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att
GitHub Repository: att/ast
 Path: blob/master/src/lib/libast/sfio/_sfputd.c
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/***********************************************************************

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*                                                                      *

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*               This software is part of the ast package               *

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*          Copyright (c) 1985-2011 AT&T Intellectual Property          *

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*                      and is licensed under the                       *

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*                 Eclipse Public License, Version 1.0                  *

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*                    by AT&T Intellectual Property                     *

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*                                                                      *

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*                A copy of the License is available at                 *

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*          http://www.eclipse.org/org/documents/epl-v10.html           *

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*         (with md5 checksum b35adb5213ca9657e911e9befb180842)         *

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*                                                                      *

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*              Information and Software Systems Research               *

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*                            AT&T Research                             *

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*                           Florham Park NJ                            *

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*                                                                      *

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*                 Glenn Fowler <[email protected]>                  *

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*                  David Korn <[email protected]>                   *

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*                   Phong Vo <[email protected]>                    *

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*                                                                      *

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***********************************************************************/

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#include	"sfhdr.h"

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/*	Write out a floating point value in a portable format

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**

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**	Written by Kiem-Phong Vo.

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*/

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#if __STD_C

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int _sfputd(Sfio_t* f, Sfdouble_t v)

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#else

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int _sfputd(f,v)

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Sfio_t*		f;

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Sfdouble_t	v;

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#endif

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{

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#define N_ARRAY		(16*sizeof(Sfdouble_t))

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	reg ssize_t	n, w;

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	reg uchar	*s, *ends;

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	int		exp;

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	uchar		c[N_ARRAY];

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	Sfdouble_t	x;

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	SFMTXDECL(f);

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	SFMTXENTER(f,-1);

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	if(f->mode != SF_WRITE && _sfmode(f,SF_WRITE,0) < 0)

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		SFMTXRETURN(f, -1);

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	SFLOCK(f,0);

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	/* get the sign of v */

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	if(v < 0.)

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	{	v = -v;

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		n = 1;

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	}

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	else	n = 0;

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	/* make the magnitude of v < 1 */

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	if(v != 0.)

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		v = frexpl(v,&exp);

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	else	exp = 0;

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	/* code the sign of v and exp */

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	if((w = exp) < 0)

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	{	n |= 02;

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		w = -w;

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	}

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	/* write out the signs and the exp */

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	SFOPEN(f,0);

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	if(sfputc(f,n) < 0 || (w = sfputu(f,w)) < 0)

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		SFMTXRETURN(f, -1);

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	SFLOCK(f,0);

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	w += 1;

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	s = (ends = &c[0])+sizeof(c);

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	while(s > ends)

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	{	/* get 2^SF_PRECIS precision at a time */

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		n = (int)(x = ldexpl(v,SF_PRECIS));

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		*--s = n|SF_MORE;

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		v = x-n;

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		if(v <= 0.)

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			break;

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	}

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	/* last byte is not SF_MORE */

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	ends = &c[0] + sizeof(c) -1;

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	*ends &= ~SF_MORE;

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	/* write out coded bytes */

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	n = ends - s + 1;

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	w = SFWRITE(f,(Void_t*)s,n) == n ? w+n : -1;

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	SFOPEN(f,0);

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	SFMTXRETURN(f,w);

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}

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