Some encode/decode practice.

src/compression/CMakeLists.txt

@@ -2,6 +2,8 @@
 list(APPEND compression_LIB_INCLUDES 
     StreamCompressor.cpp
     HuffmanEncoder.cpp
+    RunLengthEncoder.cpp
+    ZlibData.cpp
     )
 
 add_library(compression SHARED ${compression_LIB_INCLUDES})

src/compression/HuffmanEncoder.cpp

@@ -1,77 +1,100 @@
 #include "HuffmanEncoder.h"
 
-#include "Tree.h"
+#include "RawTree.h"
 
 #include <unordered_map>
 #include <queue>
 #include <tuple>
 #include <iostream>
 
+void HuffmanEncoder::dumpNode(RawNode<CountPair>* node, unsigned depth) const
+{
+    if (!node)
+    {
+        return;
+    }
+
+    auto data = node->getData();
+
+    std::string prefix(depth, '_');
+
+    if (node->isLeaf())
+    {
+        std::cout << prefix << "Leaf with value: " << data.first << " and sum " << data.second << std::endl;
+    }
+    else
+    {
+        std::cout << prefix << "Intermediate with sum " << data.second << std::endl;
+        std::cout << prefix << "Doing Left.." << std::endl;
+        dumpNode(node->getLeftChild(), depth+1);
+
+        std::cout << prefix << "Doing Right.." << std::endl;
+        dumpNode(node->getRightChild(), depth+1);
+
+        std::cout << prefix << "*****" << std::endl;
+    }
+}
+
+void HuffmanEncoder::dumpTree(const RawTree<CountPair>& tree) const
+{
+    dumpNode(tree.getRootNode(), 0);
+}
+
 void HuffmanEncoder::encode(const HuffmanEncoder::DataStream& stream)
 {
-	std::unordered_map<unsigned char, unsigned> counts;
-	for (auto c : stream)
-	{
-		counts[c]++;
-	}
-
-	using CountPair = std::pair<unsigned char, unsigned>;
-	auto cmp = [](CountPair left, CountPair right)
-		{
-			return left.second > right.second;
-		};
-	std::priority_queue<CountPair, std::vector<CountPair>, decltype(cmp)> q(cmp);
-	for (const auto& entry : counts)
-	{
-		q.push({entry.first, entry.second});
-	}
-
-	NodePtr<CountPair> lastNode;
-	while(!q.empty())
-	{
-		const auto charData = q.top();
-		auto characterNode = std::make_unique<Node<CountPair> >(charData);
-		q.pop();
-
-		if (!lastNode)
-		{
-			const auto rightCharData = q.top();
-			auto rightCharacterNode = std::make_unique<Node<CountPair> >(rightCharData);
-			q.pop();
-
-			const auto sum = charData.second + rightCharData.second;
-			CountPair data{0, sum};
-			auto midNode = std::make_unique<Node<CountPair> >(data);
-
-			midNode->addChild(std::move(characterNode));
-			midNode->addChild(std::move(rightCharacterNode));
-			lastNode = std::move(midNode);
-		}
-		else
-		{
-			const auto sum = lastNode->getData().second;
-			CountPair data{0, sum};
-			auto midNode = std::make_unique<Node<CountPair> >(data);
-
-			if (charData.second < lastNode->getData().second)
-			{
-				midNode->addChild(std::move(lastNode));
-				midNode->addChild(std::move(characterNode));
-			}
-			else
-			{
-				midNode->addChild(std::move(characterNode));
-				midNode->addChild(std::move(lastNode));
-			}
-			lastNode = std::move(midNode);
-		}
-	}
-
-	Tree<CountPair> tree;
-	tree.addRootNode(std::move(lastNode));
-
-	//using TableEntry = std::tuple<>
-
-
-	std::cout << "********" << std::endl;
+    std::unordered_map<unsigned char, unsigned> counts;
+    for (auto c : stream)
+    {
+        counts[c]++;
+    }
+    encode(counts);
+}
+
+void HuffmanEncoder::encode(const std::unordered_map<unsigned char, unsigned>& counts)
+{
+    std::cout << "Counts" << std::endl;
+    for (const auto& data: counts)
+    {
+        std::cout << data.first << " | " << data.second << std::endl;
+    }
+    std::cout << "*******" << std::endl;
+
+    auto cmp = [](RawNode<CountPair>* left, RawNode<CountPair>* right)
+        {
+            return left->getData().second > right->getData().second;
+        };
+
+    std::priority_queue<RawNode<CountPair>*, std::vector<RawNode<CountPair>* >, decltype(cmp)> q(cmp);
+    for (const auto& entry : counts)
+    {
+        q.push(new RawNode<CountPair>(entry));
+    }
+
+    while(q.size() > 1)
+    {
+        auto node0 = q.top();
+        q.pop();
+
+        auto node1 = q.top();
+        q.pop();
+
+        const auto sum = node0->getData().second + node1->getData().second;
+        auto new_node = new RawNode<CountPair>(CountPair{0, sum});
+
+        new_node->addChild(node0);
+        new_node->addChild(node1);
+        q.push(new_node);
+    }
+
+    auto root = q.top();
+    q.pop();
+
+    RawTree<CountPair> tree;
+    tree.addRootNode(root);
+
+    //using TableEntry = std::tuple<>
+
+    dumpTree(tree);
+
+    std::cout << "********" << std::endl;
 }

