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/// \file
// Range v3 library
//
// Copyright Eric Niebler 2013-present
//
// 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_V3_VIEW_SPLIT_WHEN_HPP
#define RANGES_V3_VIEW_SPLIT_WHEN_HPP
#include <type_traits>
#include <utility>
#include <meta/meta.hpp>
#include <range/v3/range_fwd.hpp>
#include <range/v3/algorithm/find_if_not.hpp>
#include <range/v3/functional/bind_back.hpp>
#include <range/v3/functional/invoke.hpp>
#include <range/v3/iterator/default_sentinel.hpp>
#include <range/v3/iterator/operations.hpp>
#include <range/v3/range/access.hpp>
#include <range/v3/range/concepts.hpp>
#include <range/v3/range/traits.hpp>
#include <range/v3/utility/static_const.hpp>
#include <range/v3/view/all.hpp>
#include <range/v3/view/facade.hpp>
#include <range/v3/view/indirect.hpp>
#include <range/v3/view/iota.hpp>
#include <range/v3/view/take_while.hpp>
#include <range/v3/view/view.hpp>
#include <range/v3/detail/prologue.hpp>
namespace ranges
{
/// \addtogroup group-views
/// @{
template<typename Rng, typename Fun>
struct split_when_view
: view_facade<split_when_view<Rng, Fun>,
is_finite<Rng>::value ? finite : range_cardinality<Rng>::value>
{
private:
friend range_access;
Rng rng_;
semiregular_box_t<Fun> fun_;
template<bool IsConst>
struct cursor
{
private:
friend range_access;
friend split_when_view;
friend struct cursor<!IsConst>;
bool zero_;
using CRng = meta::const_if_c<IsConst, Rng>;
iterator_t<CRng> cur_;
sentinel_t<CRng> last_;
using fun_ref_t = semiregular_box_ref_or_val_t<Fun, IsConst>;
fun_ref_t fun_;
struct search_pred
{
bool zero_;
iterator_t<CRng> first_;
sentinel_t<CRng> last_;
fun_ref_t fun_;
bool operator()(iterator_t<CRng> cur) const
{
return (zero_ && cur == first_) ||
(cur != last_ && !invoke(fun_, cur, last_).first);
}
};
using reference_ =
indirect_view<take_while_view<iota_view<iterator_t<CRng>>, search_pred>>;
reference_ read() const
{
return reference_{{views::iota(cur_), {zero_, cur_, last_, fun_}}};
}
void next()
{
RANGES_EXPECT(cur_ != last_);
// If the last match consumed zero elements, bump the position.
if(zero_)
{
zero_ = false;
++cur_;
}
for(; cur_ != last_; ++cur_)
{
auto p = invoke(fun_, cur_, last_);
if(p.first)
{
zero_ = (cur_ == p.second);
cur_ = p.second;
return;
}
}
}
bool equal(default_sentinel_t) const
{
return cur_ == last_;
}
bool equal(cursor const & that) const
{
return cur_ == that.cur_;
}
cursor(fun_ref_t fun, iterator_t<CRng> first, sentinel_t<CRng> last)
: cur_(first)
, last_(last)
, fun_(fun)
{
// For skipping an initial zero-length match
auto p = invoke(fun, first, last);
zero_ = p.first && first == p.second;
}
public:
cursor() = default;
template(bool Other)(
requires IsConst AND CPP_NOT(Other)) //
cursor(cursor<Other> that)
: cursor{std::move(that.cur_), std::move(that.last_), std::move(that.fun_)}
{}
};
cursor<false> begin_cursor()
{
return {fun_, ranges::begin(rng_), ranges::end(rng_)};
}
template(bool Const = true)(
requires Const AND range<meta::const_if_c<Const, Rng>> AND
invocable<Fun const &, iterator_t<meta::const_if_c<Const, Rng>>,
sentinel_t<meta::const_if_c<Const, Rng>>>)
cursor<Const> begin_cursor() const
{
return {fun_, ranges::begin(rng_), ranges::end(rng_)};
}
public:
split_when_view() = default;
split_when_view(Rng rng, Fun fun)
: rng_(std::move(rng))
, fun_(std::move(fun))
{}
};
#if RANGES_CXX_DEDUCTION_GUIDES >= RANGES_CXX_DEDUCTION_GUIDES_17
template(typename Rng, typename Fun)(
requires copy_constructible<Fun>)
split_when_view(Rng &&, Fun)
-> split_when_view<views::all_t<Rng>, Fun>;
#endif
namespace views
{
struct split_when_base_fn
{
private:
template<typename Pred>
struct predicate_pred_
{
semiregular_box_t<Pred> pred_;
template(typename I, typename S)(
requires sentinel_for<S, I>)
std::pair<bool, I> operator()(I cur, S last) const
{
auto where = ranges::find_if_not(cur, last, std::ref(pred_));
return {cur != where, where};
}
};
public:
template(typename Rng, typename Fun)(
requires viewable_range<Rng> AND forward_range<Rng> AND
invocable<Fun &, iterator_t<Rng>, sentinel_t<Rng>> AND
invocable<Fun &, iterator_t<Rng>, iterator_t<Rng>> AND
copy_constructible<Fun> AND
convertible_to<
invoke_result_t<Fun &, iterator_t<Rng>, sentinel_t<Rng>>,
std::pair<bool, iterator_t<Rng>>>)
split_when_view<all_t<Rng>, Fun> operator()(Rng && rng, Fun fun) const //
{
return {all(static_cast<Rng &&>(rng)), std::move(fun)};
}
template(typename Rng, typename Fun)(
requires viewable_range<Rng> AND forward_range<Rng> AND
predicate<Fun const &, range_reference_t<Rng>> AND
copy_constructible<Fun>)
split_when_view<all_t<Rng>, predicate_pred_<Fun>> //
operator()(Rng && rng, Fun fun) const
{
return {all(static_cast<Rng &&>(rng)),
predicate_pred_<Fun>{std::move(fun)}};
}
};
struct split_when_fn : split_when_base_fn
{
using split_when_base_fn::operator();
template<typename T>
constexpr auto operator()(T && t) const
{
return make_view_closure(
bind_back(split_when_base_fn{}, static_cast<T &&>(t)));
}
};
/// \relates split_when_fn
/// \ingroup group-views
RANGES_INLINE_VARIABLE(split_when_fn, split_when)
} // namespace views
/// @}
} // namespace ranges
#include <range/v3/detail/epilogue.hpp>
#include <range/v3/detail/satisfy_boost_range.hpp>
RANGES_SATISFY_BOOST_RANGE(::ranges::split_when_view)
#endif
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