pread.c revision 1.1 
1/*	$NetBSD: pread.c,v 1.1 1997/03/14 02:40:33 perry Exp $	*/
2
3/*
4 * Copyright (c) 1996
5 *	Matthias Drochner.  All rights reserved.
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
9 * are met:
10 * 1. Redistributions of source code must retain the above copyright
11 *    notice, this list of conditions and the following disclaimer.
12 * 2. Redistributions in binary form must reproduce the above copyright
13 *    notice, this list of conditions and the following disclaimer in the
14 *    documentation and/or other materials provided with the distribution.
15 * 3. All advertising materials mentioning features or use of this software
16 *    must display the following acknowledgement:
17 *	This product includes software developed for the NetBSD Project
18 *	by Matthias Drochner.
19 * 4. The name of the author may not be used to endorse or promote products
20 *    derived from this software without specific prior written permission.
21 *
22 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
23 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
24 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
25 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
26 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
27 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
28 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
29 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
30 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
31 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
32 *
33 */
34
35/* read into destination in flat addr space */
36
37#include <lib/libsa/stand.h>
38
39#include "libi386.h"
40
41#ifdef SAVE_MEMORY
42#define BUFSIZE (1*1024)
43#else
44#define BUFSIZE (4*1024)
45#endif
46
47static char buf[BUFSIZE];
48
49int pread(fd, dest, size)
50int fd;
51physaddr_t dest;
52int size;
53{
54  int rsize;
55
56  rsize = size;
57  while(rsize > 0) {
58    int count, got;
59
60    count = (rsize < BUFSIZE ? rsize : BUFSIZE);
61
62    got = read(fd, buf, count);
63    if(got < 0) return(-1);
64
65    /* put to physical space */
66    vpbcopy(buf, dest, got);
67
68    dest += got;
69    rsize -= got;
70    if(got < count) break;	/* EOF */
71  }
72  return(size - rsize);
73}
74