(svn r12004) -Codechange: refactor the random functions to reduce code duplication.

2 files changed, 53 insertions, 32 deletions

diff --git a/src/core/random_func.cpp b/src/core/random_func.cpp
index b0939229e..f74309a6e 100644
--- a/src/core/random_func.cpp
+++ b/src/core/random_func.cpp
@@ -6,20 +6,26 @@
 #include "random_func.hpp"
 #include "bitmath_func.hpp"
 
-uint32 _random_seeds[2][2];
+Randomizer _random, _interactive_random;
 
-uint32 InteractiveRandom()
+uint32 Randomizer::Next()
 {
-	const uint32 s = _random_seeds[1][0];
-	const uint32 t = _random_seeds[1][1];
+	const uint32 s = this->state[0];
+	const uint32 t = this->state[1];
 
-	_random_seeds[1][0] = s + ROR(t ^ 0x1234567F, 7) + 1;
-	return _random_seeds[1][1] = ROR(s, 3) - 1;
+	this->state[0] = s + ROR(t ^ 0x1234567F, 7) + 1;
+	return this->state[1] = ROR(s, 3) - 1;
 }
 
-uint InteractiveRandomRange(uint max)
+uint32 Randomizer::Next(uint16 max)
 {
-	return GB(InteractiveRandom(), 0, 16) * max >> 16;
+	return GB(this->Next(), 0, 16) * max >> 16;
+}
+
+void Randomizer::SetSeed(uint32 seed)
+{
+	this->state[0] = seed;
+	this->state[1] = seed;
 }
 
 #ifdef MERSENNE_TWISTER
@@ -119,28 +125,21 @@ uint32 Random()
 #else /* MERSENNE_TWISTER */
 void SetRandomSeed(uint32 seed)
 {
-	_random_seeds[0][0] = seed;
-	_random_seeds[0][1] = seed;
-	_random_seeds[1][0] = seed * 0x1234567;
-	_random_seeds[1][1] = _random_seeds[1][0];
+	_random.SetSeed(seed);
+	_interactive_random.SetSeed(seed * 0x1234567);
 }
 
 #ifdef RANDOM_DEBUG
 #include "../network/network_data.h"
 uint32 DoRandom(int line, const char *file)
 {
-	if (_networking && (DEREF_CLIENT(0)->status != STATUS_INACTIVE || !_network_server))
+	if (_networking && (DEREF_CLIENT(0)->status != STATUS_INACTIVE || !_network_server)) {
 		printf("Random [%d/%d] %s:%d\n",_frame_counter, (byte)_current_player, file, line);
-#else /* RANDOM_DEBUG */
-uint32 Random()
-{
-#endif /* RANDOM_DEBUG */
-	const uint32 s = _random_seeds[0][0];
-	const uint32 t = _random_seeds[0][1];
+	}
 
-	_random_seeds[0][0] = s + ROR(t ^ 0x1234567F, 7) + 1;
-	return _random_seeds[0][1] = ROR(s, 3) - 1;
+	return _random->Next()
 }
+#endif /* RANDOM_DEBUG */
 #endif /* MERSENNE_TWISTER */
 
 #if defined(RANDOM_DEBUG) && !defined(MERSENNE_TWISTER)
@@ -148,9 +147,4 @@ uint DoRandomRange(uint max, int line, const char *file)
 {
 	return GB(DoRandom(line, file), 0, 16) * max >> 16;
 }
-#else /* RANDOM_DEBUG & !MERSENNE_TWISTER */
-uint RandomRange(uint max)
-{
-	return GB(Random(), 0, 16) * max >> 16;
-}
 #endif /* RANDOM_DEBUG & !MERSENNE_TWISTER */
diff --git a/src/core/random_func.hpp b/src/core/random_func.hpp
index f3d35d987..d941f283c 100644
--- a/src/core/random_func.hpp
+++ b/src/core/random_func.hpp
@@ -27,6 +27,35 @@
 // Doesn't work with network yet.
 // #define MERSENNE_TWISTER
 
+/**
+ * Structure to encapsulate the pseudo random number generators.
+ */
+struct Randomizer {
+	/** The state of the randomizer */
+	uint32 state[2];
+
+	/**
+	 * Generate the next pseudo random number
+	 * @return the random number
+	 */
+	uint32 Next();
+
+	/**
+	 * Generate the next pseudo random number scaled to max
+	 * @param max the maximum value of the returned random number
+	 * @return the random number
+	 */
+	uint32 Next(uint16 max);
+
+	/**
+	 * (Re)set the state of the random number generator.
+	 * @param seed the new state
+	 */
+	void SetSeed(uint32 seed);
+};
+extern Randomizer _random; ///< Random used in the game state calculations
+extern Randomizer _interactive_random; ///< Random used every else where is does not (directly) influence the game state
+
 void SetRandomSeed(uint32 seed);
 #ifdef RANDOM_DEBUG
 	#define Random() DoRandom(__LINE__, __FILE__)
@@ -34,12 +63,12 @@ void SetRandomSeed(uint32 seed);
 	#define RandomRange(max) DoRandomRange(max, __LINE__, __FILE__)
 	uint DoRandomRange(uint max, int line, const char *file);
 #else
-	uint32 Random();
-	uint RandomRange(uint max);
+	static inline uint32 Random() { return _random.Next(); }
+	static inline uint32 RandomRange(uint16 max) { return _random.Next(max); }
 #endif
 
-uint32 InteractiveRandom(); // Used for random sequences that are not the same on the other end of the multiplayer link
-uint InteractiveRandomRange(uint max);
+static inline uint32 InteractiveRandom() { return _interactive_random.Next(); }
+static inline uint32 InteractiveRandomRange(uint16 max) { return _interactive_random.Next(max); }
 
 /**
  * Checks if a given randomize-number is below a given probability.
@@ -100,6 +129,4 @@ static inline bool Chance16R(const uint a, const uint b, uint32 &r)
 	return Chance16I(a, b, r);
 }
 
-extern uint32 _random_seeds[2][2];
-
 #endif /* RANDOM_FUNC_HPP */