1   
//
1   
//
2   
// Copyright (c) 2025 Vinnie Falco (vinnie.falco@gmail.com)
2   
// Copyright (c) 2025 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/capy
7   
// Official repository: https://github.com/cppalliance/capy
8   
//
8   
//
9  
9  
10   
#include <boost/capy/buffers/buffer_array.hpp>
10   
#include <boost/capy/buffers/buffer_array.hpp>
11  
11  
12   
namespace boost {
12   
namespace boost {
13   
namespace capy {
13   
namespace capy {
14   
namespace detail {
14   
namespace detail {
15  
15  
16   
namespace {
16   
namespace {
17  
17  
18   
template<class Buffer>
18   
template<class Buffer>
19   
void
19   
void
20   
do_remove_prefix(
20   
do_remove_prefix(
21   
    Buffer* arr,
21   
    Buffer* arr,
22   
    std::size_t* count,
22   
    std::size_t* count,
23   
    std::size_t* total_size,
23   
    std::size_t* total_size,
24   
    std::size_t n) noexcept
24   
    std::size_t n) noexcept
25   
{
25   
{
26   
    if(n >= *total_size)
26   
    if(n >= *total_size)
27   
    {
27   
    {
28   
        while(*count > 0)
28   
        while(*count > 0)
29   
            arr[--(*count)].~Buffer();
29   
            arr[--(*count)].~Buffer();
30   
        *total_size = 0;
30   
        *total_size = 0;
31   
        return;
31   
        return;
32   
    }
32   
    }
33  
33  
34   
    std::size_t i = 0;
34   
    std::size_t i = 0;
35   
    while(i < *count && n > 0)
35   
    while(i < *count && n > 0)
36   
    {
36   
    {
37   
        auto& b = arr[i];
37   
        auto& b = arr[i];
38   
        if(n < b.size())
38   
        if(n < b.size())
39   
        {
39   
        {
40   
            b += n;
40   
            b += n;
41   
            *total_size -= n;
41   
            *total_size -= n;
42   
            break;
42   
            break;
43   
        }
43   
        }
44   
        n -= b.size();
44   
        n -= b.size();
45   
        *total_size -= b.size();
45   
        *total_size -= b.size();
46   
        b.~Buffer();
46   
        b.~Buffer();
47   
        ++i;
47   
        ++i;
48   
    }
48   
    }
49  
49  
50   
    // Compact: move remaining buffers to front
50   
    // Compact: move remaining buffers to front
51   
    if(i > 0)
51   
    if(i > 0)
52   
    {
52   
    {
53   
        std::size_t j = 0;
53   
        std::size_t j = 0;
54   
        while(i < *count)
54   
        while(i < *count)
55   
        {
55   
        {
56   
            arr[j] = arr[i];
56   
            arr[j] = arr[i];
57   
            arr[i].~Buffer();
57   
            arr[i].~Buffer();
58   
            ++i;
58   
            ++i;
59   
            ++j;
59   
            ++j;
60   
        }
60   
        }
61   
        *count = j;
61   
        *count = j;
62   
    }
62   
    }
63   
}
63   
}
64  
64  
65   
template<class Buffer>
65   
template<class Buffer>
66   
void
66   
void
67   
do_keep_prefix(
67   
do_keep_prefix(
68   
    Buffer* arr,
68   
    Buffer* arr,
69   
    std::size_t* count,
69   
    std::size_t* count,
70   
    std::size_t* total_size,
70   
    std::size_t* total_size,
71   
    std::size_t n) noexcept
71   
    std::size_t n) noexcept
72   
{
72   
{
73   
    if(n >= *total_size)
73   
    if(n >= *total_size)
74   
        return;
74   
        return;
75  
75  
76   
    if(n == 0)
76   
    if(n == 0)
77   
    {
77   
    {
78   
        while(*count > 0)
78   
        while(*count > 0)
79   
            arr[--(*count)].~Buffer();
79   
            arr[--(*count)].~Buffer();
80   
        *total_size = 0;
