1 /* vi: set sw=4 ts=4: */
2 /*
3 * Utility routines.
4 *
5 * Copyright (C) many different people. If you wrote this, please
6 * acknowledge your work.
7 *
8 * This program is free software; you can redistribute it and/or modify
9 * it under the terms of the GNU General Public License as published by
10 * the Free Software Foundation; either version 2 of the License, or
11 * (at your option) any later version.
12 *
13 * This program is distributed in the hope that it will be useful, but
14 * WITHOUT ANY WARRANTY; without even the implied warranty of
15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
16 * General Public License for more details.
17 *
18 * You should have received a copy of the GNU General Public License
19 * along with this program; if not, write to the Free Software
20 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307
21 * USA
22 */
23
24 #include <stdio.h>
25 #include <sys/stat.h>
26 #include "libbb.h"
27
28 /* Copy CHUNKSIZE bytes (or until EOF if CHUNKSIZE equals -1) from SRC_FILE
29 * to DST_FILE. */
copy_file_chunk(FILE * src_file,FILE * dst_file,unsigned long long chunksize)30 extern int copy_file_chunk(FILE * src_file, FILE * dst_file,
31 unsigned long long chunksize)
32 {
33 size_t nread, nwritten, size;
34 char buffer[BUFSIZ];
35
36 while (chunksize != 0) {
37 if (chunksize > BUFSIZ)
38 size = BUFSIZ;
39 else
40 size = chunksize;
41
42 nread = fread(buffer, 1, size, src_file);
43
44 if (nread != size && ferror(src_file)) {
45 perror_msg("read");
46 return -1;
47 } else if (nread == 0) {
48 if (chunksize != -1) {
49 error_msg("Unable to read all data");
50 return -1;
51 }
52
53 return 0;
54 }
55
56 nwritten = fwrite(buffer, 1, nread, dst_file);
57
58 if (nwritten != nread) {
59 if (ferror(dst_file))
60 perror_msg("write");
61 else
62 error_msg("Unable to write all data");
63 return -1;
64 }
65
66 if (chunksize != -1)
67 chunksize -= nwritten;
68 }
69
70 return 0;
71 }
72