git-svn-id: svn://db.shs.com.ru/pip@840 12ceb7fc-bf1f-11e4-8940-5bc7170c53b5

src_main/core/pibase.h

@@ -30,6 +30,7 @@
 #include "piplatform.h"
 #include "pip_export.h"
 #include "pip_defs.h"
+#include "string.h"
 
 //! Version of PIP in hex - 0x##(Major)##(Minor)##(Revision)
 #define PIP_VERSION ((PIP_VERSION_MAJOR << 16) | (PIP_VERSION_MINOR < 8) | PIP_VERSION_REVISION)
@@ -459,6 +460,46 @@ uint letobe_i(uint v) {return (v >> 24) | ((v >> 8) & 0xFF00) | ((v << 8) & 0xFF
 
 #endif
 
+/// \brief Generic hash function, impements murmur3/32 algorithm
+inline uint piHash(const uchar * data, uint len, uint seed = 0) {
+	if (!data || len <= 0) return 0u;
+	uint h = seed;
+	if (len > 3) {
+		uint i = len >> 2;
+		do {
+			uint k;
+			memcpy(&k, data, sizeof(uint));
+			data += sizeof(uint);
+			k *= 0xcc9e2d51;
+			k = (k << 15) | (k >> 17);
+			k *= 0x1b873593;
+			h ^= k;
+			h = (h << 13) | (h >> 19);
+			h = h * 5 + 0xe6546b64;
+		} while (--i);
+	}
+	if (len & 3) {
+		uint i = len & 3;
+		uint k = 0;
+		do {
+			k <<= 8;
+			k |= data[i - 1];
+		} while (--i);
+		k *= 0xcc9e2d51;
+		k = (k << 15) | (k >> 17);
+		k *= 0x1b873593;
+		h ^= k;
+	}
+	h ^= len;
+	h ^= h >> 16;
+	h *= 0x85ebca6b;
+	h ^= h >> 13;
+	h *= 0xc2b2ae35;
+	h ^= h >> 16;
+	return h;
+}
+
+
 #define piRoundf piRound<float>
 #define piRoundd piRound<double>
 #define piFloorf piFloor<float>