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Diffstat (limited to 'immer/array_transient.hpp')
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1 files changed, 202 insertions, 0 deletions
diff --git a/immer/array_transient.hpp b/immer/array_transient.hpp new file mode 100644 index 000000000000..bc2d1a5b7b2c --- /dev/null +++ b/immer/array_transient.hpp @@ -0,0 +1,202 @@ +// +// 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/arrays/with_capacity.hpp> +#include <immer/memory_policy.hpp> + +namespace immer { + +template <typename T, typename MemoryPolicy> +class array; + +/*! + * Mutable version of `immer::array`. + * + * @rst + * + * Refer to :doc:`transients` to learn more about when and how to use + * the mutable versions of immutable containers. + * + * @endrst + */ +template <typename T, typename MemoryPolicy = default_memory_policy> +class array_transient : MemoryPolicy::transience_t::owner +{ + using impl_t = detail::arrays::with_capacity<T, MemoryPolicy>; + using impl_no_capacity_t = detail::arrays::no_capacity<T, MemoryPolicy>; + using owner_t = typename MemoryPolicy::transience_t::owner; + +public: + using value_type = T; + using reference = const T&; + using size_type = std::size_t; + using difference_type = std::ptrdiff_t; + using const_reference = const T&; + + using iterator = const T*; + using const_iterator = iterator; + using reverse_iterator = std::reverse_iterator<iterator>; + + using memory_policy = MemoryPolicy; + using persistent_type = array<T, MemoryPolicy>; + + /*! + * Default constructor. It creates a mutable array of `size() == + * 0`. It does not allocate memory and its complexity is + * @f$ O(1) @f$. + */ + array_transient() = default; + + /*! + * Returns an iterator pointing at the first element of the + * collection. It does not allocate memory and its complexity is + * @f$ O(1) @f$. + */ + IMMER_NODISCARD iterator begin() const { return impl_.data(); } + + /*! + * Returns an iterator pointing just after the last element of the + * collection. It does not allocate and its complexity is @f$ O(1) @f$. + */ + IMMER_NODISCARD iterator end() const { return impl_.data() + impl_.size; } + + /*! + * Returns an iterator that traverses the collection backwards, + * pointing at the first element of the reversed collection. It + * does not allocate memory and its complexity is @f$ 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$. + */ + IMMER_NODISCARD std::size_t size() const { return impl_.size; } + + /*! + * Returns `true` if there are no elements in the container. It + * does not allocate memory and its complexity is @f$ O(1) @f$. + */ + IMMER_NODISCARD bool empty() const { return impl_.size == 0; } + + /*! + * Access the raw data. + */ + IMMER_NODISCARD const T* data() const { return impl_.data(); } + + /*! + * Provide mutable access to the raw underlaying data. + */ + IMMER_NODISCARD T* data_mut() { return impl_.data_mut(*this); } + + /*! + * Access the last element. + */ + IMMER_NODISCARD const T& back() const { return data()[size() - 1]; } + + /*! + * Access the first element. + */ + IMMER_NODISCARD const T& front() const { return data()[0]; } + + /*! + * Returns a `const` reference to the element at position `index`. + * It is undefined when @f$ 0 index \geq size() @f$. It does not + * allocate memory and its complexity is *effectively* @f$ O(1) + * @f$. + */ + reference operator[](size_type index) const { return impl_.get(index); } + + /*! + * Returns a `const` reference to the element at position + * `index`. It throws an `std::out_of_range` exception when @f$ + * index \geq size() @f$. It does not allocate memory and its + * complexity is *effectively* @f$ O(1) @f$. + */ + reference at(size_type index) const { return impl_.get_check(index); } + + /*! + * Inserts `value` at the end. It may allocate memory and its + * complexity is *effectively* @f$ O(1) @f$. + */ + void push_back(value_type value) + { + impl_.push_back_mut(*this, std::move(value)); + } + + /*! + * Sets to the value `value` at position `idx`. + * Undefined for `index >= size()`. + * It may allocate memory and its complexity is + * *effectively* @f$ O(1) @f$. + */ + void set(size_type index, value_type value) + { + impl_.assoc_mut(*this, index, std::move(value)); + } + + /*! + * Updates the array to contain the result of the expression + * `fn((*this)[idx])` at position `idx`. + * Undefined for `0 >= size()`. + * It may allocate memory and its complexity is + * *effectively* @f$ O(1) @f$. + */ + template <typename FnT> + void update(size_type index, FnT&& fn) + { + impl_.update_mut(*this, index, std::forward<FnT>(fn)); + } + + /*! + * Resizes the array to only contain the first `min(elems, size())` + * elements. It may allocate memory and its complexity is + * *effectively* @f$ O(1) @f$. + */ + void take(size_type elems) { impl_.take_mut(*this, elems); } + + /*! + * Returns an @a immutable form of this container, an + * `immer::array`. + */ + IMMER_NODISCARD persistent_type persistent() & + { + this->owner_t::operator=(owner_t{}); + return persistent_type{impl_}; + } + IMMER_NODISCARD persistent_type persistent() && + { + return persistent_type{std::move(impl_)}; + } + +private: + friend persistent_type; + + array_transient(impl_t impl) + : impl_(std::move(impl)) + {} + + impl_t impl_ = impl_t::empty(); +}; + +} // namespace immer |