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.
var c = new int[BMAX + 1]; // bit length count table
int j; // counter
var r = new int[3]; // table entry for structure assignment
var u = new int[BMAX]; // table stack
var x = new int[BMAX + 1]; // bit offsets, then code stack
int y; // number of dummy codes added
// Generate counts for each bit length
var p = 0; var 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
var l = m[0];
for (j = 1; j <= BMAX; j++)
{
if (c[j] != 0)
{
break;
}
}
var k = j;
if (l < j)
{
l = j;
}
for (i = BMAX; i != 0; i--)
{
if (c[i] != 0)
{
break;
}
}
var g = i;
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; var 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
var h = -1;
var w = -l;
u[0] = 0; // just to keep compilers happy
var q = 0;
var z = 0;
// go through the bit lengths (k already is bits in shortest code)
for (; k <= g; k++)
{
var a = c[k]; // counter for codes of length k
while (a-- != 0)
{
// here i is the Huffman code of length k bits for value *p
// make tables up to required level
int f; // i repeats in table every f entries
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_DATA_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] = 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
var mask = (1 << w) - 1; // (1 << w) - 1, to avoid cc -O bug on HP
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);
}
internal int proc(InfBlocks s, ZStream z, int r)
{
//int[] t; // temporary pointer
// copy input/output information to locals (UPDATE macro restores)
var p = z.next_in_index; var n = z.avail_in; var b = s.bitb; var k = s.bitk;
var q = s.write; var m = q < s.read?s.read - q - 1:s.end - q;
// process input and output based on current state
while (true)
{
int j; // temporary storage
int tindex; // temporary pointer
int e; // extra bits or operation
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
var f = q - dist; // pointer to copy strings from
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));
}
}
}