// Called with number of bytes left to write in window at least 258
// (the maximum string length) and number of input bytes available
// at least ten. The ten bytes are six bytes for the longest length/
// distance pair plus four bytes for overloading the bit buffer.
internal int inflate_fast(int bl, int bd, int[] tl, int tl_index, int[] td, int td_index, InfBlocks s, ZStream z)
{
int t; // temporary pointer
int[] tp; // temporary pointer
int tp_index; // temporary pointer
int e; // extra bits or operation
int b; // bit buffer
int k; // bits in bit buffer
int p; // 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 ml; // mask for literal/length tree
int md; // mask for distance tree
int c; // bytes to copy
int d; // distance back to copy from
int r; // copy source pointer
// load input, output, bit values
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;
// initialize masks
ml = inflate_mask[bl];
md = inflate_mask[bd];
// do until not enough input or output space for fast loop
do
{
// assume called with m >= 258 && n >= 10
// get literal/length code
while (k < 20)
{
// max bits for literal/length code
n--;
b |= (z.next_in[p++] & 0xff) << k; k += 8;
}
t = b & ml;
tp = tl;
tp_index = tl_index;
if ((e = tp[(tp_index + t) * 3]) == 0)
{
b >>= tp[(tp_index + t) * 3 + 1]; k -= tp[(tp_index + t) * 3 + 1];
s.window[q++] = (byte)tp[(tp_index + t) * 3 + 2];
m--;
continue;
}
do
{
b >>= tp[(tp_index + t) * 3 + 1]; k -= tp[(tp_index + t) * 3 + 1];
if ((e & 16) != 0)
{
e &= 15;
c = tp[(tp_index + t) * 3 + 2] + (b & inflate_mask[e]);
b >>= e; k -= e;
// decode distance base of block to copy
while (k < 15)
{
// max bits for distance code
n--;
b |= (z.next_in[p++] & 0xff) << k; k += 8;
}
t = b & md;
tp = td;
tp_index = td_index;
e = tp[(tp_index + t) * 3];
do
{
b >>= tp[(tp_index + t) * 3 + 1]; k -= tp[(tp_index + t) * 3 + 1];
if ((e & 16) != 0)
{
// get extra bits to add to distance base
e &= 15;
while (k < e)
{
// get extra bits (up to 13)
n--;
b |= (z.next_in[p++] & 0xff) << k; k += 8;
}
d = tp[(tp_index + t) * 3 + 2] + (b & inflate_mask[e]);
b >>= e; k -= e;
// do the copy
m -= c;
if (q >= d)
{
// offset before dest
// just copy
r = q - d;
if (q - r > 0 && 2 > q - r)
{
s.window[q++] = s.window[r++]; c--; // minimum count is three,
s.window[q++] = s.window[r++]; c--; // so unroll loop a little
}
else
{
Array.Copy(s.window, r, s.window, q, 2);
q += 2; r += 2; c -= 2;
}
}
else
{
// else offset after destination
r = q - d;
do
{
r += s.end; // force pointer in window
}while (r < 0); // covers invalid distances
e = s.end - r;
if (c > e)
{
// if source crosses,
c -= e; // wrapped copy
if (q - r > 0 && e > q - r)
{
do
{
s.window[q++] = s.window[r++];
}while (--e != 0);
}
else
{
Array.Copy(s.window, r, s.window, q, e);
q += e; r += e; e = 0;
}
r = 0; // copy rest from start of window
}
}
// copy all or what's left
if (q - r > 0 && c > q - r)
{
do
{
s.window[q++] = s.window[r++];
}while (--c != 0);
}
else
{
Array.Copy(s.window, r, s.window, q, c);
q += c; r += c; c = 0;
}
break;
}
if ((e & 64) == 0)
{
t += tp[(tp_index + t) * 3 + 2];
t += b & inflate_mask[e];
e = tp[(tp_index + t) * 3];
}
else
{
z.msg = "invalid distance code";
c = z.avail_in - n; c = k >> 3 < c?k >> 3:c; n += c; p -= c; k -= c << 3;
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(Z_DATA_ERROR);
}
}while (true);
break;
}
if ((e & 64) == 0)
{
t += tp[(tp_index + t) * 3 + 2];
t += b & inflate_mask[e];
if ((e = tp[(tp_index + t) * 3]) == 0)
{
b >>= tp[(tp_index + t) * 3 + 1]; k -= tp[(tp_index + t) * 3 + 1];
s.window[q++] = (byte)tp[(tp_index + t) * 3 + 2];
m--;
break;
}
}
else if ((e & 32) != 0)
{
c = z.avail_in - n; c = k >> 3 < c?k >> 3:c; n += c; p -= c; k -= c << 3;
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(Z_STREAM_END);
}
else
{
z.msg = "invalid literal/length code";
c = z.avail_in - n; c = k >> 3 < c?k >> 3:c; n += c; p -= c; k -= c << 3;
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(Z_DATA_ERROR);
}
}while (true);
}while (m >= 258 && n >= 10);
// not enough input or output--restore pointers and return
c = z.avail_in - n; c = k >> 3 < c?k >> 3:c; n += c; p -= c; k -= c << 3;
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(Z_OK);
}
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
var b = 0; // bit buffer
var k = 0; // bits in bit buffer
var 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));
}
}
}