2,6 +2,7 @@
 
 #include "PngHeader.h"
 #include "Image.h"
+#include "DeflateElements.h"
 
 #include <memory>
 #include <string>
@@ -46,6 +47,8 @@ private:
     unsigned mPngInfoUserSet{false};
     PngInfo mPngInfo;
     PngHeader mPngHeader;
+
+    Deflate::CompressionMethod mCompressionMethod{Deflate::CompressionMethod::NONE};
 };
 
 using PngWriterPtr = std::unique_ptr<PngWriter>;

test/image/TestPngWriter.cpp

@@ -9,21 +9,26 @@
 
 int main()
 {
-    unsigned width = 20;
+    unsigned width = 10;
-    unsigned height = 20;
+    unsigned height = 10;
-    unsigned numChannels = 3;
+    unsigned numChannels = 1;
     auto image = Image<unsigned char>::Create(width, height);
     image->setNumChannels(numChannels);
+    image->setBitDepth(8);
 
-    std::vector<unsigned char> data(image->getBytesPerRow()*height, 0);
+    std::vector<unsigned char> data(width*height, 0);
+    for (unsigned idx=0; idx<width*height; idx++)
+    {
+        data[idx] = 10;
+    }
 
-    ImagePrimitives::drawAlternatingStrips(data, width, height, numChannels, image->getBytesPerRow());
     image->setData(data);
 
     PngWriter writer;
     writer.setPath("test.png");
     writer.write(image);
 
+    return 0;
     File test_file("test.png");
     test_file.SetAccessMode(File::AccessMode::Read);
     test_file.Open(true);