scanf.c,v

TCP-IP红宝书源代码

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1.1
date	97.09.21.19.27.40;	author dls;	state Dist;
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@pre-3e code
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@/* scanf.c - scanf, fscanf, sscanf, getch, ungetch, sgetch, sungetch */

#include <conf.h>
#include <kernel.h>
#include <io.h>
#include <tty.h>

static	getch(), sungetch(), ungetch();

/*------------------------------------------------------------------------
 *  scanf  --  read from the console according to a format
 *------------------------------------------------------------------------
 */
scanf(fmt, args)
	char	*fmt;
	int	args;
{
	int	getch();
	int	ungetch();
	int	buf;

	buf = EMPTY;
	return(_doscan(fmt, &args, getch, ungetch, CONSOLE, &buf));
}

/*------------------------------------------------------------------------
 *  fscanf  --  read from a device (file) according to a format
 *------------------------------------------------------------------------
 */
fscanf(dev, fmt, args)
	int	dev;
	char	*fmt;
	int	args;
{
	int	getch();
	int	ungetch();
	int	buf;

	buf = EMPTY;
	return(_doscan(fmt, &args, getch, ungetch, dev, &buf));
}

/*------------------------------------------------------------------------
 *  getch  --  get a character from a device with pushback
 *------------------------------------------------------------------------
 */
static	getch(dev, buf)
	int	dev;
	int	*buf;
{
	if( *buf != EOF && *buf != EMPTY)
		*buf = getc(dev);
	if( *buf != EOF )
		*buf = control(dev, TTC_NEXTC);
	return(*buf);
}

/*------------------------------------------------------------------------
 *  ungetch  --  pushback a character for getch
 *------------------------------------------------------------------------
 */
static	ungetch(dev, buf)
	int	dev;
	int	*buf;
{
	*buf = EMPTY;
}

/*------------------------------------------------------------------------
 *  sscanf  --  read from a string according to a format
 *------------------------------------------------------------------------
 */
sscanf(str, fmt, args)
	char	*str;
	char	*fmt;
	int	args;
{
	int	sgetch();
	int	sungetch();
	char	*s;

	s = str;
	return(_doscan(fmt, &args, sgetch, sungetch, 0, &s));
}

/*------------------------------------------------------------------------
 *  sgetch  -- get the next character from a string
 *------------------------------------------------------------------------
 */
static	sgetch(dummy,cpp)
	int	dummy;
	char	**cpp;
{
	return( *(*cpp) == '\0' ? EOF : *(*cpp)++ );
}

/*------------------------------------------------------------------------
 *  sungetc  --  pushback a character in a string
 *------------------------------------------------------------------------
 */
static	sungetch(dummy,cpp)
	int	dummy;
	char	**cpp;
{
	return(*(*cpp)--);
}
@