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50 lines
1.7 KiB
C++
50 lines
1.7 KiB
C++
#ifndef XRPL_BASICS_MATHUTILITIES_H_INCLUDED
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#define XRPL_BASICS_MATHUTILITIES_H_INCLUDED
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#include <algorithm>
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#include <cassert>
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#include <cstddef>
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namespace xrpl {
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/** Calculate one number divided by another number in percentage.
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* The result is rounded up to the next integer, and capped in the range [0,100]
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* E.g. calculatePercent(1, 100) = 1 because 1/100 = 0.010000
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* calculatePercent(1, 99) = 2 because 1/99 = 0.010101
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* calculatePercent(0, 100) = 0
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* calculatePercent(100, 100) = 100
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* calculatePercent(200, 100) = 100 because the result is capped to 100
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*
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* @param count dividend
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* @param total divisor
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* @return the percentage, in [0, 100]
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*
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* @note total cannot be zero.
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* */
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constexpr std::size_t
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calculatePercent(std::size_t count, std::size_t total)
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{
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assert(total != 0); // NOTE No XRPL_ASSERT here, because constexpr
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return ((std::min(count, total) * 100) + total - 1) / total;
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}
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// unit tests
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static_assert(calculatePercent(1, 2) == 50);
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static_assert(calculatePercent(0, 100) == 0);
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static_assert(calculatePercent(100, 100) == 100);
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static_assert(calculatePercent(200, 100) == 100);
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static_assert(calculatePercent(1, 100) == 1);
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static_assert(calculatePercent(1, 99) == 2);
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static_assert(calculatePercent(6, 14) == 43);
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static_assert(calculatePercent(29, 33) == 88);
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static_assert(calculatePercent(1, 64) == 2);
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static_assert(calculatePercent(0, 100'000'000) == 0);
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static_assert(calculatePercent(1, 100'000'000) == 1);
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static_assert(calculatePercent(50'000'000, 100'000'000) == 50);
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static_assert(calculatePercent(50'000'001, 100'000'000) == 51);
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static_assert(calculatePercent(99'999'999, 100'000'000) == 100);
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} // namespace xrpl
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#endif
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