jodd.csselly.selector.PseudoFunctionExpression Maven / Gradle / Ivy

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// Copyright (c) 2003-present, Jodd Team (http://jodd.org)
// All rights reserved.
//
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions are met:
//
// 1. Redistributions of source code must retain the above copyright notice,
// this list of conditions and the following disclaimer.
//
// 2. 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.
//
// 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 HOLDER 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
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package jodd.csselly.selector;

import jodd.csselly.CSSellyException;
import jodd.util.StringPool;
import jodd.util.StringUtil;

/**
 * {@link PseudoFunction Pseudo function expression}, in form: an + b.
 */
public class PseudoFunctionExpression {

    protected final int a;
    protected final int b;

    public PseudoFunctionExpression(String expression) {
        expression = StringUtil.removeChars(expression, "+ \t\n\r\n");
        if (expression.equals("odd")) {
            a = 2;
            b = 1;
        } else if (expression.equals("even")) {
            a = 2;
            b = 0;
        } else {
            int nndx = expression.indexOf('n');
            if (nndx != -1) {
                String aVal = expression.substring(0, nndx).trim();
                if (aVal.length() == 0) {
                    a = 1;
                } else {
                    if (aVal.equals(StringPool.DASH)) {
                        a = -1;
                    } else {
                        a = parseInt(aVal);
                    }
                }
                String bVal = expression.substring(nndx + 1);
                if (bVal.length() == 0) {
                    b = 0;
                } else {
                    b = parseInt(bVal);
                }
            } else {
                a = 0;
                b = parseInt(expression);
            }
        }
    }

    /**
     * Parses int value or throws CSSellyException on failure.
     */
    protected int parseInt(String value) {
        try {
            return Integer.parseInt(value);
        } catch (NumberFormatException nfex) {
            throw new CSSellyException(nfex);
        }
    }


    /**
     * Returns a value of the function expression.
     */
    public int getValueA() {
        return a;
    }

    /**
     * Returns b value of the function expression.
     */
    public int getValueB() {
        return b;
    }

    /**
     * Matches expression with the value.
     */
    public boolean match(int value) {
        if (a == 0) {
            return value == b;
        }

        if (a > 0) {
            if (value < b) {
                return false;
            }
            return (value - b) % a == 0;
        }

        if (value > b) {
            return false;
        }
        return (b - value) % (-a) == 0;
    }

}