mirror of
https://github.com/matrix-construct/construct
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64 lines
1.7 KiB
C++
64 lines
1.7 KiB
C++
// Matrix Construct
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//
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// Copyright (C) Matrix Construct Developers, Authors & Contributors
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// Copyright (C) 2016-2018 Jason Volk <jason@zemos.net>
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//
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// Permission to use, copy, modify, and/or distribute this software for any
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// purpose with or without fee is hereby granted, provided that the above
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// copyright notice and this permission notice is present in all copies. The
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// full license for this software is available in the LICENSE file.
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#pragma once
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#define HAVE_IRCD_BYTE_VIEW_H
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namespace ircd
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{
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template<class T = string_view> struct byte_view;
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template<> struct byte_view<string_view>;
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}
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/// string_view -> bytes
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template<class T>
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struct ircd::byte_view
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{
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string_view s;
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operator const T &() const
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{
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assert(sizeof(T) <= size(s));
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if(unlikely(sizeof(T) > s.size()))
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throw std::bad_cast();
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return *reinterpret_cast<const T *>(s.data());
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}
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byte_view(const string_view &s = {})
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:s{s}
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{}
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// bytes -> bytes (completeness)
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byte_view(const T &t)
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:s{byte_view<string_view>{t}}
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{}
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};
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/// bytes -> string_view. A byte_view<string_view> is raw data of byte_view<T>.
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///
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/// This is an important specialization to take note of. When you see
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/// byte_view<string_view> know that another type's bytes are being represented
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/// by the string_view if that type is not string_view family itself.
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template<>
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struct ircd::byte_view<ircd::string_view>
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:string_view
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{
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template<class T,
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typename std::enable_if<!std::is_base_of<std::string_view, T>::value, int *>::type = nullptr>
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byte_view(const T &t)
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:string_view{reinterpret_cast<const char *>(&t), sizeof(T)}
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{}
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/// string_view -> string_view (completeness)
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byte_view(const string_view &t = {})
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:string_view{t}
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{}
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};
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