de.uni.bremen.monty.moco.ast.expression.literal.StringLiteral.java Source code

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Here is the source code for de.uni.bremen.monty.moco.ast.expression.literal.StringLiteral.java

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/*
 * moco, the Monty Compiler
 * Copyright (c) 2013-2014, Monty's Coconut, All rights reserved.
 *
 * This file is part of moco, the Monty Compiler.
 *
 * moco is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public
 * License as published by the Free Software Foundation; either
 * version 3.0 of the License, or (at your option) any later version.
 *
 * moco 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
 * General Public License for more details.
 *
 * Linking this program and/or its accompanying libraries statically or
 * dynamically with other modules is making a combined work based on this
 * program. Thus, the terms and conditions of the GNU General Public License
 * cover the whole combination.
 *
 * As a special exception, the copyright holders of moco give
 * you permission to link this programm and/or its accompanying libraries
 * with independent modules to produce an executable, regardless of the
 * license terms of these independent modules, and to copy and distribute the
 * resulting executable under terms of your choice, provided that you also meet,
 * for each linked independent module, the terms and conditions of the
 * license of that module.
 *
 * An independent module is a module which is not
 * derived from or based on this program and/or its accompanying libraries.
 * If you modify this library, you may extend this exception to your version of
 * the program or library, but you are not obliged to do so. If you do not wish
 * to do so, delete this exception statement from your version.
 *
 * You should have received a copy of the GNU General Public
 * License along with this library.
 */
package de.uni.bremen.monty.moco.ast.expression.literal;

import de.uni.bremen.monty.moco.ast.CoreClasses;
import de.uni.bremen.monty.moco.ast.Position;
import de.uni.bremen.monty.moco.visitor.BaseVisitor;
import org.apache.commons.lang3.StringUtils;

import java.nio.charset.StandardCharsets;
import java.util.regex.Matcher;
import java.util.regex.Pattern;

public class StringLiteral extends LiteralExpression<String> {
    public StringLiteral(Position position, String value) {
        super(position, prepareStrLiteral(value));
    }

    @Override
    public void visit(BaseVisitor visitor) {
        visitor.visit(this);
    }

    /** Removes leading and trailing quotes of string literals
     *
     * @param value
     *            the string to prepare
     * @return value without leading and trailing quotes */
    protected static String prepareStrLiteral(String value) {
        if ((value.startsWith("\"")) && (value.endsWith("\""))) {
            value = value.substring(1, value.length() - 1);
        }
        return value;
    }

    /** @param value
     * @return */
    public static int getStrLiteralLength(String value) {
        // every backslash is followed by two numbers, but those three characters
        // represent only one char in the IR string literal
        return value.length() - (StringUtils.countMatches(value, "\\") * 2);
    }

    /** replaces escape sequences of string literals by the LLVM IR equivalents
     *
     * @param value
     *            the string which should be escaped
     * @return an escaped string */
    public static String replaceEscapeSequences(String value) {
        // replace escape sequences
        value = value.replace("\\t", "\\09"); // horizontal tab
        value = value.replace("\\b", "\\08"); // backspace
        value = value.replace("\\n", "\\0A"); // line feed
        value = value.replace("\\r", "\\0D"); // carriage return
        value = value.replace("\\f", "\\0C"); // formfeed
        value = value.replace("\\'", "\\27"); // single quote
        value = value.replace("\\\"", "\\22"); // double quote
        value = value.replace("\\\\", "\\5C"); // backslash

        // replace unicode escape sequences by utf-8 codes
        StringBuffer output = new StringBuffer();
        Pattern regex = Pattern.compile("(\\\\u....)|\\P{ASCII}");
        Matcher matcher = regex.matcher(value);
        byte[] utf8;
        while (matcher.find()) {
            String replacement = "";

            if (matcher.group().startsWith("\\u")) {
                // convert hexadecimal unicode number to utf-8 encoded bytes
                utf8 = Character.toString((char) Integer.parseInt(matcher.group().substring(2), 16))
                        .getBytes(StandardCharsets.UTF_8);
            } else {
                // convert a unicode character to utf-8 encoded bytes
                utf8 = matcher.group().getBytes(StandardCharsets.UTF_8);
            }
            // convert utf-8 bytes to hex strings (for LLVM IR)
            for (byte c : utf8) {
                replacement += String.format("\\\\%02x", c);
            }
            matcher.appendReplacement(output, replacement);
        }
        matcher.appendTail(output);

        return output.toString();
    }
}