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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_SCAN_COMMON_H
#define SCN_SCAN_COMMON_H
#include "../detail/locale.h"
#include "../detail/result.h"
#include "../unicode/common.h"
namespace scn {
SCN_BEGIN_NAMESPACE
namespace detail {
template <typename CharT>
constexpr int to_format(int i)
{
return i;
}
template <typename T>
constexpr auto to_format(T&& f) -> decltype(string_view{SCN_FWD(f)})
{
return {SCN_FWD(f)};
}
template <typename T>
constexpr auto to_format(T&& f) -> decltype(wstring_view{SCN_FWD(f)})
{
return {SCN_FWD(f)};
}
template <typename CharT>
basic_string_view<CharT> to_format(const std::basic_string<CharT>& str)
{
return {str.data(), str.size()};
}
template <typename CharT>
struct until_pred {
array<CharT, 4> until;
size_t size;
constexpr until_pred(CharT ch) : until({{ch}}), size(1) {}
until_pred(code_point cp)
{
auto ret = encode_code_point(until.begin(), until.end(), cp);
SCN_ENSURE(ret);
size = ret.value() - until.begin();
}
SCN_CONSTEXPR14 bool operator()(span<const CharT> ch) const
{
if (ch.size() != size) {
return false;
}
for (size_t i = 0; i < ch.size(); ++i) {
if (ch[i] != until[i]) {
return false;
}
}
return true;
}
static constexpr bool is_localized()
{
return false;
}
constexpr bool is_multibyte() const
{
return size != 1;
}
};
template <typename Error, typename Range>
using generic_scan_result_for_range = decltype(detail::wrap_result(
SCN_DECLVAL(Error),
SCN_DECLVAL(detail::range_tag<Range>),
SCN_DECLVAL(range_wrapper_for_t<Range>)));
template <typename Range>
using scan_result_for_range =
generic_scan_result_for_range<wrapped_error, Range>;
} // namespace detail
template <typename T>
struct discard_type {
discard_type() = default;
};
/**
* Scans an instance of `T`, but doesn't store it anywhere.
* Uses `scn::temp` internally, so the user doesn't have to bother.
*
* \code{.cpp}
* int i{};
* // 123 is discarded, 456 is read into `i`
* auto result = scn::scan("123 456", "{} {}", scn::discard<T>(), i);
* // result == true
* // i == 456
* \endcode
*/
template <typename T>
discard_type<T>& discard()
{
return temp(discard_type<T>{})();
}
template <typename T>
struct scanner<discard_type<T>> : public scanner<T> {
template <typename Context>
error scan(discard_type<T>&, Context& ctx)
{
T tmp;
return scanner<T>::scan(tmp, ctx);
}
};
SCN_END_NAMESPACE
} // namespace scn
#endif
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