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// Copyright Yahoo. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
#pragma once
#include <cstddef>
#include <vector>
#include <array>
namespace vespalib {
/**
* This is a simple wrapper class for a typed array with no memory ownership.
* It is similar to vespalib::stringref
**/
template <typename T>
class ArrayRef {
public:
constexpr ArrayRef() noexcept : _v(nullptr), _sz(0) { }
constexpr ArrayRef(T * v, size_t sz) noexcept : _v(v), _sz(sz) { }
template<typename A=std::allocator<T>>
ArrayRef(std::vector<T, A> & v) noexcept : _v(v.data()), _sz(v.size()) { }
template<size_t SZ>
ArrayRef(std::array<T, SZ> & v) noexcept : _v(v.data()), _sz(SZ) { }
T & operator [] (size_t i) noexcept { return _v[i]; }
const T & operator [] (size_t i) const noexcept { return _v[i]; }
T * data() noexcept { return _v; }
const T * data() const noexcept { return _v; }
[[nodiscard]] size_t size() const noexcept { return _sz; }
[[nodiscard]] bool empty() const noexcept { return _sz == 0; }
T *begin() noexcept { return _v; }
T *end() noexcept { return _v + _sz; }
private:
T * _v;
size_t _sz;
};
template <typename T>
class ConstArrayRef {
public:
constexpr ConstArrayRef(const T *v, size_t sz) noexcept : _v(v), _sz(sz) { }
template<typename A=std::allocator<T>>
ConstArrayRef(const std::vector<T, A> & v) noexcept : _v(v.data()), _sz(v.size()) { }
template<size_t SZ>
ConstArrayRef(const std::array<T, SZ> & v) noexcept : _v(v.data()), _sz(SZ) { }
ConstArrayRef(const ArrayRef<T> & v) noexcept : _v(v.data()), _sz(v.size()) { }
constexpr ConstArrayRef() noexcept : _v(nullptr), _sz(0) {}
const T & operator [] (size_t i) const noexcept { return _v[i]; }
[[nodiscard]] size_t size() const noexcept { return _sz; }
[[nodiscard]] bool empty() const noexcept { return _sz == 0; }
const T *cbegin() const noexcept { return _v; }
const T *cend() const noexcept { return _v + _sz; }
const T *begin() const noexcept { return _v; }
const T *end() const noexcept { return _v + _sz; }
const T *data() const noexcept { return _v; }
private:
const T *_v;
size_t _sz;
};
// const-cast for array references; use with care
template <typename T>
ArrayRef<T> unconstify(const ConstArrayRef<T> &ref) {
return ArrayRef<T>(const_cast<T*>(ref.data()), ref.size());
}
}
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