usr/src/lib/libast/common/string/fmtscale.c

   1 /***********************************************************************
   2 *                                                                      *
   3 *               This software is part of the ast package               *
   4 *          Copyright (c) 1985-2010 AT&T Intellectual Property          *
   5 *                      and is licensed under the                       *
   6 *                  Common Public License, Version 1.0                  *
   7 *                    by AT&T Intellectual Property                     *
   8 *                                                                      *
   9 *                A copy of the License is available at                 *
  10 *            http://www.opensource.org/licenses/cpl1.0.txt             *
  11 *         (with md5 checksum 059e8cd6165cb4c31e351f2b69388fd9)         *
  12 *                                                                      *
  13 *              Information and Software Systems Research               *
  14 *                            AT&T Research                             *
  15 *                           Florham Park NJ                            *
  16 *                                                                      *
  17 *                 Glenn Fowler <gsf@research.att.com>                  *
  18 *                  David Korn <dgk@research.att.com>                   *
  19 *                   Phong Vo <kpv@research.att.com>                    *
  20 *                                                                      *
  21 ***********************************************************************/
  22 #pragma prototyped
  23 /*
  24  * Glenn Fowler
  25  * AT&T Research
  26  *
  27  * return number n scaled to metric multiples of k { 1000 1024 }
  28  * return string length is at most 5 chars + terminating nul
  29  */
  30
  31 #include <ast.h>
  32 #include <lclib.h>
  33
  34 char*
  35 fmtscale(register Sfulong_t n, int k)
  36 {
  37         register Sfulong_t      m;
  38         int                     r;
  39         int                     z;
  40         const char*             u;
  41         char                    suf[3];
  42         char*                   s;
  43         char*                   buf;
  44         Lc_numeric_t*           p = (Lc_numeric_t*)LCINFO(AST_LC_NUMERIC)->data;
  45
  46         static const char       scale[] = "bkMGTPE";
  47
  48         u = scale;
  49         if (n < 1000)
  50                 r = 0;
  51         else
  52         {
  53                 m = 0;
  54                 while (n >= k && *(u + 1))
  55                 {
  56                         m = n;
  57                         n /= k;
  58                         u++;
  59                 }
  60                 if ((r = (10 * (m % k) + (k / 2)) / k) > 9)
  61                 {
  62                         r = 0;
  63                         n++;
  64                 }
  65                 if (k == 1024 && n >= 1000)
  66                 {
  67                         n = 1;
  68                         r = 0;
  69                         u++;
  70                 }
  71         }
  72         buf = fmtbuf(z = 8);
  73         s = suf;
  74         if (u > scale)
  75         {
  76                 if (k == 1024)
  77                 {
  78                         *s++ = *u == 'k' ? 'K' : *u;
  79                         *s++ = 'i';
  80                 }
  81                 else
  82                         *s++ = *u;
  83         }
  84         *s = 0;
  85         if (n > 0 && n < 10)
  86                 sfsprintf(buf, z, "%I*u%c%d%s", sizeof(n), n, p->decimal >= 0 ? p->decimal : '.', r, suf);
  87         else
  88         {
  89                 if (r >= 5)
  90                         n++;
  91                 sfsprintf(buf, z, "%I*u%s", sizeof(n), n, suf);
  92         }
  93         return buf;
  94 }