RawCharUtil.java

/*
 * Copyright (C) 2010, Google Inc. and others
 *
 * This program and the accompanying materials are made available under the
 * terms of the Eclipse Distribution License v. 1.0 which is available at
 * https://www.eclipse.org/org/documents/edl-v10.php.
 *
 * SPDX-License-Identifier: BSD-3-Clause
 */

package org.eclipse.jgit.util;

/**
 * Utility class for character functions on raw bytes
 * <p>
 * Characters are assumed to be 8-bit US-ASCII.
 */
public class RawCharUtil {
    private static final boolean[] WHITESPACE = new boolean[256];

    static {
        WHITESPACE['\r'] = true;
        WHITESPACE['\n'] = true;
        WHITESPACE['\t'] = true;
        WHITESPACE[' '] = true;
    }

    /**
     * Determine if an 8-bit US-ASCII encoded character is represents whitespace
     *
     * @param c
     *            the 8-bit US-ASCII encoded character
     * @return true if c represents a whitespace character in 8-bit US-ASCII
     */
    public static boolean isWhitespace(byte c) {
        return WHITESPACE[c & 0xff];
    }

    /**
     * Returns the new end point for the byte array passed in after trimming any
     * trailing whitespace characters, as determined by the isWhitespace()
     * function. start and end are assumed to be within the bounds of raw.
     *
     * @param raw
     *            the byte array containing the portion to trim whitespace for
     * @param start
     *            the start of the section of bytes
     * @param end
     *            the end of the section of bytes
     * @return the new end point
     */
    public static int trimTrailingWhitespace(byte[] raw, int start, int end) {
        int ptr = end - 1;
        while (start <= ptr && isWhitespace(raw[ptr]))
            ptr--;

        return ptr + 1;
    }

    /**
     * Returns the new start point for the byte array passed in after trimming
     * any leading whitespace characters, as determined by the isWhitespace()
     * function. start and end are assumed to be within the bounds of raw.
     *
     * @param raw
     *            the byte array containing the portion to trim whitespace for
     * @param start
     *            the start of the section of bytes
     * @param end
     *            the end of the section of bytes
     * @return the new start point
     */
    public static int trimLeadingWhitespace(byte[] raw, int start, int end) {
        while (start < end && isWhitespace(raw[start]))
            start++;

        return start;
    }

    private RawCharUtil() {
        // This will never be called
    }
}