src/compression/HuffmanEncoder.h

@@ -1,11 +1,21 @@
 #pragma once
 
+#include "RawTree.h"
+
 #include <vector>
+#include <unordered_map>
 
 class HuffmanEncoder
 {
 using DataStream = std::vector<unsigned char>;
+using CountPair = std::pair<unsigned char, unsigned>;
 
 public:
-	void encode(const DataStream& stream);
+    void encode(const DataStream& stream);
+
+    void encode(const std::unordered_map<unsigned char, unsigned>& counts);
+
+private:
+    void dumpTree(const RawTree<CountPair>& tree) const;
+    void dumpNode(RawNode<CountPair>* node, unsigned depth) const;
 };

src/compression/RunLengthEncoder.h

@@ -0,0 +1,110 @@
+#pragma once
+
+#include "StringUtils.h"
+
+#include <vector>
+#include <string>
+
+class RunLengthEncoder
+{
+public:
+    std::string encode(const std::string& string)
+    {
+        std::string ret;
+        if (string.empty())
+        {
+            return ret;
+        }
+
+        char working_char{0};
+        unsigned count = 1;
+        for(unsigned idx=0; idx<string.size(); idx++)
+        {
+            auto c = string[idx];
+            if (idx == 0)
+            {
+                working_char = c;
+                continue;
+            }
+
+            if (c == working_char)
+            {
+                count++;
+            }
+            else
+            {
+                insertCharacter(ret, working_char, count);
+                working_char = c;
+                count = 1;
+            }
+        }
+        insertCharacter(ret, working_char, count);
+
+        return ret;
+    }
+
+    std::string decode(const std::string& string)
+    {
+        std::string ret;
+        if (string.empty())
+        {
+            return ret;
+        }
+
+        unsigned count{0};
+        while(count < string.size())
+        {
+            auto c = string[count];
+            if (c == mDelimiter)
+            {
+                count++;
+                std::string reps;
+                char working_char{0};
+                while(count < string.size())
+                {
+                    auto rep_char = string[count];
+                    count++;
+                    if (StringUtils::IsAlphabetical(rep_char))
+                    {
+                        working_char = rep_char;
+                        break;
+                    }
+                    else
+                    {
+                        reps += rep_char;
+                    }
+                }
+                for (unsigned idx=0; idx<std::stoul(reps); idx++)
+                {
+                    ret += working_char;
+                }
+            }
+            else
+            {
+                ret += c;
+                count++;
+            }
+        }
+        return ret;
+    }
+
+private:
+
+    void insertCharacter(std::string& output, char c, unsigned count)
+    {
+        if (count >= 3)
+        {
+            output += mDelimiter + std::to_string(count) + c;
+        }
+        else
+        {
+            for (unsigned jdx=0;jdx<count; jdx++)
+            {
+                output += c;
+            }
+        }
+    }
+
+    char mDelimiter {'@'};
+
+};

