// OutputWindow.cs
// Copyright (C) 2001 Mike Krueger
//
// This file was translated from java, it was part of the GNU Classpath
// Copyright (C) 2001 Free Software Foundation, Inc.
//
// This program 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
// of the License, or (at your option) any later version.
//
// This program 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 this program; if not, write to the Free Software
// Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
//
// Linking this library statically or dynamically with other modules is
// making a combined work based on this library. Thus, the terms and
// conditions of the GNU General Public License cover the whole
// combination.
//
// As a special exception, the copyright holders of this library give you
// permission to link this library with independent modules to produce an
// executable, regardless of the license terms of these independent
// modules, and to copy and distribute the resulting executable under
// terms of your choice, provided that you also meet, for each linked
// independent module, the terms and conditions of the license of that
// module. An independent module is a module which is not derived from
// or based on this library. If you modify this library, you may extend
// this exception to your version of the library, but you are not
// obligated to do so. If you do not wish to do so, delete this
// exception statement from your version.
using System;
namespace ICSharpCode.SharpZipLib.Zip.Compression.Streams
{
/// <summary>
/// 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 of the original java version : John Leuner
/// </summary>
public class OutputWindow
{
private static int WINDOW_SIZE = 1 << 15;
private static 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 InvalidOperationException("Window full");
}
window[window_end++] = (byte) abyte;
window_end &= WINDOW_MASK;
}
private 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 InvalidOperationException("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.Array.Copy(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.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 void CopyDict(byte[] dict, int offset, int len)
{
if (window_filled > 0)
{
throw new InvalidOperationException();
}
if (len > WINDOW_SIZE)
{
offset += len - WINDOW_SIZE;
len = WINDOW_SIZE;
}
System.Array.Copy(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.Array.Copy(window, WINDOW_SIZE - tailLen,
output, offset, tailLen);
offset += tailLen;
len = copy_end;
}
System.Array.Copy(window, copy_end - len, output, offset, len);
window_filled -= copied;
if (window_filled < 0)
{
throw new InvalidOperationException();
}
return copied;
}
public void Reset()
{
window_filled = window_end = 0;
}
}
}