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Diffstat (limited to 'immer/flex_vector.hpp')
| -rw-r--r-- | immer/flex_vector.hpp | 608 |
1 files changed, 608 insertions, 0 deletions
diff --git a/immer/flex_vector.hpp b/immer/flex_vector.hpp new file mode 100644 index 000000000000..d03c3f7e4585 --- /dev/null +++ b/immer/flex_vector.hpp @@ -0,0 +1,608 @@ +// +// immer: immutable data structures for C++ +// Copyright (C) 2016, 2017, 2018 Juan Pedro Bolivar Puente +// +// This software is distributed under the Boost Software License, Version 1.0. +// See accompanying file LICENSE or copy at http://boost.org/LICENSE_1_0.txt +// + +#pragma once + +#include <immer/detail/rbts/rrbtree.hpp> +#include <immer/detail/rbts/rrbtree_iterator.hpp> +#include <immer/memory_policy.hpp> + +namespace immer { + +template <typename T, + typename MP, + detail::rbts::bits_t B, + detail::rbts::bits_t BL> +class vector; + +template <typename T, + typename MP, + detail::rbts::bits_t B, + detail::rbts::bits_t BL> +class flex_vector_transient; + +/*! + * Immutable sequential container supporting both random access, + * structural sharing and efficient concatenation and slicing. + * + * @tparam T The type of the values to be stored in the container. + * @tparam MemoryPolicy Memory management policy. See @ref + * memory_policy. + * + * @rst + * + * This container is very similar to `vector`_ but also supports + * :math:`O(log(size))` *concatenation*, *slicing* and *insertion* at + * any point. Its performance characteristics are almost identical + * until one of these operations is performed. After that, + * performance is degraded by a constant factor that usually oscilates + * in the range :math:`[1, 2)` depending on the operation and the + * amount of flexible operations that have been performed. + * + * .. tip:: A `vector`_ can be converted to a `flex_vector`_ in + * constant time without any allocation. This is so because the + * internal structure of a *vector* is a strict subset of the + * internal structure of a *flexible vector*. You can take + * advantage of this property by creating normal vectors as long as + * the flexible operations are not needed, and convert later in + * your processing pipeline once and if these are needed. + * + * @endrst + */ +template <typename T, + typename MemoryPolicy = default_memory_policy, + detail::rbts::bits_t B = default_bits, + detail::rbts::bits_t BL = + detail::rbts::derive_bits_leaf<T, MemoryPolicy, B>> +class flex_vector +{ + using impl_t = detail::rbts::rrbtree<T, MemoryPolicy, B, BL>; + + using move_t = + std::integral_constant<bool, MemoryPolicy::use_transient_rvalues>; + +public: + static constexpr auto bits = B; + static constexpr auto bits_leaf = BL; + using memory_policy = MemoryPolicy; + + using value_type = T; + using reference = const T&; + using size_type = detail::rbts::size_t; + using difference_type = std::ptrdiff_t; + using const_reference = const T&; + + using iterator = detail::rbts::rrbtree_iterator<T, MemoryPolicy, B, BL>; + using const_iterator = iterator; + using reverse_iterator = std::reverse_iterator<iterator>; + + using transient_type = flex_vector_transient<T, MemoryPolicy, B, BL>; + + /*! + * Default constructor. It creates a flex_vector of `size() == 0`. + * It does not allocate memory and its complexity is @f$ O(1) @f$. + */ + flex_vector() = default; + + /*! + * Constructs a flex_vector containing the elements in `values`. + */ + flex_vector(std::initializer_list<T> values) + : impl_{impl_t::from_initializer_list(values)} + {} + + /*! + * Constructs a flex_vector containing the elements in the range + * defined by the input iterator `first` and range sentinel `last`. + */ + template <typename Iter, + typename Sent, + std::enable_if_t<detail::compatible_sentinel_v<Iter, Sent>, + bool> = true> + flex_vector(Iter first, Sent last) + : impl_{impl_t::from_range(first, last)} + {} + + /*! + * Constructs a vector containing the element `val` repeated `n` + * times. + */ + flex_vector(size_type n, T v = {}) + : impl_{impl_t::from_fill(n, v)} + {} + + /*! + * Default