src/compression/ZlibData.h

@@ -0,0 +1,97 @@
+#pragma once
+
+#include "ByteUtils.h"
+
+#include <vector>
+#include <iostream>
+
+class ZlibData
+{
+public:
+    void setByte(unsigned idx, unsigned char data)
+    {
+        mData[idx] = data;
+    }
+
+    void setDataSize(std::size_t size)
+    {
+        mData = std::vector<unsigned char>(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;
+        unsigned working_byte_id = 0;
+        for (unsigned idx=0; idx<mData.size(); idx++)
+        {
+            auto working_byte = mData[working_byte_id];
+            std::cout << "Into process data, byte is: " << static_cast<int>(working_byte) << std::endl;
+
+            auto final_block = ByteUtils::getBitN(working_byte, 0);
+            if (final_block)
+            {
+                std::cout << "Got final block" << std::endl;
+                in_final_block = true;
+            }
+
+            auto compress_type = ByteUtils::getTwoBitsAtN(working_byte, 1);
+            std::cout << "Compress type byte is: " << static_cast<int>(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;
+            }
+            else if (compress_type == ERROR)
+            {
+                std::cout << "Got ERROR" << std::endl;
+            }
+            break;
+        }
+    }
+
+private:
+    std::vector<unsigned char> mData;
+    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/core/ByteUtils.h

@@ -25,6 +25,46 @@ public:
         return word & ByteUtils::WORD_LAST_BYTE;
     }
 
+    static unsigned char getHigherNBits(unsigned char input, unsigned num)
+    {
+        return input >> 8 - num;
+    }
+
+    static unsigned char getLowerNBits(unsigned char input, unsigned num)
+    {
+        switch (num)
+        {
+        case 1:
+            return input & 0x01;
+        case 2:
+            return input & 0x03;
+        case 3:
+            return input & 0x07;
+        case 4:
+            return input & 0x0F;
+        case 5:
+            return input & 0x1F;
+        case 6:
+            return input & 0x3F;
+        case 7:
+            return input & 0x7F;
+        case 8:
+            return input;
+        default:
+            return 0;
+        }
+    }
+
+    static unsigned char getTwoBitsAtN(unsigned char input, unsigned n)
+    {
+        return (input & (0x03 << n)) >> n;
+    }
+
+    static unsigned char getBitN(unsigned char input, unsigned n)
+    {
+        return input & (1 << n);
+    }
+
     static void ReverseBuffer(char* buffer, char* reverse, unsigned size, unsigned targetSize)
     {
         for(unsigned idx=0; idx<targetSize; idx++)

src/core/CMakeLists.txt

@@ -18,6 +18,7 @@ list(APPEND core_LIB_INCLUDES
     Dictionary.cpp
     Color.cpp
     CommandLineArgs.cpp
+    data_structures/RawTree.cpp
     data_structures/Tree.cpp
     loggers/FileLogger.cpp
     file_utilities/Directory.cpp

src/core/StringUtils.cpp

@@ -20,6 +20,11 @@ bool StringUtils::IsSpace(char c)
     return std::isspace(c, loc);
 }
 
+bool StringUtils::IsAlphabetical(char c)
+{
+    return std::isalpha(c);
+}
+
 std::vector<std::string> StringUtils::toLines(const std::string& input)
 {
     auto result = std::vector<std::string>{};

src/core/StringUtils.h

@@ -17,6 +17,9 @@ public:
     static constexpr char COLON = ':';
 
     static bool IsAlphaNumeric(char c);
+
+    static bool IsAlphabetical(char c);
+
     static bool IsSpace(char c);
     static std::string ToLower(const std::string& s);
     static std::string convert(const std::wstring& input);

src/core/data_structures/RawTree.h

@@ -0,0 +1,97 @@
+#pragma once
+
+#include <memory>
+
+template<typename T>
+class RawNode
+{
+public:
+    RawNode(T data)
+        : mData(data)
+    {
+
+
+    }
+
+    ~RawNode()
+    {
+        if(mLeftChild)
+        {
+            delete mLeftChild;
+        }
+
+        if(mRightChild)
+        {
+            delete mRightChild;
+        }
+    }
+
+    void addChild(RawNode* child)
+    {
+        if(!mLeftChild)
+        {
+            mLeftChild = child;
+        }
+        else
+        {
+            mRightChild = child;
+        }
+    }
+
+    bool isLeaf() const
+    {
+        return !mLeftChild && !mRightChild;
+    }
+
+    T getData() const
+    {
+        return mData;
+    }
+
+    RawNode* getLeftChild() const
+    {
+        return mLeftChild;
+    }
+
+    RawNode* getRightChild() const
+    {
+        return mRightChild;
+    }
+
+private:
+    T mData;
+    unsigned char mTag{0};
+    RawNode* mLeftChild{nullptr};
+    RawNode* mRightChild{nullptr};
+};
+
+template<typename T>
+class RawTree
+{
+public:
+    RawTree()
+    {
+
+    }
+
+    ~RawTree()
+    {
+        if (mRootNode)
+        {
+            delete mRootNode;
+        }
+    }
+
+    void addRootNode(RawNode<T>* root)
+    {
+        mRootNode = root;
+    }
+
+    RawNode<T>* getRootNode() const
+    {
+        return mRootNode;
+    }
+
+private:
+    RawNode<T>* mRootNode{nullptr};
+};

