/*

 * Copyright 1995-1997 Sun Microsystems, Inc.  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.  Sun designates this

 * particular file as subject to the "Classpath" exception as provided

 * by Sun in the LICENSE file that accompanied this code.

 *

 * 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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,

 * CA 95054 USA or visit www.sun.com if you need additional information or

 * have any questions.

 */

package sun.misc;

import java.io.PrintStream;

import java.io.OutputStream;

import java.io.IOException;

/**

 * This class encodes a buffer into the classic: "Hexadecimal Dump" format of

 * the past. It is useful for analyzing the contents of binary buffers.

 * The format produced is as follows:

 * <pre>

 * xxxx: 00 11 22 33 44 55 66 77   88 99 aa bb cc dd ee ff ................

 * </pre>

 * Where xxxx is the offset into the buffer in 16 byte chunks, followed

 * by ascii coded hexadecimal bytes followed by the ASCII representation of

 * the bytes or '.' if they are not valid bytes.

 *

 * @author      Chuck McManis

 */

public class HexDumpEncoder extends CharacterEncoder {

    private int offset;

    private int thisLineLength;

    private int currentByte;

    private byte thisLine[] = new byte[16];

    static void hexDigit(PrintStream p, byte x) {

        char c;

        c = (char) ((x >> 4) & 0xf);

        if (c > 9)

            c = (char) ((c-10) + 'A');

        else

            c = (char)(c + '0');

        p.write(c);

        c = (char) (x & 0xf);

        if (c > 9)

            c = (char)((c-10) + 'A');

        else

            c = (char)(c + '0');

        p.write(c);

    }

    protected int bytesPerAtom() {

        return (1);

    }

    protected int bytesPerLine() {

        return (16);

    }

    protected void encodeBufferPrefix(OutputStream o) throws IOException {

        offset = 0;

        super.encodeBufferPrefix(o);

    }

    protected void encodeLinePrefix(OutputStream o, int len) throws IOException {

        hexDigit(pStream, (byte)((offset >>> 8) & 0xff));

        hexDigit(pStream, (byte)(offset & 0xff));

        pStream.print(": ");

        currentByte = 0;

        thisLineLength = len;

    }

    protected void encodeAtom(OutputStream o, byte buf[], int off, int len) throws IOException {

        thisLine[currentByte] = buf[off];

        hexDigit(pStream, buf[off]);

        pStream.print(" ");

        currentByte++;

        if (currentByte == 8)

            pStream.print("  ");

    }

    protected void encodeLineSuffix(OutputStream o) throws IOException {

        if (thisLineLength < 16) {

            for (int i = thisLineLength; i < 16; i++) {

                pStream.print("   ");

                if (i == 7)

                    pStream.print("  ");

            }

        }

        pStream.print(" ");

        for (int i = 0; i < thisLineLength; i++) {

            if ((thisLine[i] < ' ') || (thisLine[i] > 'z')) {

                pStream.print(".");

            } else {

                pStream.write(thisLine[i]);

            }

        }

        pStream.println();

        offset += thisLineLength;

    }

}