Java example source code file (Utils.java)

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Java - Java tags/keywords

base, bytearrayoutputstream, invalid, ioexception, runtimeexception, stringbuffer, stringreader, utils

The Utils.java Java example source code

/*
 * Copyright (c) 2005, 2010, Oracle and/or its affiliates. All rights reserved.
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
 * This code is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 only, as
 * published by the Free Software Foundation.
 *
 * This code is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
 * version 2 for more details (a copy is included in the LICENSE file that
 * accompanied this code).
 *
 * You should have received a copy of the GNU General Public License version
 * 2 along with this work; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
 *
 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
 * or visit www.oracle.com if you need additional information or have any
 * questions.
 */

import java.io.*;

class Utils {

    static final String BASE = System.getProperty("test.src", ".");

    private final static char[] hexDigits = "0123456789abcdef".toCharArray();

    public static String toString(byte[] b) {
        if (b == null) {
            return "(null)";
        }
        StringBuffer sb = new StringBuffer(b.length * 3);
        for (int i = 0; i < b.length; i++) {
            int k = b[i] & 0xff;
            if (i != 0) {
                sb.append(':');
            }
            sb.append(hexDigits[k >>> 4]);
            sb.append(hexDigits[k & 0xf]);
        }
        return sb.toString();
    }

    public static byte[] parse(String s) {
        if (s.equals("(null)")) {
            return null;
        }
        try {
            int n = s.length();
            ByteArrayOutputStream out = new ByteArrayOutputStream(n / 3);
            StringReader r = new StringReader(s);
            while (true) {
                int b1 = nextNibble(r);
                if (b1 < 0) {
                    break;
                }
                int b2 = nextNibble(r);
                if (b2 < 0) {
                    throw new RuntimeException("Invalid string " + s);
                }
                int b = (b1 << 4) | b2;
                out.write(b);
            }
            return out.toByteArray();
        } catch (IOException e) {
            throw new RuntimeException(e);
        }
    }

    private static int nextNibble(StringReader r) throws IOException {
        while (true) {
            int ch = r.read();
            if (ch == -1) {
                return -1;
            } else if ((ch >= '0') && (ch <= '9')) {
                return ch - '0';
            } else if ((ch >= 'a') && (ch <= 'f')) {
                return ch - 'a' + 10;
            } else if ((ch >= 'A') && (ch <= 'F')) {
                return ch - 'A' + 10;
            }
        }
    }

}