Mercurial > hg > octave-nkf > gnulib-hg
changeset 3541:3c24470988a8
*** empty log message ***
author | Jim Meyering <jim@meyering.net> |
---|---|
date | Fri, 05 Oct 2001 11:44:30 +0000 |
parents | 202333c7e30b |
children | 57cdbbe871f5 |
files | lib/hash-pjw.c lib/hash-pjw.h |
diffstat | 2 files changed, 62 insertions(+), 0 deletions(-) [+] |
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new file mode 100644 --- /dev/null +++ b/lib/hash-pjw.c @@ -0,0 +1,42 @@ +/* hash-pjw.c -- compute a hash value from a NUL-terminated string. + Copyright 2001 Free Software Foundation, Inc. + + This program is free software; you can redistribute it and/or modify + it under the terms of the GNU General Public License as published by + the Free Software Foundation; either version 2, or (at your option) + any later version. + + This program is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + GNU General Public License for more details. + + You should have received a copy of the GNU General Public License + along with this program; if not, write to the Free Software Foundation, + Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. */ + +#if HAVE_CONFIG_H +# include <config.h> +#endif + +#include "hash-pjw.h" + +/* A hash function for NUL-terminated char* strings using + the method described in Aho, Sethi, & Ullman, p 436. */ + +unsigned int +hash_pjw (const void *x, unsigned int tablesize) +{ + const char *s = x; + unsigned int h = 0; + unsigned int g; + + while (*s != 0) + { + h = (h << 4) + *s++; + if ((g = h & (unsigned int) 0xf0000000) != 0) + h = (h ^ (g >> 24)) ^ g; + } + + return (h % tablesize); +}
new file mode 100644 --- /dev/null +++ b/lib/hash-pjw.h @@ -0,0 +1,20 @@ +/* hash-pjw.h -- declaration for a simple hash function + Copyright 2001 Free Software Foundation, Inc. + + This program is free software; you can redistribute it and/or modify + it under the terms of the GNU General Public License as published by + the Free Software Foundation; either version 2, or (at your option) + any later version. + + This program is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + GNU General Public License for more details. + + You should have received a copy of the GNU General Public License + along with this program; see the file COPYING. + If not, write to the Free Software Foundation, + 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. */ + +unsigned int +hash_pjw (const void *x, unsigned int tablesize);