#include <stdint.h>
#include <stdlib.h>
#include <stdio.h>

#include "nirvana_murmurhash.h"

unsigned int murmurhash2(const void * key, int len, const unsigned int seed)
{
	// 'm' and 'r' are mixing constants generated offline.
	// They're not really 'magic', they just happen to work well.

	const unsigned int m = 0x5bd1e995;
	const int r = 24;

	// Initialize the hash to a 'random' value

	unsigned int h = seed ^ len;

	// Mix 4 bytes at a time into the hash

	const unsigned char * data = (const unsigned char *)key;

	while(len >= 4)
	{
		unsigned int k = *(unsigned int *)data;

		k *= m;
		k ^= k >> r;
		k *= m;

		h *= m;
		h ^= k;

		data += 4;
		len -= 4;
	}

	// Handle the last few bytes of the input array

	switch(len)
	{
		case 3: h ^= data[2] << 16;
		case 2: h ^= data[1] << 8;
		case 1: h ^= data[0];
		        h *= m;
		default:break;
	};

	// Do a few final mixes of the hash to ensure the last few
	// bytes are well-incorporated.

	h ^= h >> 13;
	h *= m;
	h ^= h >> 15;
	return h;
}

/*64-bit hash for 64-bit platforms*/
u_int64_t MurmurHash64A(const void * key, int len, unsigned int seed)
{
	const uint64_t m = 0xc6a4a7935bd1e995;
	const int r = 47;
	uint64_t k, h = seed ^ (len * m);
	const uint64_t * data = (const uint64_t *)key;
	const uint64_t * end = data + (len/8);

	while (data != end)
	{
		k = *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 ^= uint64_t(data2[6]) << 48;
		case 6: h ^= uint64_t(data2[5]) << 40;
		case 5: h ^= uint64_t(data2[4]) << 32;
		case 4: h ^= uint64_t(data2[3]) << 24;
		case 3: h ^= uint64_t(data2[2]) << 16;
		case 2: h ^= uint64_t(data2[1]) << 8;
		case 1: h ^= uint64_t(data2[0]);
		h *= m;
	};

	h ^= h >> r;
	h *= m;
	h ^= h >> r;

	return h;
}