shithub: sl

ref: 063bab70488f5abd3d5d975503d9c2e3aef16c05
dir: /src/hashing.c/

#include "flisp.h"
#include "hashing.h"
#include "spooky.h"

value_t
nextipow2(value_t i)
{
	if(i == 0)
		return 1;
	i |= i >> 1;
	i |= i >> 2;
	i |= i >> 4;
	i |= i >> 8;
	i |= i >> 16;
#if defined(BITS64)
	i |= i >> 32;
#endif
	i++;
	return i ? i : TOP_BIT;
}

value_t
inthash(value_t a)
{
#if defined(BITS64)
	a = (~a) + (a << 21); // a = (a << 21) - a - 1;
	a = a ^ (a >> 24);
	a = (a + (a << 3)) + (a << 8); // a * 265
	a = a ^ (a >> 14);
	a = (a + (a << 2)) + (a << 4); // a * 21
	a = a ^ (a >> 28);
	a = a + (a << 31);
	return a;
}
#else
	a = (a+0x7ed55d16) + (a<<12);
	a = (a^0xc761c23c) ^ (a>>19);
	a = (a+0x165667b1) + (a<<5);
	a = (a+0xd3a2646c) ^ (a<<9);
	a = (a+0xfd7046c5) + (a<<3);
	a = (a^0xb55a4f09) ^ (a>>16);
	return a;
}

uint32_t
int64to32hash(uint64_t key)
{
	key = (~key) + (key << 18); // key = (key << 18) - key - 1;
	key = key ^ (key >> 31);
	key = key * 21;			 // key = (key + (key << 2)) + (key << 4);
	key = key ^ (key >> 11);
	key = key + (key << 6);
	key = key ^ (key >> 22);
	return (uint32_t)key;
}
#endif

uint64_t
memhash(const char *buf, size_t n)
{
	return spooky_hash64(buf, n, 0xcafe8881);
}

uint32_t
memhash32(const char *buf, size_t n)
{
	return spooky_hash32(buf, n, 0xcafe8881);
}