source: cpp/common/nonstd_span.h @ 1340

// This file is a part of Framsticks SDK.  http://www.framsticks.com/
// Copyright (C) 2019-2024  Maciej Komosinski and Szymon Ulatowski.
// See LICENSE.txt for details.

#ifndef _NONSTD_SPAN_H_
#define _NONSTD_SPAN_H_

#include <string>
#include <vector>

// Remove this and use std::span when available (c++20)

template<class ElementType> class span
{
public:
        constexpr span() noexcept
        {
                data_ = NULL;
                size_ = 0;
        }
        constexpr span(ElementType* first, size_t count) noexcept
        {
                data_ = first;
                size_ = count;
        }
        constexpr span(ElementType* first, ElementType* end) noexcept
        {
                data_ = first;
                size_ = end - first;
        }
        template<size_t N> constexpr span(ElementType(&arr)[N]) noexcept
        {
                data_ = arr;
                size_ = N;
        }

        size_t size() const { return size_; }
        size_t size_bytes() const { return size_ * sizeof(ElementType); }
        ElementType& operator[](size_t idx) const { return data_[idx]; }

        ElementType* begin() const { return data_; }
        ElementType* end() const { return data_ + size_; }

protected:
        ElementType* data_;
        size_t size_;
};

inline std::string stringFromSpan(const span<uint8_t>& s) { return std::string(s.begin(), s.end()); }
inline std::string stringFromSpan(const span<char>& s) { return std::string(s.begin(), s.end()); }
// in both lines below, in the last argument, &*v.end() was replaced by front+size, because the debugging+extensive checking version of the STL library with std::vector complained when calling &*v.end().
inline span<uint8_t> spanFromVector(std::vector<uint8_t>& v) { return span<uint8_t>(&v.front(), ((uint8_t*)&v.front())+v.size()); }
inline span<uint8_t> spanFromVector(std::vector<char>& v) { return span<uint8_t>((uint8_t*)&v.front(), ((uint8_t*)&v.front())+v.size()); }

#endif