Logback: the reliable, generic, fast and flexible logging framework.
Copyright (C) 1999-2015, QOS.ch. All rights reserved.
This program and the accompanying materials are dual-licensed under
either the terms of the Eclipse Public License v1.0 as published by
the Eclipse Foundation
  or (per the licensee's choosing)
under the terms of the GNU Lesser General Public License version 2.1
as published by the Free Software Foundation.
/**
 * Logback: the reliable, generic, fast and flexible logging framework.
 * Copyright (C) 1999-2015, QOS.ch. All rights reserved.
 *
 * This program and the accompanying materials are dual-licensed under
 * either the terms of the Eclipse Public License v1.0 as published by
 * the Eclipse Foundation
 *
 *   or (per the licensee's choosing)
 *
 * under the terms of the GNU Lesser General Public License version 2.1
 * as published by the Free Software Foundation.
 */
package ch.qos.logback.core.pattern.util;

This implementation is intended for use in PatternLayout.
Author:
Ceki Gülcü/**
 * This implementation is intended for use in PatternLayout.
 * 
 * @author Ceki Gülcü
 */
public class RegularEscapeUtil implements IEscapeUtil {

    public void escape(String escapeChars, StringBuffer buf, char next, int pointer) {
        if (escapeChars.indexOf(next) >= 0) {
            buf.append(next);
        } else
            switch (next) {
            case '_':
                // the \_ sequence is swallowed
                break;
            case '\\':
                buf.append(next);
                break;
            case 't':
                buf.append('\t');
                break;
            case 'r':
                buf.append('\r');
                break;
            case 'n':
                buf.append('\n');
                break;
            default:
                String commaSeperatedEscapeChars = formatEscapeCharsForListing(escapeChars);
                throw new IllegalArgumentException("Illegal char '" + next + " at column " + pointer + ". Only \\\\, \\_" + commaSeperatedEscapeChars
                                + ", \\t, \\n, \\r combinations are allowed as escape characters.");
            }
    }

    String formatEscapeCharsForListing(String escapeChars) {
        StringBuilder commaSeperatedEscapeChars = new StringBuilder();
        for (int i = 0; i < escapeChars.length(); i++) {
            commaSeperatedEscapeChars.append(", \\").append(escapeChars.charAt(i));
        }
        return commaSeperatedEscapeChars.toString();
    }

    public static String basicEscape(String s) {
        char c;
        int len = s.length();
        StringBuilder sbuf = new StringBuilder(len);

        int i = 0;
        while (i < len) {
            c = s.charAt(i++);
            if (c == '\\') {
                c = s.charAt(i++);
                if (c == 'n') {
                    c = '\n';
                } else if (c == 'r') {
                    c = '\r';
                } else if (c == 't') {
                    c = '\t';
                } else if (c == 'f') {
                    c = '\f';
                } else if (c == '\b') {
                    c = '\b';
                } else if (c == '\"') {
                    c = '\"';
                } else if (c == '\'') {
                    c = '\'';
                } else if (c == '\\') {
                    c = '\\';
                }
            }
            sbuf.append(c);
        }
        return sbuf.toString();
    }
}