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private inflate_fast ( int bl, int bd, int tl, int tl_index, int td, int td_index, |
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| bl | int | |
| bd | int | |
| tl | int | |
| tl_index | int | |
| td | int | |
| td_index | int | |
| s | ||
| z | ||
| return | int | |
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] + ((int) 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
{
Buffer.BlockCopy(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
{
Buffer.BlockCopy(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
{
Buffer.BlockCopy(s.window, r, s.window, q, c);
q += c; r += c; c = 0;
}
break;
}
else 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;
}