56 lines
2.5 KiB
C++
56 lines
2.5 KiB
C++
/*
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* Copyright (C) 2010, Google Inc. All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY APPLE INC. AND ITS CONTRIBUTORS ``AS IS'' AND ANY
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* EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
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* WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
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* DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR ITS CONTRIBUTORS BE LIABLE FOR ANY
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* DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
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* (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
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* LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
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* ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
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* SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*/
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#pragma once
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namespace WTF {
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// An abstract number of element in a sequence. The sequence has a first element.
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// This type should be used instead of integer because 2 contradicting traditions can
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// call a first element '0' or '1' which makes integer type ambiguous.
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class OrdinalNumber {
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WTF_MAKE_FAST_ALLOCATED;
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public:
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static OrdinalNumber beforeFirst() { return OrdinalNumber(-1); }
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static OrdinalNumber fromZeroBasedInt(int zeroBasedInt) { return OrdinalNumber(zeroBasedInt); }
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static OrdinalNumber fromOneBasedInt(int oneBasedInt) { return OrdinalNumber(oneBasedInt - 1); }
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OrdinalNumber() : m_zeroBasedValue(0) { }
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int zeroBasedInt() const { return m_zeroBasedValue; }
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int oneBasedInt() const { return m_zeroBasedValue + 1; }
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bool operator==(OrdinalNumber other) const { return m_zeroBasedValue == other.m_zeroBasedValue; }
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bool operator!=(OrdinalNumber other) const { return !((*this) == other); }
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bool operator>(OrdinalNumber other) const { return m_zeroBasedValue > other.m_zeroBasedValue; }
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private:
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OrdinalNumber(int zeroBasedInt) : m_zeroBasedValue(zeroBasedInt) { }
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int m_zeroBasedValue;
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};
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}
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using WTF::OrdinalNumber;
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