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buffer.h
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buffer.h
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////
//// Created by xuanyi on 4/25/20.
////
//
#ifndef XYNET_BUFFER_H
#define XYNET_BUFFER_H
#include <span>
#include <vector>
#include <climits>
#include <array>
#include <ranges>
#include <sys/uio.h>
namespace xynet
{
namespace detail
{
template<std::size_t Extent>
struct buffer_sequence_storage
{
using iterator = typename std::array<::iovec, Extent>::iterator;
using size_t = typename std::array<::iovec, Extent>::size_type;
template<typename... Spans>
constexpr explicit buffer_sequence_storage(Spans&&... spans)
:m_val{::iovec{
.iov_base = const_cast<void *>(static_cast<const void *>(spans.data())),
.iov_len = static_cast<decltype(std::declval<::iovec>().iov_len)>(spans.size_bytes())
}...}
{}
std::array<::iovec, Extent> m_val;
};
template<std::size_t... sizes>
buffer_sequence_storage(std::span<std::byte, sizes>... spans)
-> buffer_sequence_storage<sizeof...(sizes)>;
template<>
struct buffer_sequence_storage<std::dynamic_extent>
{
using iterator = typename std::vector<::iovec>::iterator;
using size_t = typename std::vector<::iovec>::size_type;
template<typename BufferRangeView>
requires std::ranges::view<BufferRangeView>
explicit buffer_sequence_storage(BufferRangeView view)
:m_val{std::ranges::begin(view), std::ranges::end(view)}
{}
std::vector<::iovec> m_val;
};
template <std::size_t Extent>
struct buffer_sequence_base
{
public:
using iov_len_t = decltype(std::declval<::iovec>().iov_len);
template<typename... Args>
buffer_sequence_base(Args&&... args)
:m_sequence{std::forward<Args>(args)...}
,m_iterator{std::ranges::begin(m_sequence.m_val)}
{}
auto get_iov_span() -> std::pair<::iovec*, iov_len_t> const
{
return m_iterator == std::ranges::end(m_sequence.m_val)
? std::make_pair(nullptr, 0)
: std::make_pair(static_cast<::iovec*>(std::addressof(*m_iterator)),
static_cast<iov_len_t>(
std::distance
(
m_iterator,
std::ranges::end(m_sequence.m_val)
)));
};
auto get_iov_ptr() -> ::iovec*
{
return m_iterator == std::ranges::end(m_sequence.m_val)
? nullptr : static_cast<::iovec*>(std::addressof(*m_iterator));
}
auto get_iov_cnt() -> iov_len_t
{
return m_iterator == std::ranges::end(m_sequence.m_val)
? 0 : static_cast<iov_len_t>(std::distance(m_iterator, std::ranges::end(m_sequence.m_val)));
}
auto commit(iov_len_t len) -> void
{
while(len > 0 && m_iterator != std::ranges::end(m_sequence.m_val))
{
if(len >= m_iterator->iov_len)
{
len -= m_iterator->iov_len;
++m_iterator;
}
else
{
m_iterator->iov_base = static_cast<char *>(m_iterator->iov_base) + len;
m_iterator->iov_len -= len;
len = 0;
}
}
}
private:
buffer_sequence_storage<Extent> m_sequence;
typename buffer_sequence_storage<Extent>::iterator m_iterator;
};
} // namespace detail
using xynet::detail::buffer_sequence_base;
using xynet::detail::buffer_sequence_storage;
// dummy template parameter for deduction guide to work with default template parameter
template<typename, std::size_t Extent = std::dynamic_extent>
struct buffer_sequence final : public buffer_sequence_base<Extent>
{
public:
template<typename... Containers>
buffer_sequence(Containers&&... containers)
:buffer_sequence_base<Extent>{std::as_writable_bytes(std::span{std::forward<Containers>(containers)})...}
{}
template<typename... Ts, std::size_t... sizes>
buffer_sequence(std::span<Ts, sizes>... spans)
:buffer_sequence_base<Extent>{std::as_writable_bytes(spans)...}
{}
template<std::size_t... sizes>
buffer_sequence(std::span<std::byte, sizes>... spans)
:buffer_sequence_base<Extent>{std::move(spans)...}
{}
template<typename BufferRange>
requires std::ranges::viewable_range<BufferRange&>
&& std::ranges::contiguous_range<std::ranges::range_value_t<BufferRange>>
buffer_sequence(BufferRange& buffer_range)
:buffer_sequence_base<Extent>{
buffer_range
| std::ranges::views::transform(
[](auto& buffer)
{
return ::iovec{
.iov_base = static_cast<void *>(std::ranges::data(buffer)),
.iov_len = static_cast<size_t>(std::ranges::size(buffer) *
sizeof(std::ranges::range_value_t<decltype(buffer)>))};
})}
{}
};
template<typename... T>
buffer_sequence(T&&...) -> buffer_sequence<void, sizeof...(T)>;
template<typename... Ts, std::size_t... sizes>
buffer_sequence(std::span<Ts, sizes>... spans) -> buffer_sequence<void, sizeof...(Ts)>;
template<std::size_t... sizes>
buffer_sequence(std::span<std::byte, sizes>... spans) -> buffer_sequence<void, sizeof...(sizes)>;
template<typename BufferRange>
requires std::ranges::viewable_range<BufferRange&>
&& std::ranges::contiguous_range<std::ranges::range_value_t<BufferRange>>
buffer_sequence(BufferRange&) -> buffer_sequence<void, std::dynamic_extent>;
/* const buffer sequence */
template<typename, std::size_t Extent = std::dynamic_extent>
struct const_buffer_sequence final : public buffer_sequence_base<Extent>
{
public:
template<typename... Containers>
const_buffer_sequence(Containers&&... containers)
:buffer_sequence_base<Extent>{std::as_bytes(std::span{std::forward<Containers>(containers)})...}
{}
template<typename... Ts, std::size_t... sizes>
const_buffer_sequence(std::span<Ts, sizes>... spans)
:buffer_sequence_base<Extent>{std::as_bytes(spans)...}
{}
template<std::size_t... sizes>
const_buffer_sequence(std::span<const std::byte, sizes>... spans)
:buffer_sequence_base<Extent>{std::move(spans)...}
{}
template<typename BufferRange>
requires std::ranges::viewable_range<BufferRange&>
&& std::ranges::contiguous_range<std::ranges::range_value_t<BufferRange>>
const_buffer_sequence(BufferRange& buffer_range)
:buffer_sequence_base<Extent>{
buffer_range
| std::ranges::views::transform(
[](auto& buffer)
{
return ::iovec{
.iov_base = const_cast<void*>(static_cast<const void *>(std::ranges::data(buffer))),
.iov_len = static_cast<size_t>(std::ranges::size(buffer) *
sizeof(std::ranges::range_value_t<decltype(buffer)>))};
})}
{}
};
template<typename... T>
const_buffer_sequence(T&&...) -> const_buffer_sequence<void, sizeof...(T)>;
template<typename... Ts, std::size_t... sizes>
const_buffer_sequence(std::span<Ts, sizes>... spans) -> const_buffer_sequence<void, sizeof...(Ts)>;
template<std::size_t... sizes>
const_buffer_sequence(std::span<const std::byte, sizes>... spans) -> const_buffer_sequence<void, sizeof...(sizes)>;
template<typename BufferRange>
requires std::ranges::viewable_range<BufferRange&>
&& std::ranges::contiguous_range<std::ranges::range_value_t<BufferRange>>
const_buffer_sequence(BufferRange&) -> const_buffer_sequence<void, std::dynamic_extent>;
}
#endif //XYNET_BUFFER_H