net.darkmist.alib.str.BackSlashEscape.java Source code

Introduction

Here is the source code for net.darkmist.alib.str.BackSlashEscape.java

Source

/*
 *  Copyright (C) 2012 Ed Schaller <schallee@darkmist.net>
 *
 *  This library is free software; you can redistribute it and/or
 *  modify it under the terms of the GNU Lesser General Public
 *  License as published by the Free Software Foundation; either
 *  version 2.1 of the License, or (at your option) any later version.
 *
 *  This library 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
 *  Lesser General Public License for more details.
 *
 *  You should have received a copy of the GNU Lesser General Public
 *  License along with this library; if not, write to the Free Software
 *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 */

package net.darkmist.alib.str;

// we may be able to use org.apache.commons.lang.StringEscapeUtils.escapeJava(String)

public class BackSlashEscape {
    private static BackSlashEscape singleton = new BackSlashEscape();

    protected byte escapeChar() {
        return (byte) '\\';
    }

    public String escape(byte[] in) {
        byte escape = escapeChar();
        byte[] out = new byte[in.length * 4];
        int in_counter;
        int out_counter = 0;
        for (in_counter = 0; in_counter < in.length; in_counter++) {
            byte b = in[in_counter];

            if (('a' <= b && b <= 'z') || ('A' <= b && b <= 'Z') || ('0' <= b && b <= '9')) {
                out[out_counter++] = b;
                continue;
            }
            switch (b) {
            case ' ':
                out[out_counter++] = b;
                continue;
            }
            // all the rest will need an escape...
            out[out_counter++] = escape;
            if (b == escape) {
                out[out_counter++] = escape;
                continue;
            }
            switch (b) {
            case '\007':
                out[out_counter++] = 'a';
                continue;
            case '\b':
                out[out_counter++] = 'b';
                continue;
            case '\f':
                out[out_counter++] = 'f';
                continue;
            case '\n':
                out[out_counter++] = 'n';
                continue;
            case '\r':
                out[out_counter++] = 'r';
                continue;
            case '\t':
                out[out_counter++] = 't';
                continue;
            case '\013':
                out[out_counter++] = 'v';
                continue;
            }
            byte[] hex = Integer.toHexString(b).getBytes();
            out[out_counter++] = 'x';
            if (hex.length == 1) {
                out[out_counter++] = '0';
                out[out_counter++] = hex[0];
            } else {
                out[out_counter++] = hex[0];
                out[out_counter++] = hex[1];
            }
        }
        return new String(out, 0, out_counter);
    }

    public String escape(String in) {
        return escape(in.getBytes());
    }

    public String escape(CharSequence in) {
        return escape(in.toString().getBytes());
    }

    public static BackSlashEscape getInstance() {
        return singleton;
    }

    protected BackSlashEscape() {
    }
}