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// PendingBuffer.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
{
/// <summary>
/// This class is general purpose class for writing data to a buffer.
///
/// It allows you to write bits as well as bytes
/// Based on DeflaterPending.java
///
/// author of the original java version : Jochen Hoenicke
/// </summary>
public class PendingBuffer
{
protected byte[] buf;
int start;
int end;
uint bits;
int bitCount;
public PendingBuffer() : this( 4096 )
{
}
public PendingBuffer(int bufsize)
{
buf = new byte[bufsize];
}
public void Reset()
{
start = end = bitCount = 0;
}
public void WriteByte(int b)
{
if (DeflaterConstants.DEBUGGING && start != 0) {
throw new Exception();
}
buf[end++] = (byte) b;
}
public void WriteShort(int s)
{
if (DeflaterConstants.DEBUGGING && start != 0) {
throw new Exception();
}
buf[end++] = (byte) s;
buf[end++] = (byte) (s >> 8);
}
public void WriteInt(int s)
{
if (DeflaterConstants.DEBUGGING && start != 0) {
throw new Exception();
}
buf[end++] = (byte) s;
buf[end++] = (byte) (s >> 8);
buf[end++] = (byte) (s >> 16);
buf[end++] = (byte) (s >> 24);
}
public void WriteBlock(byte[] block, int offset, int len)
{
if (DeflaterConstants.DEBUGGING && start != 0) {
throw new Exception();
}
System.Array.Copy(block, offset, buf, end, len);
end += len;
}
public int BitCount {
get {
return bitCount;
}
}
public void AlignToByte()
{
if (DeflaterConstants.DEBUGGING && start != 0) {
throw new Exception();
}
if (bitCount > 0) {
buf[end++] = (byte) bits;
if (bitCount > 8) {
buf[end++] = (byte) (bits >> 8);
}
}
bits = 0;
bitCount = 0;
}
public void WriteBits(int b, int count)
{
if (DeflaterConstants.DEBUGGING && start != 0) {
throw new Exception();
}
// if (DeflaterConstants.DEBUGGING) {
// //Console.WriteLine("writeBits("+b+","+count+")");
// }
bits |= (uint)(b << bitCount);
bitCount += count;
if (bitCount >= 16) {
buf[end++] = (byte) bits;
buf[end++] = (byte) (bits >> 8);
bits >>= 16;
bitCount -= 16;
}
}
public void WriteShortMSB(int s)
{
if (DeflaterConstants.DEBUGGING && start != 0) {
throw new Exception();
}
buf[end++] = (byte) (s >> 8);
buf[end++] = (byte) s;
}
public bool IsFlushed {
get {
return end == 0;
}
}
/// <summary>
/// Flushes the pending buffer into the given output array. If the
/// output array is to small, only a partial flush is done.
/// </summary>
/// <param name="output">
/// the output array;
/// </param>
/// <param name="offset">
/// the offset into output array;
/// </param>
/// <param name="length">
/// length the maximum number of bytes to store;
/// </param>
/// <exception name="ArgumentOutOfRangeException">
/// IndexOutOfBoundsException if offset or length are invalid.
/// </exception>
public int Flush(byte[] output, int offset, int length)
{
if (bitCount >= 8) {
buf[end++] = (byte) bits;
bits >>= 8;
bitCount -= 8;
}
if (length > end - start) {
length = end - start;
System.Array.Copy(buf, start, output, offset, length);
start = 0;
end = 0;
} else {
System.Array.Copy(buf, start, output, offset, length);
start += length;
}
return length;
}
public byte[] ToByteArray()
{
byte[] ret = new byte[end - start];
System.Array.Copy(buf, start, ret, 0, ret.Length);
start = 0;
end = 0;
return ret;
}
}
}
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