femtolisp/llt/hashing.c

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/*
Hashing
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*/
#include <stdlib.h>
#include <stdio.h>
#include <math.h>
#include "ieee754.h"
#include "dtypes.h"
#include "utils.h"
#include "hashing.h"
#include "timefuncs.h"
#include "ios.h"
#include "random.h"
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uint_t nextipow2(uint_t i)
{
if (i==0) return 1;
if ((i&(i-1))==0) return i;
if (i&TOP_BIT) return TOP_BIT;
// repeatedly clear bottom bit
while (i&(i-1))
i = i&(i-1);
return i<<1;
}
u_int32_t int32hash(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;
}
u_int64_t int64hash(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;
}
u_int32_t int64to32hash(u_int64_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 (u_int32_t)key;
}
#include "lookup3.c"
u_int64_t memhash(char* buf, size_t n)
{
u_int32_t c=0xcafe8881, b=0x4d6a087c;
hashlittle2(buf, n, &c, &b);
return (u_int64_t)c | (((u_int64_t)b)<<32);
}
u_int32_t memhash32(char* buf, size_t n)
{
u_int32_t c=0xcafe8881, b=0x4d6a087c;
hashlittle2(buf, n, &c, &b);
return c;
}
double D_PNAN;
double D_NNAN;
double D_PINF;
double D_NINF;
float F_PNAN;
float F_NNAN;
float F_PINF;
float F_NINF;
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void llt_init()
{
randomize();
ios_init_stdstreams();
D_PNAN = strtod("+NaN",NULL);
D_NNAN = -strtod("+NaN",NULL);
D_PINF = strtod("+Inf",NULL);
D_NINF = strtod("-Inf",NULL);
F_PNAN = strtof("+NaN",NULL);
F_NNAN = -strtof("+NaN",NULL);
F_PINF = strtof("+Inf",NULL);
F_NINF = strtof("-Inf",NULL);
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}