Function RoundUpToPowerOf2

cpp/src/arrow/util/bit_util.h:101–103

Returns 'value' rounded up to the nearest multiple of 'factor' when factor is a power of two. The result is undefined on overflow, i.e. if `value > 2**64 - factor`, since we cannot return the correct result which would be 2**64.

// The result is undefined on overflow, i.e. if `value > 2**64 - factor`,
// since we cannot return the correct result which would be 2**64.
constexpr int64_t RoundUpToPowerOf2(int64_t value, int64_t factor) {
  return (value + (factor - 1)) & ~(factor - 1);
}

constexpr uint64_t RoundUpToPowerOf2(uint64_t value, uint64_t factor) {
  return (value + (factor - 1)) & ~(factor - 1);