// ==========================================================================
//                 SeqAn - The Library for Sequence Analysis
// ==========================================================================
// Copyright (c) 2006-2012, Knut Reinert, FU Berlin
// 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 Knut Reinert or the FU Berlin 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 KNUT REINERT OR THE FU BERLIN 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.
//
// ==========================================================================
// Author: Andreas Gogol-Doering <andreas.doering@mdc-berlin.de>
// ==========================================================================
// Basic comparison code.
// ==========================================================================

#ifndef SEQAN_CORE_INCLUDE_SEQAN_FUNDAMENTAL_COMPARISON_H_
#define SEQAN_CORE_INCLUDE_SEQAN_FUNDAMENTAL_COMPARISON_H_

namespace seqan {

// ============================================================================
// Forwards
// ============================================================================

// ============================================================================
// Tags, Classes, Enums
// ============================================================================

// ============================================================================
// Metafunctions
// ============================================================================

/**
.Metafunction.CompareType
..cat:Basic
..summary:Type to convert other types for comparisons.
..signature:CompareType<T1, T2>::Type
..param.T1:Type of the left operand of a comparison.
..param.T2:Type of the right operand of a comparison.
..return.Type:The Type in which the arguments are converted in order to compare them.
..remarks:Comparisons are for example operators like $==$ or $<$.
..remarks:Do not implement, implement @Metafunction.CompareTypeImpl@ instead.
..remarks.text:Note that there is no rule that guarantees that $CompareType<T1, T2>::Type$
is the same as $CompareType<T2, T1>::Type$. It is also possible, that only one of these
two types is defined.
..see:Metafunction.CompareTypeImpl
..remarks.text:This metafunction is used for the implementation of
comparisons that involve @Class.SimpleType@.
..include:seqan/basic.h

.Metafunction.CompareTypeImpl
..cat:Basic
..summary:Implementation of @Metafunction.CompareType@.
..signature:CompareType<T1, T2>::Type
..param.T1:Type of the left operand of a comparison.
..param.T2:Type of the right operand of a comparison.
..return.Type:The Type in which the arguments are converted in order to compare them.
..see:Metafunction.CompareType
..include:seqan/basic.h
*/

// Given two types, the CompareType is a type that both types can be cast to
// and where the results are then used to compare two values.

template <typename T1, typename T2>
struct CompareType;

template <typename T1, typename T2>
struct CompareTypeImpl;

template <typename T>
struct CompareTypeImpl<T, T>
{
    typedef T Type;
};

template <typename T1, typename T2>
struct CompareType
{
    typedef typename RemoveConst<T1>::Type T1_;
    typedef typename RemoveConst<T2>::Type T2_;
    typedef typename CompareTypeImpl<T1_, T2_>::Type Type;
};

// ============================================================================
// Functions
// ============================================================================

// TODO(holtgrew): What does this do / extend / complement?

template <typename T_>
inline bool lexLess(const T_& _Left, const T_& Right_)
{
    typedef typename MakeUnsigned_<T_>::Type TUnsigned;
    return (TUnsigned)_Left < (TUnsigned)Right_;
}

}  // namespace seqan

#endif  // #ifndef SEQAN_CORE_INCLUDE_SEQAN_FUNDAMENTAL_COMPARISON_H_