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//
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//
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// Copyright (c) 2025 Vinnie Falco (vinnie.falco@gmail.com)
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// Copyright (c) 2025 Vinnie Falco (vinnie.falco@gmail.com)
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//
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//
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// Distributed under the Boost Software License, Version 1.0. (See accompanying
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// Distributed under the Boost Software License, Version 1.0. (See accompanying
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// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
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// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
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//
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//
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// Official repository: https://github.com/cppalliance/capy
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// Official repository: https://github.com/cppalliance/capy
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//
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//
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#ifndef BOOST_CAPY_BUFFERS_SPAN_HPP
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#ifndef BOOST_CAPY_BUFFERS_SPAN_HPP
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#define BOOST_CAPY_BUFFERS_SPAN_HPP
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#define BOOST_CAPY_BUFFERS_SPAN_HPP
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#include <boost/capy/detail/config.hpp>
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#include <boost/capy/detail/config.hpp>
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#include <boost/capy/buffers.hpp>
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#include <boost/capy/buffers.hpp>
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#include <span>
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#include <span>
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16  
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namespace boost {
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namespace boost {
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namespace capy {
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namespace capy {
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/** Remove bytes from the beginning of a span of const buffers.
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/** Remove bytes from the beginning of a span of const buffers.
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21  
22   
    Modifies the span and its buffer contents in-place to
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    Modifies the span and its buffer contents in-place to
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    remove the first `n` bytes.
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    remove the first `n` bytes.
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    @param bs The span to modify.
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    @param bs The span to modify.
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    @param n The number of bytes to remove.
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    @param n The number of bytes to remove.
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*/
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*/
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inline
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inline
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void
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void
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remove_span_prefix(
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remove_span_prefix(
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    std::span<const_buffer>& bs,
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    std::span<const_buffer>& bs,
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    std::size_t n) noexcept
32   
    std::size_t n) noexcept
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{
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{
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    while(bs.size() > 0)
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    while(bs.size() > 0)
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    {
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    {
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        if(n < bs.front().size())
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        if(n < bs.front().size())
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        {
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        {
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            bs.front() += n;
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            bs.front() += n;
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            return;
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            return;
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        }
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        }
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        n -= bs.front().size();
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        n -= bs.front().size();
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        bs = bs.subspan(1);
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        bs = bs.subspan(1);
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    }
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    }
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}
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}
45  
45  
46   
/** Remove bytes from the beginning of a span of mutable buffers.
46   
/** Remove bytes from the beginning of a span of mutable buffers.
47  
47  
48   
    Modifies the span and its buffer contents in-place to
48   
    Modifies the span and its buffer contents in-place to
49   
    remove the first `n` bytes.
49   
    remove the first `n` bytes.
50  
50  
51   
    @param bs The span to modify.
51   
    @param bs The span to modify.
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    @param n The number of bytes to remove.
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    @param n The number of bytes to remove.
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*/
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*/
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inline
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inline
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void
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void
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remove_span_prefix(
56   
remove_span_prefix(
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    std::span<mutable_buffer>& bs,
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    std::span<mutable_buffer>& bs,
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    std::size_t n) noexcept
58   
    std::size_t n) noexcept
59   
{
59   
{
60   
    while(bs.size() > 0)
60   
    while(bs.size() > 0)
61   
    {
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    {
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        if(n < bs.front().size())
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        if(n < bs.front().size())
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        {
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        {
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            bs.front() += n;
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            bs.front() += n;
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            return;
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            return;
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        }
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        }
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        n -= bs.front().size();
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        n -= bs.front().size();
68   
        bs = bs.subspan(1);
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        bs = bs.subspan(1);
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    }
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    }
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}
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}
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71  
72   
/** Remove bytes from the end of a span of const buffers.
72   
/** Remove bytes from the end of a span of const buffers.
73  
73  
74   
    Modifies the span and its buffer contents in-place to
74   
    Modifies the span and its buffer contents in-place to
75   
    remove the last `n` bytes.
75   
    remove the last `n` bytes.
76  
76  
77   
    @param bs The span to modify.
77   
    @param bs The span to modify.
78   
    @param n The number of bytes to remove.
78   
    @param n The number of bytes to remove.
79   
*/
79   
*/
80   
inline
80   
inline
81   
void
81   
void
82   
remove_span_suffix(
82   
remove_span_suffix(
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    std::span<const_buffer>& bs,
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    std::span<const_buffer>& bs,
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    std::size_t n) noexcept
84   
    std::size_t n) noexcept
85   
{
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{
86   
    while(bs.size() > 0)
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    while(bs.size() > 0)
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    {
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    {
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        if(n < bs.back().size())
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        if(n < bs.back().size())
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        {
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        {
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            auto& b = bs.back();
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            auto& b = bs.back();
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            b = const_buffer(b.data(), b.size() - n);
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            b = const_buffer(b.data(), b.size() - n);
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            return;
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            return;
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        }
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        }
94   
        n -= bs.back().size();
94   
        n -= bs.back().size();
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        bs = bs.subspan(0, bs.size() - 1);
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        bs = bs.subspan(0, bs.size() - 1);
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    }
96   
    }
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}
97   
}
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98  
99   
/** Remove bytes from the end of a span of mutable buffers.
99   
/** Remove bytes from the end of a span of mutable buffers.
100  
100  
101   
    Modifies the span and its buffer contents in-place to
101   
    Modifies the span and its buffer contents in-place to
102   
    remove the last `n` bytes.
102   
    remove the last `n` bytes.
