public int CopyStored(StreamManipulator input, int len)
{
len = Math.Min(Math.Min(len, WINDOW_SIZE - window_filled), input.AvailableBytes);
int copied;
int tailLen = WINDOW_SIZE - window_end;
if (len > tailLen) {
copied = input.CopyBytes(window, window_end, tailLen);
if (copied == tailLen) {
copied += input.CopyBytes(window, 0, len - tailLen);
}
} else {
copied = input.CopyBytes(window, window_end, len);
}
window_end = (window_end + copied) & WINDOW_MASK;
window_filled += copied;
return copied;
}
public bool Decode(StreamManipulator input)
{
decode_loop:
for (;;) {
switch (mode) {
case LNUM:
lnum = input.PeekBits(5);
if (lnum < 0) {
return false;
}
lnum += 257;
input.DropBits(5);
litlenLens = new byte[lnum];
// System.err.println("LNUM: "+lnum);
mode = DNUM;
goto case DNUM;/* fall through */
case DNUM:
dnum = input.PeekBits(5);
if (dnum < 0) {
return false;
}
dnum++;
input.DropBits(5);
distLens = new byte[dnum];
// System.err.println("DNUM: "+dnum);
mode = BLNUM;
goto case BLNUM;/* fall through */
case BLNUM:
blnum = input.PeekBits(4);
if (blnum < 0) {
return false;
}
blnum += 4;
input.DropBits(4);
blLens = new byte[19];
ptr = 0;
// System.err.println("BLNUM: "+blnum);
mode = BLLENS;
goto case BLLENS;/* fall through */
case BLLENS:
while (ptr < blnum) {
int len = input.PeekBits(3);
if (len < 0) {
return false;
}
input.DropBits(3);
// System.err.println("blLens["+BL_ORDER[ptr]+"]: "+len);
blLens[BL_ORDER[ptr]] = (byte) len;
ptr++;
}
blTree = new InflaterHuffmanTree(blLens);
blLens = null;
ptr = 0;
mode = LLENS;
goto case LLENS;/* fall through */
case LLENS:
while (ptr < lnum) {
int symbol = blTree.GetSymbol(input);
if (symbol < 0) {
return false;
}
switch (symbol) {
default:
// System.err.println("litlenLens["+ptr+"]: "+symbol);
litlenLens[ptr++] = (byte) symbol;
break;
case 16: /* repeat last len 3-6 times */
if (ptr == 0) {
throw new Exception("Repeating, but no prev len");
}
// System.err.println("litlenLens["+ptr+"]: repeat");
repeatedLen = litlenLens[ptr-1];
repBits = 2;
for (int i = 3; i-- > 0; ) {
if (ptr >= lnum) {
throw new Exception();
}
litlenLens[ptr++] = repeatedLen;
}
mode = LREPS;
goto decode_loop;
case 17: /* repeat zero 3-10 times */
// System.err.println("litlenLens["+ptr+"]: zero repeat");
repeatedLen = 0;
repBits = 3;
for (int i = 3; i-- > 0; ) {
if (ptr >= lnum) {
throw new Exception();
}
litlenLens[ptr++] = repeatedLen;
}
mode = LREPS;
goto decode_loop;
case 18: /* repeat zero 11-138 times */
// System.err.println("litlenLens["+ptr+"]: zero repeat");
repeatedLen = 0;
repBits = 7;
for (int i = 11; i-- > 0; ) {
if (ptr >= lnum) {
throw new Exception();
}
litlenLens[ptr++] = repeatedLen;
}
mode = LREPS;
goto decode_loop;
}
}
ptr = 0;
mode = DLENS;
goto case DLENS;/* fall through */
case DLENS:
while (ptr < dnum) {
int symbol = blTree.GetSymbol(input);
if (symbol < 0) {
return false;
}
switch (symbol) {
default:
distLens[ptr++] = (byte) symbol;
// System.err.println("distLens["+ptr+"]: "+symbol);
break;
case 16: /* repeat last len 3-6 times */
