97 lines
		
	
	
		
			2.0 KiB
		
	
	
	
		
			C
		
	
	
	
			
		
		
	
	
			97 lines
		
	
	
		
			2.0 KiB
		
	
	
	
		
			C
		
	
	
	
| /*
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|   Hashing
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| */
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| 
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| #ifndef WIN32
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| #include <sys/param.h> /* attempt to define endianness */
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| #else
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| typedef unsigned int uint32_t;
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| typedef unsigned char uint8_t;
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| typedef unsigned short uint16_t;
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| #endif
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| 
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| #ifdef LINUX
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| #include <endian.h> /* attempt to define endianness */
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| #endif
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| 
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| #include <math.h>
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| #include <stdarg.h>
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| #include <stdint.h>
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| #include <stdio.h>
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| #include <stdlib.h>
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| 
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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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| 
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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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| 
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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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| 
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|     return i << 1;
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| }
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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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| 
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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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| 
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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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| 
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| #include "lookup3.h"
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| 
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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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| 
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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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| 
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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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| 
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|     hashlittle2(buf, n, &c, &b);
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|     return c;
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| }
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