private static JpegHuffmanCanonicalCode[] BuildCanonicalCode(ReadOnlySpan <byte> bits, ReadOnlySpan <Symbol> symbols)
{
int codeCount = symbols.Length;
var codes = new JpegHuffmanCanonicalCode[codeCount];
int currentCodeLength = 1;
ref byte codeLengthsRef = ref MemoryMarshal.GetReference(bits);
public void GetCode(int symbol, out ushort code, out int codeLength)
{
Debug.Assert((uint)symbol < 256);
JpegHuffmanCanonicalCode c = _codes[_symbolMap[symbol]];
code = c.Code;
codeLength = c.CodeLength;
}
private static JpegHuffmanCanonicalCode[] BuildCanonicalCode(ReadOnlySpan <byte> codeLengths, ReadOnlySpan <byte> codeValues)
{
int codeCount = codeValues.Length;
var codes = new JpegHuffmanCanonicalCode[codeCount];
Span <byte> codeLengthsBuffer = stackalloc byte[16];
codeLengths.CopyTo(codeLengthsBuffer);
int currentCodeLength = 1;
ref byte codeLengthsRef = ref MemoryMarshal.GetReference(codeLengthsBuffer);
public JpegHuffmanEncodingTable(JpegHuffmanCanonicalCode[] codes)
{
_codes = codes ?? throw new ArgumentNullException(nameof(codes));
int codeCount = 0;
_symbolMap = new byte[256];
for (int i = 0; i < codes.Length; i++)
{
JpegHuffmanCanonicalCode code = codes[i];
if (code.CodeLength != 0)
{
_symbolMap[code.Symbol] = (byte)i;
codeCount++;
}
}
_codeCount = codeCount;
}
