78 lines
1.7 KiB
C
78 lines
1.7 KiB
C
/*
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Hashing
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*/
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#include <stdlib.h>
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#include <stdio.h>
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#include <math.h>
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#include "dtypes.h"
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#include "utils.h"
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#include "hashing.h"
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#include "timefuncs.h"
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#include "ios.h"
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#include "random.h"
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uint_t nextipow2(uint_t i)
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{
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if (i==0) return 1;
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if ((i&(i-1))==0) return i;
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if (i&TOP_BIT) return TOP_BIT;
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// repeatedly clear bottom bit
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while (i&(i-1))
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i = i&(i-1);
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return i<<1;
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}
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u_int32_t int32hash(u_int32_t a)
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{
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a = (a+0x7ed55d16) + (a<<12);
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a = (a^0xc761c23c) ^ (a>>19);
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a = (a+0x165667b1) + (a<<5);
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a = (a+0xd3a2646c) ^ (a<<9);
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a = (a+0xfd7046c5) + (a<<3);
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a = (a^0xb55a4f09) ^ (a>>16);
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return a;
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}
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u_int64_t int64hash(u_int64_t key)
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{
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key = (~key) + (key << 21); // key = (key << 21) - key - 1;
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key = key ^ (key >> 24);
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key = (key + (key << 3)) + (key << 8); // key * 265
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key = key ^ (key >> 14);
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key = (key + (key << 2)) + (key << 4); // key * 21
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key = key ^ (key >> 28);
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key = key + (key << 31);
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return key;
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}
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u_int32_t int64to32hash(u_int64_t key)
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{
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key = (~key) + (key << 18); // key = (key << 18) - key - 1;
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key = key ^ (key >> 31);
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key = key * 21; // key = (key + (key << 2)) + (key << 4);
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key = key ^ (key >> 11);
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key = key + (key << 6);
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key = key ^ (key >> 22);
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return (u_int32_t)key;
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}
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#include "lookup3.c"
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u_int64_t memhash(const char* buf, size_t n)
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{
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u_int32_t c=0xcafe8881, b=0x4d6a087c;
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hashlittle2(buf, n, &c, &b);
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return (u_int64_t)c | (((u_int64_t)b)<<32);
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}
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u_int32_t memhash32(const char* buf, size_t n)
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{
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u_int32_t c=0xcafe8881, b=0x4d6a087c;
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hashlittle2(buf, n, &c, &b);
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return c;
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}
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