--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/src/core/overflowsafe_type.hpp Fri Dec 21 08:34:53 2007 +0000
@@ -0,0 +1,147 @@
+/* $Id$ */
+
+/** @file overflowsafe_type.hpp An overflow safe integer-like type. */
+
+#ifndef OVERFLOWSAFE_TYPE_HPP
+#define OVERFLOWSAFE_TYPE_HPP
+
+/**
+ * Overflow safe template for integers, i.e. integers that will never overflow
+ * you multiply the maximum value with 2, or add 2, or substract somethng from
+ * the minimum value, etc.
+ * @param T the type these integers are stored with.
+ * @param T_MAX the maximum value for the integers.
+ * @param T_MIN the minimum value for the integers.
+ */
+template <class T, T T_MAX, T T_MIN>
+class OverflowSafeInt
+{
+private:
+ /** The non-overflow safe backend to store the value in. */
+ T m_value;
+public:
+ OverflowSafeInt() : m_value(0) { }
+
+ OverflowSafeInt(const OverflowSafeInt& other) { this->m_value = other.m_value; }
+ OverflowSafeInt(const int64 int_) { this->m_value = int_; }
+
+ FORCEINLINE OverflowSafeInt& operator = (const OverflowSafeInt& other) { this->m_value = other.m_value; return *this; }
+
+ FORCEINLINE OverflowSafeInt operator - () const { return OverflowSafeInt(-this->m_value); }
+
+ /**
+ * 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).
+ */
+ FORCEINLINE 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 ;
+ } else {
+ this->m_value += other.m_value;
+ }
+ return *this;
+ }
+
+ /* Operators for addition and substraction */
+ FORCEINLINE OverflowSafeInt operator + (const OverflowSafeInt& other) const { OverflowSafeInt result = *this; result += other; return result; }
+ FORCEINLINE OverflowSafeInt operator + (const int other) const { OverflowSafeInt result = *this; result += (int64)other; return result; }
+ FORCEINLINE OverflowSafeInt operator + (const uint other) const { OverflowSafeInt result = *this; result += (int64)other; return result; }
+ FORCEINLINE OverflowSafeInt& operator -= (const OverflowSafeInt& other) { return *this += (-other); }
+ FORCEINLINE OverflowSafeInt operator - (const OverflowSafeInt& other) const { OverflowSafeInt result = *this; result -= other; return result; }
+ FORCEINLINE OverflowSafeInt operator - (const int other) const { OverflowSafeInt result = *this; result -= (int64)other; return result; }
+ FORCEINLINE OverflowSafeInt operator - (const uint other) const { OverflowSafeInt result = *this; result -= (int64)other; return result; }
+
+ FORCEINLINE OverflowSafeInt& operator ++ () { return *this += 1; }
+ FORCEINLINE OverflowSafeInt& operator -- () { return *this += -1; }
+ FORCEINLINE OverflowSafeInt operator ++ (int) { OverflowSafeInt org = *this; *this += 1; return org; }
+ FORCEINLINE OverflowSafeInt operator -- (int) { OverflowSafeInt org = *this; *this += -1; return org; }
+
+ /**
+ * Safe implementation of multiplication.
+ * @param factor the factor to multiply this with.
+ * @note when the multiplication would yield more than T_MAX (or less than T_MIN),
+ * it will be T_MAX (respectively T_MIN).
