mirror of
https://git.FreeBSD.org/src.git
synced 2024-12-17 10:26:15 +00:00
28 lines
585 B
C++
28 lines
585 B
C++
/*
|
|
Copyright (C) 1990, 2000 Free Software Foundation
|
|
written by Doug Lea (dl@rocky.oswego.edu)
|
|
*/
|
|
|
|
#include <hash.h>
|
|
|
|
/*
|
|
Some useful hash function.
|
|
It's not a particularly good hash function (<< 5 would be better than << 4),
|
|
but people believe in it because it comes from Dragon book.
|
|
*/
|
|
|
|
unsigned int
|
|
hashpjw (const char *x, unsigned int len) // From Dragon book, p436
|
|
{
|
|
unsigned int h = 0;
|
|
unsigned int g;
|
|
|
|
for (; len > 0; len--)
|
|
{
|
|
h = (h << 4) + (unsigned char) *x++;
|
|
if ((g = h & 0xf0000000) != 0)
|
|
h = (h ^ (g >> 24)) ^ g;
|
|
}
|
|
return h;
|
|
}
|