/*
* CVS identifier:
*
* $Id: ByteOutputBuffer.java,v 1.10 2001/05/17 15:21:16 grosbois Exp $
*
* Class:                   ByteOutputBuffer
*
* Description:             Provides buffering for byte based output, similar
*                          to the standard class ByteArrayOutputStream
*
*                          the old jj2000.j2k.io.ByteArrayOutput class by
*                          Diego SANTA CRUZ, Apr-26-1999
*
*
* COPYRIGHT:
* 
* This software module was originally developed by Raphaël Grosbois and
* Diego Santa Cruz (Swiss Federal Institute of Technology-EPFL); Joel
* Askelöf (Ericsson Radio Systems AB); and Bertrand Berthelot, David
* Bouchard, Félix Henry, Gerard Mozelle and Patrice Onno (Canon Research
* Centre France S.A) in the course of development of the JPEG2000
* standard as specified by ISO/IEC 15444 (JPEG 2000 Standard). This
* software module is an implementation of a part of the JPEG 2000
* Standard. Swiss Federal Institute of Technology-EPFL, Ericsson Radio
* Systems AB and Canon Research Centre France S.A (collectively JJ2000
* Partners) agree not to assert against ISO/IEC and users of the JPEG
* 2000 Standard (Users) any of their rights under the copyright, not
* including other intellectual property rights, for this software module
* with respect to the usage by ISO/IEC and Users of this software module
* or modifications thereof for use in hardware or software products
* claiming conformance to the JPEG 2000 Standard. Those intending to use
* this software module in hardware or software products are advised that
* their use may infringe existing patents. The original developers of
* this software module, JJ2000 Partners and ISO/IEC assume no liability
* for use of this software module or modifications thereof. No license
* or right to this software module is granted for non JPEG 2000 Standard
* conforming products. JJ2000 Partners have full right to use this
* software module for his/her own purpose, assign or donate this
* software module to any third party and to inhibit third parties from
* using this software module for non JPEG 2000 Standard conforming
* products. This copyright notice must be included in all copies or
* derivative works of this software module.
* 
* Copyright (c) 1999/2000 JJ2000 Partners.
* */
using System;
namespace CSJ2K.j2k.entropy.encoder
{
	
	/// <summary> This class provides a buffering output stream similar to
	/// ByteArrayOutputStream, with some additional methods.
	/// 
	/// <p>Once an array has been written to an output stream or to a byte array,
	/// the object can be reused as a new stream if the reset() method is
	/// called.</p>
	/// 
	/// <p>Unlike the ByteArrayOutputStream class, this class is not thread
	/// safe.</p>
	/// 
	/// </summary>
	/// <seealso cref="reset">
	/// 
	/// </seealso>
	public class ByteOutputBuffer
	{
		
		/// <summary>The buffer where the data is stored </summary>
		internal byte[] buf;
		
		/// <summary>The number of valid bytes in the buffer </summary>
		internal int count;
		
		/// <summary>The buffer increase size </summary>
		public const int BUF_INC = 512;
		
		/// <summary>The default initial buffer size </summary>
		public const int BUF_DEF_LEN = 256;
		
		/// <summary> Creates a new byte array output stream. The buffer capacity is
		/// initially BUF_DEF_LEN bytes, though its size increases if necessary.
		/// 
		/// </summary>
		public ByteOutputBuffer()
		{
			buf = new byte[BUF_DEF_LEN];
		}
		
		/// <summary> Creates a new byte array output stream, with a buffer capacity of the
		/// specified size, in bytes.
		/// 
		/// </summary>
		/// <param name="size">the initial size.
		/// 
		/// </param>
		public ByteOutputBuffer(int size)
		{
			buf = new byte[size];
		}
		
		/// <summary> Writes the specified byte to this byte array output stream. The
		/// functionality provided by this implementation is the same as for the
		/// one in the superclass, however this method is not synchronized and
		/// therefore not safe thread, but faster.
		/// 
		/// </summary>
		/// <param name="b">The byte to write
		/// 
		/// </param>
		public void  write(int b)
		{
			if (count == buf.Length)
			{
				// Resize buffer
				byte[] tmpbuf = buf;
				buf = new byte[buf.Length + BUF_INC];
				Array.Copy(tmpbuf, 0, buf, 0, count);
			}
			buf[count++] = (byte) b;
		}
		
		/// <summary> Copies the specified part of the stream to the 'outbuf' byte array.
		/// 
		/// </summary>
		/// <param name="off">The index of the first element in the stream to copy.
		/// 
		/// </param>
		/// <param name="len">The number of elements of the array to copy
		/// 
		/// </param>
		/// <param name="outbuf">The destination array
		/// 
		/// </param>
		/// <param name="outoff">The index of the first element in 'outbuf' where to write
		/// the data.
		/// 
		/// </param>
		public virtual void  toByteArray(int off, int len, byte[] outbuf, int outoff)
		{
			// Copy the data
			Array.Copy(buf, off, outbuf, outoff, len);
		}
		
		/// <summary> Returns the number of valid bytes in the output buffer (count class
		/// variable).
		/// 
		/// </summary>
		/// <returns> The number of bytes written to the buffer
		/// 
		/// </returns>
		public virtual int size()
		{
			return count;
		}
		
		/// <summary> Discards all the buffered data, by resetting the counter of written
		/// bytes to 0.
		/// 
		/// </summary>
		public virtual void  reset()
		{
			count = 0;
		}
		
		/// <summary> Returns the byte buffered at the given position in the buffer. The
		/// position in the buffer is the index of the 'write()' method call after
		/// the last call to 'reset()'.
		/// 
		/// </summary>
		/// <param name="pos">The position of the byte to return
		/// 
		/// </param>
		/// <returns> The value (betweeb 0-255) of the byte at position 'pos'.
		/// 
		/// </returns>
		public virtual int getByte(int pos)
		{
			if (pos >= count)
			{
				throw new System.ArgumentException();
			}
			return buf[pos] & 0xFF;
		}
	}
}