src/core/data_structures/Tree.h

@@ -6,37 +6,47 @@ template<typename T>
 class Node
 {
 public:
-	Node(T data)
-		: mData(data)
-	{}
+    Node(T data)
+        : mData(data)
+    {}
 
-	void addChild(std::unique_ptr<Node> child)
-	{
-		if(!mLeftChild)
-		{
-			mLeftChild = std::move(child);
-		}
-		else
-		{
-			mRightChild = std::move(child);
-		}
-	}
+    void addChild(std::unique_ptr<Node> child)
+    {
+        if(!mLeftChild)
+        {
+            mLeftChild = std::move(child);
+        }
+        else
+        {
+            mRightChild = std::move(child);
+        }
+    }
 
-	bool isLeaf() const
-	{
-		return !mLeftChild && !mRightChild;
-	}
+    bool isLeaf() const
+    {
+        return !mLeftChild && !mRightChild;
+    }
 
-	T getData() const
-	{
-		return mData;
-	}
+    T getData() const
+    {
+        return mData;
+    }
+
+    Node* getLeftChild() const
+    {
+        return mLeftChild.get();
+    }
+
+    Node* getRightChild() const
+    {
+        return mRightChild.get();
+    }
 
 private:
-	T mData;
-	unsigned char mTag{0};
-	std::unique_ptr<Node> mLeftChild;
-	std::unique_ptr<Node> mRightChild;
+    T mData;
+    unsigned char mTag{0};
+    std::unique_ptr<Node> mLeftChild;
+    std::unique_ptr<Node> mRightChild;
 };
 
 template<typename T>
@@ -46,21 +56,21 @@ template<typename T>
 class Tree
 {
 public:
-	Tree()
-	{
+    Tree()
+    {
 
-	}
+    }
 
-	void addRootNode(NodePtr<T> root)
-	{
-		mRootNode = std::move(root);
-	}
+    void addRootNode(NodePtr<T> root)
+    {
+        mRootNode = std::move(root);
+    }
 
-	Node<T>* getRootNode() const
-	{
-		return mRootNode.get();
-	}
+    Node<T>* getRootNode() const
+    {
+        return mRootNode.get();
+    }
 
 private:
-	NodePtr<T> mRootNode;
+    NodePtr<T> mRootNode;
 };

src/core/file_utilities/File.cpp

@@ -32,6 +32,11 @@ std::ofstream* File::GetOutHandle() const
     return mOutHandle.get();
 }
 
+unsigned char File::readNextByte()
+{
+    return mInHandle->get();
+}
+
 void File::Open(bool asBinary)
 {
     if(mAccessMode == AccessMode::Read)

src/core/file_utilities/File.h

@@ -48,6 +48,8 @@ public:
 
     void Close();
 
+    unsigned char readNextByte();
+
 
 private:
 

src/image/CMakeLists.txt

@@ -1,38 +1,22 @@
 list(APPEND image_HEADERS 
     Image.h
     PngWriter.h
-    PngWriterBasic.h
-    PngWriterImpl.h
     )
 
 list(APPEND image_LIB_INCLUDES 
     Image.cpp
     PngWriter.cpp
-    PngWriterBasic.cpp
     PngReader.cpp
     )
 
-list(APPEND image_LIBS core)
+list(APPEND image_LIBS core compression)
 list(APPEND image_DEFINES "")
 
-find_package(PNG QUIET)
-if(PNG_FOUND)
-	list(APPEND image_LIBS PNG::PNG)
-	list(APPEND image_LIB_INCLUDES 
-	    PngWriterLibPng.cpp
-	    )
-	list(APPEND image_DEFINES HAS_LIBPNG)
-else()
-	message(STATUS "LIBRARY CHECK: libPNG not found - disabling libPNG based image i/o.")
-endif() 
-
 
 add_library(image SHARED ${image_LIB_INCLUDES} ${image_HEADERS})
 #target_compile_definitions(image PRIVATE ${image_DEFINES})
 
