activeio-core/src/main/java/org/apache/activeio/util/ByteArrayInputStream.java

/**
 *
 * Copyright 2005-2006 The Apache Software Foundation
 *
 * Licensed under the Apache 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.apache.org/licenses/LICENSE-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.apache.activeio.util;

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

import org.apache.activeio.packet.ByteSequence;

/**
 * Very similar to the java.io.ByteArrayInputStream but this version 
 * is not thread safe.
 */
public class ByteArrayInputStream extends InputStream {

    byte buffer[];
    int limit;
    int pos;
    int mark;

    public ByteArrayInputStream(byte data[]) {
        this(data, 0, data.length);
    }
    
    public ByteArrayInputStream(ByteSequence sequence) {
        this(sequence.getData(), sequence.getOffset(), sequence.getLength());
    }

    public ByteArrayInputStream(byte data[], int offset, int size) {
        this.buffer = data;
        this.mark= this.pos = offset;        
        this.limit = offset+size;
    }
    
    public int read() throws IOException {
        if( pos < limit )
            return buffer[pos++] & 0xff;
        else
            return -1;
    }

    public int read(byte[] b) throws IOException {
        return read(b, 0, b.length);
    }
    
    public int read(byte b[], int off, int len) {
        if (pos < limit) {
            len = Math.min(len, limit-pos);
            if (len > 0) {
                System.arraycopy(buffer, pos, b, off, len);
                pos += len;
            }
            return len;
        } else {
            return -1;
        }
    }

    public long skip(long len) throws IOException {
        if (pos < limit) {
            len = Math.min(len, limit-pos);
            if (len > 0) {
                pos += len;
            }
            return len;
        } else {
            return -1;
        }
    }
    
    public int available() {
        return limit - pos;
    }

    public boolean markSupported() {
        return true;
    }
    
    public void mark(int markpos) {
        mark = pos;
    }
    
    public void reset() {
        pos = mark;
    }
}