de.schlichtherle.io.rof.AbstractReadOnlyFile Maven / Gradle / Ivy

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/*
 * Copyright (C) 2007-2010 Schlichtherle IT Services
 *
 * 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 de.schlichtherle.io.rof;

import java.io.*;

/**
 * A base class for {@code ReadOnlyFile} implementations which
 * implements the common boilerplate.
 *
 * @author Christian Schlichtherle
 * @version $Id: AbstractReadOnlyFile.java 06f3ba684701 2010/11/04 01:15:55 christian $
 * @since TrueZIP 6.5
 */
public abstract class AbstractReadOnlyFile implements ReadOnlyFile {

    public int read(byte[] b) throws IOException {
        return read(b, 0, b.length);
    }

    public void readFully(byte[] b) throws IOException {
        readFully(b, 0, b.length);
    }

    public void readFully(final byte[] buf, final int off, final int len)
    throws IOException {
        int total = 0;
	do {
	    final int read = read(buf, off + total, len - total);
	    if (read < 0)
		throw new EOFException();
	    total += read;
	} while (total < len);
    }

    /** @deprecated Use {@link #seek} instead. */
    public int skipBytes(int n) throws IOException {
        if (n <= 0)
            return 0; // for compatibility to RandomAccessFile

        final long fp = getFilePointer(); // should fail when closed
        final long len = length(); // may succeed when closed
        final long rem = len - fp;
        if (n > rem)
            n = (int) rem;
        seek(fp + n);
        assert getFilePointer() == fp + n;
        return n;
    }
}