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/*
* LIB/HASH.C
*
* (c)Copyright 1997, Matthew Dillon, All Rights Reserved. Refer to
* the COPYRIGHT file in the base directory of this distribution
* for specific rights granted.
*
* CRC hash generator
*/
#include "defs.h"
Prototype hash_t hhash(const char *msgid);
Prototype void bhash(hash_t *h, const char *p, int len);
Prototype const char *GFName(const char *group, const char *prefix, int artBase);
#define P1 7834891
#define P2 6017489
#define HINIT1 0xFAC432B1
#define HINIT2 0x0CD5E44A
#define POLY1 0x00600340UL
#define POLY2 0x00F0D50BUL
#define OPOLY2 0x00F0D50AUL
hash_t CrcXor[3][256];
int DidCrcInit;
void
crcinit(int method)
{
int i;
for (i = 0; i < 256; ++i) {
int j;
int v = i;
hash_t hv = { 0, 0 };
for (j = 0; j < 8; ++j, (v <<= 1)) {
if (v & 0x80) {
hv.h1 ^= POLY1;
hv.h2 ^= (method == HASH_CRC) ? POLY2 : OPOLY2;
}
hv.h2 = (hv.h2 << 1);
if (hv.h1 & 0x80000000)
hv.h2 |= 1;
hv.h1 <<= 1;
}
CrcXor[method][i] = hv;
}
DidCrcInit = 1;
}
hash_t
hhash(const char *msgid)
{
hash_t t;
if (DiabloHashMethod == HASH_CRC || DiabloHashMethod == HASH_OCRC) {
/*
* HASH_CRC - CRC64
*/
if (DidCrcInit == 0) {
crcinit(HASH_CRC);
crcinit(HASH_OCRC);
}
t.h1 = HINIT1;
t.h2 = HINIT2;
while (*msgid) {
int i = (t.h1 >> 24) & 255;
t.h1 = (t.h1 << 8) ^ (int)((uint32)t.h2 >> 24) ^ CrcXor[DiabloHashMethod][i].h1;
t.h2 = (t.h2 << 8) ^ (uint8)*msgid ^ CrcXor[DiabloHashMethod][i].h2;
++msgid;
}
if (t.h1 & 0x80000000)
t.h1 = (t.h1 & 0x7FFFFFFF) | 1;
if (t.h2 & 0x80000000)
t.h2 = (t.h2 & 0x7FFFFFFF) | 1;
t.h1 |= 0x80000000; /* indicate CRC64 hash */
} else {
/*
* HASH_PRIME
*/
int h1 = 0x0034629D;
int h2 = 0x007395DD;
int hv = 0x1A3F5C4F;
while (*msgid) {
h1 = h1 * *(const unsigned char *)msgid % P1;
h2 = h2 * *(const unsigned char *)msgid % P2;
hv = (hv << 5) ^ *(const unsigned char *)msgid ^ (hv >> 23);
++msgid;
}
t.h1 = (h1 ^ (hv << 14)) & 0x7FFFFFFF; /* bit 31 reserved */
t.h2 = (h2 ^ (hv << 20)) & 0x7FFFFFFF; /* bit 31 reserved */
}
return(t);
}
/*
* Slightly different and faster hash algorithm to handle message bodies.
* This is simpler.
*/
void
bhash(hash_t *h, const char *p, int len)
{
while (len) {
h->h1 += *(unsigned char *)p; /* simple checksum */
h->h2 = (h->h2 << 5) ^ h->h1 ^ (h->h2 >> 27);
++p;
--len;
}
}
const char *
GFName(const char *group, const char *prefix, int artBase)
{
hash_t hv = hhash(group);
static char GFBuf[64];
snprintf(GFBuf, sizeof(GFBuf), "%02lx/%s.%d.%08lx.%08lx",
(long)(uint8)hv.h1,
prefix,
artBase,
(long)hv.h1,
(long)hv.h2
);
return(GFBuf);
}
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