home/src/ranges.hh
2020-02-18 19:28:41 +11:00

518 lines
16 KiB
C++

#ifndef ranges_hh_INCLUDED
#define ranges_hh_INCLUDED
#include <algorithm>
#include <utility>
#include <iterator>
#include <numeric>
#include "constexpr_utils.hh"
namespace Kakoune
{
template<typename Func> struct ViewFactory { Func func; };
template<typename Func>
ViewFactory<std::decay_t<Func>>
make_view_factory(Func&& func) { return {std::forward<Func>(func)}; }
template<typename Range, typename Func>
decltype(auto) operator| (Range&& range, ViewFactory<Func> factory)
{
return factory.func(std::forward<Range>(range));
}
template<typename Range>
struct decay_range_impl { using type = std::decay_t<Range>; };
template<typename Range>
struct decay_range_impl<Range&> { using type = Range&; };
template<typename Range>
using decay_range = typename decay_range_impl<Range>::type;
template<typename Range>
struct ReverseView
{
decltype(auto) begin() { return m_range.rbegin(); }
decltype(auto) end() { return m_range.rend(); }
decltype(auto) rbegin() { return m_range.begin(); }
decltype(auto) rend() { return m_range.end(); }
decltype(auto) begin() const { return m_range.rbegin(); }
decltype(auto) end() const { return m_range.rend(); }
decltype(auto) rbegin() const { return m_range.begin(); }
decltype(auto) rend() const { return m_range.end(); }
Range m_range;
};
inline auto reverse()
{
return make_view_factory([](auto&& range) {
using Range = decltype(range);
return ReverseView<decay_range<Range>>{std::forward<Range>(range)};
});
}
template<typename Range>
using IteratorOf = decltype(std::begin(std::declval<Range>()));
template<typename Range>
using ValueOf = decltype(*std::declval<IteratorOf<Range>>());
template<typename Range>
struct SkipView
{
auto begin() const { return std::next(std::begin(m_range), m_skip_count); }
auto end() const { return std::end(m_range); }
Range m_range;
size_t m_skip_count;
};
inline auto skip(size_t count)
{
return make_view_factory([count](auto&& range) {
using Range = decltype(range);
return SkipView<decay_range<Range>>{std::forward<Range>(range), count};
});
}
template<typename Range>
struct DropView
{
auto begin() const { return std::begin(m_range); }
auto end() const { return std::end(m_range) - m_drop_count; }
Range m_range;
size_t m_drop_count;
};
inline auto drop(size_t count)
{
return make_view_factory([count](auto&& range) {
using Range = decltype(range);
return DropView<decay_range<Range>>{std::forward<Range>(range), count};
});
}
template<typename Range, typename Filter>
struct FilterView
{
using RangeIt = IteratorOf<Range>;
struct Iterator : std::iterator<std::forward_iterator_tag,
typename std::iterator_traits<RangeIt>::value_type>
{
Iterator(Filter& filter, RangeIt it, RangeIt end)
: m_it{std::move(it)}, m_end{std::move(end)}, m_filter{&filter}
{
do_filter();
}
decltype(auto) operator*() { return *m_it; }
Iterator& operator++() { ++m_it; do_filter(); return *this; }
Iterator operator++(int) { auto copy = *this; ++(*this); return copy; }
friend bool operator==(const Iterator& lhs, const Iterator& rhs)
{
return lhs.m_it == rhs.m_it;
}
friend bool operator!=(const Iterator& lhs, const Iterator& rhs)
{
return not (lhs == rhs);
}
const RangeIt& base() const { return m_it; }
private:
void do_filter()
{
while (m_it != m_end and not (*m_filter)(*m_it))
++m_it;
}
RangeIt m_it;
RangeIt m_end;
Filter* m_filter;
};
Iterator begin() const { return {m_filter, std::begin(m_range), std::end(m_range)}; }
Iterator end() const { return {m_filter, std::end(m_range), std::end(m_range)}; }
