common/sfio/sfgetd.c

	sfgetd.c revision 3e14f97f673e8a630f076077de35afdd43dc1587
/***********************************************************************
*                                                                      *
*               This software is part of the ast package               *
*          Copyright (c) 1985-2010 AT&T Intellectual Property          *
*                      and is licensed under the                       *
*                  Common Public License, Version 1.0                  *
*                    by AT&T Intellectual Property                     *
*                                                                      *
*                A copy of the License is available at                 *
*            http://www.opensource.org/licenses/cpl1.0.txt             *
*         (with md5 checksum 059e8cd6165cb4c31e351f2b69388fd9)         *
*                                                                      *
*              Information and Software Systems Research               *
*                            AT&T Research                             *
*                           Florham Park NJ                            *
*                                                                      *
*                 Glenn Fowler <gsf@research.att.com>                  *
*                  David Korn <dgk@research.att.com>                   *
*                   Phong Vo <kpv@research.att.com>                    *
*                                                                      *
***********************************************************************/
#include    "sfhdr.h"

/*  Read a portably coded double value
**
**  Written by Kiem-Phong Vo
*/

#if __STD_C
Sfdouble_t sfgetd(Sfio_t* f)
#else
Sfdouble_t sfgetd(f)
Sfio_t* f;
#endif
{
    reg uchar   *s, *ends, c;
    reg int     p, sign, exp;
    Sfdouble_t  v;
    SFMTXDECL(f);

    SFMTXENTER(f,-1.);

    if((sign = sfgetc(f)) < 0 || (exp = (int)sfgetu(f)) < 0)
        SFMTXRETURN(f, -1.);

    if(f->mode != SF_READ && _sfmode(f,SF_READ,0) < 0)
        SFMTXRETURN(f, -1.);

    SFLOCK(f,0);

    v = 0.;
    for(;;)
    {   /* fast read for data */
        if(SFRPEEK(f,s,p) <= 0)
        {   f->flags |= SF_ERROR;
            v = -1.;
            goto done;
        }

        for(ends = s+p; s < ends; )
        {   c = *s++;
            v += SFUVALUE(c);
            v = ldexpl(v,-SF_PRECIS);
            if(!(c&SF_MORE))
            {   f->next = s;
                goto done;
            }
        }
        f->next = s;
    }

done:
    v = ldexpl(v,(sign&02) ? -exp : exp);
    if(sign&01)
        v = -v;

    SFOPEN(f,0);
    SFMTXRETURN(f, v);
}