// 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 InflateFast(int bl, int bd, int[] tl, int tl_index, int[] td, int td_index, InflateBlocks s, ZlibCodec 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
int tp_index_t_3; // (tp_index+t)*3
// load input, output, bit values
p = z.NextIn; n = z.AvailableBytesIn; 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.InputBuffer[p++] & 0xff) << k; k += 8;
}
t = b & ml;
tp = tl;
tp_index = tl_index;
tp_index_t_3 = (tp_index + t) * 3;
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.InputBuffer[p++] & 0xff) << k; k += 8;
}
t = b & md;
tp = td;
tp_index = td_index;
tp_index_t_3 = (tp_index + t) * 3;
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.InputBuffer[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++]; // minimum count is three,
s.window[q++] = s.window[r++]; // so unroll loop a little
c -= 2;
}
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;
}
else if ((e & 64) == 0)
{
t += tp[tp_index_t_3 + 2];
t += (b & inflate_mask[e]);
tp_index_t_3 = (tp_index + t) * 3;
e = tp[tp_index_t_3];
}
else
{
z.Message = "invalid distance code";
c = z.AvailableBytesIn - n; c = (k >> 3) < c ? k >> 3 : c; n += c; p -= c; k -= (c << 3);
s.bitb = b; s.bitk = k;
z.AvailableBytesIn = n; z.TotalBytesIn += p - z.NextIn; z.NextIn = p;
s.write = q;
return ZlibConstants.Z_DATA_ERROR;
}
}
while (true);
break;
}
if ((e & 64) == 0)
{
t += tp[tp_index_t_3 + 2];
t += (b & inflate_mask[e]);
tp_index_t_3 = (tp_index + t) * 3;
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.AvailableBytesIn - n; c = (k >> 3) < c ? k >> 3 : c; n += c; p -= c; k -= (c << 3);
s.bitb = b; s.bitk = k;
z.AvailableBytesIn = n; z.TotalBytesIn += p - z.NextIn; z.NextIn = p;
s.write = q;
return ZlibConstants.Z_STREAM_END;
}
else
{
z.Message = "invalid literal/length code";
c = z.AvailableBytesIn - n; c = (k >> 3) < c ? k >> 3 : c; n += c; p -= c; k -= (c << 3);
s.bitb = b; s.bitk = k;
z.AvailableBytesIn = n; z.TotalBytesIn += p - z.NextIn; z.NextIn = p;
s.write = q;
return ZlibConstants.Z_DATA_ERROR;
}
}
while (true);
}
while (m >= 258 && n >= 10);
// not enough input or output--restore pointers and return
c = z.AvailableBytesIn - n; c = (k >> 3) < c ? k >> 3 : c; n += c; p -= c; k -= (c << 3);
s.bitb = b; s.bitk = k;
z.AvailableBytesIn = n; z.TotalBytesIn += p - z.NextIn; z.NextIn = p;
s.write = q;
return ZlibConstants.Z_OK;
}
internal int End()
{
if (blocks != null)
blocks.Free();
blocks = null;
return ZlibConstants.Z_OK;
}
internal int Initialize(ZlibCodec codec, int w)
{
_codec = codec;
_codec.Message = null;
blocks = null;
// handle undocumented nowrap option (no zlib header or check)
//nowrap = 0;
//if (w < 0)
//{
// w = - w;
// nowrap = 1;
//}
// set window size
if (w < 8 || w > 15)
{
End();
throw new ZlibException("Bad window size.");
//return ZlibConstants.Z_STREAM_ERROR;
}
wbits = w;
blocks = new InflateBlocks(codec,
HandleRfc1950HeaderBytes ? this : null,
1 << w);
// reset state
Reset();
return ZlibConstants.Z_OK;
}
internal int Process(InflateBlocks blocks, int r)
{
int j; // temporary storage
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
ZlibCodec z = blocks._codec;
// copy input/output information to locals (UPDATE macro restores)
p = z.NextIn;
n = z.AvailableBytesIn;
b = blocks.bitb;
k = blocks.bitk;
q = blocks.write; m = q < blocks.read ? blocks.read - q - 1 : blocks.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)
{
blocks.bitb = b; blocks.bitk = k;
z.AvailableBytesIn = n;
z.TotalBytesIn += p - z.NextIn;
z.NextIn = p;
blocks.write = q;
r = InflateFast(lbits, dbits, ltree, ltree_index, dtree, dtree_index, blocks, z);
p = z.NextIn;
n = z.AvailableBytesIn;
b = blocks.bitb;
k = blocks.bitk;
q = blocks.write; m = q < blocks.read ? blocks.read - q - 1 : blocks.end - q;
if (r != ZlibConstants.Z_OK)
{
mode = (r == ZlibConstants.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 = ZlibConstants.Z_OK;
else
{
blocks.bitb = b; blocks.bitk = k;
z.AvailableBytesIn = n;
