예제 #1
0
        internal const int BMAX = 15;         // maximum bit length of any code

        internal static int huft_build(int[] b, int bindex, int n, int s, int[] d, int[] e, int[] t, int[] m, int[] hp, int[] hn, int[] v)
        {
            // Given a list of code lengths and a maximum table size, make a set of
            // tables to decode that set of codes.  Return Z_OK on success, Z_BUF_ERROR
            // if the given code set is incomplete (the tables are still built in this
            // case), Z_DATA_ERROR if the input is invalid (an over-subscribed set of
            // lengths), or Z_MEM_ERROR if not enough memory.

            int a;                       // counter for codes of length k

            int[] c = new int[BMAX + 1]; // bit length count table
            int   f;                     // i repeats in table every f entries
            int   g;                     // maximum code length
            int   h;                     // table level
            int   i;                     // counter, current code
            int   j;                     // counter
            int   k;                     // number of bits in current code
            int   l;                     // bits per table (returned in m)
            int   mask;                  // (1 << w) - 1, to avoid cc -O bug on HP
            int   p;                     // pointer into c[], b[], or v[]
            int   q;                     // points to current table

            int[] r = new int[3];        // table entry for structure assignment
            int[] u = new int[BMAX];     // table stack
            int   w;                     // bits before this table == (l * h)

            int[] x = new int[BMAX + 1]; // bit offsets, then code stack
            int   xp;                    // pointer into x
            int   y;                     // number of dummy codes added
            int   z;                     // number of entries in current table

            // Generate counts for each bit length

            p = 0; i = n;
            do
            {
                c[b[bindex + p]]++; p++; i--;                 // assume all entries <= BMAX
            }while (i != 0);

            if (c[0] == n)
            {
                // null input--all zero length codes
                t[0] = -1;
                m[0] = 0;
                return(Z_OK);
            }

            // Find minimum and maximum length, bound *m by those
            l = m[0];
            for (j = 1; j <= BMAX; j++)
            {
                if (c[j] != 0)
                {
                    break;
                }
            }
            k = j;             // minimum code length
            if (l < j)
            {
                l = j;
            }
            for (i = BMAX; i != 0; i--)
            {
                if (c[i] != 0)
                {
                    break;
                }
            }
            g = i;             // maximum code length
            if (l > i)
            {
                l = i;
            }
            m[0] = l;

            // Adjust last length count to fill out codes, if needed
            for (y = 1 << j; j < i; j++, y <<= 1)
            {
                if ((y -= c[j]) < 0)
                {
                    return(Z_DATA_ERROR);
                }
            }
            if ((y -= c[i]) < 0)
            {
                return(Z_DATA_ERROR);
            }
            c[i] += y;

            // Generate starting offsets into the value table for each length
            x[1] = j = 0;
            p    = 1; xp = 2;
            while (--i != 0)
            {
                // note that i == g from above
                x[xp] = (j += c[p]);
                xp++;
                p++;
            }

            // Make a table of values in order of bit lengths
            i = 0; p = 0;
            do
            {
                if ((j = b[bindex + p]) != 0)
                {
                    v[x[j]++] = i;
                }
                p++;
            }while (++i < n);
            n = x[g];             // set n to length of v

            // Generate the Huffman codes and for each, make the table entries
            x[0] = i = 0;      // first Huffman code is zero
            p    = 0;          // grab values in bit order
            h    = -1;         // no tables yet--level -1
            w    = -l;         // bits decoded == (l * h)
            u[0] = 0;          // just to keep compilers happy
            q    = 0;          // ditto
            z    = 0;          // ditto

            // go through the bit lengths (k already is bits in shortest code)
            for (; k <= g; k++)
            {
                a = c[k];
                while (a-- != 0)
                {
                    // here i is the Huffman code of length k bits for value *p
                    // make tables up to required level
                    while (k > w + l)
                    {
                        h++;
                        w += l;                         // previous table always l bits
                        // compute minimum size table less than or equal to l bits
                        z = g - w;
                        z = (z > l)?l:z;                         // table size upper limit
                        if ((f = 1 << (j = k - w)) > a + 1)
                        {
                            // try a k-w bit table
                            // too few codes for k-w bit table
                            f -= (a + 1);                             // deduct codes from patterns left
                            xp = k;
                            if (j < z)
                            {
                                while (++j < z)
                                {
                                    // try smaller tables up to z bits
                                    if ((f <<= 1) <= c[++xp])
                                    {
                                        break;                                      // enough codes to use up j bits
                                    }
                                    f -= c[xp];                                     // else deduct codes from patterns
                                }
                            }
                        }
                        z = 1 << j;                         // table entries for j-bit table

                        // allocate new table
                        if (hn[0] + z > MANY)
                        {
                            // (note: doesn't matter for fixed)
                            return(Z_MEM_ERROR);                  // overflow of MANY
                        }
                        u[h]   = q = hn[0];                       // DEBUG
                        hn[0] += z;

                        // connect to last table, if there is one
                        if (h != 0)
                        {
                            x[h] = i;                                    // save pattern for backing up
                            r[0] = (byte)j;                              // bits in this table
                            r[1] = (byte)l;                              // bits to dump before this table
                            j    = SupportClass.URShift(i, (w - l));
                            r[2] = (int)(q - u[h - 1] - j);              // offset to this table
                            Array.Copy(r, 0, hp, (u[h - 1] + j) * 3, 3); // connect to last table
                        }
                        else
                        {
                            t[0] = q;                             // first table is returned result
                        }
                    }

                    // set up table entry in r
                    r[1] = (byte)(k - w);
                    if (p >= n)
                    {
                        r[0] = 128 + 64;                         // out of values--invalid code
                    }
                    else if (v[p] < s)
                    {
                        r[0] = (byte)(v[p] < 256?0:32 + 64);   // 256 is end-of-block
                        r[2] = v[p++];                         // simple code is just the value
                    }
                    else
                    {
                        r[0] = (byte)(e[v[p] - s] + 16 + 64);                          // non-simple--look up in lists
                        r[2] = d[v[p++] - s];
                    }

                    // fill code-like entries with r
                    f = 1 << (k - w);
                    for (j = SupportClass.URShift(i, w); j < z; j += f)
                    {
                        Array.Copy(r, 0, hp, (q + j) * 3, 3);
                    }

                    // backwards increment the k-bit code i
                    for (j = 1 << (k - 1); (i & j) != 0; j = SupportClass.URShift(j, 1))
                    {
                        i ^= j;
                    }
                    i ^= j;

                    // backup over finished tables
                    mask = (1 << w) - 1;                     // needed on HP, cc -O bug
                    while ((i & mask) != x[h])
                    {
                        h--;                         // don't need to update q
                        w   -= l;
                        mask = (1 << w) - 1;
                    }
                }
            }
            // Return Z_BUF_ERROR if we were given an incomplete table
            return(y != 0 && g != 1?Z_BUF_ERROR:Z_OK);
        }
예제 #2
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));
                }
            }
        }