usr/src/lib/libast/common/sfio/sfgetd.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 /*      Read a portably coded double value
  25 **
  26 **      Written by Kiem-Phong Vo
  27 */
  28
  29 #if __STD_C
  30 Sfdouble_t sfgetd(Sfio_t* f)
  31 #else
  32 Sfdouble_t sfgetd(f)
  33 Sfio_t* f;
  34 #endif
  35 {
  36         reg uchar       *s, *ends, c;
  37         reg int         p, sign, exp;
  38         Sfdouble_t      v;
  39         SFMTXDECL(f);
  40
  41         SFMTXENTER(f,-1.);
  42
  43         if((sign = sfgetc(f)) < 0 || (exp = (int)sfgetu(f)) < 0)
  44                 SFMTXRETURN(f, -1.);
  45
  46         if(f->mode != SF_READ && _sfmode(f,SF_READ,0) < 0)
  47                 SFMTXRETURN(f, -1.);
  48
  49         SFLOCK(f,0);
  50
  51         v = 0.;
  52         for(;;)
  53         {       /* fast read for data */
  54                 if(SFRPEEK(f,s,p) <= 0)
  55                 {       f->flags |= SF_ERROR;
  56                         v = -1.;
  57                         goto done;
  58                 }
  59
  60                 for(ends = s+p; s < ends; )
  61                 {       c = *s++;
  62                         v += SFUVALUE(c);
  63                         v = ldexpl(v,-SF_PRECIS);
  64                         if(!(c&SF_MORE))
  65                         {       f->next = s;
  66                                 goto done;
  67                         }
  68                 }
  69                 f->next = s;
  70         }
  71
  72 done:
  73         v = ldexpl(v,(sign&02) ? -exp : exp);
  74         if(sign&01)
  75                 v = -v;
  76
  77         SFOPEN(f,0);
  78         SFMTXRETURN(f, v);
  79 }