
/* ====================================================================
   Copyright 2002-2004   Apache Software Foundation

   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 org.apache.poi.util;

import java.io.*;

/**
 * dump data in hexadecimal format; derived from a HexDump utility I
 * wrote in June 2001.
 *
 * @author Marc Johnson
 * @author Glen Stampoultzis  (glens at apache.org)
 */

public class HexDump
{
    public static final String        EOL         =
        System.getProperty("line.separator");
//    private static final StringBuffer _lbuffer    = new StringBuffer(8);
//    private static final StringBuffer _cbuffer    = new StringBuffer(2);
    private static final char         _hexcodes[] =
    {
        '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'A', 'B', 'C', 'D',
        'E', 'F'
    };
    private static final int          _shifts[]   =
    {
        28, 24, 20, 16, 12, 8, 4, 0
    };


    // all static methods, so no need for a public constructor
    private HexDump()
    {
    }

    /**
     * dump an array of bytes to an OutputStream
     *
     * @param data the byte array to be dumped
     * @param offset its offset, whatever that might mean
     * @param stream the OutputStream to which the data is to be
     *               written
     * @param index initial index into the byte array
     * @param length number of characters to output
     *
     * @exception IOException is thrown if anything goes wrong writing
     *            the data to stream
     * @exception ArrayIndexOutOfBoundsException if the index is
     *            outside the data array's bounds
     * @exception IllegalArgumentException if the output stream is
     *            null
     */
    public synchronized static void dump(final byte [] data, final long offset,
                            final OutputStream stream, final int index, final int length)
            throws IOException, ArrayIndexOutOfBoundsException,
                    IllegalArgumentException
    {
        if ((index < 0) || (data.length != 0 && index >= data.length))
        {
            throw new ArrayIndexOutOfBoundsException(
                "illegal index: " + index + " into array of length "
                + data.length);
        }
        if (data.length == 0)
            return; // nothing more to do.
        if (stream == null)
        {
            throw new IllegalArgumentException("cannot write to nullstream");
        }
        long         display_offset = offset + index;
        StringBuffer buffer         = new StringBuffer(74);


        int data_length = Math.min(data.length,index+length);
        for (int j = index; j < data_length; j += 16)
        {
            int chars_read = data_length - j;

            if (chars_read > 16)
            {
                chars_read = 16;
            }
            buffer.append(
                        dump(display_offset)
                         ).append(' ');
            for (int k = 0; k < 16; k++)
            {
                if (k < chars_read)
                {
                    buffer.append(dump(data[ k + j ]));
                }
                else
                {
                    buffer.append("  ");
                }
                buffer.append(' ');
            }
            for (int k = 0; k < chars_read; k++)
            {
                if ((data[ k + j ] >= ' ') && (data[ k + j ] < 127))
                {
                    buffer.append(( char ) data[ k + j ]);
                }
                else
                {
                    buffer.append('.');
                }
            }
            buffer.append(EOL);
            stream.write(buffer.toString().getBytes());
            stream.flush();
            buffer.setLength(0);
            display_offset += chars_read;
        }

    }

    /**
     * dump an array of bytes to an OutputStream
     *
     * @param data the byte array to be dumped
     * @param offset its offset, whatever that might mean
     * @param stream the OutputStream to which the data is to be
     *               written
     * @param index initial index into the byte array
     *
     * @exception IOException is thrown if anything goes wrong writing
     *            the data to stream
     * @exception ArrayIndexOutOfBoundsException if the index is
     *            outside the data array's bounds
     * @exception IllegalArgumentException if the output stream is
     *            null
     */

    public synchronized static void dump(final byte [] data, final long offset,
                            final OutputStream stream, final int index)
        throws IOException, ArrayIndexOutOfBoundsException,
                IllegalArgumentException
    {
        dump(data, offset, stream, index, data.length-index);
    }

