stringconverter.java

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/* Copyright (c) 1995-2000, The Hypersonic SQL Group.
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *
 * Redistributions of source code must retain the above copyright notice, this
 * list of conditions and the following disclaimer.
 *
 * Redistributions in binary form must reproduce the above copyright notice,
 * this list of conditions and the following disclaimer in the documentation
 * and/or other materials provided with the distribution.
 *
 * Neither the name of the Hypersonic SQL Group nor the names of its
 * contributors may be used to endorse or promote products derived from this
 * software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED. IN NO EVENT SHALL THE HYPERSONIC SQL GROUP,
 * OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 *
 * This software consists of voluntary contributions made by many individuals 
 * on behalf of the Hypersonic SQL Group.
 *
 *
 * For work added by the HSQL Development Group:
 *
 * Copyright (c) 2001-2005, The HSQL Development Group
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *
 * Redistributions of source code must retain the above copyright notice, this
 * list of conditions and the following disclaimer.
 *
 * Redistributions in binary form must reproduce the above copyright notice,
 * this list of conditions and the following disclaimer in the documentation
 * and/or other materials provided with the distribution.
 *
 * Neither the name of the HSQL Development Group nor the names of its
 * contributors may be used to endorse or promote products derived from this
 * software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED. IN NO EVENT SHALL HSQL DEVELOPMENT GROUP, HSQLDB.ORG,
 * OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */


package org.hsqldb.lib;

import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.StringWriter;
import java.io.UTFDataFormatException;

/**
 * Collection of static methods for converting strings between different
 * formats and to and from byte arrays.<p>
 *
 * New class, with extensively enhanced and rewritten Hypersonic code.
 *
 * @author Thomas Mueller (Hypersonic SQL Group)
 * @author fredt@users
 * @version 1.8.0
 * @since 1.7.2
 */

// fredt@users 20020328 - patch 1.7.0 by fredt - error trapping
public class StringConverter {

    private static final byte[] HEXBYTES = {
        (byte) '0', (byte) '1', (byte) '2', (byte) '3', (byte) '4',
        (byte) '5', (byte) '6', (byte) '7', (byte) '8', (byte) '9',
        (byte) 'a', (byte) 'b', (byte) 'c', (byte) 'd', (byte) 'e', (byte) 'f'
    };
    private static final String HEXINDEX = "0123456789abcdef0123456789ABCDEF";

    /**
     * Converts a String into a byte array by using a big-endian two byte
     * representation of each char value in the string.
     */
    byte[] stringToFullByteArray(String s) {

        int    length = s.length();
        byte[] buffer = new byte[length * 2];
        int    c;

        for (int i = 0; i < length; i++) {
            c                 = s.charAt(i);
            buffer[i * 2]     = (byte) ((c & 0x0000ff00) >> 8);
            buffer[i * 2 + 1] = (byte) (c & 0x000000ff);
        }

        return buffer;
    }

    /**
     * Compacts a hexadecimal string into a byte array
     *
     *
     * @param s hexadecimal string
     *
     * @return byte array for the hex string
     * @throws IOException
     */
    public static byte[] hexToByte(String s) throws IOException {

        int    l    = s.length() / 2;
        byte[] data = new byte[l];
        int    j    = 0;

        if (s.length() % 2 != 0) {
            throw new IOException(
                "hexadecimal string with odd number of characters");
        }

        for (int i = 0; i < l; i++) {
            char c = s.charAt(j++);
            int  n, b;

            n = HEXINDEX.indexOf(c);

            if (n == -1) {
                throw new IOException(
                    "hexadecimal string contains non hex character");
            }

            b       = (n & 0xf) << 4;
            c       = s.charAt(j++);
            n       = HEXINDEX.indexOf(c);
            b       += (n & 0xf);
            data[i] = (byte) b;
        }

        return data;
    }

    /**
     * Converts a byte array into a hexadecimal string
     *
     *
     * @param b byte array
     *
     * @return hex string
     */
    public static String byteToHex(byte[] b) {

        int    len = b.length;
        char[] s   = new char[len * 2];