Range m_range;
mutable Filter m_filter;
};
template<typename Filter>
inline auto filter(Filter f)
{
return make_view_factory([f = std::move(f)](auto&& range) {
using Range = decltype(range);
return FilterView<decay_range<Range>, Filter>{std::forward<Range>(range), std::move(f)};
});
}
template<typename Range, typename Transform>
struct TransformView
{
using RangeIt = IteratorOf<Range>;
using ResType = decltype(std::declval<Transform>()(*std::declval<RangeIt>()));
struct Iterator
{
using iterator_category = typename std::iterator_traits<RangeIt>::iterator_category;
using value_type = std::remove_reference_t<ResType>;
using difference_type = typename std::iterator_traits<RangeIt>::difference_type;
using pointer = value_type*;
using reference = value_type&;
Iterator(Transform& transform, RangeIt it)
: m_it{std::move(it)}, m_transform{&transform} {}
decltype(auto) operator*() { return (*m_transform)(*m_it); }
decltype(auto) operator[](difference_type i) const { return (*m_transform)(m_it[i]); }
Iterator& operator++() { ++m_it; return *this; }
Iterator operator++(int) { auto copy = *this; ++m_it; return copy; }
Iterator& operator--() { --m_it; return *this; }
Iterator operator--(int) { auto copy = *this; --m_it; return copy; }
Iterator& operator+=(difference_type diff) { m_it += diff; return *this; }
Iterator& operator-=(difference_type diff) { m_it -= diff; return *this; }
Iterator operator+(difference_type diff) const { return {*m_transform, m_it + diff}; }
Iterator operator-(difference_type diff) const { return {*m_transform, m_it - diff}; }
friend bool operator==(const Iterator& lhs, const Iterator& rhs) { return lhs.m_it == rhs.m_it; }
friend bool operator!=(const Iterator& lhs, const Iterator& rhs) { return not (lhs == rhs); }
friend difference_type operator-(const Iterator& lhs, const Iterator& rhs) { return lhs.m_it - rhs.m_it; }
RangeIt base() const { return m_it; }
private:
RangeIt m_it;
Transform* m_transform;
};
Iterator begin() const { return {m_transform, std::begin(m_range)}; }
Iterator end() const { return {m_transform, std::end(m_range)}; }
Range m_range;
mutable Transform m_transform;
};
template<typename Transform>
inline auto transform(Transform t)
{
return make_view_factory([t = std::move(t)](auto&& range) {
using Range = decltype(range);
return TransformView<decay_range<Range>, Transform>{std::forward<Range>(range), std::move(t)};
});
}
template<typename T, typename U, typename = void>
struct is_pointer_like : std::false_type {};
template<typename T, typename U>
struct is_pointer_like<T, U, std::enable_if_t<std::is_same_v<std::decay_t<decltype(*std::declval<U>())>, std::decay_t<T>>>> : std::true_type {};
template<typename M, typename T>
inline auto transform(M T::*member)
{
return transform([member](auto&& arg) -> decltype(auto) {
using Arg = decltype(arg);
using Member = decltype(member);
auto get_object = [&] () mutable -> decltype(auto) {
if constexpr (is_pointer_like<T, Arg>::value)
return *std::forward<Arg>(arg);
else
return std::forward<Arg>(arg);
};
if constexpr (std::is_member_function_pointer_v<Member>)
return (get_object().*member)();
else
return get_object().*member;
});
}
template<typename Range, bool escape, bool include_separator,
typename Element = ValueOf<Range>,
typename ValueTypeParam = void>
struct SplitView
{
using RangeIt = IteratorOf<Range>;
using ValueType = std::conditional_t<std::is_same<void, ValueTypeParam>::value,
std::pair<IteratorOf<Range>, IteratorOf<Range>>,
ValueTypeParam>;
struct Iterator : std::iterator<std::forward_iterator_tag, ValueType>