-target_include_directories(image PUBLIC
-                          "${CMAKE_CURRENT_SOURCE_DIR}"
-                          )
+target_include_directories(image PUBLIC "${CMAKE_CURRENT_SOURCE_DIR}")
 set_target_properties( image PROPERTIES WINDOWS_EXPORT_ALL_SYMBOLS ON ) 
 
 target_link_libraries( image PUBLIC ${image_LIBS})

src/image/ImagePrimitives.h

@@ -23,4 +23,19 @@ public:
             }
         }
     }
+
+    static void drawAlternatingStrips(std::vector<unsigned char>& data, unsigned width, unsigned height, unsigned channels, unsigned bytesPerRow)
+    {
+        for(unsigned jdx=0;jdx<height;jdx++)
+        {
+            const auto heightOffset = jdx*bytesPerRow;
+            for(unsigned idx=0;idx<width*channels;idx+=channels)
+            {
+                const auto index = heightOffset + idx;
+                data[index] = (idx%2 == 0) ? 255*jdx/(height+1) : 0;
+                data[index+1] = 0;
+                data[index+2] = 0;
+            }
+        }
+    }
 };

src/image/PngElements.h

@@ -0,0 +1,33 @@
+#pragma once
+
+#include <string>
+#include <sstream>
+
+
+namespace Png
+{
+    struct IHDRChunk
+    {
+        unsigned width{0};
+        unsigned height{0};
+        char bitDepth{0};
+        char colorType{0};
+        char compressionMethod{0};
+        char filterMethod{0};
+        char interlaceMethod{0};
+
+        std::string toString() const
+        {
+            std::stringstream sstr;
+            sstr << "width: " << width << "\n";
+            sstr << "height: " << height << "\n";
+            sstr << "bitDepth: " << (int)bitDepth << "\n";
+            sstr << "colorType: " << (int)colorType << "\n";
+            sstr << "compressionMethod: " << (int)compressionMethod << "\n";
+            sstr << "filterMethod: " << (int)filterMethod << "\n";
+            sstr << "interlaceMethod: " << (int)interlaceMethod << "\n";
+            return sstr.str();
+        }
+    };
+}
+

src/image/PngReader.cpp

@@ -1,7 +1,6 @@
 #include "PngReader.h"
-#include "BinaryStream.h"
 
-#include "Image.h"
+#include "BinaryStream.h"
 
 #include <iostream>
 #include <sstream>
@@ -11,120 +10,135 @@ PngReader::~PngReader()
 
 }
 
-void PngReader::setPath(const std::string& path)
+void PngReader::setPath(const Path& path)
 {
-	mPath = path;
+    mPath = path;
 }
 
 bool PngReader::checkSignature()
 {
-	const int highBitCheck = 0x89;
-	const auto firstPos = mFile->GetInHandle()->get();
-	if (firstPos != highBitCheck)
-	{
-		return false;
-	}
+    const int highBitCheck = 0x89;
+    const auto firstPos = mFile->GetInHandle()->get();
+    if (firstPos != highBitCheck)
+    {
+        return false;
+    }
 
-	std::string fileType;
-	BinaryStream::getNextString(mFile->GetInHandle(), fileType, 3);
-	if (fileType != "PNG")
-	{
-		return false;
-	}
+    std::string fileType;
+    BinaryStream::getNextString(mFile->GetInHandle(), fileType, 3);
+    if (fileType != "PNG")
+    {
+        return false;
+    }
 
-	std::vector<char> sequence{13, 10, 26, 10};
-	for (auto c : sequence)
-	{
-		if (mFile->GetInHandle()->get() != c)
-		{
-			return false;
-		}
-	}
+    std::vector<char> sequence{13, 10, 26, 10};
+    for (auto c : sequence)
+    {
+        if (mFile->GetInHandle()->get() != c)
+        {
+            return false;
+        }
+    }
 
-	mCurrentOffset += 8;
-	return true;
+    mCurrentOffset += 8;
+    return true;
 }
 
 bool PngReader::readChunk()
 {
-	unsigned length = *BinaryStream::getNextDWord(mFile->GetInHandle());
+    unsigned length = *BinaryStream::getNextDWord(mFile->GetInHandle());
 
