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/* java.util.zip.OutputWindow
Copyright (C) 2001 Free Software Foundation, Inc.
This file is part of GNU Classpath.
GNU Classpath is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2, or (at your option)
any later version.
GNU Classpath is distributed in the hope that it will be useful, but
WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
General Public License for more details.
You should have received a copy of the GNU General Public License
along with GNU Classpath; see the file COPYING. If not, write to the
Free Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
02111-1307 USA.
As a special exception, if you link this library with other files to
produce an executable, this library does not by itself cause the
resulting executable to be covered by the GNU General Public License.
This exception does not however invalidate any other reasons why the
executable file might be covered by the GNU General Public License. */
package java.util.zip;
/*
* Contains the output from the Inflation process.
*
* We need to have a window so that we can refer backwards into the output stream
* to repeat stuff.
*
* @author John Leuner
* @since JDK 1.1
*/
class OutputWindow
{
private final int WINDOW_SIZE = 1 << 15;
private final int WINDOW_MASK = WINDOW_SIZE - 1;
private byte[] window = new byte[WINDOW_SIZE]; //The window is 2^15 bytes
private int window_end = 0;
private int window_filled = 0;
public void write(int abyte)
{
if (window_filled++ == WINDOW_SIZE)
throw new IllegalStateException("Window full");
window[window_end++] = (byte) abyte;
window_end &= WINDOW_MASK;
}
private final void slowRepeat(int rep_start, int len, int dist)
{
while (len-- > 0)
{
window[window_end++] = window[rep_start++];
window_end &= WINDOW_MASK;
rep_start &= WINDOW_MASK;
}
}
public void repeat(int len, int dist)
{
if ((window_filled += len) > WINDOW_SIZE)
throw new IllegalStateException("Window full");
int rep_start = (window_end - dist) & WINDOW_MASK;
int border = WINDOW_SIZE - len;
if (rep_start <= border && window_end < border)
{
if (len <= dist)
{
System.arraycopy(window, rep_start, window, window_end, len);
window_end += len;
}
else
{
/* We have to copy manually, since the repeat pattern overlaps.
*/
while (len-- > 0)
window[window_end++] = window[rep_start++];
}
}
else
slowRepeat(rep_start, len, dist);
}
public int copyStored(StreamManipulator input, int len)
{
len = Math.min(Math.min(len, WINDOW_SIZE - window_filled),
input.getAvailableBytes());
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 void copyDict(byte[] dict, int offset, int len)
{
if (window_filled > 0)
throw new IllegalStateException();
if (len > WINDOW_SIZE)
{
offset += len - WINDOW_SIZE;
len = WINDOW_SIZE;
}
System.arraycopy(dict, offset, window, 0, len);
window_end = len & WINDOW_MASK;
}
public int getFreeSpace()
{
return WINDOW_SIZE - window_filled;
}
public int getAvailable()
{
return window_filled;
}
public int copyOutput(byte[] output, int offset, int len)
{
int copy_end = window_end;
if (len > window_filled)
len = window_filled;
else
copy_end = (window_end - window_filled + len) & WINDOW_MASK;
int copied = len;
int tailLen = len - copy_end;
if (tailLen > 0)
{
System.arraycopy(window, WINDOW_SIZE - tailLen,
output, offset, tailLen);
offset += tailLen;
len = copy_end;
}
System.arraycopy(window, copy_end - len, output, offset, len);
window_filled -= copied;
if (window_filled < 0)
throw new IllegalStateException();
return copied;
}
public void reset() {
window_filled = window_end = 0;
}
}
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