private ZlibHeader(
byte compressionMethod, byte compressionInfo, byte check, bool dict, FLevel level)
{
CompressionMethod = compressionMethod;
CompressionInfo = compressionInfo;
Check = check;
Dict = dict;
Level = level;
}
public static ZlibHeader Decode(byte cmf, byte flg)
{
byte CompressionMethod = Convert.ToByte(cmf & 0x0F);
byte CompressionInfo = Convert.ToByte((cmf & 0xF0) >> 4);
byte FCheck = Convert.ToByte(flg & 0x1F);
bool FDict = Convert.ToBoolean(Convert.ToByte((flg & 0x20) >> 5));
FLevel Level = (FLevel)Convert.ToByte((flg & 0xC0) >> 6);
return(new ZlibHeader(CompressionMethod, CompressionInfo, FCheck, FDict, Level));
}
public static CompressionLevel ConvertLevel(FLevel level)
{
switch (level)
{
case FLevel.Faster: return(CompressionLevel.NoCompression);
case FLevel.Default: return(CompressionLevel.Fastest);
case FLevel.Optimal: return(CompressionLevel.Optimal);
default:
throw new ArgumentOutOfRangeException(nameof(level));
}
}
public ZlibHeader(byte compressionMethod, byte compressionInfo, bool dict, FLevel level) : this()
{
if (compressionMethod > 15)
{
throw new ArgumentOutOfRangeException(
nameof(compressionMethod), "Argument cannot be greater than 15.");
}
if (compressionInfo > 15)
{
throw new ArgumentOutOfRangeException(
nameof(compressionInfo), "Argument cannot be greater than 15.");
}
CompressionMethod = compressionMethod;
CompressionInfo = compressionInfo;
Dict = dict;
Level = level;
byte byteFLG = (byte)((byte)Level << 1);
byteFLG |= Convert.ToByte(Dict);
Check = Convert.ToByte(31 - Convert.ToByte((GetCMF() * 256 + byteFLG) % 31));
}
