cde/programs/dtksh/ksh93/src/lib/libast/sfio/sfgetd.c

   1 /*
   2  * CDE - Common Desktop Environment
   3  *
   4  * Copyright (c) 1993-2012, The Open Group. All rights reserved.
   5  *
   6  * These libraries and programs are free software; you can
   7  * redistribute them and/or modify them under the terms of the GNU
   8  * Lesser General Public License as published by the Free Software
   9  * Foundation; either version 2 of the License, or (at your option)
  10  * any later version.
  11  *
  12  * These libraries and programs are distributed in the hope that
  13  * they will be useful, but WITHOUT ANY WARRANTY; without even the
  14  * implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR
  15  * PURPOSE. See the GNU Lesser General Public License for more
  16  * details.
  17  *
  18  * You should have received a copy of the GNU Lesser General Public
  19  * License along with these librararies and programs; if not, write
  20  * to the Free Software Foundation, Inc., 51 Franklin Street, Fifth
  21  * Floor, Boston, MA 02110-1301 USA
  22  */
  23 /* $XConsortium: sfgetd.c /main/3 1995/11/01 18:29:27 rswiston $ */
  24 /***************************************************************
  25 *                                                              *
  26 *                      AT&T - PROPRIETARY                      *
  27 *                                                              *
  28 *         THIS IS PROPRIETARY SOURCE CODE LICENSED BY          *
  29 *                          AT&T CORP.                          *
  30 *                                                              *
  31 *                Copyright (c) 1995 AT&T Corp.                 *
  32 *                     All Rights Reserved                      *
  33 *                                                              *
  34 *           This software is licensed by AT&T Corp.            *
  35 *       under the terms and conditions of the license in       *
  36 *       http://www.research.att.com/orgs/ssr/book/reuse        *
  37 *                                                              *
  38 *               This software was created by the               *
  39 *           Software Engineering Research Department           *
  40 *                    AT&T Bell Laboratories                    *
  41 *                                                              *
  42 *               For further information contact                *
  43 *                     gsf@research.att.com                     *
  44 *                                                              *
  45 ***************************************************************/
  46 #include        "sfhdr.h"
  47
  48 /*      Read a portably coded double value
  49 **
  50 **      Written by Kiem-Phong Vo (08/05/90)
  51 */
  52
  53 #if __STD_C
  54 double sfgetd(Sfio_t* f)
  55 #else
  56 double sfgetd(f)
  57 Sfio_t  *f;
  58 #endif
  59 {
  60         reg uchar       *s, *ends, c;
  61         reg double      v;
  62         reg int         p, sign, exp;
  63
  64         if((sign = sfgetc(f)) < 0 || (exp = (int)sfgetu(f)) < 0)
  65                 return -1.;
  66
  67         SFLOCK(f,0);
  68
  69         v = 0.;
  70         for(;;)
  71         {       /* fast read for data */
  72                 if(SFRPEEK(f,s,p) <= 0)
  73                 {       f->flags |= SF_ERROR;
  74                         v = -1.;
  75                         goto done;
  76                 }
  77
  78                 for(ends = s+p; s < ends; )
  79                 {
  80                         c = *s++;
  81                         v += SFUVALUE(c);
  82                         v = ldexp(v,-SF_PRECIS);
  83                         if(!(c&SF_MORE))
  84                         {       f->next = s;
  85                                 goto done;
  86                         }
  87                 }
  88                 f->next = s;
  89         }
  90
  91 done:
  92         v = ldexp(v,(sign&02) ? -exp : exp);
  93         if(sign&01)
  94                 v = -v;
  95
  96         SFOPEN(f,0);
  97         return v;
  98 }