libc/src/__support/number_pair.h

   1 //===-- Utilities for pairs of numbers. -------------------------*- C++ -*-===//
   2 //
   3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
   4 // See https://llvm.org/LICENSE.txt for license information.
   5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
   6 //
   7 //===----------------------------------------------------------------------===//
   8
   9 #ifndef LLVM_LIBC_SRC_SUPPORT_NUMBER_PAIR_H
  10 #define LLVM_LIBC_SRC_SUPPORT_NUMBER_PAIR_H
  11
  12 #include "CPP/type_traits.h"
  13 #include "named_pair.h"
  14
  15 #include <stddef.h>
  16
  17 namespace __llvm_libc {
  18
  19 DEFINE_NAMED_PAIR_TEMPLATE(NumberPair, lo, hi);
  20
  21 template <typename T>
  22 cpp::enable_if_t<cpp::is_integral_v<T> && cpp::is_unsigned_v<T>, NumberPair<T>>
  23 split(T a) {
  24   constexpr size_t HALF_BIT_WIDTH = sizeof(T) * 4;
  25   constexpr T LOWER_HALF_MASK = (T(1) << HALF_BIT_WIDTH) - T(1);
  26   NumberPair<T> result;
  27   result.lo = a & LOWER_HALF_MASK;
  28   result.hi = a >> HALF_BIT_WIDTH;
  29   return result;
  30 }
  31
  32 } // namespace __llvm_libc
  33
  34 #endif // LLVM_LIBC_SRC_SUPPORT_NUMBER_PAIR_H