khodowany
41 lines
1.0 KiB
C++
41 lines
1.0 KiB
C++
#pragma once
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#include <charconv>
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#include <concepts>
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#include <expected>
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#include <string>
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#include <string_view>
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#include <system_error>
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#include <type_traits>
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#include <modulus/result.hpp>
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#include <vamp_zero/errors.hpp>
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namespace vamp_zero {
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template <std::integral VALUE>
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requires(!std::is_same_v<VALUE, std::bool_t>)
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auto parse_integer(std::string_view text, std::string_view name) -> std::expected<VALUE, modulus::error> {
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auto invalid = [&](std::string_view reason) {
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return modulus::fail<VALUE>(
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make_error(error_code::INVALID_ARGUMENT, std::string{name} + " " + std::string{reason}));
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};
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if (text.empty()) {
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return invalid("must be an integer");
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}
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auto value = VALUE{};
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auto end = text.data() + text.size();
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auto parsed = std::from_chars(text.data(), end, value);
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if (parsed.ec == std::errc::result_out_of_range) {
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return invalid("is out of range");
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}
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if (parsed.ec != std::errc{} || parsed.ptr != end) {
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return invalid("must be an integer");
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}
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return modulus::success(value);
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}
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}
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