/// <summary>
/// Initializes the inflate algorithm
/// </summary>
/// <param name="z">A ZStream object</param>
/// <param name="windowBits">Window size</param>
/// <returns>Operation result code</returns>
internal int inflateInit(ZStream z, int windowBits)
{
z.msg = null;
blocks = null;
// handle undocumented nowrap option (no zlib header or check)
nowrap = 0;
if (windowBits < 0)
{
windowBits = -windowBits;
nowrap = 1;
}
// set Window size
if (windowBits < 8 || windowBits > 15)
{
inflateEnd(z);
return((int)ZLibResultCode.Z_STREAM_ERROR);
}
wbits = windowBits;
z.istate.blocks = new InfBlocks(z, z.istate.nowrap == 0, 1 << windowBits);
// reset state
inflateReset(z);
return((int)ZLibResultCode.Z_OK);
}
/// <summary>
/// Finishes the inflate algorithm processing
/// </summary>
/// <param name="z">A ZStream object</param>
/// <returns>Operation result code</returns>
internal int inflateEnd(ZStream z)
{
if (blocks != null)
{
blocks.free(z);
}
blocks = null;
// ZFREE(z, z->state);
return((int)ZLibResultCode.Z_OK);
}
/// <summary>
/// Fast inflate procedure. Called with number of bytes left to WritePos 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.
/// </summary>
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 WritePos pointer
int m; // bytes to End of Window or ReadPos 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.WritePos; m = q < s.ReadPos?s.ReadPos - q - 1:s.End - q;
// initialize masks
ml = ZLibUtil.inflate_mask[bl];
md = ZLibUtil.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 & ZLibUtil.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 & ZLibUtil.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;
}
else if ((e & 64) == 0)
{
t += tp[(tp_index + t) * 3 + 2];
t += (b & ZLibUtil.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.WritePos = q;
return((int)ZLibResultCode.Z_DATA_ERROR);
}
}while (true);
break;
}
if ((e & 64) == 0)
{
t += tp[(tp_index + t) * 3 + 2];
t += (b & ZLibUtil.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.WritePos = q;
return((int)ZLibResultCode.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.WritePos = q;
return((int)ZLibResultCode.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.WritePos = q;
return((int)ZLibResultCode.Z_OK);
}
/// <summary>
/// Block processing method
/// </summary>
/// <param name="s">An instance of the InfBlocks class</param>
/// <param name="z">A ZStream object</param>
/// <param name="r">A result code</param>
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 WritePos pointer
int m; // bytes to End of Window or ReadPos 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.WritePos; m = q < s.ReadPos?s.ReadPos - 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 InflateCodesMode.START: // x: set up for InflateCodesMode.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.WritePos = 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.WritePos; m = q < s.ReadPos?s.ReadPos - q - 1:s.End - q;
if (r != (int)ZLibResultCode.Z_OK)
{
mode = r == (int)ZLibResultCode.Z_STREAM_END? InflateCodesMode.WASH: InflateCodesMode.BADCODE;
break;
}
}
need = lbits;
tree = ltree;
tree_index = ltree_index;
mode = InflateCodesMode.LEN;
goto case InflateCodesMode.LEN;
case InflateCodesMode.LEN: // i: get length/literal/eob next
j = need;
while (k < (j))
{
if (n != 0)
{
r = (int)ZLibResultCode.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.WritePos = q;
return(s.inflate_flush(z, r));
}
n--;
b |= (z.next_in[p++] & 0xff) << k;
k += 8;
}
tindex = (tree_index + (b & ZLibUtil.inflate_mask[j])) * 3;
b = ZLibUtil.URShift(b, (tree[tindex + 1]));
k -= (tree[tindex + 1]);
e = tree[tindex];
if (e == 0)
{
// literal
lit = tree[tindex + 2];
mode = InflateCodesMode.LIT;
break;
}
if ((e & 16) != 0)
{
// length
get_Renamed = e & 15;
count = tree[tindex + 2];
mode = InflateCodesMode.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 = InflateCodesMode.WASH;
break;
}