+ */
+ FORCEINLINE 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 ;
+ } else {
+ this->m_value *= factor ;
+ }
+ return *this;
+ }
+
+ /* Operators for multiplication */
+ FORCEINLINE OverflowSafeInt operator * (const int64 factor) const { OverflowSafeInt result = *this; result *= factor; return result; }
+ FORCEINLINE OverflowSafeInt operator * (const int factor) const { OverflowSafeInt result = *this; result *= (int64)factor; return result; }
+ FORCEINLINE OverflowSafeInt operator * (const uint factor) const { OverflowSafeInt result = *this; result *= (int64)factor; return result; }
+ FORCEINLINE OverflowSafeInt operator * (const uint16 factor) const { OverflowSafeInt result = *this; result *= (int64)factor; return result; }
+ FORCEINLINE OverflowSafeInt operator * (const byte factor) const { OverflowSafeInt result = *this; result *= (int64)factor; return result; }
+
+ /* Operators for division */
+ FORCEINLINE OverflowSafeInt& operator /= (const int divisor) { this->m_value /= divisor; return *this; }
+ FORCEINLINE OverflowSafeInt operator / (const OverflowSafeInt& divisor) const { OverflowSafeInt result = *this; result /= divisor.m_value; return result; }
+ FORCEINLINE OverflowSafeInt operator / (const int divisor) const { OverflowSafeInt result = *this; result /= divisor; return result; }
+ FORCEINLINE OverflowSafeInt operator / (const uint divisor) const { OverflowSafeInt result = *this; result /= (int)divisor; return result; }
+
+ /* Operators for modulo */
+ FORCEINLINE OverflowSafeInt& operator %= (const int divisor) { this->m_value %= divisor; return *this; }
+ FORCEINLINE OverflowSafeInt operator % (const int divisor) const { OverflowSafeInt result = *this; result %= divisor; return result; }
+
+ /* Operators for shifting */
+ FORCEINLINE OverflowSafeInt& operator <<= (const int shift) { this->m_value <<= shift; return *this; }
+ FORCEINLINE OverflowSafeInt operator << (const int shift) const { OverflowSafeInt result = *this; result <<= shift; return result; }
+ FORCEINLINE OverflowSafeInt& operator >>= (const int shift) { this->m_value >>= shift; return *this; }
+ FORCEINLINE OverflowSafeInt operator >> (const int shift) const { OverflowSafeInt result = *this; result >>= shift; return result; }
+
+ /* Operators for (in)equality when comparing overflow safe ints */
+ FORCEINLINE bool operator == (const OverflowSafeInt& other) const { return this->m_value == other.m_value; }
+ FORCEINLINE bool operator != (const OverflowSafeInt& other) const { return !(*this == other); }
+ FORCEINLINE bool operator > (const OverflowSafeInt& other) const { return this->m_value > other.m_value; }
+ FORCEINLINE bool operator >= (const OverflowSafeInt& other) const { return this->m_value >= other.m_value; }
+ FORCEINLINE bool operator < (const OverflowSafeInt& other) const { return !(*this >= other); }
+ FORCEINLINE bool operator <= (const OverflowSafeInt& other) const { return !(*this > other); }
+
+ /* Operators for (in)equality when comparing non-overflow safe ints */
+ FORCEINLINE bool operator == (const int other) const { return this->m_value == other; }
+ FORCEINLINE bool operator != (const int other) const { return !(*this == other); }
+ FORCEINLINE bool operator > (const int other) const { return this->m_value > other; }
+ FORCEINLINE bool operator >= (const int other) const { return this->m_value >= other; }
+ FORCEINLINE bool operator < (const int other) const { return !(*this >= other); }
