Continue work on png writer.

src/core/ByteUtils.cpp

@@ -21,6 +21,11 @@ unsigned char ByteUtils::getHigherNBits(unsigned char input, unsigned num)
     return input >> 8 - num;
 }
 
+unsigned char ByteUtils::getByteN(uint32_t input, unsigned n)
+{
+    return (input << 8*n) >> 24;
+}
+
 unsigned char ByteUtils::getLowerNBits(unsigned char input, unsigned num)
 {
     switch (num)

src/core/ByteUtils.h

@@ -17,6 +17,8 @@ public:
 
     static Word GetWordLastByte(const Word word);
 
+    static unsigned char getByteN(uint32_t input, unsigned n);
+
     static unsigned char getHigherNBits(unsigned char input, unsigned num);
 
     static unsigned char getLowerNBits(unsigned char input, unsigned num);

src/core/file_utilities/File.cpp

@@ -32,9 +32,23 @@ std::ofstream* File::GetOutHandle() const
     return mOutHandle.get();
 }
 
-unsigned char File::readNextByte()
+std::optional<unsigned char> File::readNextByte()
 {
-    return mInHandle->get();
+    if (mInHandle->good())
+    {
+        if (auto val = mInHandle->get(); val == EOF)
+        {
+            return std::nullopt;
+        }
+        else
+        {
+            return val;
+        }
+    }
+    else
+    {
+        return std::nullopt;
+    }
 }
 
 void File::Open(bool asBinary)

src/core/file_utilities/File.h

@@ -7,6 +7,7 @@
 #include <fstream>
 #include <memory>
 #include <vector>
+#include <optional>
 
 using Path = std::filesystem::path;
 
@@ -48,7 +49,7 @@ public:
 
     void Close();
 
-    unsigned char readNextByte();
+    std::optional<unsigned char> readNextByte();
 
 
 private:

src/core/streams/BitStream.h

@@ -27,6 +27,8 @@ public:
 
     virtual void writeByte(unsigned char data) = 0;
 
+    virtual void writeBytes(const std::vector<unsigned char> data) = 0;
+
 protected:
     int mByteOffset{0};
     unsigned mBitOffset{0};

src/core/streams/BufferBitStream.h

@@ -17,6 +17,11 @@ public:
 
     void writeByte(unsigned char data) override;
 
+    void writeBytes(const std::vector<unsigned char> data) override
+    {
+        std::copy(data.begin(), data.end(), std::back_inserter(mBuffer));
+    }
+
     const std::vector<unsigned char>& getBuffer() const
     {
         return mBuffer;

src/core/streams/InputBitStream.h

@@ -16,6 +16,11 @@ class InputBitStream : public BitStream
 
     void writeByte(unsigned char data) override;
 
+    void writeBytes(const std::vector<unsigned char> data) override
+    {
+
+    }
+
 private:
     std::basic_istream<unsigned char>* mStream{nullptr};
 };

src/core/streams/OutputBitStream.cpp

@@ -26,3 +26,11 @@ void OutputBitStream::writeByte(unsigned char data)
 {
     (*mStream) << data;
 }
+
+void OutputBitStream::writeBytes(const std::vector<unsigned char> data)
+{
+    for(auto byte : data)
+    {
+        writeByte(byte);
+    }
+}

src/core/streams/OutputBitStream.h

@@ -17,6 +17,8 @@ public:
 
     void writeByte(unsigned char data) override;
 
+    void writeBytes(const std::vector<unsigned char> data) override;
+
 private:
     std::basic_ostream<char>* mStream{nullptr};
 };