1 /*
2 Copyright (C) 1990, 2000, 2002 Free Software Foundation
3 written by Doug Lea <dl@rocky.oswego.edu>
4 */
5
6 #include <hash.h>
7
8 /*
9 Some useful hash function.
10 It's not a particularly good hash function (<< 5 would be better than << 4),
11 but people believe in it because it comes from Dragon book.
12 */
13
14 unsigned int
hashpjw(const unsigned char * x,unsigned int len)15 hashpjw (const unsigned char *x, unsigned int len) // From Dragon book, p436
16 {
17 unsigned int h = 0;
18 unsigned int g;
19
20 for (; len > 0; len--)
21 {
22 h = (h << 4) + *x++;
23 if ((g = h & 0xf0000000) != 0)
24 h = (h ^ (g >> 24)) ^ g;
25 }
26 return h;
27 }
28