usr/src/lib/libast/common/sfio/_sfputd.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 #include        "sfhdr.h"
  23
  24 /*      Write out a floating point value in a portable format
  25 **
  26 **      Written by Kiem-Phong Vo.
  27 */
  28
  29 #if __STD_C
  30 int _sfputd(Sfio_t* f, Sfdouble_t v)
  31 #else
  32 int _sfputd(f,v)
  33 Sfio_t*         f;
  34 Sfdouble_t      v;
  35 #endif
  36 {
  37 #define N_ARRAY         (16*sizeof(Sfdouble_t))
  38         reg ssize_t     n, w;
  39         reg uchar       *s, *ends;
  40         int             exp;
  41         uchar           c[N_ARRAY];
  42         Sfdouble_t      x;
  43         SFMTXDECL(f);
  44
  45         SFMTXENTER(f,-1);
  46
  47         if(f->mode != SF_WRITE && _sfmode(f,SF_WRITE,0) < 0)
  48                 SFMTXRETURN(f, -1);
  49         SFLOCK(f,0);
  50
  51         /* get the sign of v */
  52         if(v < 0.)
  53         {       v = -v;
  54                 n = 1;
  55         }
  56         else    n = 0;
  57
  58         /* make the magnitude of v < 1 */
  59         if(v != 0.)
  60                 v = frexpl(v,&exp);
  61         else    exp = 0;
  62
  63         /* code the sign of v and exp */
  64         if((w = exp) < 0)
  65         {       n |= 02;
  66                 w = -w;
  67         }
  68
  69         /* write out the signs and the exp */
  70         SFOPEN(f,0);
  71         if(sfputc(f,n) < 0 || (w = sfputu(f,w)) < 0)
  72                 SFMTXRETURN(f, -1);
  73         SFLOCK(f,0);
  74         w += 1;
  75
  76         s = (ends = &c[0])+sizeof(c);
  77         while(s > ends)
  78         {       /* get 2^SF_PRECIS precision at a time */
  79                 n = (int)(x = ldexpl(v,SF_PRECIS));
  80                 *--s = n|SF_MORE;
  81                 v = x-n;
  82                 if(v <= 0.)
  83                         break;
  84         }
  85
  86         /* last byte is not SF_MORE */
  87         ends = &c[0] + sizeof(c) -1;
  88         *ends &= ~SF_MORE;
  89
  90         /* write out coded bytes */
  91         n = ends - s + 1;
  92         w = SFWRITE(f,(Void_t*)s,n) == n ? w+n : -1;
  93
  94         SFOPEN(f,0);
  95         SFMTXRETURN(f,w);
  96 }