27 lines
978 B
C++
27 lines
978 B
C++
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#pragma once
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#include <cstddef>
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#include <type_traits>
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namespace tf {
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template <typename B, typename E, typename S>
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constexpr std::enable_if_t<std::is_integral<std::decay_t<B>>::value &&
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std::is_integral<std::decay_t<E>>::value &&
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std::is_integral<std::decay_t<S>>::value, bool>
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is_range_invalid(B beg, E end, S step) {
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return ((step == 0 && beg != end) ||
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(beg < end && step <= 0) || // positive range
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(beg > end && step >= 0)); // negative range
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}
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template <typename B, typename E, typename S>
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constexpr std::enable_if_t<std::is_integral<std::decay_t<B>>::value &&
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std::is_integral<std::decay_t<E>>::value &&
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std::is_integral<std::decay_t<S>>::value, size_t>
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distance(B beg, E end, S step) {
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return (end - beg + step + (step > 0 ? -1 : 1)) / step;
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}
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} // end of namespace tf -----------------------------------------------------
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