vdio.c

/***********************************************************************
*                                                                      *
*               This software is part of the ast package               *
*          Copyright (c) 1995-2012 AT&T Intellectual Property          *
*                      and is licensed under the                       *
*                 Eclipse Public License, Version 1.0                  *
*                    by AT&T Intellectual Property                     *
*                                                                      *
*                A copy of the License is available at                 *
*          http://www.eclipse.org/org/documents/epl-v10.html           *
*         (with md5 checksum b35adb5213ca9657e911e9befb180842)         *
*                                                                      *
*              Information and Software Systems Research               *
*                            AT&T Research                             *
*                           Florham Park NJ                            *
*                                                                      *
*                   Phong Vo <[email protected]>                    *
*                                                                      *
***********************************************************************/
#include	"vdelhdr.h"

/*	IO subsystem for the delta routines
**
**	Written by Kiem-Phong Vo (12/15/94)
*/

#if __STD_C
static void _vdinit(reg Vdio_t* io)
#else
static void _vdinit(io)
reg Vdio_t*	io;
#endif
{
	if((io->data = (uchar*)io->delta->data) )
		io->size = io->delta->size;
	else
	{	io->data = io->buf;
		io->size = sizeof(io->buf);
	}
	io->next = io->data;
	io->endb = io->data + io->size;
	io->left = io->delta->size;
}

#if __STD_C
static int _vdfilbuf(reg Vdio_t* io)
#else
static int _vdfilbuf(io)
reg Vdio_t*	io;
#endif
{	reg int	n;

	if(!io->data)
		_vdinit(io);

	if(io->data != io->buf)	/* all data was given in core */
		return REMAIN(io);

	if ((n = SIZE(io)) > LEFT(io))
		n = LEFT(io);
	if((n = (*READF(io))(DATA(io),n,HERE(io),DELTA(io))) > 0)
	{	ENDB(io) = (NEXT(io) = DATA(io)) + n;
		HERE(io) += n;
		LEFT(io) -= n;
	}
	return n;
}

#if __STD_C
static int _vdflsbuf(reg Vdio_t* io)
#else
static int _vdflsbuf(io)
reg Vdio_t*	io;
#endif
{	reg int n;

	if(!io->data )
		_vdinit(io);

	if(io->data != io->buf)	/* all space was given	*/
		return REMAIN(io);

	if((n = NEXT(io) - DATA(io)) > 0 &&
	   (*WRITEF(io))(DATA(io),n,HERE(io),DELTA(io)) != n)
		return -1;

	HERE(io) += n;
	NEXT(io) = DATA(io);
	return SIZE(io);
}

#if __STD_C
static ulong _vdgetu(reg Vdio_t* io, reg ulong v)
#else
static ulong _vdgetu(io,v)
reg Vdio_t*	io;
reg ulong	v;
#endif
{	reg int		c;

	for(v &= I_MORE-1;;)
	{	if((c = VDGETC(io)) < 0)
			return (ulong)(-1L);
		if(!(c&I_MORE) )
			return ((v<<I_SHIFT) | c);
		v = (v<<I_SHIFT) | (c & (I_MORE-1));
	}
}

#if __STD_C
static int _vdputu(reg Vdio_t* io, ulong v)
#else
static int _vdputu(io, v)
reg Vdio_t*	io;
reg ulong	v;
#endif
{
	reg uchar	*s, *next;
	reg int		len;
	uchar		c[sizeof(ulong)+1];

	s = next = &c[sizeof(c)-1];
	*s = I_CODE(v);
	while((v >>= I_SHIFT) )
		*--s = I_CODE(v)|I_MORE;
	len = (next-s) + 1;

	if(REMAIN(io) < len && _vdflsbuf(io) < len)
		return -1;

	next = io->next;
	switch(len)
	{
	default: memcpy((Void_t*)next,(Void_t*)s,len); next += len; break;
	case 3:	*next++ = *s++;
	case 2:	*next++ = *s++;
	case 1:	*next++ = *s;
	}
	io->next = next;

	return len;
}

#if __STD_C
static int _vdread(Vdio_t* io, reg uchar* s, reg int n)
#else
static int _vdread(io, s, n)
Vdio_t*		io;
reg uchar*	s;
reg int		n;
#endif
{
	reg uchar*	next;
	reg int		r, m;

	for(m = n; m > 0; )
	{	if((r = REMAIN(io)) <= 0 && (r = _vdfilbuf(io)) <= 0)
			break;
		if(r > m)
			r = m;

		next = io->next;
		MEMCPY(s,next,r);
		io->next = next;

		m -= r;
	}
	return n-m;
}

#if __STD_C
static int _vdwrite(Vdio_t* io, reg uchar* s, reg int n)
#else
static int _vdwrite(io, s, n)
Vdio_t*		io;
reg uchar*	s;
reg int		n;
#endif
{
	reg uchar*	next;
	reg int		w, m;

	for(m = n; m > 0; )
	{	if((w = REMAIN(io)) <= 0 && (w = _vdflsbuf(io)) <= 0)
			break;
		if(w > m)
			w = m;

		next = io->next;
		MEMCPY(next,s,w);
		io->next = next;

		m -= w;
	}
	return n-m;
}


Vdbufio_t	_Vdbufio =
{	_vdfilbuf,
	_vdflsbuf,
	_vdgetu,
	_vdputu,
	_vdread,
	_vdwrite
};