z.TotalBytesIn += p - z.NextIn;
z.NextIn = p;
blocks.write = q;
return blocks.Flush(r);
}
n--;
b |= (z.InputBuffer[p++] & 0xff) << k;
k += 8;
}
tindex = (tree_index + (b & inflate_mask[j])) * 3;
b = SharedUtils.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.Message = "invalid literal/length code";
r = ZlibConstants.Z_DATA_ERROR;
blocks.bitb = b; blocks.bitk = k;
z.AvailableBytesIn = n;
z.TotalBytesIn += p - z.NextIn;
z.NextIn = p;
blocks.write = q;
return blocks.Flush(r);
case LENEXT: // i: getting length extra (have base)
j = get_Renamed;
while (k < (j))
{
if (n != 0)
r = ZlibConstants.Z_OK;
else
{
blocks.bitb = b; blocks.bitk = k;
z.AvailableBytesIn = n; z.TotalBytesIn += p - z.NextIn; z.NextIn = p;
blocks.write = q;
return blocks.Flush(r);
}
n--; b |= (z.InputBuffer[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 = ZlibConstants.Z_OK;
else
{
blocks.bitb = b; blocks.bitk = k;
z.AvailableBytesIn = n; z.TotalBytesIn += p - z.NextIn; z.NextIn = p;
blocks.write = q;
return blocks.Flush(r);
}
n--; b |= (z.InputBuffer[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.Message = "invalid distance code";
r = ZlibConstants.Z_DATA_ERROR;
blocks.bitb = b; blocks.bitk = k;
z.AvailableBytesIn = n; z.TotalBytesIn += p - z.NextIn; z.NextIn = p;
blocks.write = q;
return blocks.Flush(r);
case DISTEXT: // i: getting distance extra
j = get_Renamed;
while (k < (j))
{
if (n != 0)
r = ZlibConstants.Z_OK;
else
{
blocks.bitb = b; blocks.bitk = k;
z.AvailableBytesIn = n; z.TotalBytesIn += p - z.NextIn; z.NextIn = p;
blocks.write = q;
return blocks.Flush(r);
}
n--; b |= (z.InputBuffer[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 += blocks.end; // of "if" handles invalid distances
}
while (len != 0)
{
if (m == 0)
{
if (q == blocks.end && blocks.read != 0)
{
q = 0; m = q < blocks.read ? blocks.read - q - 1 : blocks.end - q;
}
if (m == 0)
{
blocks.write = q; r = blocks.Flush(r);
q = blocks.write; m = q < blocks.read ? blocks.read - q - 1 : blocks.end - q;
if (q == blocks.end && blocks.read != 0)
{
q = 0; m = q < blocks.read ? blocks.read - q - 1 : blocks.end - q;
}
if (m == 0)
{
blocks.bitb = b; blocks.bitk = k;
z.AvailableBytesIn = n;
z.TotalBytesIn += p - z.NextIn;
z.NextIn = p;
blocks.write = q;
return blocks.Flush(r);
}
}
}
blocks.window[q++] = blocks.window[f++]; m--;
if (f == blocks.end)
f = 0;
len--;
}
mode = START;
break;
case LIT: // o: got literal, waiting for output space
if (m == 0)
{
if (q == blocks.end && blocks.read != 0)
{
q = 0; m = q < blocks.read ? blocks.read - q - 1 : blocks.end - q;
}
if (m == 0)
{
blocks.write = q; r = blocks.Flush(r);
q = blocks.write; m = q < blocks.read ? blocks.read - q - 1 : blocks.end - q;
if (q == blocks.end && blocks.read != 0)
{
q = 0; m = q < blocks.read ? blocks.read - q - 1 : blocks.end - q;
}
if (m == 0)
{
blocks.bitb = b; blocks.bitk = k;
z.AvailableBytesIn = n; z.TotalBytesIn += p - z.NextIn; z.NextIn = p;
blocks.write = q;
return blocks.Flush(r);
}
}
}
r = ZlibConstants.Z_OK;
blocks.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
}
blocks.write = q; r = blocks.Flush(r);
q = blocks.write; m = q < blocks.read ? blocks.read - q - 1 : blocks.end - q;
if (blocks.read != blocks.write)
{
blocks.bitb = b; blocks.bitk = k;
z.AvailableBytesIn = n; z.TotalBytesIn += p - z.NextIn; z.NextIn = p;
blocks.write = q;
return blocks.Flush(r);
}
mode = END;
goto case END;
case END:
r = ZlibConstants.Z_STREAM_END;
blocks.bitb = b; blocks.bitk = k;
z.AvailableBytesIn = n; z.TotalBytesIn += p - z.NextIn; z.NextIn = p;
blocks.write = q;
return blocks.Flush(r);
case BADCODE: // x: got error
r = ZlibConstants.Z_DATA_ERROR;
blocks.bitb = b; blocks.bitk = k;
z.AvailableBytesIn = n; z.TotalBytesIn += p - z.NextIn; z.NextIn = p;
blocks.write = q;
return blocks.Flush(r);
default:
r = ZlibConstants.Z_STREAM_ERROR;
blocks.bitb = b; blocks.bitk = k;
z.AvailableBytesIn = n; z.TotalBytesIn += p - z.NextIn; z.NextIn = p;
blocks.write = q;
return blocks.Flush(r);
}
}
}