{
Iterator(RangeIt pos, const RangeIt& end, Element separator, Element escaper)
: done{pos == end}, pos{pos}, sep{pos}, end(end), separator{std::move(separator)}, escaper{std::move(escaper)}
{
bool escaped = false;
while (sep != end and (escaped or *sep != separator))
{
escaped = escape and not escaped and *sep == escaper;
++sep;
}
}
Iterator& operator++() { advance(); return *this; }
Iterator operator++(int) { auto copy = *this; advance(); return copy; }
bool operator==(const Iterator& other) const { return pos == other.pos and done == other.done; }
bool operator!=(const Iterator& other) const { return pos != other.pos or done != other.done; }
ValueType operator*() { return {pos, (not include_separator or sep == end) ? sep : sep + 1}; }
private:
void advance()
{
if (sep == end)
{
pos = end;
done = true;
return;
}
pos = sep+1;
if (include_separator and pos == end)
{
done = true;
return;
}
bool escaped = escape and *sep == escaper;
for (sep = pos; sep != end; ++sep)
{
if (not escaped and *sep == separator)
break;
escaped = escape and not escaped and *sep == escaper;
}
}
bool done;
RangeIt pos;
RangeIt sep;
RangeIt end;
Element separator;
Element escaper;
};
Iterator begin() const { return {std::begin(m_range), std::end(m_range), m_separator, m_escaper}; }
Iterator end() const { return {std::end(m_range), std::end(m_range), m_separator, m_escaper}; }
Range m_range;
Element m_separator;
Element m_escaper;
};
template<typename ValueType = void, typename Element>
auto split(Element separator)
{
return make_view_factory([s = std::move(separator)](auto&& range) {
using Range = decltype(range);
return SplitView<decay_range<Range>, false, false, Element, ValueType>{std::forward<Range>(range), std::move(s), {}};
});
}
template<typename ValueType = void, typename Element>
auto split_after(Element separator)
{
return make_view_factory([s = std::move(separator)](auto&& range) {
using Range = decltype(range);
return SplitView<decay_range<Range>, false, true, Element, ValueType>{std::forward<Range>(range), std::move(s), {}};
});
}
template<typename ValueType = void, typename Element>
auto split(Element separator, Element escaper)
{
return make_view_factory([s = std::move(separator), e = std::move(escaper)](auto&& range) {
using Range = decltype(range);
return SplitView<decay_range<Range>, true, false, Element, ValueType>{std::forward<Range>(range), std::move(s), std::move(e)};
});
}
template<typename Range1, typename Range2>
struct ConcatView
{
using RangeIt1 = decltype(std::declval<Range1>().begin());
using RangeIt2 = decltype(std::declval<Range2>().begin());
using ValueType = typename std::common_type_t<typename std::iterator_traits<RangeIt1>::value_type,
typename std::iterator_traits<RangeIt2>::value_type>;
struct Iterator : std::iterator<std::forward_iterator_tag, ValueType>
{
static_assert(std::is_convertible<typename std::iterator_traits<RangeIt1>::value_type, ValueType>::value, "");
static_assert(std::is_convertible<typename std::iterator_traits<RangeIt2>::value_type, ValueType>::value, "");
Iterator(RangeIt1 it1, RangeIt1 end1, RangeIt2 it2)
: m_it1(std::move(it1)), m_end1(std::move(end1)),
m_it2(std::move(it2)) {}
decltype(auto) operator*() { return is2() ? *m_it2 : *m_it1; }
Iterator& operator++() { if (is2()) ++m_it2; else ++m_it1; return *this; }
Iterator operator++(int) { auto copy = *this; ++*this; return copy; }
friend bool operator==(const Iterator& lhs, const Iterator& rhs)
{
return lhs.m_it1 == rhs.m_it1 and lhs.m_end1 == rhs.m_end1 and
lhs.m_it2 == rhs.m_it2;
}
