예제 #1
0
        internal int proc(InfBlocks s, ZStream z, int r)
        {
            int j;             // temporary storage
            //int[] t; // temporary pointer
            int tindex;        // temporary pointer
            int e;             // extra bits or operation
            int b = 0;         // bit buffer
            int k = 0;         // bits in bit buffer
            int p = 0;         // input data pointer
            int n;             // bytes available there
            int q;             // output window write pointer
            int m;             // bytes to end of window or read pointer
            int f;             // pointer to copy strings from

            // copy input/output information to locals (UPDATE macro restores)
            p = z.next_in_index; n = z.avail_in; b = s.bitb; k = s.bitk;
            q = s.write; m = q < s.read?s.read - q - 1:s.end - q;

            // process input and output based on current state
            while (true)
            {
                switch (mode)
                {
                // waiting for "i:"=input, "o:"=output, "x:"=nothing
                case START:                          // x: set up for LEN
                    if (m >= 258 && n >= 10)
                    {
                        s.bitb     = b; s.bitk = k;
                        z.avail_in = n; z.total_in += p - z.next_in_index; z.next_in_index = p;
                        s.write    = q;
                        r          = inflate_fast(lbits, dbits, ltree, ltree_index, dtree, dtree_index, s, z);

                        p = z.next_in_index; n = z.avail_in; b = s.bitb; k = s.bitk;
                        q = s.write; m = q < s.read?s.read - q - 1:s.end - q;

                        if (r != Z_OK)
                        {
                            mode = r == Z_STREAM_END?WASH:BADCODE;
                            break;
                        }
                    }
                    need       = lbits;
                    tree       = ltree;
                    tree_index = ltree_index;

                    mode = LEN;
                    goto case LEN;

                case LEN:                          // i: get length/literal/eob next
                    j = need;

                    while (k < (j))
                    {
                        if (n != 0)
                        {
                            r = Z_OK;
                        }
                        else
                        {
                            s.bitb     = b; s.bitk = k;
                            z.avail_in = n; z.total_in += p - z.next_in_index; z.next_in_index = p;
                            s.write    = q;
                            return(s.inflate_flush(z, r));
                        }
                        n--;
                        b |= (z.next_in[p++] & 0xff) << k;
                        k += 8;
                    }

                    tindex = (tree_index + (b & inflate_mask[j])) * 3;

                    b  = SupportClass.URShift(b, (tree[tindex + 1]));
                    k -= (tree[tindex + 1]);

                    e = tree[tindex];

                    if (e == 0)
                    {
                        // literal
                        lit  = tree[tindex + 2];
                        mode = LIT;
                        break;
                    }
                    if ((e & 16) != 0)
                    {
                        // length
                        get_Renamed = e & 15;
                        len         = tree[tindex + 2];
                        mode        = LENEXT;
                        break;
                    }
                    if ((e & 64) == 0)
                    {
                        // next table
                        need       = e;
                        tree_index = tindex / 3 + tree[tindex + 2];
                        break;
                    }
                    if ((e & 32) != 0)
                    {
                        // end of block
                        mode = WASH;
                        break;
                    }
                    mode  = BADCODE;                            // invalid code
                    z.msg = "invalid literal/length code";
                    r     = Z_DATA_ERROR;

                    s.bitb     = b; s.bitk = k;
                    z.avail_in = n; z.total_in += p - z.next_in_index; z.next_in_index = p;
                    s.write    = q;
                    return(s.inflate_flush(z, r));


                case LENEXT:                          // i: getting length extra (have base)
                    j = get_Renamed;

                    while (k < (j))
                    {
                        if (n != 0)
                        {
                            r = Z_OK;
                        }
                        else
                        {
                            s.bitb     = b; s.bitk = k;
                            z.avail_in = n; z.total_in += p - z.next_in_index; z.next_in_index = p;
                            s.write    = q;
                            return(s.inflate_flush(z, r));
                        }
                        n--; b |= (z.next_in[p++] & 0xff) << k;
                        k      += 8;
                    }

                    len += (b & inflate_mask[j]);

                    b >>= j;
                    k  -= j;

                    need       = dbits;
                    tree       = dtree;
                    tree_index = dtree_index;
                    mode       = DIST;
                    goto case DIST;

                case DIST:                          // i: get distance next
                    j = need;

                    while (k < (j))
                    {
                        if (n != 0)
                        {
                            r = Z_OK;
                        }
                        else
                        {
                            s.bitb     = b; s.bitk = k;
                            z.avail_in = n; z.total_in += p - z.next_in_index; z.next_in_index = p;
                            s.write    = q;
                            return(s.inflate_flush(z, r));
                        }
                        n--; b |= (z.next_in[p++] & 0xff) << k;
                        k      += 8;
                    }

                    tindex = (tree_index + (b & inflate_mask[j])) * 3;

                    b >>= tree[tindex + 1];
                    k  -= tree[tindex + 1];

                    e = (tree[tindex]);
                    if ((e & 16) != 0)
                    {
                        // distance
                        get_Renamed = e & 15;
                        dist        = tree[tindex + 2];
                        mode        = DISTEXT;
                        break;
                    }
                    if ((e & 64) == 0)
                    {
                        // next table
                        need       = e;
                        tree_index = tindex / 3 + tree[tindex + 2];
                        break;
                    }
                    mode  = BADCODE;                            // invalid code
                    z.msg = "invalid distance code";
                    r     = Z_DATA_ERROR;

