ref: 1c35aa34f2b5b603beb8242861722293988d0ff2
dir: /llt/ptrhash.c/
/*
pointer hash table
optimized for storing info about particular values
*/
#ifdef __plan9__
#include <u.h>
#include <libc.h>
#else
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <assert.h>
#include <limits.h>
#endif
#include "dtypes.h"
#include "ptrhash.h"
#define OP_EQ(x,y) ((x)==(y))
#ifdef BITS64
static u_int64_t _pinthash(u_int64_t key)
{
key = (~key) + (key << 21); // key = (key << 21) - key - 1;
key = key ^ (key >> 24);
key = (key + (key << 3)) + (key << 8); // key * 265
key = key ^ (key >> 14);
key = (key + (key << 2)) + (key << 4); // key * 21
key = key ^ (key >> 28);
key = key + (key << 31);
return key;
}
#else
static u_int32_t _pinthash(u_int32_t a)
{
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;
}
#endif
#include "htable.inc"
HTIMPL(ptrhash, _pinthash, OP_EQ)