mode = InflateCodesMode.BADCODE; // invalid code
z.msg = "invalid literal/length code";
r = (int)ZLibResultCode.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.WritePos = q;
return(s.inflate_flush(z, r));
case InflateCodesMode.LENEXT: // i: getting length extra (have base)
j = get_Renamed;
while (k < (j))
{
if (n != 0)
{
r = (int)ZLibResultCode.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.WritePos = q;
return(s.inflate_flush(z, r));
}
n--; b |= (z.next_in[p++] & 0xff) << k;
k += 8;
}
count += (b & ZLibUtil.inflate_mask[j]);
b >>= j;
k -= j;
need = dbits;
tree = dtree;
tree_index = dtree_index;
mode = InflateCodesMode.DIST;
goto case InflateCodesMode.DIST;
case InflateCodesMode.DIST: // i: get distance next
j = need;
while (k < (j))
{
if (n != 0)
{
r = (int)ZLibResultCode.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.WritePos = q;
return(s.inflate_flush(z, r));
}
n--; b |= (z.next_in[p++] & 0xff) << k;
k += 8;
}
tindex = (tree_index + (b & ZLibUtil.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 = InflateCodesMode.DISTEXT;
break;
}
if ((e & 64) == 0)
{
// next table
need = e;
tree_index = tindex / 3 + tree[tindex + 2];
break;
}
mode = InflateCodesMode.BADCODE; // invalid code
z.msg = "invalid distance code";
r = (int)ZLibResultCode.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.WritePos = q;
return(s.inflate_flush(z, r));
case InflateCodesMode.DISTEXT: // i: getting distance extra
j = get_Renamed;
while (k < (j))
{
if (n != 0)
{
r = (int)ZLibResultCode.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.WritePos = q;
return(s.inflate_flush(z, r));
}
n--; b |= (z.next_in[p++] & 0xff) << k;
k += 8;
}
dist += (b & ZLibUtil.inflate_mask[j]);
b >>= j;
k -= j;
mode = InflateCodesMode.COPY;
goto case InflateCodesMode.COPY;
case InflateCodesMode.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 (count != 0)
{
if (m == 0)
{
if (q == s.End && s.ReadPos != 0)
{
q = 0; m = q < s.ReadPos?s.ReadPos - q - 1:s.End - q;
}
if (m == 0)
{
s.WritePos = q; r = s.inflate_flush(z, r);
q = s.WritePos; m = q < s.ReadPos?s.ReadPos - q - 1:s.End - q;
if (q == s.End && s.ReadPos != 0)
{
q = 0; m = q < s.ReadPos?s.ReadPos - 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.WritePos = q;
return(s.inflate_flush(z, r));
}
}
}
s.Window[q++] = s.Window[f++]; m--;
if (f == s.End)
{
f = 0;
}
count--;
}
mode = InflateCodesMode.START;
break;
case InflateCodesMode.LIT: // o: got literal, waiting for output space
if (m == 0)
{
if (q == s.End && s.ReadPos != 0)
{
q = 0; m = q < s.ReadPos?s.ReadPos - q - 1:s.End - q;
}
if (m == 0)
{
s.WritePos = q; r = s.inflate_flush(z, r);
q = s.WritePos; m = q < s.ReadPos?s.ReadPos - q - 1:s.End - q;
if (q == s.End && s.ReadPos != 0)
{
q = 0; m = q < s.ReadPos?s.ReadPos - 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.WritePos = q;
return(s.inflate_flush(z, r));
}
}
}
r = (int)ZLibResultCode.Z_OK;
s.Window[q++] = (byte)lit; m--;
mode = InflateCodesMode.START;
break;
case InflateCodesMode.WASH: // o: got eob, possibly more output
if (k > 7)
{
// return unused byte, if any
k -= 8;
n++;
p--; // can always return one
}
s.WritePos = q; r = s.inflate_flush(z, r);
q = s.WritePos; m = q < s.ReadPos?s.ReadPos - q - 1:s.End - q;
if (s.ReadPos != s.WritePos)
{
s.BitB = b; s.BitK = k;
z.avail_in = n; z.total_in += p - z.next_in_index; z.next_in_index = p;
s.WritePos = q;
return(s.inflate_flush(z, r));
}
mode = InflateCodesMode.END;
goto case InflateCodesMode.END;
case InflateCodesMode.END:
r = (int)ZLibResultCode.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.WritePos = q;
return(s.inflate_flush(z, r));
case InflateCodesMode.BADCODE: // x: got error
r = (int)ZLibResultCode.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.WritePos = q;
return(s.inflate_flush(z, r));
default:
r = (int)ZLibResultCode.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.WritePos = q;
return(s.inflate_flush(z, r));
}
}
}