update RNG and uniform distribution (#391)

DUEL_OLD_REPLAY
The duel created by old replay files.
It will use the original almost-uniform distribution.

Random Number Generator
C++11 has a built-in std::mersenne_twister_engine()
It can be replaced by std::mt19937.

class mt19937
rand()
mersenne_twister_engine std:mt19937

get_random_integer()
uniform_int_distribution based on std::mt19937

shuffle_vector()
Fisher–Yates shuffle based on get_random_integer()

* update RNG and uniform distribution

* add class mt19937

* typos

* avoid windows macro

* fix rand()

common.h

@@ -218,14 +218,14 @@ struct card_sort {
 #define QUERY_LINK			0x800000
 
 //Link markers
-#define LINK_MARKER_BOTTOM_LEFT		0001
-#define LINK_MARKER_BOTTOM			0002
-#define LINK_MARKER_BOTTOM_RIGHT	0004
-#define LINK_MARKER_LEFT			0010
-#define LINK_MARKER_RIGHT			0040
-#define LINK_MARKER_TOP_LEFT		0100
-#define LINK_MARKER_TOP				0200
-#define LINK_MARKER_TOP_RIGHT		0400
+#define LINK_MARKER_BOTTOM_LEFT		0x001
+#define LINK_MARKER_BOTTOM			0x002
+#define LINK_MARKER_BOTTOM_RIGHT	0x004
+#define LINK_MARKER_LEFT			0x008
+#define LINK_MARKER_RIGHT			0x020
+#define LINK_MARKER_TOP_LEFT		0x040
+#define LINK_MARKER_TOP				0x080
+#define LINK_MARKER_TOP_RIGHT		0x100
 
 //Messages
 #define MSG_RETRY				1
@@ -385,7 +385,7 @@ struct card_sort {
 //Options
 #define DUEL_TEST_MODE			0x01
 #define DUEL_ATTACK_FIRST_TURN	0x02
-//#define DUEL_NO_CHAIN_HINT		0x04
+#define DUEL_OLD_REPLAY			0x04
 #define DUEL_OBSOLETE_RULING	0x08
 #define DUEL_PSEUDO_SHUFFLE		0x10
 #define DUEL_TAG_MODE			0x20

duel.cpp

@@ -139,5 +139,10 @@ void duel::set_responseb(byte* resp) {
 	std::memcpy(game_field->returns.bvalue, resp, 64);
 }
 int32 duel::get_next_integer(int32 l, int32 h) {
-	return (int32) (random.real() * (h - l + 1)) + l;
+	if (game_field->core.duel_options & DUEL_OLD_REPLAY) {
+		return random.get_random_integer_old(l, h);
+	}
+	else {
+		return random.get_random_integer(l, h);
+	}
 }

duel.h

@@ -28,7 +28,7 @@ public:
 	byte* bufferp;
 	interpreter* lua;
 	field* game_field;
-	mtrandom random;
+	mt19937 random;
 	std::unordered_set<card*> cards;
 	std::unordered_set<card*> assumes;
 	std::unordered_set<group*> groups;

field.cpp

@@ -950,13 +950,10 @@ void field::shuffle(uint8 playerid, uint8 location) {
 		if(location == LOCATION_EXTRA)
 			s = s - player[playerid].extra_p_count;
 		if(s > 1) {
-			uint32 i = 0, r;
-			for(i = 0; i < s - 1; ++i) {
-				r = pduel->get_next_integer(i, s - 1);
-				card* t = svector[i];
-				svector[i] = svector[r];
-				svector[r] = t;
-			}
+			if (core.duel_options & DUEL_OLD_REPLAY)
+				pduel->random.shuffle_vector_old(svector);
+			else
+				pduel->random.shuffle_vector(svector);
 			reset_sequence(playerid, location);
 		}
 	}

mtrandom.h

@@ -8,6 +8,63 @@
 #ifndef MTRANDOM_H_
 #define MTRANDOM_H_
 
+#include <random>
+
+class mt19937 {
+public:
+	mt19937() :
+		rng(), rand_max((rng.max)()) {}
+	explicit mt19937(unsigned int seed) :
+		rng(seed), rand_max((rng.max)()) {}
+
+	// mersenne_twister_engine
+	void reset(unsigned int seed) {
+		rng.seed(seed);
+	}
+	unsigned int rand() {
+		return rng();
+	}
+
+	// uniform_int_distribution
+	int get_random_integer(int l, int h) {
+		unsigned int range = (unsigned int)(h - l + 1);
+		unsigned int secureMax = rand_max - rand_max % range;
+		unsigned int x;
+		do {
+			x = rng();
+		} while (x >= secureMax);
+		return (int)(l + x % range);
+	}
+	int get_random_integer_old(int l, int h) {
+		int result = (int)((double)rng() / rand_max * (h - l + 1)) + l;
+		if (result > h)
+			result = h;
+		return result;
+	}
+	
+	// Fisher-Yates shuffle
+	template<typename T>
+	void shuffle_vector(std::vector<T>& v) {
+		int n = (int)v.size();
+		for (int i = 0; i < n - 1; ++i) {
+			int r = get_random_integer(i, n - 1);
+			std::swap(v[i], v[r]);
+		}
+	}
+	template<typename T>
+	void shuffle_vector_old(std::vector<T>& v) {
+		int n = (int)v.size();
+		for (int i = 0; i < n - 1; ++i) {
+			int r = get_random_integer_old(i, n - 1);
+			std::swap(v[i], v[r]);
+		}
+	}
+
+private:
+	std::mt19937 rng;
+	const unsigned int rand_max;
+};
+
 //Mersenne Twister
 class mtrandom {
 public: