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replace enable_if with if constexpr

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Signed-off-by: Rosen Penev <rosenp@gmail.com>
This commit is contained in:
Rosen Penev 2023-03-04 16:43:26 -08:00
parent 2fd523873b
commit e854d93841
1 changed files with 24 additions and 62 deletions
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64
src/safe_op.hpp
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@ -54,68 +54,28 @@ namespace Internal {
*
* Further information:
* https://wiki.sei.cmu.edu/confluence/display/c/INT32-C.+Ensure+that+operations+on+signed+integers+do+not+result+in+overflow
* https://wiki.sei.cmu.edu/confluence/display/c/INT02-C.+Understand+integer+conversion+rules
* https://wiki.sei.cmu.edu/confluence/display/c/INT30-C.+Ensure+that+unsigned+integer+operations+do+not+wrap
*/
template <typename T>
std::enable_if_t<std::is_signed_v<T> && sizeof(T) >= sizeof(int), bool> fallback_add_overflow(T summand_1, T summand_2,
T& result) {
bool fallback_add_overflow(T summand_1, T summand_2, T& result) {
if constexpr (std::is_signed_v<T> && sizeof(T) >= sizeof(int)) {
if (((summand_2 >= 0) && (summand_1 > std::numeric_limits<T>::max() - summand_2)) ||
((summand_2 < 0) && (summand_1 < std::numeric_limits<T>::min() - summand_2))) {
((summand_2 < 0) && (summand_1 < std::numeric_limits<T>::min() - summand_2)))
return true;
}
result = summand_1 + summand_2;
return false;
}
/*!
* @brief Check the addition of two numbers for overflows for signed
* integer types smaller than int.
*
* This function adds summand_1 and summand_2 exploiting integer
* promotion rules, thereby not causing undefined behavior. The
* result is checked against the limits of T and true is returned if
* they are exceeded. Otherwise the sum is saved in result and false
* is returned.
*
* @return true on overflow, false on no overflow
*
* @param[in] summand_1, summand_2 The summands with are added
* @param[out] result Result of the addition, only populated when no
* overflow occurs.
*
* Further information:
* https://wiki.sei.cmu.edu/confluence/display/c/INT02-C.+Understand+integer+conversion+rules
*/
template <typename T>
std::enable_if_t<std::is_signed_v<T> && sizeof(T) < sizeof(int), bool> fallback_add_overflow(T summand_1, T summand_2,
T& result) {
} else if constexpr (std::is_signed_v<T> && sizeof(T) < sizeof(int)) {
const int res = summand_1 + summand_2;
if ((res > std::numeric_limits<T>::max()) || (res < std::numeric_limits<T>::min())) {
return true;
}
result = static_cast<T>(res);
return false;
}
/*!
* @brief Check the addition of two numbers for overflows for unsigned
* integer types.
*
* This function adds summand_1 and summand_2 and checks after that if
* the operation overflowed. Since these are unsigned integers, no
* undefined behavior is invoked.
*
* @return true on overflow, false on no overflow
*
* @param[in] summand_1, summand_2 The summands with are added
* @param[out] result Result of the addition
*
* Further information:
* https://wiki.sei.cmu.edu/confluence/display/c/INT30-C.+Ensure+that+unsigned+integer+operations+do+not+wrap
*/
template <typename T>
std::enable_if_t<!std::is_signed_v<T>, bool> fallback_add_overflow(T summand_1, T summand_2, T& result) {
} else {
result = summand_1 + summand_2;
return result < summand_1;
}
}
/*!
@ -223,11 +183,13 @@ T add(T summand_1, T summand_2) {
* when `num == std::numeric_limits<T>::min()`.
*/
template <typename T>
std::enable_if_t<std::is_signed_v<T>, T> abs(T num) throw() {
if (num == std::numeric_limits<T>::min()) {
T abs(T num) noexcept {
if constexpr (std::is_signed_v<T>) {
if (num == std::numeric_limits<T>::min())
return std::numeric_limits<T>::max();
}
return num < 0 ? -num : num;
}
return num;
}
} // namespace Safe