103  
103  
104   
    @param bs The span to modify.
104   
    @param bs The span to modify.
105   
    @param n The number of bytes to remove.
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    @param n The number of bytes to remove.
106   
*/
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*/
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inline
107   
inline
108   
void
108   
void
109   
remove_span_suffix(
109   
remove_span_suffix(
110   
    std::span<mutable_buffer>& bs,
110   
    std::span<mutable_buffer>& bs,
111   
    std::size_t n) noexcept
111   
    std::size_t n) noexcept
112   
{
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{
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    while(bs.size() > 0)
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    while(bs.size() > 0)
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    {
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    {
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        if(n < bs.back().size())
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        if(n < bs.back().size())
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        {
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        {
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            auto& b = bs.back();
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            auto& b = bs.back();
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            b = mutable_buffer(b.data(), b.size() - n);
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            b = mutable_buffer(b.data(), b.size() - n);
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            return;
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            return;
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        }
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        }
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        n -= bs.back().size();
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        n -= bs.back().size();
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        bs = bs.subspan(0, bs.size() - 1);
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        bs = bs.subspan(0, bs.size() - 1);
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    }
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    }
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}
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}
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/** Keep only the first bytes of a span of const buffers.
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/** Keep only the first bytes of a span of const buffers.
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127  
128   
    Modifies the span and its buffer contents in-place to
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    Modifies the span and its buffer contents in-place to
129   
    keep only the first `n` bytes.
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    keep only the first `n` bytes.
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130  
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    @param bs The span to modify.
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    @param bs The span to modify.
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    @param n The number of bytes to keep.
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    @param n The number of bytes to keep.
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*/
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*/
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inline
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inline
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void
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void
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keep_span_prefix(
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keep_span_prefix(
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    std::span<const_buffer>& bs,
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    std::span<const_buffer>& bs,
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    std::size_t n) noexcept
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    std::size_t n) noexcept
139   
{
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{
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    auto total = buffer_size(bs);
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    auto total = buffer_size(bs);
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    if(n < total)
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    if(n < total)
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        remove_span_suffix(bs, total - n);
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        remove_span_suffix(bs, total - n);
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}
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}
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/** Keep only the first bytes of a span of mutable buffers.
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/** Keep only the first bytes of a span of mutable buffers.
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146  
147   
    Modifies the span and its buffer contents in-place to
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    Modifies the span and its buffer contents in-place to
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    keep only the first `n` bytes.
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    keep only the first `n` bytes.
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149  
150   
    @param bs The span to modify.
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    @param bs The span to modify.
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    @param n The number of bytes to keep.
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    @param n The number of bytes to keep.
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*/
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*/
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inline
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inline
154   
void
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void
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keep_span_prefix(
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keep_span_prefix(
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    std::span<mutable_buffer>& bs,
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    std::span<mutable_buffer>& bs,
157   
    std::size_t n) noexcept
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    std::size_t n) noexcept
158   
{
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{
159   
    auto total = buffer_size(bs);
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    auto total = buffer_size(bs);
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    if(n < total)
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    if(n < total)
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        remove_span_suffix(bs, total - n);
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        remove_span_suffix(bs, total - n);
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}
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}
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163  
164   
/** Keep only the last bytes of a span of const buffers.
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/** Keep only the last bytes of a span of const buffers.
165  
165  
166   
    Modifies the span and its buffer contents in-place to
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    Modifies the span and its buffer contents in-place to
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    keep only the last `n` bytes.
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    keep only the last `n` bytes.
168  
168  
169   
    @param bs The span to modify.
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    @param bs The span to modify.
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    @param n The number of bytes to keep.
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    @param n The number of bytes to keep.
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*/
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*/
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inline
172   
inline
173   
void
173   
void
174   
keep_span_suffix(
174   
keep_span_suffix(
175   
    std::span<const_buffer>& bs,
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    std::span<const_buffer>& bs,
176   
    std::size_t n) noexcept
176   
    std::size_t n) noexcept
177   
{
177   
{
178   
    auto total = buffer_size(bs);
178   
    auto total = buffer_size(bs);
179   
    if(n < total)
179   
    if(n < total)
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        remove_span_prefix(bs, total - n);
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        remove_span_prefix(bs, total - n);
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}
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}
182  
182  
183   
/** Keep only the last bytes of a span of mutable buffers.
183   
/** Keep only the last bytes of a span of mutable buffers.
184  
184  
185   
    Modifies the span and its buffer contents in-place to
185   
    Modifies the span and its buffer contents in-place to
186   
    keep only the last `n` bytes.
186   
    keep only the last `n` bytes.
187  
187  
188   
    @param bs The span to modify.
188   
    @param bs The span to modify.
189   
    @param n The number of bytes to keep.
189   
    @param n The number of bytes to keep.
190   
*/
190   
*/
191   
inline
191   
inline
192   
void
192   
void
193   
keep_span_suffix(
193   
keep_span_suffix(
194   
    std::span<mutable_buffer>& bs,
194   
    std::span<mutable_buffer>& bs,
195   
    std::size_t n) noexcept
195   
    std::size_t n) noexcept
196   
{
196   
{
197   
    auto total = buffer_size(bs);
197   
    auto total = buffer_size(bs);
198   
    if(n < total)
198   
    if(n < total)
199   
        remove_span_prefix(bs, total - n);
199   
        remove_span_prefix(bs, total - n);
200   
}
200   
}
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} // capy
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} // capy
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} // boost
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} // boost
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#endif
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#endif