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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_IGNORE_H
#define SCN_SCAN_IGNORE_H
#include "common.h"
namespace scn {
SCN_BEGIN_NAMESPACE
namespace detail {
template <typename CharT>
struct ignore_iterator {
using value_type = CharT;
using pointer = value_type*;
using reference = value_type&;
using difference_type = std::ptrdiff_t;
using iterator_category = std::output_iterator_tag;
constexpr ignore_iterator() = default;
SCN_CONSTEXPR14 ignore_iterator& operator=(CharT) noexcept
{
return *this;
}
constexpr const ignore_iterator& operator=(CharT) const noexcept
{
return *this;
}
SCN_CONSTEXPR14 ignore_iterator& operator*() noexcept
{
return *this;
}
constexpr const ignore_iterator& operator*() const noexcept
{
return *this;
}
SCN_CONSTEXPR14 ignore_iterator& operator++() noexcept
{
return *this;
}
constexpr const ignore_iterator& operator++() const noexcept
{
return *this;
}
};
template <typename CharT>
struct ignore_iterator_n {
using value_type = CharT;
using pointer = value_type*;
using reference = value_type&;
using difference_type = std::ptrdiff_t;
using iterator_category = std::output_iterator_tag;
ignore_iterator_n() = default;
ignore_iterator_n(difference_type n) : i(n) {}
constexpr const ignore_iterator_n& operator=(CharT) const noexcept
{
return *this;
}
constexpr const ignore_iterator_n& operator*() const noexcept
{
return *this;
}
SCN_CONSTEXPR14 ignore_iterator_n& operator++() noexcept
{
++i;
return *this;
}
constexpr bool operator==(const ignore_iterator_n& o) const noexcept
{
return i == o.i;
}
constexpr bool operator!=(const ignore_iterator_n& o) const noexcept
{
return !(*this == o);
}
difference_type i{0};
};
template <typename WrappedRange,
typename Until,
typename CharT = typename WrappedRange::char_type>
error ignore_until_impl(WrappedRange& r, Until until)
{
ignore_iterator<CharT> it{};
return read_until_space(r, it, until_pred<CharT>{until}, false);
}
template <typename WrappedRange,
typename Until,
typename CharT = typename WrappedRange::char_type>
error ignore_until_n_impl(WrappedRange& r,
ranges::range_difference_t<WrappedRange> n,
Until until)
{
ignore_iterator_n<CharT> begin{}, end{n};
return read_until_space_ranged(r, begin, end,
until_pred<CharT>{until}, false);
}
} // namespace detail
/**
* Advances the beginning of \c r until \c until is found.
*/
#if SCN_DOXYGEN
template <typename Range, typename Until>
auto ignore_until(Range&& r, Until until)
-> detail::scan_result_for_range<Range>;
#else
template <typename Range, typename Until>
SCN_NODISCARD auto ignore_until(Range&& r, Until until)
-> detail::scan_result_for_range<Range>
{
auto wrapped = wrap(SCN_FWD(r));
auto err = detail::ignore_until_impl(wrapped, until);
if (!err) {
auto e = wrapped.reset_to_rollback_point();
if (!e) {
err = e;
}
}
else {
wrapped.set_rollback_point();
}
return detail::wrap_result(
wrapped_error{err}, detail::range_tag<Range>{}, SCN_MOVE(wrapped));
}
#endif
/**
* Advances the beginning of \c r until \c until is found, or the
* beginning has been advanced \c n times.
*
* `Until` can be the `r` character type (`char` or `wchar_t`), or
* `code_point`.
*/
#if SCN_DOXYGEN
template <typename Range, typename Until>
auto ignore_until_n(Range&& r,
ranges::range_difference_t<Range> n,
Until until) -> detail::scan_result_for_range<Range>;
#else
template <typename Range, typename Until>
SCN_NODISCARD auto ignore_until_n(Range&& r,
ranges::range_difference_t<Range> n,
Until until)
-> detail::scan_result_for_range<Range>
{
auto wrapped = wrap(SCN_FWD(r));
auto err = detail::ignore_until_n_impl(wrapped, n, until);
if (!err) {
auto e = wrapped.reset_to_rollback_point();
if (!e) {
err = e;
}
}
return detail::wrap_result(
wrapped_error{err}, detail::range_tag<Range>{}, SCN_MOVE(wrapped));
}
#endif
SCN_END_NAMESPACE
} // namespace scn
#endif
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