80   
        *total_size = 0;
81   
        return;
81   
        return;
82   
    }
82   
    }
83  
83  
84   
    std::size_t remaining = n;
84   
    std::size_t remaining = n;
85   
    std::size_t i = 0;
85   
    std::size_t i = 0;
86   
    while(i < *count && remaining > 0)
86   
    while(i < *count && remaining > 0)
87   
    {
87   
    {
88   
        auto& b = arr[i];
88   
        auto& b = arr[i];
89   
        if(remaining < b.size())
89   
        if(remaining < b.size())
90   
        {
90   
        {
91   
            b = Buffer(b.data(), remaining);
91   
            b = Buffer(b.data(), remaining);
92   
            ++i;
92   
            ++i;
93   
            break;
93   
            break;
94   
        }
94   
        }
95   
        remaining -= b.size();
95   
        remaining -= b.size();
96   
        ++i;
96   
        ++i;
97   
    }
97   
    }
98  
98  
99   
    // Destruct elements beyond the new count
99   
    // Destruct elements beyond the new count
100   
    while(*count > i)
100   
    while(*count > i)
101   
        arr[--(*count)].~Buffer();
101   
        arr[--(*count)].~Buffer();
102  
102  
103   
    *total_size = n;
103   
    *total_size = n;
104   
}
104   
}
105  
105  
106   
} // anonymous namespace
106   
} // anonymous namespace
107  
107  
108   
void
108   
void
109   
buffer_array_remove_prefix(
109   
buffer_array_remove_prefix(
110   
    const_buffer* arr,
110   
    const_buffer* arr,
111   
    std::size_t* count,
111   
    std::size_t* count,
112   
    std::size_t* total_size,
112   
    std::size_t* total_size,
113   
    std::size_t n) noexcept
113   
    std::size_t n) noexcept
114   
{
114   
{
115   
    do_remove_prefix(arr, count, total_size, n);
115   
    do_remove_prefix(arr, count, total_size, n);
116   
}
116   
}
117  
117  
118   
void
118   
void
119   
buffer_array_remove_prefix(
119   
buffer_array_remove_prefix(
120   
    mutable_buffer* arr,
120   
    mutable_buffer* arr,
121   
    std::size_t* count,
121   
    std::size_t* count,
122   
    std::size_t* total_size,
122   
    std::size_t* total_size,
123   
    std::size_t n) noexcept
123   
    std::size_t n) noexcept
124   
{
124   
{
125   
    do_remove_prefix(arr, count, total_size, n);
125   
    do_remove_prefix(arr, count, total_size, n);
126   
}
126   
}
127  
127  
128   
void
128   
void
129   
buffer_array_keep_prefix(
129   
buffer_array_keep_prefix(
130   
    const_buffer* arr,
130   
    const_buffer* arr,
131   
    std::size_t* count,
131   
    std::size_t* count,
132   
    std::size_t* total_size,
132   
    std::size_t* total_size,
133   
    std::size_t n) noexcept
133   
    std::size_t n) noexcept
134   
{
134   
{
135   
    do_keep_prefix(arr, count, total_size, n);
135   
    do_keep_prefix(arr, count, total_size, n);
136   
}
136   
}
137  
137  
138   
void
138   
void
139   
buffer_array_keep_prefix(
139   
buffer_array_keep_prefix(
140   
    mutable_buffer* arr,
140   
    mutable_buffer* arr,
141   
    std::size_t* count,
141   
    std::size_t* count,
142   
    std::size_t* total_size,
142   
    std::size_t* total_size,
143   
    std::size_t n) noexcept
143   
    std::size_t n) noexcept
144   
{
144   
{
145   
    do_keep_prefix(arr, count, total_size, n);
145   
    do_keep_prefix(arr, count, total_size, n);
146   
}
146   
}
147  
147  
148   
} // namespace detail
148   
} // namespace detail
149   
} // namespace capy
149   
} // namespace capy
150   
} // namespace boost
150   
} // namespace boost