1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
|
package resize_fat::io; # $Id: io.pm 208669 2004-08-12 04:20:25Z prigaux $
use diagnostics;
use strict;
use resize_fat::fat;
use c;
1;
sub read($$$) {
my ($fs, $pos, $size) = @_;
my $buf = "\0" x $size;
sysseek $fs->{fd}, $pos, 0 or die "seeking to byte #$pos failed on device $fs->{fs_name}";
sysread $fs->{fd}, $buf, $size or die "reading at byte #$pos failed on device $fs->{fs_name}";
$buf;
}
sub write($$$$) {
my ($fs, $pos, $_size, $buf) = @_;
sysseek $fs->{fd}, $pos, 0 or die "seeking to byte #$pos failed on device $fs->{fs_name}";
syswrite $fs->{fd}, $buf or die "writing at byte #$pos failed on device $fs->{fs_name}";
}
sub read_cluster($$) {
my ($fs, $cluster) = @_;
my $buf;
my $pos = $fs->{cluster_offset} / 512 + $cluster * ($fs->{cluster_size} / 512);
c::lseek_sector(fileno $fs->{fd}, $pos, 0) or die "seeking to sector #$pos failed on device $fs->{fs_name}";
sysread $fs->{fd}, $buf, $fs->{cluster_size} or die "reading at sector #$pos failed on device $fs->{fs_name}";
$buf;
}
sub write_cluster($$$) {
my ($fs, $cluster, $buf) = @_;
my $pos = $fs->{cluster_offset} / 512 + $cluster * ($fs->{cluster_size} / 512);
c::lseek_sector(fileno $fs->{fd}, $pos, 0) or die "seeking to sector #$pos failed on device $fs->{fs_name}";
syswrite $fs->{fd}, $buf or die "writing at sector #$pos failed on device $fs->{fs_name}";
}
sub read_file($$) {
my ($fs, $cluster) = @_;
my $buf = '';
for (; !resize_fat::fat::is_eof($cluster); $cluster = resize_fat::fat::next($fs, $cluster)) {
$cluster == 0 and die "Bad FAT: unterminated chain\n";
$buf .= read_cluster($fs, $cluster);
}
$buf;
}
sub open {
my ($fs) = @_;
sysopen $fs->{fd}, $fs->{fs_name}, 2 or
sysopen $fs->{fd}, $fs->{fs_name}, 0 or die "error opening device $fs->{fs_name} for writing\n";
}
|
