public HuffmanCodesBinaryTree()
{
valueToHuffmanCodeDictionary = new Dictionary <byte, Stack <bool> >();
binaryTree = new HackBinaryTree();
}
public static JpgHeaders readJpgFileHeader(ref byte[] fileBytes)
{
JpgHeaders jpgFileHeaders = new JpgHeaders();
jpgFileHeaders.fileOk = true;
jpgFileHeaders.imageDataStartOffsetInBytes = 2;
jpgFileHeaders.isLittleEndian = true;
jpgFileHeaders.codeToSignedValueDictionary = new Dictionary <string, Int16>();
jpgFileHeaders.codeToSignedValueDictionary.Add("", 0);
jpgFileHeaders.signedValueToCodeDictionary = new Dictionary <Int16, string>();
jpgFileHeaders.signedValueToCodeDictionary.Add(0, "");
jpgFileHeaders.huffmanCodesBinaryTrees = new Dictionary <byte, HuffmanCodesBinaryTree>();
Int16 rangeMin = -2047;
Int16 rangeMax = 2047;
Int16 currentStartingMinValue = -1;
Int16 currentMinValue = 0;
Int16 currentMaxValue = 0;
byte codeLength = 1;
while (currentMinValue > rangeMin && currentMaxValue < rangeMax)
{
Int16 numberOfValuesInCurrentHalfIteration = (Int16)(1 << (codeLength - 1));
Int16 currentValueIteration = 0;
while (currentValueIteration < numberOfValuesInCurrentHalfIteration)
{
currentMinValue = (Int16)(currentStartingMinValue + currentValueIteration);
jpgFileHeaders.codeToSignedValueDictionary.Add(binaryToString(currentValueIteration, codeLength), currentMinValue);
jpgFileHeaders.signedValueToCodeDictionary.Add(currentMinValue, binaryToString(currentValueIteration, codeLength));
currentValueIteration++;
}
currentValueIteration = 0;
while (currentValueIteration < numberOfValuesInCurrentHalfIteration)
{
currentMaxValue = (Int16)(numberOfValuesInCurrentHalfIteration + currentValueIteration);
jpgFileHeaders.codeToSignedValueDictionary.Add(binaryToString((Int16)(numberOfValuesInCurrentHalfIteration + currentValueIteration), codeLength), currentMaxValue);
jpgFileHeaders.signedValueToCodeDictionary.Add(currentMaxValue, binaryToString((Int16)(numberOfValuesInCurrentHalfIteration + currentValueIteration), codeLength));
currentValueIteration++;
}
currentStartingMinValue -= (Int16)(1 << (codeLength));
codeLength++;
}
MemoryStreamWithTypedReads binaryReader = new MemoryStreamWithTypedReads(fileBytes);
UInt16 readMarker;
bool firstPass = true;
bool dataNotStarted = true;
while (((readMarker = binaryReader.readUInt16()) != JpgMarkers.endOfImage) && jpgFileHeaders.fileOk && dataNotStarted)
{
dataNotStarted = readMarker != JpgMarkers.startOfScan;
if (dataNotStarted)
{
switch (readMarker)
{
case (JpgMarkers.startOfHuffmanTables): {
UInt16 expectedTablesLength = binaryReader.readUInt16();
jpgFileHeaders.imageDataStartOffsetInBytes += 2 + expectedTablesLength;
for (UInt64 readBytes = 2; readBytes < expectedTablesLength; readBytes++)
{
UInt32 currentTableLength = 0;
byte classAndIndetifierByte = binaryReader.readByte();
currentTableLength += 8;
readBytes++;
HuffmanCodesBinaryTree huffmanCodesBinaryTree = new HuffmanCodesBinaryTree();
ref HackBinaryTree currentBinaryTree = ref huffmanCodesBinaryTree.binaryTree;
byte maxCodeLength = 0;
byte[] extractedHuffmanCodeCounts = new byte[16];
for (int lengthOfCode = 1; lengthOfCode <= 16; lengthOfCode++)
{
extractedHuffmanCodeCounts[lengthOfCode - 1] = binaryReader.readByte();
currentTableLength += 8;
readBytes++;
}
for (int lengthOfCode = 1; lengthOfCode <= 16; lengthOfCode++)
{
for (int codeIndex = 0; codeIndex < extractedHuffmanCodeCounts[lengthOfCode - 1]; codeIndex++)
{
maxCodeLength = (byte)lengthOfCode;
HackBinaryTreeElement nextElement = currentBinaryTree.freeNodesAtCurrentDepth.Peek();
byte value = binaryReader.readByte();
huffmanCodesBinaryTree.valueToHuffmanCodeDictionary.Add(value, nextElement.unwind());
currentBinaryTree.addValue(value);
currentTableLength += 8;
readBytes++;
}
currentBinaryTree.addDepth();
}
huffmanCodesBinaryTree.maxCodeLength = maxCodeLength;
huffmanCodesBinaryTree.inFileLength = currentTableLength;
jpgFileHeaders.huffmanCodesBinaryTrees.Add(classAndIndetifierByte, huffmanCodesBinaryTree);
}
} break;
