hash.cc revision 296373
1/* 2Copyright (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 14unsigned int 15hashpjw (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