+ FORCEINLINE bool operator <= (const int other) const { return !(*this > other); }
+
+ FORCEINLINE operator int64 () const { return this->m_value; }
+};
+
+/* Sometimes we got int64 operator OverflowSafeInt instead of vice versa. Handle that properly */
+template <class T, int64 T_MAX, int64 T_MIN> FORCEINLINE OverflowSafeInt<T, T_MAX, T_MIN> operator + (int64 a, OverflowSafeInt<T, T_MAX, T_MIN> b) { return b + a; }
+template <class T, int64 T_MAX, int64 T_MIN> FORCEINLINE OverflowSafeInt<T, T_MAX, T_MIN> operator - (int64 a, OverflowSafeInt<T, T_MAX, T_MIN> b) { return -b + a; }
+template <class T, int64 T_MAX, int64 T_MIN> FORCEINLINE OverflowSafeInt<T, T_MAX, T_MIN> operator * (int64 a, OverflowSafeInt<T, T_MAX, T_MIN> b) { return b * a; }
+template <class T, int64 T_MAX, int64 T_MIN> FORCEINLINE OverflowSafeInt<T, T_MAX, T_MIN> operator / (int64 a, OverflowSafeInt<T, T_MAX, T_MIN> b) { return (OverflowSafeInt<T, T_MAX, T_MIN>)a / (int)b; }
+
+/* Sometimes we got int operator OverflowSafeInt instead of vice versa. Handle that properly */
+template <class T, int64 T_MAX, int64 T_MIN> FORCEINLINE OverflowSafeInt<T, T_MAX, T_MIN> operator + (int a, OverflowSafeInt<T, T_MAX, T_MIN> b) { return b + a; }
+template <class T, int64 T_MAX, int64 T_MIN> FORCEINLINE OverflowSafeInt<T, T_MAX, T_MIN> operator - (int a, OverflowSafeInt<T, T_MAX, T_MIN> b) { return -b + a; }
+template <class T, int64 T_MAX, int64 T_MIN> FORCEINLINE OverflowSafeInt<T, T_MAX, T_MIN> operator * (int a, OverflowSafeInt<T, T_MAX, T_MIN> b) { return b * a; }
+template <class T, int64 T_MAX, int64 T_MIN> FORCEINLINE OverflowSafeInt<T, T_MAX, T_MIN> operator / (int a, OverflowSafeInt<T, T_MAX, T_MIN> b) { return (OverflowSafeInt<T, T_MAX, T_MIN>)a / (int)b; }
+
+/* Sometimes we got uint operator OverflowSafeInt instead of vice versa. Handle that properly */
+template <class T, int64 T_MAX, int64 T_MIN> FORCEINLINE OverflowSafeInt<T, T_MAX, T_MIN> operator + (uint a, OverflowSafeInt<T, T_MAX, T_MIN> b) { return b + a; }
+template <class T, int64 T_MAX, int64 T_MIN> FORCEINLINE OverflowSafeInt<T, T_MAX, T_MIN> operator - (uint a, OverflowSafeInt<T, T_MAX, T_MIN> b) { return -b + a; }
+template <class T, int64 T_MAX, int64 T_MIN> FORCEINLINE OverflowSafeInt<T, T_MAX, T_MIN> operator * (uint a, OverflowSafeInt<T, T_MAX, T_MIN> b) { return b * a; }
+template <class T, int64 T_MAX, int64 T_MIN> FORCEINLINE OverflowSafeInt<T, T_MAX, T_MIN> operator / (uint a, OverflowSafeInt<T, T_MAX, T_MIN> b) { return (OverflowSafeInt<T, T_MAX, T_MIN>)a / (int)b; }
+
+/* Sometimes we got byte operator OverflowSafeInt instead of vice versa. Handle that properly */
+template <class T, int64 T_MAX, int64 T_MIN> FORCEINLINE OverflowSafeInt<T, T_MAX, T_MIN> operator + (byte a, OverflowSafeInt<T, T_MAX, T_MIN> b) { return b + a; }
+template <class T, int64 T_MAX, int64 T_MIN> FORCEINLINE OverflowSafeInt<T, T_MAX, T_MIN> operator - (byte a, OverflowSafeInt<T, T_MAX, T_MIN> b) { return -b + a; }
+template <class T, int64 T_MAX, int64 T_MIN> FORCEINLINE OverflowSafeInt<T, T_MAX, T_MIN> operator * (byte a, OverflowSafeInt<T, T_MAX, T_MIN> b) { return b * a; }
+template <class T, int64 T_MAX, int64 T_MIN> FORCEINLINE OverflowSafeInt<T, T_MAX, T_MIN> operator / (byte a, OverflowSafeInt<T, T_MAX, T_MIN> b) { return (OverflowSafeInt<T, T_MAX, T_MIN>)a / (int)b; }
+
+typedef OverflowSafeInt<int64, INT64_MAX, INT64_MIN> OverflowSafeInt64;
+
+#endif /* OVERFLOWSAFE_TYPE_HPP */