bsnes/nall/arithmetic/unsigned.hpp

#pragma once

namespace nall {

template<typename T, enable_if_t<is_unsigned<T>::value>>
inline auto upper(T value) -> T {
  return value >> sizeof(T) * 4;
}

template<typename T, enable_if_t<is_unsigned<T>::value>>
inline auto lower(T value) -> T {
  static const T Mask = ~T(0) >> sizeof(T) * 4;
  return value & Mask;
}

template<typename T, typename U, enable_if_t<is_unsigned<T>::value>, enable_if_t<is_unsigned<U>::value>>
inline auto mul(T lhs, U rhs) -> uintmax {
  return lhs * rhs;
}

template<typename T, enable_if_t<is_unsigned<T>::value>>
inline auto square(T value) -> uintmax {
  return value * value;
}

template<typename T, typename U>
inline auto rol(T lhs, U rhs, enable_if_t<is_unsigned<T>::value>* = 0) -> T {
  return lhs << rhs | lhs >> sizeof(T) * 8 - rhs;
}

template<typename T, typename U>
inline auto ror(T lhs, U rhs, enable_if_t<is_unsigned<T>::value>* = 0) -> T {
  return lhs >> rhs | lhs << sizeof(T) * 8 - rhs;
}

#if INTMAX_BITS >= 128
inline auto operator"" _u128(const char* s) -> uint128_t {
  uint128_t p = 0;
  if(s[0] == '0' && (s[1] == 'x' || s[1] == 'X')) {
    s += 2;
    while(*s) {
      auto c = *s++;
      if(c == '\'');
      else if(c >= '0' && c <= '9') p = (p << 4) + (c - '0');
      else if(c >= 'a' && c <= 'f') p = (p << 4) + (c - 'a' + 10);
      else if(c >= 'A' && c <= 'F') p = (p << 4) + (c - 'A' + 10);
      else break;
    }
  } else {
    while(*s) {
      auto c = *s++;
      if(c == '\'');
      else if(c >= '0' && c <= '9') p = (p << 3) + (p << 1) + (c - '0');
      else break;
    }
  }
  return p;
}
#endif

}