public SubchunkCompression(DataReader sourceData)
{
source_ = sourceData;
byte version = sourceData.ReadByte();
if (version > 8)
{
throw new InvalidDataException($"Invalid version {version}; expected 0-8");
}
version_ = version;
if (version_ == 8)
{
int blockStorageCount = sourceData.ReadByte();
for (int i = 0; i < 1; i++)
{
byte type = sourceData.ReadByte();
bool networkMode = ((type & 0x1) == 1);
PalettedCompressionType compressionType = (PalettedCompressionType)((type & (byte)PalettedCompressionType.BIT_MASK) >> 1);
type_ = compressionType;
if (GetStorageParameters(type_, out int size, out int padding))
{
offsetToPalette_ = 3 + // version, block storage, compression type
size + padding;
}
else
{
throw new InvalidDataException($"Unsupported compression type value {type_}");
}
}
private static bool GetIndexReaderParameters(PalettedCompressionType type, out uint[] masks, out uint width, out uint count, out int initialOffset)
{
switch (type)
{
case PalettedCompressionType.Paletted1:
masks = PAL1_MASKS;
width = PAL1_WIDTH;
initialOffset = PAL1_FIRST_OFFSET;
count = 32;
return(true);
case PalettedCompressionType.Paletted2:
masks = PAL2_MASKS;
width = PAL2_WIDTH;
initialOffset = PAL2_FIRST_OFFSET;
count = 16;
return(true);
case PalettedCompressionType.Paletted3:
masks = PAL3_MASKS;
width = PAL3_WIDTH;
initialOffset = PAL3_FIRST_OFFSET;
count = 10;
return(true);
case PalettedCompressionType.Paletted4:
masks = PAL4_MASKS;
width = PAL4_WIDTH;
initialOffset = PAL4_FIRST_OFFSET;
count = 8;
return(true);
case PalettedCompressionType.Paletted5:
masks = PAL5_MASKS;
width = PAL5_WIDTH;
initialOffset = PAL5_FIRST_OFFSET;
count = 6;
return(true);
case PalettedCompressionType.Paletted6:
masks = PAL6_MASKS;
width = PAL6_WIDTH;
initialOffset = PAL6_FIRST_OFFSET;
count = 5;
return(true);
case PalettedCompressionType.Paletted8:
masks = PAL8_MASKS;
width = PAL8_WIDTH;
initialOffset = PAL8_FIRST_OFFSET;
count = 4;
return(true);
case PalettedCompressionType.Paletted16:
masks = PAL16_MASKS;
width = PAL16_WIDTH;
initialOffset = PAL16_FIRST_OFFSET;
count = 2;
return(true);
default:
masks = null;
width = 0;
initialOffset = 0;
count = 0;
return(false);
}
}
public NumberSpan(uint n, PalettedCompressionType type)
{
n_ = n;
type_ = type;
}
