buffer_mutable.hpp

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// SPDX-License-Identifier: BSL-1.0
// SPDX-FileCopyrightText: Copyright (C) 2019 Tobias Hienzsch
 
#ifndef TETL_NET_BUFFER_MUTABLE_HPP
#define TETL_NET_BUFFER_MUTABLE_HPP
 
#include <etl/version.hpp>
 
#include <etl/array.hpp>
#include <etl/cstddef.hpp>
 
namespace etl::experimental::net {
struct mutable_buffer {
    /// \brief Construct an empty buffer.
    mutable_buffer() noexcept = default;
 
    /// \brief Construct a buffer to represent a given memory range.
    mutable_buffer(void* data, etl::size_t size)
        : _data{data}
        , _size{size}
    {
    }
 
    /// \brief Get a pointer to the beginning of the memory range.
    [[nodiscard]] auto data() const noexcept -> void*
    {
        return _data;
    }
 
    /// \brief Get the size of the memory range.
    [[nodiscard]] auto size() const noexcept -> etl::size_t
    {
        return _size;
    }
 
    /// \brief Move the start of the buffer by the specified number of bytes.
    auto operator+=(etl::size_t n) noexcept -> mutable_buffer&
    {
        auto const offset = n < _size ? n : _size;
        _data             = static_cast<char*>(_data) + offset;
        _size -= offset;
        return *this;
    }
 
private:
    void* _data       = nullptr;
    etl::size_t _size = 0;
};
 
/// \brief Create a new modifiable buffer that is offset from the start of
/// another.
/// \relates mutable_buffer
inline auto operator+(mutable_buffer const& b, etl::size_t const n) noexcept -> mutable_buffer
{
    auto offset = n < b.size() ? n : b.size();
    auto* data  = static_cast<char*>(b.data()) + offset;
    auto size   = b.size() - offset;
    return mutable_buffer{data, size};
}
 
/// \brief Create a new modifiable buffer that is offset from the start of
/// another.
/// \relates mutable_buffer
inline auto operator+(etl::size_t const n, mutable_buffer const& b) noexcept -> mutable_buffer
{
    return b + n;
}
 
} // namespace etl::experimental::net
 
#endif // TETL_NET_BUFFER_MUTABLE_HPP