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// Range v3 library
//
// Copyright Casey Carter 2017
//
// Use, modification and distribution is subject to 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)
//
// Project home: https://github.com/ericniebler/range-v3
//
#ifndef RANGES_TEST_DEBUG_VIEW_HPP
#define RANGES_TEST_DEBUG_VIEW_HPP
#include <cstddef>
#include <atomic>
#include <memory>
#include <range/v3/iterator/operations.hpp>
#include <range/v3/utility/swap.hpp>
template<typename T, bool Sized = true>
struct debug_input_view : ranges::view_base
{
static_assert(std::is_object<T>::value, "");
using index_t = std::ptrdiff_t;
using version_t = long;
struct data
{
T *const first_;
index_t const n_;
std::atomic<index_t> offset_ {-1};
data(T *p, index_t n)
: first_(p), n_(n)
{
RANGES_ENSURE(n >= 0);
RANGES_ENSURE(p || !n);
}
};
std::shared_ptr<data> data_{};
version_t version_ = 0;
debug_input_view() = default;
debug_input_view(T* p, index_t size)
: data_(std::make_shared<data>(p, size))
{}
template<index_t N>
debug_input_view(T (&data)[N])
: debug_input_view{data, N}
{}
debug_input_view(debug_input_view const &that) = default;
debug_input_view &operator=(debug_input_view const &that)
{
data_ = that.data_;
++version_; // invalidate outstanding iterators
return *this;
}
struct sentinel
{
debug_input_view *view_ = nullptr;
version_t version_ = 0;
sentinel() = default;
explicit constexpr sentinel(debug_input_view &view) noexcept
: view_{&view}, version_{view.version_}
{}
};
struct iterator
{
using iterator_category = std::input_iterator_tag;
using value_type = meta::_t<std::remove_cv<T>>;
using difference_type = index_t;
using reference = T &;
using pointer = T *;
debug_input_view *view_ = nullptr;
version_t version_ = 0;
index_t offset_ = -1;
iterator() = default;
explicit constexpr iterator(debug_input_view &view) noexcept
: view_{&view}, version_{view.version_}
, offset_{view.data_ ? view.data_->offset_.load() : -1}
{}
void check_current() const noexcept
{
RANGES_ENSURE(view_);
RANGES_ENSURE(view_->version_ == version_);
RANGES_ENSURE(view_->data_);
RANGES_ENSURE(view_->data_->offset_ == offset_);
}
void check_dereferenceable() const noexcept
{
check_current();
RANGES_ENSURE(view_->data_->offset_ < view_->data_->n_);
}
reference operator*() const noexcept
{
check_dereferenceable();
return view_->data_->first_[offset_];
}
iterator &operator++() noexcept
{
check_dereferenceable();
RANGES_ENSURE(view_->data_->offset_.compare_exchange_strong(offset_, offset_ + 1));
++offset_;
return *this;
}
void operator++(int) noexcept
{
++*this;
}
friend bool operator==(iterator const &i, sentinel const &s)
{
RANGES_ENSURE(i.view_ == s.view_);
RANGES_ENSURE(i.version_ == s.version_);
i.check_current();
return i.offset_ == i.view_->data_->n_;
}
friend bool operator==(sentinel const &s, iterator const &i)
{
return i == s;
}
friend bool operator!=(iterator const &i, sentinel const &s)
{
return !(i == s);
}
friend bool operator!=(sentinel const &s, iterator const &i)
{
return !(i == s);
}
CPP_member
friend auto operator-(sentinel const& s, iterator const& i) ->
CPP_ret(difference_type)(
requires Sized)
{
RANGES_ENSURE(i.view_ == s.view_);
RANGES_ENSURE(i.version_ == s.version_);
i.check_current();
return i.view_->data_->n_ - i.offset_;
}
CPP_member
friend auto operator-(iterator const& i, sentinel const& s) ->
CPP_ret(difference_type)(
requires Sized)
{
return -(s - i);
}
};
iterator begin() noexcept
{
RANGES_ENSURE(data_);
index_t tmp = -1;
RANGES_ENSURE(data_->offset_.compare_exchange_strong(tmp, 0));
return iterator{*this};
}
sentinel end() noexcept
{
RANGES_ENSURE(data_);
return sentinel{*this};
}
CPP_member
auto size() const noexcept -> CPP_ret(std::size_t)(
requires Sized)
{
RANGES_ENSURE(data_);
RANGES_ENSURE(data_->offset_ == -1);
return static_cast<std::size_t>(data_->n_);
}
};
#endif
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