-	std::string chunkType;
-	BinaryStream::getNextString(mFile->GetInHandle(), chunkType, 4);
-	mCurrentOffset += 8;
+    std::string chunkType;
+    BinaryStream::getNextString(mFile->GetInHandle(), chunkType, 4);
+    mCurrentOffset += 8;
 
-	std::cout << "Got chunk with type: " << chunkType << " and length: " << length << std::endl;
-	bool lastChunk = false;
-	if (chunkType == "IHDR")
-	{
-		parseHeader();
-	}
-	else if(chunkType == "IEND")
-	{
-		lastChunk = true;
-	}
-	else
-	{
-		for(unsigned idx=0;idx<length;idx++)
-		{
-			mFile->GetInHandle()->get();
-		}
-	}
+    std::cout << "Got chunk with type: " << chunkType << " and length: " << length << std::endl;
+    bool lastChunk = false;
+    if (chunkType == "IHDR")
+    {
+        readHeaderChunk();
+    }
+    else if(chunkType == "IEND")
+    {
+        lastChunk = true;
+    }
+    else if(chunkType == "IDAT")
+    {
+        readIDATChunk(length);
+    }
+    else
+    {
+        for(unsigned idx=0;idx<length;idx++)
+        {
+            mFile->GetInHandle()->get();
+        }
+    }
 
-	unsigned crcCheck = *BinaryStream::getNextDWord(mFile->GetInHandle());
+    unsigned crcCheck = *BinaryStream::getNextDWord(mFile->GetInHandle());
 
-	mCurrentOffset += 4;
-	return !lastChunk;
+    mCurrentOffset += 4;
+    return !lastChunk;
 }
 
-void PngReader::parseHeader()
+void PngReader::readIDATChunk(unsigned length)
 {
-	mIHDRChunk.width = *BinaryStream::getNextDWord(mFile->GetInHandle());
-	mIHDRChunk.height = *BinaryStream::getNextDWord(mFile->GetInHandle());
-	mIHDRChunk.bitDepth = mFile->GetInHandle()->get();
-	mIHDRChunk.colorType = mFile->GetInHandle()->get();
-	mIHDRChunk.compressionMethod = mFile->GetInHandle()->get();
-	mIHDRChunk.filterMethod = mFile->GetInHandle()->get();
-	mIHDRChunk.interlaceMethod = mFile->GetInHandle()->get();
+    if (mAwaitingDataBlock)
+    {
+        mImageData.setCompressionMethod(mFile->readNextByte());
+        mImageData.setExtraFlags(mFile->readNextByte());
+        mImageData.setDataSize(length-2);
+        for(unsigned idx=0; idx<length-2; idx++)
+        {
+            mImageData.setByte(idx, mFile->readNextByte());
+        }
+        mAwaitingDataBlock = false;
+    }
+    else
+    {
+        for(unsigned idx=0; idx<length; idx++)
+        {
+            mImageData.setByte(idx, mFile->readNextByte());
+        }
+    }
+}
 
-	mCurrentOffset += 13;
+void PngReader::readHeaderChunk()
+{
+    mIHDRChunk.width = *BinaryStream::getNextDWord(mFile->GetInHandle());
+    mIHDRChunk.height = *BinaryStream::getNextDWord(mFile->GetInHandle());
+    mIHDRChunk.bitDepth = mFile->GetInHandle()->get();
+    mIHDRChunk.colorType = mFile->GetInHandle()->get();
+    mIHDRChunk.compressionMethod = mFile->GetInHandle()->get();
+    mIHDRChunk.filterMethod = mFile->GetInHandle()->get();
+    mIHDRChunk.interlaceMethod = mFile->GetInHandle()->get();
 
-	logHeader();
+    mCurrentOffset += 13;
+
+    logHeader();
 }
 
 void PngReader::logHeader()
 {
-    std::stringstream sstr;
-    sstr << "IHDR\n";
-    sstr << "width: " << mIHDRChunk.width << "\n";
-    sstr << "height: " << mIHDRChunk.height << "\n";
-    sstr << "bitDepth: " << (int)mIHDRChunk.bitDepth << "\n";
-    sstr << "colorType: " << (int)mIHDRChunk.colorType << "\n";
-    sstr << "compressionMethod: " << (int)mIHDRChunk.compressionMethod << "\n";
-    sstr << "filterMethod: " << (int)mIHDRChunk.filterMethod << "\n";
-    sstr << "interlaceMethod: " << (int)mIHDRChunk.interlaceMethod << "\n";
-
-    sstr << "************\n";
-    std::cout << sstr.str() << std::endl;
+    std::cout << "IHDR\n" << mIHDRChunk.toString() << "*************\n";
 }
 