        for (int i = 0, j = 0; i < len; i++) {
            int c = ((int) b[i]) & 0xff;

            s[j++] = (char) HEXBYTES[c >> 4 & 0xf];
            s[j++] = (char) HEXBYTES[c & 0xf];
        }

        return new String(s);
    }

    /**
     * Converts a byte array into hexadecimal characters
     * which are written as ASCII to the given output stream.
     *
     * @param o output stream
     * @param b byte array
     */
    public static void writeHex(byte[] o, int from, byte[] b) {

        int len = b.length;

        for (int i = 0; i < len; i++) {
            int c = ((int) b[i]) & 0xff;

            o[from++] = HEXBYTES[c >> 4 & 0xf];
            o[from++] = HEXBYTES[c & 0xf];
        }
    }

    public static String byteToString(byte[] b, String charset) {

        try {
            return (charset == null) ? new String(b)
                                     : new String(b, charset);
        } catch (Exception e) {}

        return null;
    }

    /**
     * Converts a Unicode string into UTF8 then convert into a hex string
     *
     *
     * @param s normal Unicode string
     *
     * @return hex string representation of UTF8 encoding of the input
     */
    public static String unicodeToHexString(String s) {

        HsqlByteArrayOutputStream bout = new HsqlByteArrayOutputStream();

        writeUTF(s, bout);

        return byteToHex(bout.toByteArray());
    }

// fredt@users 20011120 - patch 450455 by kibu@users - modified
// method return type changed to HsqlStringBuffer with spare
// space for end-of-line characters -- to reduce String concatenation

    /**
     * Hsqldb specific encoding used only for log files.
     *
     * The SQL statements that need to be written to the log file (input) are
     * Java Unicode strings. input is converted into a 7bit escaped ASCII
     * string (output)with the following transformations.
     * All characters outside the 0x20-7f range are converted to a
     * escape sequence and added to output.
     * If a backslash character is immdediately followed by 'u', the
     * backslash character is converted to escape sequence and
     * added to output.
     * All the remaining characters in input are added to output without
     * conversion.
     *
     * The escape sequence is backslash, letter u, xxxx, where xxxx
     * is the hex representation of the character code.
     * (fredt@users)
     *
     * @param b output stream to wite to
     * @param s Java Unicode string
     *
     * @return number of bytes written out
     *
     */
    public static int unicodeToAscii(HsqlByteArrayOutputStream b, String s,
                                     boolean doubleSingleQuotes) {

        int count = 0;

        if ((s == null) || (s.length() == 0)) {
            return 0;
        }

        int len = s.length();

        for (int i = 0; i < len; i++) {
            char c = s.charAt(i);

            if (c == '\\') {
                if ((i < len - 1) && (s.charAt(i + 1) == 'u')) {
                    b.write(c);    // encode the \ as unicode, so 'u' is ignored
                    b.write('u');
                    b.write('0');
                    b.write('0');
                    b.write('5');
                    b.write('c');

                    count += 6;
                } else {
                    b.write(c);

                    count++;
                }
            } else if ((c >= 0x0020) && (c <= 0x007f)) {
                b.write(c);        // this is 99%

                count++;

                if (c == '\'' && doubleSingleQuotes) {
                    b.write(c);

                    count++;
                }
            } else {
                b.write('\\');
                b.write('u');
                b.write(HEXBYTES[(c >> 12) & 0xf]);
                b.write(HEXBYTES[(c >> 8) & 0xf]);
                b.write(HEXBYTES[(c >> 4) & 0xf]);
                b.write(HEXBYTES[c & 0xf]);

                count += 6;
            }
        }

        return count;
    }

// fredt@users 20020522 - fix for 557510 - backslash bug
// this legacy bug resulted from forward reading the input when a backslash
// was present and manifested itself when a backslash was followed
// immdediately by a character outside the 0x20-7f range in a database field.

    /**
     * Hsqldb specific decoding used only for log files.
     *
     * This method converts the 7 bit escaped ASCII strings in a log file
     * back into Java Unicode strings. See unicodeToAccii() above,
     *
     * @param s encoded ASCII string in byte array
     * @param offset position of first byte