125 lines
3.5 KiB
C++
125 lines
3.5 KiB
C++
/*
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* This file is part of the DXX-Rebirth project <https://www.dxx-rebirth.com/>.
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* It is copyright by its individual contributors, as recorded in the
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* project's Git history. See COPYING.txt at the top level for license
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* terms and a link to the Git history.
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*/
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#pragma once
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#include <span>
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#include <type_traits>
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#include <utility>
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#include "dxxsconf.h"
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template <bool capture_source_location = false>
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class location_wrapper
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{
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public:
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location_wrapper() = default;
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/* Allow callers to pass explicit file/line, for signature
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* compatibility with `location_wrapper<true>`.
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*/
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location_wrapper(const char *, unsigned)
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{
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}
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/* This must be a template to be compatible with the `scratch_buffer`
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* template-typedef in `location_wrapper<true>`.
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*/
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template <std::size_t N>
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using scratch_buffer = std::false_type;
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template <std::size_t N>
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static std::pair<std::size_t, std::span<char, N>> insert_location_leader(std::array<char, N> &buffer)
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{
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return {{}, buffer};
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}
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/* Define overloads to preserve const qualification */
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static std::span<char> prepare_buffer(scratch_buffer<0> &, const std::span<char> text)
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{
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return text;
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}
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static std::span<const char> prepare_buffer(scratch_buffer<0> &, const std::span<const char> text)
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{
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return text;
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}
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};
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#if DXX_HAVE_CXX_BUILTIN_FILE_LINE
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#include <cstdio>
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template <>
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class location_wrapper<true>
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{
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const char *file;
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unsigned line;
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public:
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template <std::size_t N>
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using scratch_buffer = std::array<char, N>;
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location_wrapper(const char *const f = __builtin_FILE(), const unsigned l = __builtin_LINE()) :
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file(f), line(l)
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{
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}
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/* Return a span describing the unwritten area into which the caller can
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* place further text.
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*/
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template <std::size_t N>
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std::pair<std::size_t, std::span<char>> insert_location_leader(std::array<char, N> &buffer)
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{
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const auto written = std::snprintf(buffer.data(), buffer.size(), "%s:%u: ", file, line);
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return {written, std::span(buffer).subspan(written)};
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}
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/* Return a span describing the written area that the caller can read
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* without accessing undefined bytes.
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*/
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template <std::size_t N>
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std::span<const char> prepare_buffer(std::array<char, N> &buffer, const std::span<const char> text) const
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{
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const auto written = std::snprintf(buffer, sizeof(buffer), "%s:%u: %.*s", file, line, static_cast<int>(text.size()), text.data());
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return {buffer, written};
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}
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/* Delegate to the const-qualified version, but return a `char *` to
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* match the non-const input `char *`, to preserve the choice of
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* overload for the function to receive this result.
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*/
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template <std::size_t N>
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std::span<char> prepare_buffer(std::array<char, N> &buffer, const std::span<char> text) const
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{
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return {buffer, prepare_buffer(buffer, std::span(const_cast<const char *>(text.data()), text.size())).size()};
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}
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};
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#endif
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template <typename T, bool capture_source_location = false>
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class location_value_wrapper : public location_wrapper<capture_source_location>
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{
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T value;
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public:
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/* Allow callers to pass explicit file/line, for signature
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* compatibility with `location_value_wrapper<T, true>`.
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*/
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#if !DXX_HAVE_CXX_BUILTIN_FILE_LINE
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location_value_wrapper(const T &v) :
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value(v)
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{
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}
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#endif
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location_value_wrapper(const T &v,
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const char *const f
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#if DXX_HAVE_CXX_BUILTIN_FILE_LINE
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= __builtin_FILE()
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#endif
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, const unsigned l
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#if DXX_HAVE_CXX_BUILTIN_FILE_LINE
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= __builtin_LINE()
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#endif
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) :
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location_wrapper<capture_source_location>(f, l),
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value(v)
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{
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}
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operator T() const
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{
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return value;
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}
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};
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