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Luaj 3.0.1 for the jme platform
There is a newer version: 3.0.1
/*******************************************************************************
 * Copyright (c) 2009 Luaj.org. All rights reserved.
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 * 
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
 * THE SOFTWARE.
 ******************************************************************************/
package org.luaj.vm2;


/**
 * String buffer for use in string library methods, optimized for production 
 * of StrValue instances. 
 */
public final class Buffer {
	private static final int DEFAULT_CAPACITY = 64;

	private byte[] bytes;
	private int length;
	
	public Buffer() {
		this(DEFAULT_CAPACITY);
	}
	
	public Buffer( int initialCapacity ) {
		bytes = new byte[ initialCapacity ];
		length = 0;
	}
	
	public final String tojstring() {
		return LuaString.valueOf(bytes, 0, length).tojstring();
	}
	
	public final Buffer append( byte b ) {
		ensureCapacity( length + 1 );
		bytes[ length++ ] = b;
		return this;
	}
	
	public final Buffer append( LuaValue val ) {
		if ( ! val.isstring() ) 
			val.error("attempt to concatenate a '"+val.typename()+"' value");
		append( val.strvalue() );
		return this;
	}
	
	public final Buffer append( LuaString str ) {
		final int alen = str.length();
		ensureCapacity( length + alen );
		str.copyInto( 0, bytes, length, alen );
		length += alen;
		return this;
	}
	
	public final Buffer append( String str ) {
		char[] chars = str.toCharArray();
		final int alen = LuaString.lengthAsUtf8( chars );
		ensureCapacity( length + alen );
		LuaString.encodeToUtf8( chars, bytes, length );
		length += alen;
		return this;
	}
	
	public final void setLength( int length ) {
		ensureCapacity( length );
		this.length = length;
	}
	
	public final LuaString tostring() {
		return LuaString.valueOf( realloc( bytes, length ) );
	}
	
	public final void ensureCapacity( int minSize ) {
		if ( minSize > bytes.length )
			realloc( minSize );
	}
	
	private final void realloc( int minSize ) {
		bytes = realloc( bytes, Math.max( bytes.length * 2, minSize ) ); 
	}
	
	private final static byte[] realloc( byte[] b, int newSize ) {
		byte[] newBytes = new byte[ newSize ];
		System.arraycopy( b, 0, newBytes, 0, Math.min( b.length, newSize ) );
		return newBytes;
	}
}