constructor. It creates a flex_vector with the same + * contents as `v`. It does not allocate memory and is + * @f$ O(1) @f$. + */ + flex_vector(vector<T, MemoryPolicy, B, BL> v) + : impl_{v.impl_.size, + v.impl_.shift, + v.impl_.root->inc(), + v.impl_.tail->inc()} + {} + + /*! + * Returns an iterator pointing at the first element of the + * collection. It does not allocate memory and its complexity is + * @f$ O(1) @f$. + */ + IMMER_NODISCARD iterator begin() const { return {impl_}; } + + /*! + * Returns an iterator pointing just after the last element of the + * collection. It does not allocate and its complexity is @f$ O(1) @f$. + */ + IMMER_NODISCARD iterator end() const + { + return {impl_, typename iterator::end_t{}}; + } + + /*! + * Returns an iterator that traverses the collection backwards, + * pointing at the first element of the reversed collection. It + * does not allocate memory and its complexity is @f$ O(1) @f$. + */ + IMMER_NODISCARD reverse_iterator rbegin() const + { + return reverse_iterator{end()}; + } + + /*! + * Returns an iterator that traverses the collection backwards, + * pointing after the last element of the reversed collection. It + * does not allocate memory and its complexity is @f$ O(1) @f$. + */ + IMMER_NODISCARD reverse_iterator rend() const + { + return reverse_iterator{begin()}; + } + + /*! + * Returns the number of elements in the container. It does + * not allocate memory and its complexity is @f$ O(1) @f$. + */ + IMMER_NODISCARD size_type size() const { return impl_.size; } + + /*! + * Returns `true` if there are no elements in the container. It + * does not allocate memory and its complexity is @f$ O(1) @f$. + */ + IMMER_NODISCARD bool empty() const { return impl_.size == 0; } + + /*! + * Access the last element. + */ + IMMER_NODISCARD const T& back() const { return impl_.back(); } + + /*! + * Access the first element. + */ + IMMER_NODISCARD const T& front() const { return impl_.front(); } + + /*! + * Returns a `const` reference to the element at position `index`. + * It is undefined when @f$ 0 index \geq size() @f$. It does not + * allocate memory and its complexity is *effectively* @f$ O(1) + * @f$. + */ + IMMER_NODISCARD reference operator[](size_type index) const + { + return impl_.get(index); + } + + /*! + * Returns a `const` reference to the element at position + * `index`. It throws an `std::out_of_range` exception when @f$ + * index \geq size() @f$. It does not allocate memory and its + * complexity is *effectively* @f$ O(1) @f$. + */ + reference at(size_type index) const { return impl_.get_check(index); } + + /*! + * Returns whether the vectors are equal. + */ + IMMER_NODISCARD bool operator==(const flex_vector& other) const + { + return impl_.equals(other.impl_); + } + IMMER_NODISCARD bool operator!=(const flex_vector& other) const + { + return !(*this == other); + } + + /*! + * Returns a flex_vector with `value` inserted at the end. It may + * allocate memory and its complexity is *effectively* @f$ O(1) @f$. + * + * @rst + * + * **Example** + * .. literalinclude:: ../example/flex-vector/flex-vector.cpp + * :language: c++ + * :dedent: 8 + * :start-after: push-back/start + * :end-before: push-back/end + * + * @endrst + */ + IMMER_NODISCARD flex_vector push_back(value_type value) const& + { + return impl_.push_back(std::move(value)); + } + + IMMER_NODISCARD decltype(auto) push_back(value_type value) && + { + return push_back_move(move_t{}, std::move(value)); + } + + /*! + * Returns a flex_vector with `value` inserted at the frony. It may + * allocate memory and its complexity is @f$ O(log(size)) @f$. + * + * @rst + * + * **Example** + * .. literalinclude:: ../example/flex-vector/flex-vector.cpp + * :language: c++ + * :dedent: 8 + * :start-after: push-front/start + * :end-before: push-front/end + * + * @endrst + */ + IMMER_NODISCARD flex_vector push_front(value_type value) const + { + return flex_vector{}.push_back(value) + *this; + } + + /*! + * Returns a flex_vector containing value `value` at position `index`. + * Undefined for `index >= size()`. + * It may allocate memory and