friend bool operator!=(const Iterator& lhs, const Iterator& rhs)
{
return not (lhs == rhs);
}
private:
bool is2() const { return m_it1 == m_end1; }
RangeIt1 m_it1;
RangeIt1 m_end1;
RangeIt2 m_it2;
};
Iterator begin() const { return {m_range1.begin(), m_range1.end(), m_range2.begin()}; }
Iterator end() const { return {m_range1.end(), m_range1.end(), m_range2.end()}; }
Range1 m_range1;
Range2 m_range2;
};
template<typename Range1, typename Range2>
ConcatView<decay_range<Range1>, decay_range<Range2>> concatenated(Range1&& range1, Range2&& range2)
{
return {range1, range2};
}
template<typename Range, typename T>
auto find(Range&& range, const T& value)
{
using std::begin; using std::end;
return std::find(begin(range), end(range), value);
}
template<typename Range, typename T>
auto find_if(Range&& range, T op)
{
using std::begin; using std::end;
return std::find_if(begin(range), end(range), op);
}
template<typename Range, typename T>
bool contains(Range&& range, const T& value)
{
using std::end;
return find(range, value) != end(range);
}
template<typename Range, typename T>
bool all_of(Range&& range, T op)
{
using std::begin; using std::end;
return std::all_of(begin(range), end(range), op);
}
template<typename Range, typename T>
bool any_of(Range&& range, T op)
{
using std::begin; using std::end;
return std::any_of(begin(range), end(range), op);
}
template<typename Range, typename U>
void unordered_erase(Range&& vec, U&& value)
{
auto it = find(vec, std::forward<U>(value));
if (it != vec.end())
{
using std::swap;
swap(vec.back(), *it);
vec.pop_back();
}
}
template<typename Range, typename Init, typename BinOp>
Init accumulate(Range&& c, Init&& init, BinOp&& op)
{
using std::begin; using std::end;
return std::accumulate(begin(c), end(c), init, op);
}
template<typename Range, typename Compare, typename Func>
void for_n_best(Range&& c, size_t count, Compare&& compare, Func&& func)
{
using std::begin; using std::end;
auto b = begin(c), e = end(c);
std::make_heap(b, e, compare);
while (count > 0 and b != e)
{
if (func(*b))
--count;
std::pop_heap(b, e--, compare);
}
}
template<typename Container>
auto gather()
{
return make_view_factory([](auto&& range) {
using std::begin; using std::end;
return Container(begin(range), end(range));
});
}
template<template <typename Element> class Container>
auto gather()
{
return make_view_factory([](auto&& range) {
using std::begin; using std::end;
using ValueType = std::remove_cv_t<std::remove_reference_t<decltype(*begin(range))>>;
return Container<ValueType>(begin(range), end(range));
});
}
template<typename ExceptionType, bool exact_size, size_t... Indexes>
auto elements()
{
return make_view_factory([=] (auto&& range) {
using std::begin; using std::end;
auto it = begin(range), end_it = end(range);
size_t i = 0;
auto elem = [&](size_t index) {
for (; i < index; ++i)
if (++it == end_it) throw ExceptionType{i};
return *it;
};
// Note that initializer lists elements are guaranteed to be sequenced
Array<std::decay_t<decltype(*begin(range))>, sizeof...(Indexes)> res{{elem(Indexes)...}};
if (exact_size and ++it != end_it)
throw ExceptionType{++i};
return res;
});
}
template<typename ExceptionType, bool exact_size, size_t... Indexes>
auto static_gather_impl(std::index_sequence<Indexes...>)
{
return elements<ExceptionType, exact_size, Indexes...>();
}
template<typename ExceptionType, size_t size, bool exact_size = true>
auto static_gather()
{
return static_gather_impl<ExceptionType, exact_size>(std::make_index_sequence<size>());
}
}
#endif // ranges_hh_INCLUDED