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/*
* Copyright (C) 2007, 2008 Apple Inc. All rights reserved.
* Copyright (C) 2008 David Smith (catfish.man@gmail.com)
*
* 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.
* 3. Neither the name of Apple Computer, Inc. ("Apple") 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 APPLE AND ITS 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 APPLE OR ITS 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.
*/
#include "config.h"
#include "CSSNthSelector.h"
namespace WebCore {
// a helper function for parsing nth-arguments
bool CSSNthSelector::parseNth()
{
if (m_parsedNth)
return true;
const String& m_ar = m_argument;
if (m_ar.isEmpty())
return false;
m_parsedNth = true;
m_a = 0;
m_b = 0;
if (m_ar == "odd") {
m_a = 2;
m_b = 1;
} else if (m_ar == "even") {
m_a = 2;
m_b = 0;
} else {
int n = m_ar.find('n');
if (n != -1) {
if (m_ar[0] == '-') {
if (n == 1)
m_a = -1; // -n == -1n
else
m_a = m_ar.substring(0, n).toInt();
} else if (!n)
m_a = 1; // n == 1n
else
m_a = m_ar.substring(0, n).toInt();
int p = m_ar.find('+', n);
if (p != -1)
m_b = m_ar.substring(p + 1, m_ar.length() - p - 1).toInt();
else {
p = m_ar.find('-', n);
m_b = -m_ar.substring(p + 1, m_ar.length() - p - 1).toInt();
}
} else
m_b = m_ar.toInt();
}
return true;
}
// a helper function for checking nth-arguments
bool CSSNthSelector::matchNth(int count)
{
if (!m_a)
return count == m_b;
else if (m_a > 0) {
if (count < m_b)
return false;
return (count - m_b) % m_a == 0;
} else {
if (count > m_b)
return false;
return (m_b - count) % (-m_a) == 0;
}
}
} // namespace WebCore
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