ext-boost/boost/url/detail/move_chars.hpp
2023-05-22 18:45:02 +10:00

91 lines
1.8 KiB
C++

//
// Copyright (c) 2019 Vinnie Falco (vinnie.falco@gmail.com)
//
// Distributed under the Boost Software License, Version 1.0. (See accompanying
// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
//
// Official repository: https://github.com/boostorg/url
//
#ifndef BOOST_URL_DETAIL_MOVE_CHARS_HPP
#define BOOST_URL_DETAIL_MOVE_CHARS_HPP
#include <boost/url/string_view.hpp>
#include <boost/assert.hpp>
#include <cstring>
#include <functional>
namespace boost {
namespace urls {
namespace detail {
// Moves characters, and adjusts any passed
// views if they point to any moved characters.
// true if s completely overlapped by buf
inline
bool
is_overlapping(
string_view buf,
string_view s) noexcept
{
auto const b0 = buf.data();
auto const e0 = b0 + buf.size();
auto const b1 = s.data();
auto const e1 = b1 + s.size();
auto const less_equal =
std::less_equal<char const*>();
if(less_equal(e0, b1))
return false;
if(less_equal(e1, b0))
return false;
// partial overlap is undefined
BOOST_ASSERT(less_equal(e1, e0));
BOOST_ASSERT(less_equal(b0, b1));
return true;
}
inline
void
move_chars_impl(
std::ptrdiff_t,
string_view const&) noexcept
{
}
template<class... Sn>
void
move_chars_impl(
std::ptrdiff_t d,
string_view const& buf,
string_view& s,
Sn&... sn) noexcept
{
if(is_overlapping(buf, s))
s = {s.data() + d, s.size()};
move_chars_impl(d, buf, sn...);
}
template<class... Args>
void
move_chars(
char* dest,
char const* src,
std::size_t n,
Args&... args) noexcept
{
string_view buf(src, n);
move_chars_impl(
dest - src,
string_view(src, n),
args...);
std::memmove(
dest, src, n);
}
} // detail
} // urls
} // boost
#endif