if (ptr == 0) {
throw new Exception("Repeating, but no prev len");
}
// System.err.println("distLens["+ptr+"]: repeat");
repeatedLen = distLens[ptr-1];
repBits = 2;
for (int i = 3; i-- > 0; ) {
if (ptr >= dnum) {
throw new Exception();
}
distLens[ptr++] = repeatedLen;
}
mode = DREPS;
goto decode_loop;
case 17: /* repeat zero 3-10 times */
// System.err.println("distLens["+ptr+"]: repeat zero");
repeatedLen = 0;
repBits = 3;
for (int i = 3; i-- > 0; ) {
if (ptr >= dnum) {
throw new Exception();
}
distLens[ptr++] = repeatedLen;
}
mode = DREPS;
goto decode_loop;
case 18: /* repeat zero 11-138 times */
// System.err.println("distLens["+ptr+"]: repeat zero");
repeatedLen = 0;
repBits = 7;
for (int i = 11; i-- > 0; ) {
if (ptr >= dnum) {
throw new Exception();
}
distLens[ptr++] = repeatedLen;
}
mode = DREPS;
goto decode_loop;
}
}
mode = FINISH;
return true;
case LREPS:
{
int count = input.PeekBits(repBits);
if (count < 0) {
return false;
}
input.DropBits(repBits);
// System.err.println("litlenLens repeat: "+repBits);
while (count-- > 0) {
if (ptr >= lnum) {
throw new Exception();
}
litlenLens[ptr++] = repeatedLen;
}
}
mode = LLENS;
goto decode_loop;
case DREPS:
{
int count = input.PeekBits(repBits);
if (count < 0) {
return false;
}
input.DropBits(repBits);
while (count-- > 0) {
if (ptr >= dnum) {
throw new Exception();
}
distLens[ptr++] = repeatedLen;
}
}
mode = DLENS;
goto decode_loop;
}
}
}
/// <summary>
/// Reads the next symbol from input. The symbol is encoded using the
/// huffman tree.
/// </summary>
/// <param name="input">
/// input the input source.
/// </param>
/// <returns>
/// the next symbol, or -1 if not enough input is available.
/// </returns>
public int GetSymbol(StreamManipulator input)
{
int lookahead, symbol;
if ((lookahead = input.PeekBits(9)) >= 0) {
if ((symbol = tree[lookahead]) >= 0) {
input.DropBits(symbol & 15);
return symbol >> 4;
}
int subtree = -(symbol >> 4);
int bitlen = symbol & 15;
if ((lookahead = input.PeekBits(bitlen)) >= 0) {
symbol = tree[subtree | (lookahead >> 9)];
input.DropBits(symbol & 15);
return symbol >> 4;
} else {
int bits = input.AvailableBits;
lookahead = input.PeekBits(bits);
symbol = tree[subtree | (lookahead >> 9)];
if ((symbol & 15) <= bits) {
input.DropBits(symbol & 15);
return symbol >> 4;
} else {
return -1;
}
}
} else {
int bits = input.AvailableBits;
lookahead = input.PeekBits(bits);
symbol = tree[lookahead];
if (symbol >= 0 && (symbol & 15) <= bits) {
input.DropBits(symbol & 15);
return symbol >> 4;
} else {
return -1;
}
}
}
/// <summary>
/// Creates a new inflater.
/// </summary>
/// <param name="nowrap">
/// true if no header and checksum field appears in the
/// stream. This is used for GZIPed input. For compatibility with
/// Sun JDK you should provide one byte of input more than needed in
/// this case.
/// </param>
public Inflater(bool nowrap)
{
this.nowrap = nowrap;
this.adler = new Adler32();
input = new StreamManipulator();
outputWindow = new OutputWindow();
mode = nowrap ? DECODE_BLOCKS : DECODE_HEADER;
}