159 lines
3.3 KiB
C++
159 lines
3.3 KiB
C++
//
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// Copyright Aliaksei Levin (levlam@telegram.org), Arseny Smirnov (arseny30@gmail.com) 2014-2024
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//
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// Distributed under the Boost Software License, Version 1.0. (See accompanying
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// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
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//
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#pragma once
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#include "td/utils/common.h"
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#include <array>
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#include <iterator>
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namespace td {
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namespace detail {
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template <class T, class InnerT>
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class SpanImpl {
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InnerT *data_{nullptr};
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size_t size_{0};
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public:
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SpanImpl() = default;
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SpanImpl(InnerT *data, size_t size) : data_(data), size_(size) {
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}
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SpanImpl(InnerT &data) : SpanImpl(&data, 1) {
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}
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template <class OtherInnerT>
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SpanImpl(const SpanImpl<T, OtherInnerT> &other) : SpanImpl(other.data(), other.size()) {
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}
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template <size_t N>
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SpanImpl(const std::array<T, N> &arr) : SpanImpl(arr.data(), arr.size()) {
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}
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template <size_t N>
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SpanImpl(std::array<T, N> &arr) : SpanImpl(arr.data(), arr.size()) {
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}
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template <size_t N>
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SpanImpl(const T (&arr)[N]) : SpanImpl(arr, N) {
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}
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template <size_t N>
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SpanImpl(T (&arr)[N]) : SpanImpl(arr, N) {
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}
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SpanImpl(const vector<T> &v) : SpanImpl(v.data(), v.size()) {
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}
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SpanImpl(vector<T> &v) : SpanImpl(v.data(), v.size()) {
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}
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template <class OtherInnerT>
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SpanImpl &operator=(const SpanImpl<T, OtherInnerT> &other) {
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SpanImpl copy{other};
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*this = copy;
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}
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template <class OtherInnerT>
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bool operator==(const SpanImpl<T, OtherInnerT> &other) const {
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if (size() != other.size()) {
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return false;
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}
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for (size_t i = 0; i < size(); i++) {
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if (!((*this)[i] == other[i])) {
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return false;
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}
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}
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return true;
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}
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InnerT &operator[](size_t i) {
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DCHECK(i < size());
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return data_[i];
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}
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const InnerT &operator[](size_t i) const {
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DCHECK(i < size());
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return data_[i];
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}
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InnerT &back() {
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DCHECK(!empty());
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return data_[size() - 1];
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}
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const InnerT &back() const {
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DCHECK(!empty());
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return data_[size() - 1];
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}
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InnerT &front() {
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DCHECK(!empty());
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return data_[0];
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}
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const InnerT &front() const {
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DCHECK(!empty());
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return data_[0];
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}
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InnerT *data() const {
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return data_;
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}
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InnerT *begin() const {
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return data_;
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}
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InnerT *end() const {
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return data_ + size_;
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}
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std::reverse_iterator<InnerT *> rbegin() const {
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return std::reverse_iterator<InnerT *>(end());
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}
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std::reverse_iterator<InnerT *> rend() const {
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return std::reverse_iterator<InnerT *>(begin());
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}
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size_t size() const {
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return size_;
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}
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bool empty() const {
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return size() == 0;
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}
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SpanImpl &truncate(size_t size) {
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if (size < size_) {
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size_ = size;
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}
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return *this;
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}
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SpanImpl substr(size_t offset) const {
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CHECK(offset <= size_);
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return SpanImpl(begin() + offset, size_ - offset);
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}
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SpanImpl substr(size_t offset, size_t size) const {
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CHECK(offset <= size_);
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CHECK(size_ - offset >= size);
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return SpanImpl(begin() + offset, size);
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}
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};
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} // namespace detail
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template <class T>
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using Span = detail::SpanImpl<T, const T>;
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template <class T>
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using MutableSpan = detail::SpanImpl<T, T>;
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template <class T>
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Span<T> as_span(const std::vector<T> &vec) {
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return Span<T>(vec);
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}
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template <class T>
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MutableSpan<T> as_mutable_span(std::vector<T> &vec) {
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return MutableSpan<T>(vec);
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}
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} // namespace td
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