                    s.bitb     = b; s.bitk = k;
                    z.avail_in = n; z.total_in += p - z.next_in_index; z.next_in_index = p;
                    s.write    = q;
                    return(s.inflate_flush(z, r));


                case DISTEXT:                          // i: getting distance extra
                    j = get_Renamed;

                    while (k < (j))
                    {
                        if (n != 0)
                        {
                            r = Z_OK;
                        }
                        else
                        {
                            s.bitb     = b; s.bitk = k;
                            z.avail_in = n; z.total_in += p - z.next_in_index; z.next_in_index = p;
                            s.write    = q;
                            return(s.inflate_flush(z, r));
                        }
                        n--; b |= (z.next_in[p++] & 0xff) << k;
                        k      += 8;
                    }

                    dist += (b & inflate_mask[j]);

                    b >>= j;
                    k  -= j;

                    mode = COPY;
                    goto case COPY;

                case COPY:                          // o: copying bytes in window, waiting for space
                    f = q - dist;
                    while (f < 0)
                    {
                        // modulo window size-"while" instead
                        f += s.end;                                 // of "if" handles invalid distances
                    }
                    while (len != 0)
                    {
                        if (m == 0)
                        {
                            if (q == s.end && s.read != 0)
                            {
                                q = 0; m = q < s.read?s.read - q - 1:s.end - q;
                            }
                            if (m == 0)
                            {
                                s.write = q; r = s.inflate_flush(z, r);
                                q       = s.write; m = q < s.read?s.read - q - 1:s.end - q;

                                if (q == s.end && s.read != 0)
                                {
                                    q = 0; m = q < s.read?s.read - q - 1:s.end - q;
                                }

                                if (m == 0)
                                {
                                    s.bitb     = b; s.bitk = k;
                                    z.avail_in = n; z.total_in += p - z.next_in_index; z.next_in_index = p;
                                    s.write    = q;
                                    return(s.inflate_flush(z, r));
                                }
                            }
                        }

                        s.window[q++] = s.window[f++]; m--;

                        if (f == s.end)
                        {
                            f = 0;
                        }
                        len--;
                    }
                    mode = START;
                    break;

                case LIT:                          // o: got literal, waiting for output space
                    if (m == 0)
                    {
                        if (q == s.end && s.read != 0)
                        {
                            q = 0; m = q < s.read?s.read - q - 1:s.end - q;
                        }
                        if (m == 0)
                        {
                            s.write = q; r = s.inflate_flush(z, r);
                            q       = s.write; m = q < s.read?s.read - q - 1:s.end - q;

                            if (q == s.end && s.read != 0)
                            {
                                q = 0; m = q < s.read?s.read - q - 1:s.end - q;
                            }
                            if (m == 0)
                            {
                                s.bitb     = b; s.bitk = k;
                                z.avail_in = n; z.total_in += p - z.next_in_index; z.next_in_index = p;
                                s.write    = q;
                                return(s.inflate_flush(z, r));
                            }
                        }
                    }
                    r = Z_OK;

                    s.window[q++] = (byte)lit; m--;

                    mode = START;
                    break;

                case WASH:                          // o: got eob, possibly more output
                    if (k > 7)
                    {
                        // return unused byte, if any
                        k -= 8;
                        n++;
                        p--;                                 // can always return one
                    }

                    s.write = q; r = s.inflate_flush(z, r);
                    q       = s.write; m = q < s.read?s.read - q - 1:s.end - q;

                    if (s.read != s.write)
                    {
                        s.bitb     = b; s.bitk = k;
                        z.avail_in = n; z.total_in += p - z.next_in_index; z.next_in_index = p;
                        s.write    = q;
                        return(s.inflate_flush(z, r));
                    }
                    mode = END;
                    goto case END;

                case END:
                    r          = Z_STREAM_END;
                    s.bitb     = b; s.bitk = k;
                    z.avail_in = n; z.total_in += p - z.next_in_index; z.next_in_index = p;
                    s.write    = q;
                    return(s.inflate_flush(z, r));


                case BADCODE:                          // x: got error

                    r = Z_DATA_ERROR;

                    s.bitb     = b; s.bitk = k;
                    z.avail_in = n; z.total_in += p - z.next_in_index; z.next_in_index = p;
                    s.write    = q;
                    return(s.inflate_flush(z, r));


                default:
                    r = Z_STREAM_ERROR;

                    s.bitb     = b; s.bitk = k;
                    z.avail_in = n; z.total_in += p - z.next_in_index; z.next_in_index = p;
                    s.write    = q;
                    return(s.inflate_flush(z, r));
                }
            }
        }
예제 #2
0
 // Mapping from a distance to a distance code. dist is the distance - 1 and
 // must not have side effects. _dist_code[256] and _dist_code[257] are never
 // used.
 internal static int d_code(int dist)
 {
     return((dist) < 256?_dist_code[dist]:_dist_code[256 + (SupportClass.URShift((dist), 7))]);
 }