1   
//
1   
//
2   
// Copyright (c) 2019 Vinnie Falco (vinnie.falco@gmail.com)
2   
// Copyright (c) 2019 Vinnie Falco (vinnie.falco@gmail.com)
3   
//
3   
//
4   
// Distributed under the Boost Software License, Version 1.0. (See accompanying
4   
// Distributed under the Boost Software License, Version 1.0. (See accompanying
5   
// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
5   
// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
6   
//
6   
//
7   
// Official repository: https://github.com/CPPAlliance/http
7   
// Official repository: https://github.com/CPPAlliance/http
8   
//
8   
//
9  
9  
10   
#ifndef BOOST_HTTP_DETAIL_MOVE_CHARS_HPP
10   
#ifndef BOOST_HTTP_DETAIL_MOVE_CHARS_HPP
11   
#define BOOST_HTTP_DETAIL_MOVE_CHARS_HPP
11   
#define BOOST_HTTP_DETAIL_MOVE_CHARS_HPP
12  
12  
13   
#include <boost/core/detail/string_view.hpp>
13   
#include <boost/core/detail/string_view.hpp>
14   
#include <cstring>
14   
#include <cstring>
15   
#include <functional>
15   
#include <functional>
16  
16  
17   
namespace boost {
17   
namespace boost {
18   
namespace http {
18   
namespace http {
19   
namespace detail {
19   
namespace detail {
20  
20  
21   
// Moves characters, and adjusts any passed
21   
// Moves characters, and adjusts any passed
22   
// views if they point to any moved characters.
22   
// views if they point to any moved characters.
23  
23  
24   
// true if s completely overlapped by buf
24   
// true if s completely overlapped by buf
25   
inline
25   
inline
26   
bool
26   
bool
27   
is_overlapping(
27   
is_overlapping(
28   
    core::string_view buf,
28   
    core::string_view buf,
29   
    core::string_view s) noexcept
29   
    core::string_view s) noexcept
30   
{
30   
{
31   
    auto const b0 = buf.data();
31   
    auto const b0 = buf.data();
32   
    auto const e0 = b0 + buf.size();
32   
    auto const e0 = b0 + buf.size();
33   
    auto const b1 = s.data();
33   
    auto const b1 = s.data();
34   
    auto const e1 = b1 + s.size();
34   
    auto const e1 = b1 + s.size();
35   
    auto const less_equal =
35   
    auto const less_equal =
36   
        std::less_equal<char const*>();
36   
        std::less_equal<char const*>();
37   
    if(less_equal(e0, b1))
37   
    if(less_equal(e0, b1))
38   
        return false;
38   
        return false;
39   
    if(less_equal(e1, b0))
39   
    if(less_equal(e1, b0))
40   
        return false;
40   
        return false;
41   
    // partial overlap is undefined
41   
    // partial overlap is undefined
42   
    BOOST_ASSERT(less_equal(e1, e0));
42   
    BOOST_ASSERT(less_equal(e1, e0));
43   
    BOOST_ASSERT(less_equal(b0, b1));
43   
    BOOST_ASSERT(less_equal(b0, b1));
44   
    return true;
44   
    return true;
45   
}
45   
}
46  
46  
47   
inline
47   
inline
48   
void
48   
void
49   
move_chars_impl(
49   
move_chars_impl(
50   
    char*,
50   
    char*,
51   
    char const*,
51   
    char const*,
52   
    core::string_view const&) noexcept
52   
    core::string_view const&) noexcept
53   
{
53   
{
54   
}
54   
}
55  
55  
56   
template<class... Sn>
56   
template<class... Sn>
57   
void
57   
void
58   
move_chars_impl(
58   
move_chars_impl(
59   
    char* dest,
59   
    char* dest,
60   
    char const* src,
60   
    char const* src,
61   
    core::string_view const& buf,
61   
    core::string_view const& buf,
62   
    core::string_view* s,
62   
    core::string_view* s,
63   
    Sn&&... sn) noexcept
63   
    Sn&&... sn) noexcept
64   
{
64   
{
65   
    if( s != nullptr &&
65   
    if( s != nullptr &&
66   
        is_overlapping(buf, *s))
66   
        is_overlapping(buf, *s))
67   
    {
67   
    {
68   
        *s = { s->data() + (dest - src), s->size() };
68   
        *s = { s->data() + (dest - src), s->size() };
69   
    }
69   
    }
70   
    move_chars_impl(dest, src, buf, sn...);
70   
    move_chars_impl(dest, src, buf, sn...);
71   
}
71   
}
72  
72  
73   
template<class... Args>
73   
template<class... Args>
74   
void
74   
void
75   
move_chars(
75   
move_chars(
76   
    char* dest,
76   
    char* dest,
77   
    char const* src,
77   
    char const* src,
78   
    std::size_t n,
78   
    std::size_t n,
79   
    Args&&... args) noexcept
79   
    Args&&... args) noexcept
80   
{
80   
{
81   
    move_chars_impl(
81   
    move_chars_impl(
82   
        dest,
82   
        dest,
83   
        src,
83   
        src,
84   
        core::string_view(src, n),
84   
        core::string_view(src, n),
85   
        args...);
85   
        args...);
86   
    std::memmove(
86   
    std::memmove(
87   
        dest, src, n);
87   
        dest, src, n);
88   
}
88   
}
89  
89  
90   
} // detail
90   
} // detail
91   
} // http
91   
} // http
92   
} // boost
92   
} // boost
93  
93  
94   
#endif
94   
#endif