Gadgetbridge/app/src/main/java/nodomain/freeyourgadget/gadgetbridge/util/ArrayUtils.java

package nodomain.freeyourgadget.gadgetbridge.util;

public class ArrayUtils {
    /**
     * Checks the two given arrays for equality, but comparing only a subset of the second
     * array with the whole first array.
     * @param first the whole array to compare against
     * @param second the array, of which a subset shall be compared against the whole first array
     * @param secondStartIndex the start index (inclusive) of the second array from which to start the comparison
     * @param secondEndIndex the end index (exclusive) of the second array until which to compare
     * @return whether the first byte array is equal to the specified subset of the second byte array
     * @throws IllegalArgumentException when one of the arrays is null or start and end index are wrong
     */
    public static boolean equals(byte[] first, byte[] second, int secondStartIndex, int secondEndIndex) {
        if (first == null) {
            throw new IllegalArgumentException("first must not be null");
        }
        if (second == null) {
            throw new IllegalArgumentException("second must not be null");
        }
        if (secondStartIndex >= secondEndIndex) {
            throw new IllegalArgumentException("secondStartIndex must be smaller than secondEndIndex");
        }
        if (second.length < secondEndIndex) {
            throw new IllegalArgumentException("secondStartIndex must be smaller than secondEndIndex");
        }
        if (first.length < secondEndIndex) {
            return false;
        }
        int len = secondEndIndex - secondStartIndex;
        for (int i = 0; i < len; i++) {
            if (first[i] != second[secondStartIndex + i]) {
                return false;
            }
        }
        return true;
    }
}