    /**
     * dump an array of bytes to a String
     *
     * @param data the byte array to be dumped
     * @param offset its offset, whatever that might mean
     * @param index initial index into the byte array
     *
     * @exception ArrayIndexOutOfBoundsException if the index is
     *            outside the data array's bounds
     * @return output string
     */
    
    public static String dump(final byte [] data, final long offset,
                            final int index) {
        StringBuffer buffer;
        if ((index < 0) || (index >= data.length))
        {
            throw new ArrayIndexOutOfBoundsException(
                "illegal index: " + index + " into array of length "
                + data.length);
        }
        long         display_offset = offset + index;
        buffer         = new StringBuffer(74);

        for (int j = index; j < data.length; j += 16)
        {
            int chars_read = data.length - j;

            if (chars_read > 16)
            {
                chars_read = 16;
            }
            buffer.append(dump(display_offset)).append(' ');
            for (int k = 0; k < 16; k++)
            {
                if (k < chars_read)
                {
                    buffer.append(dump(data[ k + j ]));
                }
                else
                {
                    buffer.append("  ");
                }
                buffer.append(' ');
            }
            for (int k = 0; k < chars_read; k++)
            {
                if ((data[ k + j ] >= ' ') && (data[ k + j ] < 127))
                {
                    buffer.append(( char ) data[ k + j ]);
                }
                else
                {
                    buffer.append('.');
                }
            }
            buffer.append(EOL);
            display_offset += chars_read;
        }                 
        return buffer.toString();
    }
    

    private static String dump(final long value)
    {
        StringBuffer buf = new StringBuffer();
        buf.setLength(0);
        for (int j = 0; j < 8; j++)
        {
            buf.append( _hexcodes[ (( int ) (value >> _shifts[ j ])) & 15 ]);
        }
        return buf.toString();
    }

    private static String dump(final byte value)
    {
        StringBuffer buf = new StringBuffer();
        buf.setLength(0);
        for (int j = 0; j < 2; j++)
        {
            buf.append(_hexcodes[ (value >> _shifts[ j + 6 ]) & 15 ]);
        }
        return buf.toString();
    }

    /**
     * Converts the parameter to a hex value.
     *
     * @param value     The value to convert
     * @return          A String representing the array of bytes
     */
    public static String toHex(final byte[] value)
    {
        StringBuffer retVal = new StringBuffer();
        retVal.append('[');
        for(int x = 0; x < value.length; x++)
        {
            retVal.append(toHex(value[x]));
            retVal.append(", ");
        }
        retVal.append(']');
        return retVal.toString();
    }

    /**
     * Converts the parameter to a hex value.
     *
     * @param value     The value to convert
     * @return          The result right padded with 0
     */
    public static String toHex(final short value)
    {
        return toHex(value, 4);
    }

    /**
     * Converts the parameter to a hex value.
     *
     * @param value     The value to convert
     * @return          The result right padded with 0
     */
    public static String toHex(final byte value)
    {
        return toHex(value, 2);
    }

    /**
     * Converts the parameter to a hex value.
     *
     * @param value     The value to convert
     * @return          The result right padded with 0
     */
    public static String toHex(final int value)
    {
        return toHex(value, 8);
    }


    private static String toHex(final long value, final int digits)
    {
        StringBuffer result = new StringBuffer(digits);
        for (int j = 0; j < digits; j++)
        {
            result.append( _hexcodes[ (int) ((value >> _shifts[ j + (8 - digits) ]) & 15)]);
        }
        return result.toString();
    }

    /**
     * Dumps <code>bytesToDump</code> bytes to an output stream.
     *
     * @param in          The stream to read from
     * @param out         The output stream
     * @param start       The index to use as the starting position for the left hand side label
     * @param bytesToDump The number of bytes to output.  Use -1 to read until the end of file.
     */
    public static void dump( InputStream in, PrintStream out, int start, int bytesToDump ) throws IOException
    {
        ByteArrayOutputStream buf = new ByteArrayOutputStream();
        if (bytesToDump == -1)
        {
            int c = in.read();
            while (c != -1)
            {
                buf.write(c);
                c = in.read();
            }
        }
        else
        {
            int bytesRemaining = bytesToDump;
            while (bytesRemaining-- > 0)
            {
                int c = in.read();
                if (c == -1)
                    break;
                else
                    buf.write(c);
            }
        }

        byte[] data = buf.toByteArray();
        dump(data, 0, out, start, data.length);
    }
}
