1 /* VTreeFS - sdbm.c - sdbm hash function */ 2 3 /* 4 * sdbm - ndbm work-alike hashed database library 5 * based on Per-Aake Larson's Dynamic Hashing algorithms. BIT 18 (1978). 6 * author: oz@nexus.yorku.ca 7 * status: public domain. keep it that way. 8 * 9 * hashing routine 10 */ 11 12 #include "inc.h" 13 14 /* 15 * polynomial conversion ignoring overflows 16 * [this seems to work remarkably well, in fact better 17 * than the ndbm hash function. Replace at your own risk] 18 * use: 65599 nice. 19 * 65587 even better. 20 */ 21 long 22 sdbm_hash(const char *str, int len) 23 { 24 unsigned long n = 0; 25 26 while (len--) 27 n = *str++ + (n << 6) + (n << 16) - n; 28 29 return n; 30 } 31