/*
 * The Apache Software License, Version 1.1
 *
 * Copyright (c) 1999 The Apache Software Foundation.  All rights
 * reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 *
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in
 *    the documentation and/or other materials provided with the
 *    distribution.
 *
 * 3. The end-user documentation included with the redistribution, if
 *    any, must include the following acknowlegement:
 *       "This product includes software developed by the
 *        Apache Software Foundation (http://www.apache.org/)."
 *    Alternately, this acknowlegement may appear in the software itself,
 *    if and wherever such third-party acknowlegements normally appear.
 *
 * 4. The names "The Jakarta Project", "Tomcat", and "Apache Software
 *    Foundation" must not be used to endorse or promote products derived
 *    from this software without prior written permission. For written
 *    permission, please contact apache@apache.org.
 *
 * 5. Products derived from this software may not be called "Apache"
 *    nor may "Apache" appear in their names without prior written
 *    permission of the Apache Group.
 *
 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 * DISCLAIMED.  IN NO EVENT SHALL THE APACHE SOFTWARE FOUNDATION OR
 * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
 * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 * ====================================================================
 *
 * This software consists of voluntary contributions made by many
 * individuals on behalf of the Apache Software Foundation.  For more
 * information on the Apache Software Foundation, please see
 * <http://www.apache.org/>.
 */


package org.apache.tools.ant.taskdefs.optional;

import java.io.ByteArrayOutputStream;
import java.io.FilterOutputStream;
import java.io.IOException;
import java.io.OutputStream;

public class StripOutputStream extends ProcessLineOutputStream {

    private final static int HEAD = 0;
    private final static int BODY = 2;
    private final static int FOOT = 3;
    private final static int CLOSE = 4;

    private final byte[] header;
    private final byte[] footer;
    private int state = HEAD;
    private boolean skipOrphant = true;

    public StripOutputStream(OutputStream os, byte[] header, byte[] footer) {
        super(os);
        this.header = new byte[header.length];
        System.arraycopy(header, 0, this.header, 0, header.length);
        this.footer = new byte[footer.length];
        System.arraycopy(footer, 0, this.footer, 0, footer.length);
    }


    protected void orphantLF(int b) throws IOException {
        if (!skipOrphant && state == BODY) {
            super.orphantLF(b);
        }
    }

    protected void processLine() throws IOException {
        final byte[] line = buffer.toByteArray();
        buffer.reset();
        switch (state) {
            case FOOT:
                break;
            case HEAD:
                if (match(header, line)) {
                    state = BODY;
                }
                break;
            case BODY:
                skipOrphant = false;
                if (match(footer, line)) {
                    state = FOOT;
                } else {
                    out.write(line);
                }
                break;
            default:
                throw new IOException("Illegal state (" + state + ").");
        }
    }

    protected boolean match(byte[] needle, byte[] haystack) {
        if (needle.length > haystack.length) return false;
        for (int i=0; i < needle.length; i++) {
            if (needle[i] != haystack[i]) return false;
        }
        return true;
    }

    protected void ensureOpen() throws IOException {
        if (state == CLOSE) throw new IOException("Stream is closed.");
    }
}