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◆ main openmsx / src / utils / format.hh
952 B · C++ · last changed chore(): initial commit 1 month ago source blame history raw
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#ifndef FORMAT_HH
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#define FORMAT_HH
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#include "zstring_view.hh"
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#include <cassert>
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#include <format>
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#include <span>
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#include <string_view>
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#include <utility>
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// Utility functions related to std::format
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template<typename... Args>
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std::string_view format_to_buf(
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	std::span<char> buf, std::format_string<Args...> fmt, Args&&... args)
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{
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	auto r = std::format_to_n(buf.begin(), buf.size(), fmt, std::forward<Args>(args)...);
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	assert(size_t(r.size) <= buf.size()); // must fit
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	return {buf.data(), size_t(r.size)};
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}
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template<typename... Args>
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zstring_view format_to_zbuf(
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	std::span<char> buf, std::format_string<Args...> fmt, Args&&... args)
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{
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	assert(!buf.empty());
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	// Reserve 1 byte for the terminating '\0'
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	auto r = std::format_to_n(buf.begin(), buf.size() - 1, fmt, std::forward<Args>(args)...);
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	assert(size_t(r.size) < buf.size()); // must fit with spare location for '\0'
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	buf[r.size] = '\0';
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	return {buf.data(), size_t(r.size)};
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}
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#endif