helper.h

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/** @file include/detail/ut/helper.h
    Small helper functions. Exists mostly because ut0ut.h is not usable from
    every translation unit.
 */
 
#ifndef detail_ut_helper_h
#define detail_ut_helper_h
 
namespace ut {
namespace detail {
 
/** Calculates the smallest multiple of m that is not smaller than n
    when m is a power of two. In other words, rounds n up to m * k.
    @param n in: number to round up
    @param m in: alignment, must be a power of two
    @return n rounded up to the smallest possible integer multiple of m
 */
constexpr size_t calc_align(size_t n, size_t m) {
  // This is a copy pasta from ut0ut.h but consuming that header from
  // this file bursts the build into flames. Let's at least stick to the
  // similar name.
  return (n + (m - 1)) & ~(m - 1);
}
 
/** Calculates the biggest multiple of m that is not bigger than n
    when m is a power of two.  In other words, rounds n down to m * k.
    @param n in: number to round down
    @param m in: alignment, must be a power of two
    @return n rounded down to the biggest possible integer multiple of m */
constexpr size_t pow2_round(size_t n, size_t m) {
  // This is a copy pasta from ut0ut.h but consuming that header from
  // this file bursts the build into flames. Let's at least stick to the
  // similar name.
  return (n & ~(m - 1));
}
 
/** Calculates the next multiple of m that is bigger or equal to n.
    @param n in: number to find the next multiple of in terms of m
    @param m in: alignment, must be a power of two
    @return next next multiple of m bigger or equal than n */
constexpr size_t round_to_next_multiple(size_t n, size_t m) {
  return pow2_round(n + (m - 1), m);
}
 
}  // namespace detail
}  // namespace ut
 
#endif