include/stxxl/bits/common/utils.h

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/***************************************************************************
 *  include/stxxl/bits/common/utils.h
 *
 *  Part of the STXXL. See http://stxxl.sourceforge.net
 *
 *  Copyright (C) 2002-2006 Roman Dementiev <dementiev@mpi-sb.mpg.de>
 *  Copyright (C) 2007-2009 Andreas Beckmann <beckmann@cs.uni-frankfurt.de>
 *  Copyright (C) 2008 Johannes Singler <singler@ira.uka.de>
 *
 *  Distributed under the Boost Software License, Version 1.0.
 *  (See accompanying file LICENSE_1_0.txt or copy at
 *  http://www.boost.org/LICENSE_1_0.txt)
 **************************************************************************/

#ifndef STXXL_UTILS_HEADER
#define STXXL_UTILS_HEADER

#include <vector>
#include <string>
#include <cmath>
#include <cstdlib>

#ifdef STXXL_BOOST_CONFIG
 #include <boost/config.hpp>
#endif

#include <stxxl/bits/namespace.h>
#include <stxxl/bits/common/types.h>
#include <stxxl/bits/compat/type_traits.h>
#include <stxxl/bits/msvc_compatibility.h>


__STXXL_BEGIN_NAMESPACE

////////////////////////////////////////////////////////////////////////////

#if defined(__GXX_EXPERIMENTAL_CXX0X__)
#define STXXL_STATIC_ASSERT(x) static_assert(x, #x)
#else
#define STXXL_STATIC_ASSERT(x) { typedef int static_assert_dummy_type[(x) ? 1 : -1]; }
#endif

////////////////////////////////////////////////////////////////////////////

inline std::vector<std::string>
split(const std::string & str, const std::string & sep)
{
    std::vector<std::string> result;
    if (str.empty())
        return result;

    std::string::size_type CurPos(0), LastPos(0);
    while (1)
    {
        CurPos = str.find(sep, LastPos);
        if (CurPos == std::string::npos)
            break;

        std::string sub =
            str.substr(LastPos,
                       std::string::size_type(CurPos -
                                              LastPos));
        if (sub.size())
            result.push_back(sub);

        LastPos = CurPos + sep.size();
    }

    std::string sub = str.substr(LastPos);
    if (sub.size())
        result.push_back(sub);

    return result;
}

////////////////////////////////////////////////////////////////////////////

inline stxxl::int64 atoint64(const char * s)
{
#ifdef BOOST_MSVC
    return _atoi64(s);
#else
    return atoll(s);
#endif
}

////////////////////////////////////////////////////////////////////////////

template <typename Tp>
inline const Tp &
STXXL_MIN(const Tp & a, const Tp & b)
{
    return std::min<Tp>(a, b);
}

template <typename Tp>
inline const Tp &
STXXL_MAX(const Tp & a, const Tp & b)
{
    return std::max<Tp>(a, b);
}

////////////////////////////////////////////////////////////////////////////

template <typename Integral>
inline Integral log2_ceil(Integral i)
{
    return Integral(ceil(log2(i)));
}

template <typename Integral>
inline Integral log2_floor(Integral i)
{
    return Integral(log2(i));
}

////////////////////////////////////////////////////////////////////////////

template <typename Integral, typename Integral2>
inline
typename compat::remove_const<Integral>::type
div_ceil(Integral __n, Integral2 __d)
{
#if 0  // ambiguous overload for std::div(unsigned_anything, unsigned_anything)
    typedef __typeof__(std::div(__n, __d)) div_type;
    div_type result = std::div(__n, __d);
    return result.quot + (result.rem != 0);
#else
    return __n / __d + ((__n % __d) != 0);
#endif
}

////////////////////////////////////////////////////////////////////////////

#ifdef __GNUC__
#define HAVE_BUILTIN_EXPECT
#endif

#ifdef HAVE_BUILTIN_EXPECT
 #define LIKELY(c)   __builtin_expect((c), 1)
#else
 #define LIKELY(c)   c
#endif

#ifdef HAVE_BUILTIN_EXPECT
 #define UNLIKELY(c)   __builtin_expect((c), 0)
#else
 #define UNLIKELY(c)   c
#endif

////////////////////////////////////////////////////////////////////////////

inline uint64 longhash1(uint64 key_)
{
    key_ += ~(key_ << 32);
    key_ ^= (key_ >> 22);
    key_ += ~(key_ << 13);
    key_ ^= (key_ >> 8);
    key_ += (key_ << 3);
    key_ ^= (key_ >> 15);
    key_ += ~(key_ << 27);
    key_ ^= (key_ >> 31);
    return key_;
}

////////////////////////////////////////////////////////////////////////////

template <class T>
inline void swap_1D_arrays(T * a, T * b, unsigned_type size)
{
    for (unsigned_type i = 0; i < size; ++i)
        std::swap(a[i], b[i]);
}

////////////////////////////////////////////////////////////////////////////

template <typename Integral>
inline Integral round_up_to_power_of_two(Integral n, unsigned_type power)
{
    Integral pot = 1 << power, // = 0..0 1 0^power
             mask = pot - 1;   // = 0..0 0 1^power
    if (n & mask)  // n not divisible by pot
        return (n & ~mask) + pot;
    else
        return n;
}

////////////////////////////////////////////////////////////////////////////

template <class Container>
inline typename Container::value_type pop(Container & c)
{
    typename Container::value_type r = c.top();
    c.pop();
    return r;
}

template <class Container>
inline typename Container::value_type pop_front(Container & c)
{
    typename Container::value_type r = c.front();
    c.pop_front();
    return r;
}

template <class Container>
inline typename Container::value_type pop_back(Container & c)
{
    typename Container::value_type r = c.back();
    c.pop_back();
    return r;
}

template <class Container>
inline typename Container::value_type pop_begin(Container & c)
{
    typename Container::value_type r = *c.begin();
    c.erase(c.begin());
    return r;
}

////////////////////////////////////////////////////////////////////////////

__STXXL_END_NAMESPACE

#endif // !STXXL_UTILS_HEADER
// vim: et:ts=4:sw=4