cmpbuf.c

这是一个同样来自贝尔实验室的和UNIX有着渊源的操作系统, 其简洁的设计和实现易于我们学习和理解

/* Buffer primitives for comparison operations.
   Copyright (C) 1993 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., 675 Mass Ave, Cambridge, MA 02139, USA.  */

#include "system.h"
#include "cmpbuf.h"

/* Least common multiple of two buffer sizes A and B.  */

size_t
buffer_lcm (a, b)
     size_t a, b;
{
  size_t m, n, r;

  /* Yield reasonable values if buffer sizes are zero.  */
  if (!a)
    return b ? b : 8 * 1024;
  if (!b)
    return a;

  /* n = gcd (a, b) */
  for (m = a, n = b;  (r = m % n) != 0;  m = n, n = r)
    continue;

  return a/n * b;
}