Accept hexadecimal and string values for seeds

4 files changed, 63 insertions, 0 deletions

diff --git a/src/util/numeric.cpp b/src/util/numeric.cpp
index 67df4ffba..0426656a5 100644
--- a/src/util/numeric.cpp
+++ b/src/util/numeric.cpp
@@ -22,6 +22,7 @@ with this program; if not, write to the Free Software Foundation, Inc.,
 
 #include "../log.h"
 #include "../constants.h" // BS, MAP_BLOCKSIZE
+#include <string.h>
 #include <iostream>
 
 // Calculate the borders of a "d-radius" cube
@@ -139,6 +140,49 @@ int myrand_range(int min, int max)
 	return (myrand()%(max-min+1))+min;
 }
 
+// 64-bit unaligned version of MurmurHash
+u64 murmur_hash_64_ua(const void *key, int len, unsigned int seed)
+{
+	const u64 m = 0xc6a4a7935bd1e995;
+	const int r = 47;
+	u64 h = seed ^ (len * m);
+
+	const u64 *data = (const u64 *)key;
+	const u64 *end = data + (len / 8);
+
+	while (data != end) {
+		u64 k;
+		memcpy(&k, data, sizeof(u64));
+		data++;
+
+		k *= m; 
+		k ^= k >> r; 
+		k *= m; 
+		
+		h ^= k;
+		h *= m; 
+	}
+
+	const unsigned char *data2 = (const unsigned char *)data;
+	switch (len & 7) {
+		case 7: h ^= (u64)data2[6] << 48;
+		case 6: h ^= (u64)data2[5] << 40;
+		case 5: h ^= (u64)data2[4] << 32;
+		case 4: h ^= (u64)data2[3] << 24;
+		case 3: h ^= (u64)data2[2] << 16;
+		case 2: h ^= (u64)data2[1] << 8;
+		case 1: h ^= (u64)data2[0];
+				h *= m;
+	}
+ 
+	h ^= h >> r;
+	h *= m;
+	h ^= h >> r;
+	
+	return h;
+} 
+
+
 /*
 	blockpos: position of block in block coordinates
 	camera_pos: position of camera in nodes
diff --git a/src/util/numeric.h b/src/util/numeric.h
index b96c94faa..8e3a617ff 100644
--- a/src/util/numeric.h
+++ b/src/util/numeric.h
@@ -222,6 +222,8 @@ int myrand_range(int min, int max);
 	Miscellaneous functions
 */
 
+u64 murmur_hash_64_ua(const void *key, int len, unsigned int seed);
+
 bool isBlockInSight(v3s16 blockpos_b, v3f camera_pos, v3f camera_dir,
 		f32 camera_fov, f32 range, f32 *distance_ptr=NULL);
 
diff --git a/src/util/string.cpp b/src/util/string.cpp
index 2c1dea497..a2312baf8 100644
--- a/src/util/string.cpp
+++ b/src/util/string.cpp
@@ -19,6 +19,7 @@ with this program; if not, write to the Free Software Foundation, Inc.,
 
 #include "string.h"
 #include "pointer.h"
+#include "numeric.h"
 
 #include "../sha1.h"
 #include "../base64.h"
@@ -136,3 +137,18 @@ char *mystrtok_r(char *s, const char *sep, char **lasts) {
 	*lasts = t;
 	return s;
 }
+
+u64 read_seed(const char *str) {
+	char *endptr;
+	u64 num;
+	
+	if (str[0] == '0' && str[1] == 'x')
+		num = strtoull(str, &endptr, 16);
+	else
+		num = strtoull(str, &endptr, 10);
+		
+	if (*endptr)
+		num = murmur_hash_64_ua(str, (int)strlen(str), 0x1337);
+		
+	return num;
+}
diff --git a/src/util/string.h b/src/util/string.h
index 7531600e3..81855962f 100644
--- a/src/util/string.h
+++ b/src/util/string.h
@@ -321,6 +321,7 @@ size_t curl_write_data(char *ptr, size_t size, size_t nmemb, void *userdata);
 u32 readFlagString(std::string str, FlagDesc *flagdesc);
 std::string writeFlagString(u32 flags, FlagDesc *flagdesc);
 char *mystrtok_r(char *s, const char *sep, char **lasts);
+u64 read_seed(const char *str);
 
 #endif