/* ----------------------------------------------------------- */

void LoadFollowers()
{
    register int x;
    register int i;

    for (x = 255; x >= 0; x--) {
        READBIT(6,Slen[x]);
        for (i = 0; i < Slen[x]; i++) {
            READBIT(8,followers[x][i]);
        }
    }
}


/* ----------------------------------------------------------- */
/*
 * The Reducing algorithm is actually a combination of two
 * distinct algorithms.  The first algorithm compresses repeated
 * byte sequences, and the second algorithm takes the compressed
 * stream from the first algorithm and applies a probabilistic
 * compression method.
 */

int L_table[] = {0, 0x7f, 0x3f, 0x1f, 0x0f};

int D_shift[] = {0, 0x07, 0x06, 0x05, 0x04};
int D_mask[]  = {0, 0x01, 0x03, 0x07, 0x0f};

int B_table[] = {8, 1, 1, 2, 2, 3, 3, 3, 3, 4, 4, 4, 4, 4, 4, 4, 4, 5,
                 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 6, 6, 6,
                 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6,
                 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 7, 7, 7, 7, 7, 7, 7,
                 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7,
                 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7,
                 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7,
                 7, 7, 7, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8,
                 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8,
                 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8,
                 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8,
                 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8,
                 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8,
                 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8,
                 8, 8, 8, 8};

/* ----------------------------------------------------------- */

void unReduce()
 /* expand probablisticly reduced data */
{
    register int lchar;
    int nchar;
    int ExState;
    int V;
    int Len;

    factor = lrec.compression_method - 1;
    ExState = 0;
    lchar = 0;
    LoadFollowers();

    while (((outpos+outcnt) < ucsize) && (!zipeof)) {
        if (Slen[lchar] == 0)
            READBIT(8,nchar)      /* ; */
        else
        {
            READBIT(1,nchar);
            if (nchar != 0)
                READBIT(8,nchar)      /* ; */
            else
            {
                int follower;
                int bitsneeded = B_table[Slen[lchar]];
                READBIT(bitsneeded,follower);
                nchar = followers[lchar][follower];
            }
        }

        /* expand the resulting byte */
        switch (ExState) {

        case 0:
            if (nchar != DLE)
                OUTB(nchar) /*;*/
            else
                ExState = 1;
            break;

        case 1:
            if (nchar != 0) {
                V = nchar;
                Len = V & L_table[factor];
                if (Len == L_table[factor])
                    ExState = 2;
                else
                    ExState = 3;
            }
            else {
                OUTB(DLE);
                ExState = 0;
            }
            break;

        case 2: {
                Len += nchar;
                ExState = 3;
            }
            break;

        case 3: {
                register int i = Len + 3;
                int offset = (((V >> D_shift[factor]) &
                                     D_mask[factor]) << 8) + nchar + 1;
                longint op = (outpos+outcnt) - offset;

                /* special case- before start of file */
                while ((op < 0L) && (i > 0)) {
                    OUTB(0);
                    op++;
                    i--;
                }

                /* normal copy of data from output buffer */
                {
                    register int ix = (int) (op % OUTBUFSIZ);

                    /* do a block memory copy if possible */
                    if ( ((ix    +i) < OUTBUFSIZ) &&
                      ((outcnt+i) < OUTBUFSIZ) ) {
                        zmemcpy(outptr,&outbuf[ix],i);
                        outptr += i;
                        outcnt += i;
                    }

                    /* otherwise copy byte by byte */
                    else while (i--) {
                        OUTB(outbuf[ix]);
                        if (++ix >= OUTBUFSIZ)
                            ix = 0;
                    }
                }

                ExState = 0;
            }
            break;
        }

        /* store character for next iteration */
        lchar = nchar;
    }
}