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construct/include/ircd/buffer/move.h
2021-04-22 12:27:56 -07:00

72 lines
1.8 KiB
C++

// The Construct
//
// Copyright (C) The Construct Developers, Authors & Contributors
// Copyright (C) 2016-2020 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_MOVE_H
// copy overlapping regions
namespace ircd::buffer
{
char *&move(char *&dest, char *const &stop, const const_buffer &src);
size_t move(const mutable_buffer &dst, const const_buffer &src);
template<size_t SIZE> size_t move(const mutable_buffer &dst, const char (&)[SIZE]);
}
template<size_t SIZE>
#ifndef __clang__
__attribute__((error
#else
__attribute__((unavailable
#endif
(
"Move source is an array. Is this a string literal? Do you want to move the \\0?"
" Disambiguate this by typing the source string_view or const_buffer."
)))
inline size_t
ircd::buffer::move(const mutable_buffer &dst,
const char (&buf)[SIZE])
{
return move(dst, const_buffer{buf});
}
inline size_t
ircd::buffer::move(const mutable_buffer &dst,
const const_buffer &src)
{
char *const &s(begin(dst)), *e(s);
e = move(e, end(dst), src);
assert(std::distance(s, e) >= 0);
return std::distance(s, e);
}
inline char *&
__attribute__((always_inline))
ircd::buffer::move(char *&dest,
char *const &stop,
const const_buffer &src)
{
assert(dest <= stop);
const size_t remain
(
std::distance(dest, stop)
);
const size_t cpsz
{
std::min(size(src), remain)
};
assert(cpsz <= size(src));
assert(cpsz <= remain);
__builtin_memmove(dest, data(src), cpsz);
dest += cpsz;
assert(dest <= stop);
return dest;
}