libcruft-util/coord/base.hpp

158 lines
4.9 KiB
C++

/*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*
* Copyright 2012-2016 Danny Robson <danny@nerdcruft.net>
*/
#ifndef __UTIL_COORD_BASE_HPP
#define __UTIL_COORD_BASE_HPP
#include "init.hpp"
#include "../maths.hpp"
#include <algorithm>
#include <cstdlib>
#include <type_traits>
namespace util::coord {
/////////////////////////////////////////////////////////////////////////
template <
size_t S,
typename T,
template <size_t, typename> class KLASS,
typename ...tags
>
struct base : public init<S,T,tags...> {
static_assert (S > 0);
static_assert (std::is_arithmetic<T>::value);
using value_type = T;
static constexpr size_t dimension = S;
static constexpr size_t elements = S;
/// returns the number of elements we contain
static constexpr size_t size (void) { return S; }
// inherit the fancy elementwise constructors from `init'.
using init<S,T,tags...>::init;
/// constructs, but does not initialise, the data.
///
/// used to avoid unnecessary initialisation in many situations where
/// we have arrays of these types that are about to be overwritten. it
/// is a very important performance optimisation.
base () = default;
/// constructs an instance where all elements are initialised to `val'.
constexpr explicit
base (T val)
{ std::fill (begin (), end (), val); }
constexpr base (const base<S,T,KLASS,tags...> &rhs) = default;
base& operator= (const base<S,T,KLASS,tags...> &rhs) = default;
// element accessors
T& operator[] (size_t i) { return this->data[i]; }
constexpr const T& operator[] (size_t i) const { return this->data[i]; }
auto cbegin (void) const { return std::cbegin (this->data); }
auto cend (void) const { return std::cend (this->data); }
auto begin (void) const { return std::begin (this->data); }
auto end (void) const { return std::end (this->data); }
auto begin (void) { return std::begin (this->data); }
auto end (void) { return std::end (this->data); }
const T& front (void) const { return this->data[0]; }
T& front (void) { return this->data[0]; }
const T& back (void) const { return this->data[S-1]; }
T& back (void) { return this->data[S-1]; }
///////////////////////////////////////////////////////////////////////
// conversions
template <template <size_t, typename> class K>
K<S,T> as (void) const
{
K<S,T> k;
std::copy (begin (), end (), k.begin ());
return k;
}
//---------------------------------
template <typename U>
KLASS<S,U>
cast (void) const
{
KLASS<S,U> out;
std::copy (std::cbegin (this->data),
std::cend (this->data),
std::begin (out.data));
return out;
}
///////////////////////////////////////////////////////////////////////
// redimension
template <size_t D>
KLASS<D,T>
redim (void) const
{
KLASS<D,T> out;
std::copy_n (std::cbegin (this->data),
min (S, D),
std::begin (out.data));
return out;
}
//---------------------------------------------------------------------
template<size_t D>
KLASS<D,T>
redim (const KLASS<D,T> fill) const
{
KLASS<D,T> out;
static constexpr auto L1 = min (S, D);
static constexpr auto L2 = D - L1;
std::copy_n (std::cbegin (this->data),
L1,
std::begin (out.data));
std::copy_n (fill.data + L1,
L2,
out.data + L1);
return out;
}
//---------------------------------------------------------------------
template <size_t D>
KLASS<D,T>
redim (T fill) const
{
KLASS<D,T> out;
auto cursor = std::copy_n (std::cbegin (this->data),
min (S, D),
std::begin (out.data));
std::fill (cursor, std::end (out.data), fill);
return out;
}
};
}
#endif