its complexity is + * *effectively* @f$ O(1) @f$. + * + * @rst + * + * **Example** + * .. literalinclude:: ../example/flex-vector/flex-vector.cpp + * :language: c++ + * :dedent: 8 + * :start-after: set/start + * :end-before: set/end + * + * @endrst + */ + IMMER_NODISCARD flex_vector set(size_type index, value_type value) const& + { + return impl_.assoc(index, std::move(value)); + } + + IMMER_NODISCARD decltype(auto) set(size_type index, value_type value) && + { + return set_move(move_t{}, index, std::move(value)); + } + + /*! + * Returns a vector containing the result of the expression + * `fn((*this)[idx])` at position `idx`. + * Undefined for `index >= size()`. + * It may allocate memory and its complexity is + * *effectively* @f$ O(1) @f$. + * + * @rst + * + * **Example** + * .. literalinclude:: ../example/flex-vector/flex-vector.cpp + * :language: c++ + * :dedent: 8 + * :start-after: update/start + * :end-before: update/end + * + * @endrst + + */ + template <typename FnT> + IMMER_NODISCARD flex_vector update(size_type index, FnT&& fn) const& + { + return impl_.update(index, std::forward<FnT>(fn)); + } + + template <typename FnT> + IMMER_NODISCARD decltype(auto) update(size_type index, FnT&& fn) && + { + return update_move(move_t{}, index, std::forward<FnT>(fn)); + } + + /*! + * Returns a vector containing only the first `min(elems, size())` + * elements. It may allocate memory and its complexity is + * *effectively* @f$ O(1) @f$. + * + * @rst + * + * **Example** + * .. literalinclude:: ../example/flex-vector/flex-vector.cpp + * :language: c++ + * :dedent: 8 + * :start-after: take/start + * :end-before: take/end + * + * @endrst + */ + IMMER_NODISCARD flex_vector take(size_type elems) const& + { + return impl_.take(elems); + } + + IMMER_NODISCARD decltype(auto) take(size_type elems) && + { + return take_move(move_t{}, elems); + } + + /*! + * Returns a vector without the first `min(elems, size())` + * elements. It may allocate memory and its complexity is + * *effectively* @f$ O(1) @f$. + * + * @rst + * + * **Example** + * .. literalinclude:: ../example/flex-vector/flex-vector.cpp + * :language: c++ + * :dedent: 8 + * :start-after: drop/start + * :end-before: drop/end + * + * @endrst + */ + IMMER_NODISCARD flex_vector drop(size_type elems) const& + { + return impl_.drop(elems); + } + + IMMER_NODISCARD decltype(auto) drop(size_type elems) && + { + return drop_move(move_t{}, elems); + } + + /*! + * Concatenation operator. Returns a flex_vector with the contents + * of `l` followed by those of `r`. It may allocate memory + * and its complexity is @f$ O(log(max(size_r, size_l))) @f$ + * + * @rst + * + * **Example** + * .. literalinclude:: ../example/flex-vector/flex-vector.cpp + * :language: c++ + * :dedent: 8 + * :start-after: concat/start + * :end-before: concat/end + * + * @endrst + */ + IMMER_NODISCARD friend flex_vector operator+(const flex_vector& l, + const flex_vector& r) + { + return l.impl_.concat(r.impl_); + } + + IMMER_NODISCARD friend decltype(auto) operator+(flex_vector&& l, + const flex_vector& r) + { + return concat_move(move_t{}, std::move(l), r); + } + + IMMER_NODISCARD friend decltype(auto) operator+(const flex_vector& l, + flex_vector&& r) + { + return concat_move(move_t{}, l, std::move(r)); + } + + IMMER_NODISCARD friend decltype(auto) operator+(flex_vector&& l, + flex_vector&& r) + { + return concat_move(move_t{}, std::move(l), std::move(r)); + } + + /*! + * Returns a flex_vector with the `value` inserted at index + * `pos`. It may allocate memory and its complexity is @f$ + * O(log(size)) @f$ + * + * @rst + * + * **Example** + * .. literalinclude:: ../example/flex-vector/flex-vector.cpp + * :language: c++ + * :dedent: 8 + * :start-after: insert/start + * :end-before: insert/end + * + * @endrst + */ + IMMER_NODISCARD flex_vector insert(size_type pos, T value) const& + { + return take(pos).push_back(std::move(value)) + drop(pos); + } + IMMER_NODISCARD decltype(auto) insert(size_type pos, T value) && + { + using std::move; + auto rs = drop(pos); + return std::move(*this).take(pos).push_back(std::move(value)) + + std::move(rs); + } + + IMMER_NODISCARD