 std::unique_ptr<Image<unsigned char> > PngReader::read()
 {
-	auto image = std::make_unique<Image<unsigned char> >(5, 5);
+    auto image = std::make_unique<Image<unsigned char> >(5, 5);
 
     mFile = std::make_unique<File>(mPath);
     mFile->Open(true);
 
     if (!checkSignature())
     {
-    	std::cout << "Signature check failed" << std::endl;
-    	return image;
+        std::cout << "Signature check failed" << std::endl;
+        return image;
     }
 
     while(readChunk())
     {
 
     }
-
-	return std::move(image);
+    mImageData.processData();
+    return std::move(image);
 }

src/image/PngReader.h

@@ -1,44 +1,42 @@
 #pragma once
 
-#include <string>
-#include <memory>
-#include <vector>
-
 #include "File.h"
 #include "Image.h"
+#include "PngElements.h"
+#include "ZlibData.h"
+
+#include <string>
+#include <memory>
+#include <filesystem>
+
+using Path = std::filesystem::path;
 
 class PngReader
 {
 public:
     ~PngReader();
-    void setPath(const std::string& path);
+    void setPath(const Path& path);
 
     std::unique_ptr<Image<unsigned char> > read();
-
 private:
-
-    struct IHDRChunk
-    {
-        unsigned width{0};
-        unsigned height{0};
-        char bitDepth{0};
-        char colorType{0};
-        char compressionMethod{0};
-        char filterMethod{0};
-        char interlaceMethod{0};
-    };
-
     bool readChunk();
-    void parseHeader();
+
+    void readHeaderChunk();
+
+    void readIDATChunk(unsigned length);
+
     void logHeader();
 
     bool checkSignature();
 
     unsigned mCurrentOffset{0};
 
-    IHDRChunk mIHDRChunk;
+    Png::IHDRChunk mIHDRChunk;
 
     std::unique_ptr<Image<unsigned char> > mWorkingImage;
     std::unique_ptr<File> mFile;
-    std::string mPath;
+    Path mPath;
+
+    ZlibData mImageData;
+    bool mAwaitingDataBlock{true};
 };

src/image/PngWriter.cpp

@@ -2,21 +2,11 @@
 
 #include "Image.h"
 
-#ifdef HAS_LIBPNG
-#include <png.h>
-#include "PngWriterLibPng.h"
-#else
-#include "PngWriterBasic.h"
-#endif
 #include <stdio.h>
 
 PngWriter::PngWriter()
 {
-#ifdef HAS_LIBPNG
-    mImpl = std::make_unique<PngWriterLibPng>();
-#else
-    mImpl = std::make_unique<PngWriterBasic>();
-#endif
+
 }
 
 std::unique_ptr<PngWriter> PngWriter::Create()
@@ -24,14 +14,14 @@ std::unique_ptr<PngWriter> PngWriter::Create()
     return std::make_unique<PngWriter>();
 }
 
-void PngWriter::SetPath(const std::string& path)
+void PngWriter::setPath(const Path& path)
 {
-    mImpl->setPath(path);
+    mPath = path;
 }
 
-void PngWriter::Write(const std::unique_ptr<Image<unsigned char> >& image) const
+void PngWriter::write(const std::unique_ptr<Image<unsigned char> >& image) const
 {
-    mImpl->write(image);
+    //mImpl->write(image);
     //auto fp = fopen(mPath.c_str(), "wb");
 
     //auto png_ptr = png_create_write_struct(PNG_LIBPNG_VER_STRING, nullptr, nullptr, nullptr);

src/image/PngWriter.h

@@ -1,11 +1,12 @@
 #pragma once
 
-#include <memory>
-#include <string>
-
 #include "Image.h"
 
-class PngWriterImpl;
+#include <memory>
+#include <string>
+#include <filesystem>
+
+using Path = std::filesystem::path;
 
 class PngWriter
 {
@@ -14,13 +15,12 @@ public:
 
     static std::unique_ptr<PngWriter> Create();
 
-    void SetPath(const std::string& path);
+    void setPath(const Path& path);
 
