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 |
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 | |