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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 trappingpublic 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     * @param length number of bytes to use