libcruft-util/view.hpp

214 lines
5.5 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 2015-2016 Danny Robson <danny@nerdcruft.net>
*/
#ifndef __UTIL_VIEW_HPP
#define __UTIL_VIEW_HPP
#include "./types/traits.hpp"
#include <cstdlib>
#include <ostream>
#include <string>
#include <cstring>
namespace util {
template <typename T>
struct view {
public:
using value_type = typename std::iterator_traits<remove_restrict_t<T>>::value_type;
constexpr
view (T first, T last) noexcept:
m_begin (first),
m_end (last)
{ ; }
template <typename K>
constexpr explicit
view (K &klass):
m_begin (std::begin (klass)),
m_end (std::end (klass))
{ ; }
template <typename K>
constexpr explicit
view (const K &klass):
m_begin (std::begin (klass)),
m_end (std::end (klass))
{ ; }
constexpr T begin (void) noexcept { return m_begin; }
constexpr T end (void) noexcept { return m_end; }
constexpr const T begin (void) const noexcept { return cbegin (); }
constexpr const T end (void) const noexcept { return cend (); }
constexpr const T cbegin (void) const noexcept { return m_begin; }
constexpr const T cend (void) const noexcept { return m_end; }
auto data (void) { return begin (); }
auto data (void) const { return begin (); }
constexpr bool
empty (void) const noexcept
{
return m_begin == m_end;
}
constexpr auto
size (void) const noexcept
{
return std::distance (m_begin, m_end);
}
constexpr value_type&
operator[] (size_t idx) noexcept
{
auto it = begin ();
std::advance (it, idx);
return *it;
}
constexpr const value_type&
operator[] (size_t idx) const noexcept
{
auto it = begin ();
std::advance (it, idx);
return *it;
}
bool
operator== (const view &rhs) const noexcept
{
return rhs.m_begin == m_begin &&
rhs.m_end == m_end;
}
private:
T m_begin;
T m_end;
};
template <typename T, size_t N>
auto
make_view (const T (&arr)[N])
{
return util::view<const T*> (arr + 0, arr + N);
}
template <typename T>
auto
make_view (T &t)
{
return util::view<decltype(std::begin (t))> { std::begin (t), std::end (t) };
}
template <typename T>
auto
make_view (const T &t)
{
return util::view<decltype(std::cbegin (t))> { std::cbegin (t), std::cend (t) };
}
template <typename T>
auto
make_view (T&&) = delete;
template <typename T>
auto
make_cview (const T &t)
{
return util::view<decltype(std::cbegin (t))> { std::cbegin (t), std::cend (t) };
}
template <typename T>
auto
make_view (T first, T last)
{
return view<T> {first, last};
}
template <typename T>
auto
make_cview (T *first, T *last)
{
return view<const T*> {first, last};
}
// string conversions
inline
view<const char*> make_view (const char *str)
{
return { str, str + strlen (str) };
}
inline
view<char*> make_view (char *str)
{
return { str, str + strlen (str) };
}
template <typename CharT, typename TraitsT, typename AllocT>
view<const CharT*>
make_view (const std::basic_string<CharT,TraitsT,AllocT> &str)
{
return {
std::data (str),
std::data (str) + std::size (str)
};
}
template <typename CharT, typename TraitsT, typename AllocT>
view<CharT*>
make_view (std::basic_string<CharT,TraitsT,AllocT> &str)
{
return {
std::data (str),
std::data (str) + std::size (str)
};
}
template <typename CharT, typename TraitsT, typename AllocT>
view<const CharT*>
make_view (const std::basic_string<CharT,TraitsT,AllocT>&&) = delete;
template <typename CharT, typename TraitsT, typename AllocT>
view<CharT*>
make_view (std::basic_string<CharT,TraitsT,AllocT>&&) = delete;
// boolean operationrs
template <typename T>
bool operator!= (view<T>, view<T>);
bool operator== (const std::string&, view<const char*>);
bool operator== (const std::string&, view<char*>);
bool operator== (const std::string&, view<std::string::const_iterator>);
bool operator== (const std::string&, view<std::string::iterator>);
bool operator== (view<const char*>, const std::string&);
bool operator== (view<char*>, const std::string&);
bool operator== (view<std::string::const_iterator>, const std::string&);
bool operator== (view<std::string::iterator>, const std::string&);
template <typename T>
std::ostream&
operator<< (std::ostream&, view<T>);
}
#endif