util/src/main/java/org/jf/util/StringUtils.java

/*
 * Copyright 2012, Google Inc.
 * 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 Google Inc. 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 COPYRIGHT
 * OWNER 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.jf.util;

import java.io.IOException;
import java.io.Writer;

public class StringUtils {
    public static void writeEscapedChar(Writer writer, char c) throws IOException {
        if ((c >= ' ') && (c < 0x7f)) {
            if ((c == '\'') || (c == '\"') || (c == '\\')) {
                writer.write('\\');
            }
            writer.write(c);
            return;
        } else if (c <= 0x7f) {
            switch (c) {
                case '\n': writer.write("\\n"); return;
                case '\r': writer.write("\\r"); return;
                case '\t': writer.write("\\t"); return;
            }
        }

        writer.write("\\u");
        writer.write(Character.forDigit(c >> 12, 16));
        writer.write(Character.forDigit((c >> 8) & 0x0f, 16));
        writer.write(Character.forDigit((c >> 4) & 0x0f, 16));
        writer.write(Character.forDigit(c & 0x0f, 16));
    }

    public static void writeEscapedString(Writer writer, String value) throws IOException {
        for (int i = 0; i < value.length(); i++) {
            char c = value.charAt(i);

            if ((c >= ' ') && (c < 0x7f)) {
                if ((c == '\'') || (c == '\"') || (c == '\\')) {
                    writer.write('\\');
                }
                writer.write(c);
                continue;
            } else if (c <= 0x7f) {
                switch (c) {
                    case '\n': writer.write("\\n"); continue;
                    case '\r': writer.write("\\r"); continue;
                    case '\t': writer.write("\\t"); continue;
                }
            }

            writer.write("\\u");
            writer.write(Character.forDigit(c >> 12, 16));
            writer.write(Character.forDigit((c >> 8) & 0x0f, 16));
            writer.write(Character.forDigit((c >> 4) & 0x0f, 16));
            writer.write(Character.forDigit(c & 0x0f, 16));
        }
    }

    public static String escapeString(String value) {
        int len = value.length();
        StringBuilder sb = new StringBuilder(len * 3 / 2);

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

            if ((c >= ' ') && (c < 0x7f)) {
                if ((c == '\'') || (c == '\"') || (c == '\\')) {
                    sb.append('\\');
                }
                sb.append(c);
                continue;
            } else if (c <= 0x7f) {
                switch (c) {
                    case '\n': sb.append("\\n"); continue;
                    case '\r': sb.append("\\r"); continue;
                    case '\t': sb.append("\\t"); continue;
                }
            }

            sb.append("\\u");
            sb.append(Character.forDigit(c >> 12, 16));
            sb.append(Character.forDigit((c >> 8) & 0x0f, 16));
            sb.append(Character.forDigit((c >> 4) & 0x0f, 16));
            sb.append(Character.forDigit(c & 0x0f, 16));
        }

        return sb.toString();
    }
}