javazoom.jl.decoder.huffcodetab.huffman_decoder C# (CSharp) Method

        public static int huffman_decoder(huffcodetab h, int[] x, int[] y, int[] v, int[] w, BitReserve br)
        {
            // array of all huffcodtable headers
            // 0..31 Huffman code table 0..31
            // 32,33 count1-tables

            int dmask = 1 << ((4 * 8) - 1);
            int hs = 4 * 8;
            int level;
            int point = 0;
            int error = 1;
            level = dmask;

            if (h.val == null)
                return 2;

            /* table 0 needs no bits */
            if (h.treelen == 0)
            {
                x[0] = y[0] = 0;
                return 0;
            }

            /* Lookup in Huffman table. */

            /*int bitsAvailable = 0;
            int bitIndex = 0;

            int bits[] = bitbuf;*/
            do
            {
                if (h.val[point][0] == 0)
                {
                    /*end of tree*/
                    x[0] = SupportClass.URShift(h.val[point][1], 4);
                    y[0] = h.val[point][1] & 0xf;
                    error = 0;
                    break;
                }

                // hget1bit() is called thousands of times, and so needs to be
                // ultra fast.
                /*
                if (bitIndex==bitsAvailable)
                {
                bitsAvailable = br.readBits(bits, 32);
                bitIndex = 0;
                }
                */
                //if (bits[bitIndex++]!=0)
                if (br.hget1bit() != 0)
                {
                    while (h.val[point][1] >= MXOFF)
                        point += h.val[point][1];
                    point += h.val[point][1];
                }
                else
                {
                    while (h.val[point][0] >= MXOFF)
                        point += h.val[point][0];
                    point += h.val[point][0];
                }
                level = SupportClass.URShift(level, 1);
                // MDM: ht[0] is always 0;
            }
            while ((level != 0) || (point < 0));

            // put back any bits not consumed
            /*
            int unread = (bitsAvailable-bitIndex);
            if (unread>0)
            br.rewindNbits(unread);
            */
            /* Process sign encodings for quadruples tables. */
            // System.out.println(h.tablename);
            if (h.tablename0 == '3' && (h.tablename1 == '2' || h.tablename1 == '3'))
            {
                v[0] = (y[0] >> 3) & 1;
                w[0] = (y[0] >> 2) & 1;
                x[0] = (y[0] >> 1) & 1;
                y[0] = y[0] & 1;

                /* v, w, x and y are reversed in the bitstream.
                switch them around to make test bistream work. */

                if (v[0] != 0)
                    if (br.hget1bit() != 0)
                        v[0] = - v[0];
                if (w[0] != 0)
                    if (br.hget1bit() != 0)
                        w[0] = - w[0];
                if (x[0] != 0)
                    if (br.hget1bit() != 0)
                        x[0] = - x[0];
                if (y[0] != 0)
                    if (br.hget1bit() != 0)
                        y[0] = - y[0];
            }
            else
            {
                // Process sign and escape encodings for dual tables.
                // x and y are reversed in the test bitstream.
                // Reverse x and y here to make test bitstream work.

                if (h.linbits != 0)
                    if ((h.xlen - 1) == x[0])
                        x[0] += br.hgetbits(h.linbits);
                if (x[0] != 0)
                    if (br.hget1bit() != 0)
                        x[0] = - x[0];
                if (h.linbits != 0)
                    if ((h.ylen - 1) == y[0])
                        y[0] += br.hgetbits(h.linbits);
                if (y[0] != 0)
                    if (br.hget1bit() != 0)
                        y[0] = - y[0];
            }
            return error;
        }