xref: /src/sys/arch/i386/stand/lib/pread.c

/*	$NetBSD: pread.c,v 1.1 1997/03/14 02:40:33 perry Exp $	*/

/*
 * Copyright (c) 1996
 *	Matthias Drochner.  All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *	This product includes software developed for the NetBSD Project
 *	by Matthias Drochner.
 * 4. The name of the author may not be used to endorse or promote products
 *    derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 *
 */

/* read into destination in flat addr space */

#include <lib/libsa/stand.h>

#include "libi386.h"

#ifdef SAVE_MEMORY
#define BUFSIZE (1*1024)
#else
#define BUFSIZE (4*1024)
#endif

static char buf[BUFSIZE];

int pread(fd, dest, size)
int fd;
physaddr_t dest;
int size;
{
  int rsize;

  rsize = size;
  while(rsize > 0) {
    int count, got;

    count = (rsize < BUFSIZE ? rsize : BUFSIZE);

    got = read(fd, buf, count);
    if(got < 0) return(-1);

    /* put to physical space */
    vpbcopy(buf, dest, got);

    dest += got;
    rsize -= got;
    if(got < count) break;	/* EOF */
  }
  return(size - rsize);
}