X-Git-Url: http://erislabs.net/gitweb/?a=blobdiff_plain;f=lib%2Fgcd.c;h=3562de56d7aa8a0d74dd2244bca1f98f609e4b37;hb=8ec8f4b42e39d3aaf2dda06c38b8db00efcc69f5;hp=4d9e88f2d9c2d802f3d7dd471f11b4712f450a25;hpb=ad4e337794aeb185ab58fef27ddee3ee4e81efe3;p=gnulib.git diff --git a/lib/gcd.c b/lib/gcd.c index 4d9e88f2d..3562de56d 100644 --- a/lib/gcd.c +++ b/lib/gcd.c @@ -1,11 +1,11 @@ /* Arithmetic. - Copyright (C) 2001 Free Software Foundation, Inc. - Written by Bruno Haible , 2001. + Copyright (C) 2001-2002, 2006 Free Software Foundation, Inc. + Written by Bruno Haible , 2001. - This program is free software; you can redistribute it and/or modify + 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. + the Free Software Foundation; either version 3 of the License, 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 @@ -13,19 +13,24 @@ 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. */ + along with this program. If not, see . */ +#include + +/* This file can also be used to define gcd functions for other unsigned + types, such as 'unsigned long long' or 'uintmax_t'. */ +#ifndef WORD_T /* Specification. */ -#include "gcd.h" +# include "gcd.h" +# define WORD_T unsigned long +# define GCD gcd +#endif #include /* Return the greatest common divisor of a > 0 and b > 0. */ -unsigned int -gcd (a, b) - unsigned int a; - unsigned int b; +WORD_T +GCD (WORD_T a, WORD_T b) { /* Why no division, as in Euclid's algorithm? Because in Euclid's algorithm the division result floor(a/b) or floor(b/a) is very often = 1 or = 2, @@ -35,7 +40,7 @@ gcd (a, b) bit in a single instruction, and the algorithm uses fewer variables than Euclid's algorithm. */ - unsigned int c = a | b; + WORD_T c = a | b; c = c ^ (c - 1); /* c = largest power of 2 that divides a and b. */