-    void Write(const std::unique_ptr<Image<unsigned char> >& image) const;
+    void write(const std::unique_ptr<Image<unsigned char> >& image) const;
 
 private:
-    std::unique_ptr<PngWriterImpl> mImpl;
-
+    Path mPath;
 };
 
 using PngWriterPtr = std::unique_ptr<PngWriter>;

src/image/PngWriterBasic.cpp

@@ -1,11 +0,0 @@
-#include "PngWriterBasic.h"
-
-void PngWriterBasic::setPath(const std::string& path)
-{
-
-}
-
-void PngWriterBasic::write(const std::unique_ptr<Image<unsigned char> >& image) const
-{
-
-}

src/image/PngWriterBasic.h

@@ -1,14 +0,0 @@
-#pragma once
-
-#include "PngWriterImpl.h"
-
-class PngWriterBasic : public PngWriterImpl
-{
-public:
-	void setPath(const std::string& path) override;
-
-	void write(const std::unique_ptr<Image<unsigned char>>& image) const override;
-
-private:
-	std::string mPath;
-};

src/image/PngWriterImpl.h

@@ -1,16 +0,0 @@
-#pragma once
-
-#include <string>
-#include <memory>
-
-#include "Image.h"
-
-class PngWriterImpl
-{
-public:
-	virtual ~PngWriterImpl() = default;
-
-	virtual void setPath(const std::string& path) = 0;
-
-	virtual void write(const std::unique_ptr<Image<unsigned char> >& image) const = 0;
-};

test/compression/TestStreamCompressor.cpp

@@ -1,14 +1,46 @@
 #include <iostream>
 
 #include "HuffmanEncoder.h"
+#include "RunLengthEncoder.h"
+
+void test_run_length_encoder()
+{
+    std::string test_data = "BCAAAADDDCCACACAC";
+
+    RunLengthEncoder encoder;
+    auto encoded = encoder.encode(test_data);
+
+    std::cout << "Encoded: " << encoded << std::endl;
+
+    auto decoded = encoder.decode(encoded);
+
+    std::cout << "Decoded: " << decoded << std::endl;
+}
+
+void test_huffman_encoder()
+{
+    //std::string testData = "BCAADDDCCACACAC";
+    //std::vector<unsigned char> stream(testData.begin(), testData.end());
+
+    std::unordered_map<unsigned char, unsigned> counts;
+    counts['A'] = 1;
+    counts['B'] = 1;
+    counts['C'] = 1;
+    counts['D'] = 2;
+    counts['E'] = 3;
+    counts['F'] = 5;
+    counts['G'] = 5;
+    counts['H'] = 12;
+
+    HuffmanEncoder encoder;
+    encoder.encode(counts);
+
+}
 
 int main()
 {
-	std::string testData = "BCAADDDCCACACAC";
-	std::vector<unsigned char> stream(testData.begin(), testData.end());
-
-	HuffmanEncoder encoder;
-	encoder.encode(stream);
+    test_huffman_encoder();
 
+    //test_run_length_encoder();
     return 0;
 }

test/image/TestPngReader.cpp

@@ -5,7 +5,7 @@
 
 int main()
 {
-    const auto path = "/home/jmsgrogan/code/MediaTool-build/bin/test.png";
+    const auto path = "/home/jmsgrogan/Downloads/test.png";
 
     PngReader reader;
     reader.setPath(path);

test/image/TestPngWriter.cpp

@@ -1,6 +1,7 @@
 #include "Image.h"
 #include "PngWriter.h"
-#include "PngWriterImpl.h"
+
+#include "ImagePrimitives.h"
 
 #include <iostream>
 
@@ -13,22 +14,13 @@ int main()
     image->setNumChannels(numChannels);
 
     std::vector<unsigned char> data(image->getBytesPerRow()*height, 0);
-    for(unsigned jdx=0;jdx<height;jdx++)
-    {
-        const auto heightOffset = jdx*image->getBytesPerRow();
-        for(unsigned idx=0;idx<width*numChannels;idx+=numChannels)
-        {
-            const auto index = heightOffset + idx;
-            data[index] = (idx%2 == 0) ? 255*jdx/(height+1) : 0;
-            data[index+1] = 0;
-            data[index+2] = 0;
-        }
-    }
+
+    ImagePrimitives::drawAlternatingStrips(data, width,height, numChannels, image->getBytesPerRow());
     image->setData(data);
 
     PngWriter writer;
-    writer.SetPath("test.png");
-    writer.Write(image);
+    writer.setPath("test.png");
+    writer.write(image);
 
     return 0;
 }