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construct/include/ircd/buffer/buffers.h

104 lines
2.8 KiB
C++

// Matrix Construct
//
// Copyright (C) Matrix Construct Developers, Authors & Contributors
// Copyright (C) 2016-2021 Jason Volk <jason@zemos.net>
//
// Permission to use, copy, modify, and/or distribute this software for any
// purpose with or without fee is hereby granted, provided that the above
// copyright notice and this permission notice is present in all copies. The
// full license for this software is available in the LICENSE file.
#pragma once
#define HAVE_IRCD_BUFFER_BUFFERS_H
namespace ircd::buffer::buffers
{
template<template<class> class I> using const_buffers = I<const_buffer>;
template<template<class> class I> using mutable_buffers = I<mutable_buffer>;
// Convenience null buffers
[[clang::internal_linkage]] extern const ilist<mutable_buffer> null_buffers;
// Iterable of buffers tools
template<template<class> class I, class T> size_t size(const I<T> &buffers);
template<template<class> class I, class T> size_t copy(const mutable_buffer &, const I<T> &buffer);
template<template<class> class I, class T> size_t consume(I<T> &buffers, const size_t &bytes);
template<template<class> class I, class T> std::ostream &operator<<(std::ostream &s, const I<T> &buffers);
}
template<template<class>
class buffers,
class T>
std::ostream &
ircd::buffer::buffers::operator<<(std::ostream &s, const buffers<T> &b)
{
using it = typename T::iterator;
std::for_each(std::begin(b), std::end(b), [&s]
(const buffer<it> &b)
{
s << b;
});
return s;
}
template<template<class>
class buffers,
class T>
size_t
ircd::buffer::buffers::consume(buffers<T> &b,
const size_t &bytes)
{
ssize_t remain(bytes);
for(auto it(std::begin(b)); it != std::end(b) && remain > 0; ++it)
{
using buffer = typename buffers<T>::value_type;
using iterator = typename buffer::iterator;
using ircd::buffer::size;
using ircd::buffer::consume;
buffer &b(const_cast<buffer &>(*it));
const ssize_t bsz(size(b));
const ssize_t csz{std::min(remain, bsz)};
remain -= consume(b, csz);
assert(remain >= 0);
}
assert(ssize_t(bytes) >= remain);
return bytes - remain;
}
template<template<class>
class buffers,
class T>
size_t
ircd::buffer::buffers::copy(const mutable_buffer &dest,
const buffers<T> &b)
{
using it = typename T::iterator;
using ircd::buffer::copy;
using ircd::buffer::size;
size_t ret(0);
for(const buffer<it> &b : b)
ret += copy(dest + ret, b);
return ret;
}
template<template<class>
class buffers,
class T>
size_t
ircd::buffer::buffers::size(const buffers<T> &b)
{
using it = typename T::iterator;
using ircd::buffer::size;
return std::accumulate(std::begin(b), std::end(b), size_t(0), []
(auto ret, const buffer<it> &b)
{
return ret += size(b);
});
}