flex_vector insert(size_type pos, flex_vector value) const& + { + return take(pos) + std::move(value) + drop(pos); + } + IMMER_NODISCARD decltype(auto) insert(size_type pos, flex_vector value) && + { + using std::move; + auto rs = drop(pos); + return std::move(*this).take(pos) + std::move(value) + std::move(rs); + } + + /*! + * Returns a flex_vector without the element at index `pos`. It + * may allocate memory and its complexity is @f$ O(log(size)) @f$ + * + * @rst + * + * **Example** + * .. literalinclude:: ../example/flex-vector/flex-vector.cpp + * :language: c++ + * :dedent: 8 + * :start-after: erase/start + * :end-before: erase/end + * + * @endrst + */ + IMMER_NODISCARD flex_vector erase(size_type pos) const& + { + return take(pos) + drop(pos + 1); + } + IMMER_NODISCARD decltype(auto) erase(size_type pos) && + { + auto rs = drop(pos + 1); + return std::move(*this).take(pos) + std::move(rs); + } + + IMMER_NODISCARD flex_vector erase(size_type pos, size_type lpos) const& + { + return lpos > pos ? take(pos) + drop(lpos) : *this; + } + IMMER_NODISCARD decltype(auto) erase(size_type pos, size_type lpos) && + { + if (lpos > pos) { + auto rs = drop(lpos); + return std::move(*this).take(pos) + std::move(rs); + } else { + return std::move(*this); + } + } + + /*! + * Returns an @a transient form of this container, an + * `immer::flex_vector_transient`. + */ + IMMER_NODISCARD transient_type transient() const& + { + return transient_type{impl_}; + } + IMMER_NODISCARD transient_type transient() && + { + return transient_type{std::move(impl_)}; + } + + // Semi-private + const impl_t& impl() const { return impl_; } + +#if IMMER_DEBUG_PRINT + void debug_print(std::ostream& out = std::cerr) const + { + impl_.debug_print(out); + } +#endif + +private: + friend transient_type; + + flex_vector(impl_t impl) + : impl_(std::move(impl)) + { +#if IMMER_DEBUG_PRINT + // force the compiler to generate debug_print, so we can call + // it from a debugger + [](volatile auto) {}(&flex_vector::debug_print); +#endif + } + + flex_vector&& push_back_move(std::true_type, value_type value) + { + impl_.push_back_mut({}, std::move(value)); + return std::move(*this); + } + flex_vector push_back_move(std::false_type, value_type value) + { + return impl_.push_back(std::move(value)); + } + + flex_vector&& set_move(std::true_type, size_type index, value_type value) + { + impl_.assoc_mut({}, index, std::move(value)); + return std::move(*this); + } + flex_vector set_move(std::false_type, size_type index, value_type value) + { + return impl_.assoc(index, std::move(value)); + } + + template <typename Fn> + flex_vector&& update_move(std::true_type, size_type index, Fn&& fn) + { + impl_.update_mut({}, index, std::forward<Fn>(fn)); + return std::move(*this); + } + template <typename Fn> + flex_vector update_move(std::false_type, size_type index, Fn&& fn) + { + return impl_.update(index, std::forward<Fn>(fn)); + } + + flex_vector&& take_move(std::true_type, size_type elems) + { + impl_.take_mut({}, elems); + return std::move(*this); + } + flex_vector take_move(std::false_type, size_type elems) + { + return impl_.take(elems); + } + + flex_vector&& drop_move(std::true_type, size_type elems) + { + impl_.drop_mut({}, elems); + return std::move(*this); + } + flex_vector drop_move(std::false_type, size_type elems) + { + return impl_.drop(elems); + } + + static flex_vector&& + concat_move(std::true_type, flex_vector&& l, const flex_vector& r) + { + concat_mut_l(l.impl_, {}, r.impl_); + return std::move(l); + } + static flex_vector&& + concat_move(std::true_type, const flex_vector& l, flex_vector&& r) + { + concat_mut_r(l.impl_, r.impl_, {}); + return std::move(r); + } + static flex_vector&& + concat_move(std::true_type, flex_vector&& l, flex_vector&& r) + { + concat_mut_lr_l(l.impl_, {}, r.impl_, {}); + return std::move(l); + } + static flex_vector + concat_move(std::false_type, const flex_vector& l, const flex_vector& r) + { + return l.impl_.concat(r.impl_); + } + + impl_t impl_ = impl_t::empty(); +}; + +} // namespace immer |