81 lines
1.7 KiB
C
81 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)
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return 1;
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if ((i & (i - 1)) == 0)
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return i;
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if (i & TOP_BIT)
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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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