src/main/java/com/android/tools/build/apkzlib/zip/utils/RandomAccessFileUtils.java

/*
 * Copyright (C) 2015 The Android Open Source Project
 *
 * 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.android.tools.build.apkzlib.zip.utils;

import java.io.IOException;
import java.io.RandomAccessFile;
import javax.annotation.Nonnull;

/**
 * Utility class with utility methods for random access files.
 */
public final class RandomAccessFileUtils {

    private RandomAccessFileUtils() {}

    /**
     * Reads from an random access file until the provided array is filled. Data is read from the
     * current position in the file.
     *
     * @param raf the file to read data from
     * @param data the array that will receive the data
     * @throws IOException failed to read the data
     */
    public static void fullyRead(@Nonnull RandomAccessFile raf, @Nonnull byte[] data)
            throws IOException {
        int r;
        int p = 0;

        while ((r = raf.read(data, p, data.length - p)) > 0) {
            p += r;
            if (p == data.length) {
                break;
            }
        }

        if (p < data.length) {
            throw new IOException(
                    "Failed to read "
                            + data.length
                            + " bytes from file. Only "
                            + p
                            + " bytes could be read.");
        }
    }
}