(svn r11490) -Codechange: Split the math functions to their own header

-Codechange: Replace the rest of the math macros with functions

1 files changed, 229 insertions, 0 deletions

diff --git a/src/core/math_func.hpp b/src/core/math_func.hpp
new file mode 100644
index 000000000..b47b06482
--- /dev/null
+++ b/src/core/math_func.hpp
@@ -0,0 +1,229 @@
+/* $Id */
+
+/** @file math_func.hpp */
+
+#ifndef MATH_FUNC_HPP
+#define MATH_FUNC_HPP
+
+#ifdef min
+#undef min
+#endif
+
+#ifdef max
+#undef max
+#endif
+
+#ifdef abs
+#undef abs
+#endif
+
+/**
+ * Returns the maximum of two values.
+ *
+ * This function returns the greater value of two given values.
+ * If they are equal the value of a is returned.
+ *
+ * @param a The first value
+ * @param b The second value
+ * @return The greater value or a if equals
+ */
+template<typename T> static inline T max(const T a, const T b)
+{
+	return (a >= b) ? a : b;
+}
+
+/**
+ * Returns the minimum of two values.
+ *
+ * This function returns the smaller value of two given values.
+ * If they are equal the value of b is returned.
+ *
+ * @param a The first value
+ * @param b The second value
+ * @return The smaller value or b if equals
+ */
+template<typename T> static inline T min(const T a, const T b)
+{
+	return (a < b) ? a : b;
+}
+
+/**
+ * Returns the minimum of two integer.
+ *
+ * This function returns the smaller value of two given integers.
+ *
+ * @param a The first integer
+ * @param b The second integer
+ * @return The smaller value
+ */
+static inline int min(const int a, const int b)
+{
+	return (a < b) ? a : b;
+}
+
+/**
+ * Returns the minimum of two unsigned integers.
+ *
+ * This function returns the smaller value of two given unsigned integers.
+ *
+ * @param a The first unsigned integer
+ * @param b The second unsigned integer
+ * @return The smaller value
+ */
+static inline uint minu(const uint a, const uint b)
+{
+	return (a < b) ? a : b;
+}
+
+/**
+ * Returns the absolute value of (scalar) variable.
+ *
+ * @note assumes variable to be signed
+ * @param a The value we want to unsign
+ * @return The unsigned value
+ */
+template <typename T> static inline T abs(T a)
+{
+	return (a < (T)0) ? -a : a;
+}
+
+/**
+ * Return the smallest multiple of n equal or greater than x
+ *
+ * @note n must be a power of 2
+ * @param x The min value
+ * @param n The base of the number we are searching
+ * @return The smallest multiple of n equal or greater than x
+ */
+template<typename T> static inline T Align(const T x, uint n)
+{
+	n--;
+	return (T)((x + n) & ~(n));
+}
+
+/**
+ * Clamp an integer between an interval.
+ *
+ * This function returns a value which is between the given interval of
+ * min and max. If the given value is in this interval the value itself
+ * is returned otherwise the border of the interval is returned, according
+ * which side of the interval was 'left'.
+ *
+ * @note The min value must be less or equal of max or you get some
+ *       unexpected results.
+ * @param a The value to clamp/truncate.
+ * @param min The minimum of the interval.
+ * @param max the maximum of the interval.
+ * @returns A value between min and max which is closest to a.
+ * @see ClampU(uint, uint, uint)
+ */
+static inline int Clamp(const int a, const int min, const int max)
+{
+	if (a <= min) return min;
+	if (a >= max) return max;
+	return a;
+}
+
+/**
+ * Clamp an unsigned integer between an interval.
+ *
+ * This function returns a value which is between the given interval of
+ * min and max. If the given value is in this interval the value itself
+ * is returned otherwise the border of the interval is returned, according
+ * which side of the interval was 'left'.
+ *
+ * @note The min value must be less or equal of max or you get some
+ *       unexpected results.
+ * @param a The value to clamp/truncate.
+ * @param min The minimum of the interval.
+ * @param max the maximum of the interval.
+ * @returns A value between min and max which is closest to a.
+ * @see Clamp(int, int, int)
+ */
+static inline uint ClampU(const uint a, const uint min, const uint max)
+{
+	if (a <= min) return min;
+	if (a >= max) return max;
+	return a;
+}
+
+/**
+ * Reduce a signed 64-bit int to a signed 32-bit one
+ *
+ * This function clamps a 64-bit integer to a 32-bit integer.
+ * If the 64-bit value is smaller than the smallest 32-bit integer
+ * value 0x80000000 this value is returned (the left one bit is the sign bit).
+ * If the 64-bit value is greater than the greatest 32-bit integer value 0x7FFFFFFF
+ * this value is returned. In all other cases the 64-bit value 'fits' in a
+ * 32-bits integer field and so the value is casted to int32 and returned.
+ *
+ * @param a The 64-bit value to clamps
+ * @return The 64-bit value reduced to a 32-bit value
+ * @see Clamp(int, int, int)
+ */
+static inline int32 ClampToI32(const int64 a)
+{
+	if (a <= (int32)0x80000000) return 0x80000000;
+	if (a >= (int32)0x7FFFFFFF) return 0x7FFFFFFF;
+	return (int32)a;
+}
+
+/**
+ * Returns the (absolute) difference between two (scalar) variables
+ *
+ * @param a The first scalar
+ * @param b The second scalar
+ * @return The absolute difference between the given scalars
+ */
+template <typename T> static inline T delta(const T a, const T b) {
+	return (a < b) ? b - a : a - b;
+}
+
+/**
+ * Checks if a value is between a window started at some base point.
+ *
+ * This function checks if the value x is between the value of base
+ * and base+size. If x equals base this returns true. If x equals
+ * base+size this returns false.
+ *
+ * @param x The value to check
+ * @param base The base value of the interval
+ * @param size The size of the interval
+ * @return True if the value is in the interval, false else.
+ */
+template<typename T> static inline bool IS_INSIDE_1D(const T x, const int base, const uint size)
+{
+	return (uint)(x - base) < size;
+}
+
+/**
+ * Checks if a byte is in an interval.
+ *
+ * Returns true if a byte value is in the interval of [min, max).
+ *
+ * @param a The byte value to check
+ * @param min The minimum of the interval
+ * @param max The maximum of the interval
+ * @see IS_INSIDE_1D
+ */
+template<typename T> static inline bool IS_BYTE_INSIDE(const T x, const byte min, const byte max)
+{
+	return (byte)(x - min) < (max - min);
+}
+
+/**
+ * Checks if an int is in an interval.
+ *
+ * Returns true if a integer value is in the interval of [min, max).
+ *
+ * @param a The integer value to check
+ * @param min The minimum of the interval
+ * @param max The maximum of the interval
+ * @see IS_INSIDE_1D
+ */
+template<typename T> static inline bool IS_INT_INSIDE(const T x, const int min, const uint max)
+{
+	return (uint)(x - min) < (max - min);
+}
+
+#endif /* MATH_FUNC_HPP */