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/**********************************************************************************
 * $URL: $
 * $Id: $
 ***********************************************************************************
 *
 * Copyright (c) 2014 Sakai Foundation
 *
 * Licensed under the Educational Community License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *       http://www.opensource.org/licenses/ECL-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 *
 **********************************************************************************/
package org.sakaiproject.content.impl;

import java.io.ByteArrayInputStream;
import java.io.IOException;
import java.io.InputStream;

/**
 * Simple InputStream that just reads the first few bytes of the wrapped stream and if it
 * looks like HTML wrap it with a header and footer. 
 * This is split out from WrappedContentResource as it's easier to test a input stream without 
 * any dependency on the Sakai classes.
 * 
 * @author Matthew Buckett
 *
 */
public class WrappedInputStream extends InputStream {

	private InputStream wrapped;
	private String header;
	private String footer;
	
	private boolean wrapping = false;
	private boolean detect = false;
	private boolean checked = false;
	
	public WrappedInputStream(InputStream wrapped, String header, String footer, boolean detect) {
		this.wrapped = wrapped;
		this.header = header;
		this.footer = footer;
		this.detect = detect; 
	}
	
	private void check() throws IOException {
		// Shortcut.
		if (checked) {
			return;
		}
		checked = true;
		if (detect) {
			byte[] buffer = new byte[256];
			int read = wrapped.read(buffer);
			if (read > 0) {
				// TODO Charset problems?
				String bufferString = new String(buffer);
				// This is the test we do.
				wrapping = !bufferString.toLowerCase().contains("