System.util.zlib.Inflate.inflateSetDictionary C# (CSharp) Method

        internal int inflateSetDictionary(ZStream z, byte[] dictionary, int dictLength)
        {
            int index=0;
            int length = dictLength;
            if(z==null || z.istate == null|| z.istate.mode != DICT0)
                return Z_STREAM_ERROR;

            if(z._adler.adler32(1L, dictionary, 0, dictLength)!=z.adler){
                return Z_DATA_ERROR;
            }

            z.adler = z._adler.adler32(0, null, 0, 0);

            if(length >= (1<<z.istate.wbits)){
                length = (1<<z.istate.wbits)-1;
                index=dictLength - length;
            }
            z.istate.blocks.set_dictionary(dictionary, index, length);
            z.istate.mode = BLOCKS;
            return Z_OK;
        }

 public int inflateSetDictionary(byte[] dictionary, int dictLength)
 {
     if (istate == null)
     {
         return(Z_STREAM_ERROR);
     }
     return(istate.inflateSetDictionary(this, dictionary, dictLength));
 }