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// Copyright 2017 Elias Kosunen
//
// 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
//
// https://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.
//
// This file is a part of scnlib:
// https://github.com/eliaskosunen/scnlib
#ifndef SCN_DETAIL_VECTORED_H
#define SCN_DETAIL_VECTORED_H
#include "../ranges/util.h"
#include "../util/math.h"
namespace scn {
SCN_BEGIN_NAMESPACE
namespace detail {
namespace _get_buffer {
struct fn {
private:
template <typename It>
static It _get_end(It begin, It end, size_t max_size)
{
return begin +
min(max_size, static_cast<std::size_t>(
ranges::distance(begin, end)));
}
template <typename CharT>
static SCN_CONSTEXPR14
span<typename std::add_const<CharT>::type>
impl(span<span<CharT>> s,
typename span<CharT>::iterator begin,
size_t max_size,
priority_tag<3>) noexcept
{
auto buf_it = s.begin();
for (; buf_it != s.end(); ++buf_it) {
if (begin >= buf_it->begin() && begin < buf_it->end()) {
break;
}
if (begin == buf_it->end()) {
++buf_it;
begin = buf_it->begin();
break;
}
}
if (buf_it == s.end()) {
return {};
}
return {begin, _get_end(begin, buf_it->end(), max_size)};
}
template <
typename Range,
typename std::enable_if<SCN_CHECK_CONCEPT(
ranges::contiguous_range<Range>)>::type* = nullptr>
static SCN_CONSTEXPR14 span<typename std::add_const<
ranges::range_value_t<const Range>>::type>
impl(const Range& s,
ranges::iterator_t<const Range> begin,
size_t max_size,
priority_tag<2>) noexcept
{
auto b = ranges::begin(s);
auto e = ranges::end(s);
return {to_address(begin),
_get_end(to_address(begin),
to_address_safe(e, b, e), max_size)};
}
template <typename Range, typename It>
static auto impl(
const Range& r,
It begin,
size_t max_size,
priority_tag<1>) noexcept(noexcept(r.get_buffer(begin,
max_size)))
-> decltype(r.get_buffer(begin, max_size))
{
return r.get_buffer(begin, max_size);
}
template <typename Range, typename It>
static auto impl(
const Range& r,
It begin,
size_t max_size,
priority_tag<0>) noexcept(noexcept(get_buffer(r,
begin,
max_size)))
-> decltype(get_buffer(r, begin, max_size))
{
return get_buffer(r, begin, max_size);
}
public:
template <typename Range, typename It>
SCN_CONSTEXPR14 auto operator()(const Range& r,
It begin,
size_t max_size) const
noexcept(noexcept(
fn::impl(r, begin, max_size, priority_tag<3>{})))
-> decltype(fn::impl(r,
begin,
max_size,
priority_tag<3>{}))
{
return fn::impl(r, begin, max_size, priority_tag<3>{});
}
template <typename Range, typename It>
SCN_CONSTEXPR14 auto operator()(const Range& r, It begin) const
noexcept(
noexcept(fn::impl(r,
begin,
std::numeric_limits<size_t>::max(),
priority_tag<3>{})))
-> decltype(fn::impl(r,
begin,
std::numeric_limits<size_t>::max(),
priority_tag<3>{}))
{
return fn::impl(r, begin,
std::numeric_limits<size_t>::max(),
priority_tag<3>{});
}
};
} // namespace _get_buffer
namespace {
static constexpr auto& get_buffer =
detail::static_const<_get_buffer::fn>::value;
} // namespace
struct provides_buffer_access_concept {
template <typename Range, typename Iterator>
auto _test_requires(const Range& r, Iterator begin)
-> decltype(scn::detail::valid_expr(
::scn::detail::get_buffer(r, begin)));
};
template <typename Range, typename = void>
struct provides_buffer_access_impl
: std::integral_constant<
bool,
::scn::custom_ranges::detail::_requires<
provides_buffer_access_concept,
Range,
::scn::ranges::iterator_t<const Range>>::value> {
};
} // namespace detail
SCN_END_NAMESPACE
} // namespace scn
#endif
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