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provide Hash_Buffer so buffers can be hashed

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This commit is contained in:
Bill Currie 2002-10-20 03:30:22 +00:00
parent 7bb6dd7197
commit b345f510fa
2 changed files with 32 additions and 0 deletions
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5
include/QF/hash.h
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@ -124,6 +124,11 @@ void *Hash_DelElement (hashtab_t *tab, void *ele);
*/ */
unsigned long Hash_String (const char *str); unsigned long Hash_String (const char *str);
/*
returh the hash value of a buffer.
*/
unsigned long Hash_Buffer (const void *buf, int len);
/* /*
return a list of all elements in the table. it is the caller's return a list of all elements in the table. it is the caller's
responsibilty to free() the array. Null terminated. responsibilty to free() the array. Null terminated.

27
libs/util/hash.c
View file

@ -90,6 +90,33 @@ Hash_String (const char *str)
#endif #endif
} }
unsigned long
Hash_Buffer (const void *_buf, int len)
{
const unsigned char *buf = _buf;
#if 0
unsigned long h = 0;
while (len-- > 0) {
h = (h << 4) + (unsigned char)*buf++;
if (h&0xf0000000)
h = (h ^ (h >> 24)) & 0xfffffff;
}
return h;
#else
// dx_hack_hash
// shamelessly stolen from Daniel Phillips <phillips@innominate.de>
// from his post to lkml
unsigned long hash0 = 0x12a3fe2d, hash1 = 0x37abe8f9;
while (len-- > 0) {
unsigned long hash = hash1 + (hash0 ^ ((unsigned char)*buf++ * 71523));
if (hash < 0) hash -= 0x7fffffff;
hash1 = hash0;
hash0 = hash;
}
return hash0;
#endif
}
static unsigned long static unsigned long
get_hash (void *ele, void *data) get_hash (void *ele, void *data)
{ {