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// license:GPL-2.0+
// copyright-holders:Couriersud
/*
* parray.h
*
*/
#ifndef PARRAY_H_
#define PARRAY_H_
#include "pconfig.h"
#include "pexception.h"
#include <memory>
#include <utility>
#include <vector>
#include <array>
#include <type_traits>
namespace plib {
template <typename FT, int SIZE>
struct sizeabs
{
static constexpr std::size_t ABS() { return (SIZE < 0) ? static_cast<std::size_t>(0 - SIZE) : static_cast<std::size_t>(SIZE); }
typedef typename std::array<FT, ABS()> container;
};
template <typename FT>
struct sizeabs<FT, 0>
{
static constexpr const std::size_t ABS = 0;
typedef typename std::vector<FT> container;
};
/**
* \brief Array with preallocated or dynamic allocation
*
* Passing SIZE > 0 has the same functionality as a std::array.
* SIZE = 0 is pure dynamic allocation, the actual array size is passed to the
* constructor.
* SIZE < 0 reserves std::abs(SIZE) elements statically in place allocated. The
* actual size is passed in by the constructor.
* This array is purely intended for HPC application where depending on the
* architecture a preference dynamic/static has to be made.
*
* This struct is not intended to be a full replacement to std::array.
* It is a subset to enable switching between dynamic and static allocation.
* I consider > 10% performance difference to be a use case.
*/
template <typename FT, int SIZE>
struct parray
{
public:
static constexpr std::size_t SIZEABS() { return sizeabs<FT, SIZE>::ABS(); }
typedef typename sizeabs<FT, SIZE>::container base_type;
typedef typename base_type::size_type size_type;
typedef typename base_type::reference reference;
typedef typename base_type::const_reference const_reference;
template <int X = SIZE >
parray(size_type size, typename std::enable_if<X==0, int>::type = 0)
: m_a(size), m_size(size)
{
}
#if 0
/* allow construction in fixed size arrays */
template <int X = SIZE >
parray(typename std::enable_if<X==0, int>::type = 0)
: m_size(0)
{
}
#endif
template <int X = SIZE >
parray(size_type size, typename std::enable_if<X!=0, int>::type = 0)
: m_size(size)
{
if (SIZE < 0 && size > SIZEABS())
throw plib::pexception("parray: size error " + plib::to_string(size) + ">" + plib::to_string(SIZEABS()));
else if (SIZE > 0 && size != SIZEABS())
throw plib::pexception("parray: size error");
}
inline size_type size() const noexcept { return SIZE <= 0 ? m_size : SIZEABS(); }
constexpr size_type max_size() const noexcept { return base_type::max_size(); }
bool empty() const noexcept { return size() == 0; }
#if 0
reference operator[](size_type i) /*noexcept*/
{
if (i >= m_size) throw plib::pexception("limits error " + to_string(i) + ">=" + to_string(m_size));
return m_a[i];
}
const_reference operator[](size_type i) const /*noexcept*/
{
if (i >= m_size) throw plib::pexception("limits error " + to_string(i) + ">=" + to_string(m_size));
return m_a[i];
}
#else
reference operator[](size_type i) noexcept { return m_a[i]; }
constexpr const_reference operator[](size_type i) const noexcept { return m_a[i]; }
#endif
FT * data() noexcept { return m_a.data(); }
const FT * data() const noexcept { return m_a.data(); }
private:
base_type m_a;
size_type m_size;
};
}
#endif /* PARRAY_H_ */
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