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-rw-r--r--src/core/overflowsafe_type.hpp42
1 files changed, 33 insertions, 9 deletions
diff --git a/src/core/overflowsafe_type.hpp b/src/core/overflowsafe_type.hpp
index 0a9df5920..00d0dfca1 100644
--- a/src/core/overflowsafe_type.hpp
+++ b/src/core/overflowsafe_type.hpp
@@ -39,25 +39,41 @@ public:
/**
* Safe implementation of addition.
* @param other the amount to add
- * @note when the addition would yield more than T_MAX (or less than T_MIN),
- * it will be T_MAX (respectively T_MIN).
+ * @note when the addition would yield more than T_MAX, it will be T_MAX.
*/
inline OverflowSafeInt& operator += (const OverflowSafeInt& other)
{
- if ((T_MAX - abs(other.m_value)) < abs(this->m_value) &&
- (this->m_value < 0) == (other.m_value < 0)) {
- this->m_value = (this->m_value < 0) ? T_MIN : T_MAX ;
+ if (this->m_value > 0 && other.m_value > 0 && (T_MAX - other.m_value) < this->m_value) {
+ this->m_value = T_MAX;
+ } else if (this->m_value < 0 && other.m_value < 0 && (this->m_value == T_MIN || other.m_value == T_MIN || ((T_MAX + this->m_value) + other.m_value < (T_MIN + T_MAX)))) {
+ this->m_value = T_MIN;
} else {
this->m_value += other.m_value;
}
return *this;
}
+ /**
+ * Safe implementation of subtraction.
+ * @param other the amount to subtract
+ * @note when the subtraction would yield less than T_MIN, it will be T_MIN.
+ */
+ inline OverflowSafeInt& operator -= (const OverflowSafeInt& other)
+ {
+ if (this->m_value > 0 && other.m_value < 0 && (T_MAX + other.m_value) < this->m_value) {
+ this->m_value = T_MAX;
+ } else if (this->m_value < 0 && other.m_value > 0 && (T_MAX + this->m_value) < (T_MIN + T_MAX) + other.m_value) {
+ this->m_value = T_MIN;
+ } else {
+ this->m_value -= other.m_value;
+ }
+ return *this;
+ }
+
/* Operators for addition and subtraction */
inline OverflowSafeInt operator + (const OverflowSafeInt& other) const { OverflowSafeInt result = *this; result += other; return result; }
inline OverflowSafeInt operator + (const int other) const { OverflowSafeInt result = *this; result += (int64)other; return result; }
inline OverflowSafeInt operator + (const uint other) const { OverflowSafeInt result = *this; result += (int64)other; return result; }
- inline OverflowSafeInt& operator -= (const OverflowSafeInt& other) { return *this += (-other); }
inline OverflowSafeInt operator - (const OverflowSafeInt& other) const { OverflowSafeInt result = *this; result -= other; return result; }
inline OverflowSafeInt operator - (const int other) const { OverflowSafeInt result = *this; result -= (int64)other; return result; }
inline OverflowSafeInt operator - (const uint other) const { OverflowSafeInt result = *this; result -= (int64)other; return result; }
@@ -75,10 +91,18 @@ public:
*/
inline OverflowSafeInt& operator *= (const int factor)
{
- if (factor != 0 && (T_MAX / abs(factor)) < abs(this->m_value)) {
- this->m_value = ((this->m_value < 0) == (factor < 0)) ? T_MAX : T_MIN ;
+ if (factor == -1) {
+ this->m_value = (this->m_value == T_MIN) ? T_MAX : -this->m_value;
+ } else if (factor > 0 && this->m_value > 0 && (T_MAX / factor) < this->m_value) {
+ this->m_value = T_MAX;
+ } else if (factor > 0 && this->m_value < 0 && (T_MIN / factor) > this->m_value) {
+ this->m_value = T_MIN;
+ } else if (factor < 0 && this->m_value > 0 && (T_MIN / factor) < this->m_value) {
+ this->m_value = T_MIN;
+ } else if (factor < 0 && this->m_value < 0 && (T_MAX / factor) > this->m_value) {
+ this->m_value = T_MAX;
} else {
- this->m_value *= factor ;
+ this->m_value *= factor;
}
return *this;
}