xref: /plan9/sys/src/ape/cmd/diff/cmpbuf.c (revision 0b459c2cb92b7c9d88818e9a2f72e678e5bc4553)
1*0b459c2cSDavid du Colombier /* Buffer primitives for comparison operations.
2*0b459c2cSDavid du Colombier    Copyright (C) 1993 Free Software Foundation, Inc.
3*0b459c2cSDavid du Colombier 
4*0b459c2cSDavid du Colombier    This program is free software; you can redistribute it and/or modify
5*0b459c2cSDavid du Colombier    it under the terms of the GNU General Public License as published by
6*0b459c2cSDavid du Colombier    the Free Software Foundation; either version 2, or (at your option)
7*0b459c2cSDavid du Colombier    any later version.
8*0b459c2cSDavid du Colombier 
9*0b459c2cSDavid du Colombier    This program is distributed in the hope that it will be useful,
10*0b459c2cSDavid du Colombier    but WITHOUT ANY WARRANTY; without even the implied warranty of
11*0b459c2cSDavid du Colombier    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
12*0b459c2cSDavid du Colombier    GNU General Public License for more details.
13*0b459c2cSDavid du Colombier 
14*0b459c2cSDavid du Colombier    You should have received a copy of the GNU General Public License
15*0b459c2cSDavid du Colombier    along with this program; if not, write to the Free Software
16*0b459c2cSDavid du Colombier    Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.  */
17*0b459c2cSDavid du Colombier 
18*0b459c2cSDavid du Colombier #include "system.h"
19*0b459c2cSDavid du Colombier #include "cmpbuf.h"
20*0b459c2cSDavid du Colombier 
21*0b459c2cSDavid du Colombier /* Least common multiple of two buffer sizes A and B.  */
22*0b459c2cSDavid du Colombier 
23*0b459c2cSDavid du Colombier size_t
buffer_lcm(a,b)24*0b459c2cSDavid du Colombier buffer_lcm (a, b)
25*0b459c2cSDavid du Colombier      size_t a, b;
26*0b459c2cSDavid du Colombier {
27*0b459c2cSDavid du Colombier   size_t m, n, r;
28*0b459c2cSDavid du Colombier 
29*0b459c2cSDavid du Colombier   /* Yield reasonable values if buffer sizes are zero.  */
30*0b459c2cSDavid du Colombier   if (!a)
31*0b459c2cSDavid du Colombier     return b ? b : 8 * 1024;
32*0b459c2cSDavid du Colombier   if (!b)
33*0b459c2cSDavid du Colombier     return a;
34*0b459c2cSDavid du Colombier 
35*0b459c2cSDavid du Colombier   /* n = gcd (a, b) */
36*0b459c2cSDavid du Colombier   for (m = a, n = b;  (r = m % n) != 0;  m = n, n = r)
37*0b459c2cSDavid du Colombier     continue;
38*0b459c2cSDavid du Colombier 
39*0b459c2cSDavid du Colombier   return a/n * b;
40*0b459c2cSDavid du Colombier }
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