diff options
| -rw-r--r-- | src/core/overflowsafe_type.hpp | 42 |
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; } |