com.avast.ByteBufferBackedInputStream Maven / Gradle / Ivy

/*
 *  Copyright 2013 Lukas Karas, Avast a.s. 
 *
 *  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 com.avast;

import java.io.IOException;
import java.io.InputStream;
import java.nio.ByteBuffer;

public class ByteBufferBackedInputStream extends InputStream {

    private final ByteBuffer buff;

    public ByteBufferBackedInputStream(ByteBuffer buff){
        this.buff = buff;
    }

    @Override
    public synchronized int read() throws IOException {
      if (!buff.hasRemaining()) {
        return -1;
      }
      return ((int)buff.get()) & 0x000000ff; // default conversion from byt to integer expand highest bit, returned integer can be negative...
    }

    @Override
    public synchronized int read(byte[] b, int off, int len) throws IOException {
        int rem = buff.remaining();
        if (rem == 0)
            return -1;
        int toRead = Math.min(len, rem);
        buff.get(b, off, toRead);
        return toRead;
    }
}