Hi All,
I have an issue with a Perl script designed to count pages in a TIFF file on AIX.
The result I get depends on the location of the TIFF file when I count it.
Specifically, when the TIFF file resides on a "JFS2" file system or a "JFS" file
system which has large file support (> 2Gb) enabled, the seek works, otherwise the
seek fails. Obviously this impacts on the correctness of the page count reported.
Code snippet and sample output follows:
-----
## open the file for reading.
open (FIN, $_[0]) || die "couldn't open the file! $_[0]";
## read the 8 header bytes (3 fields), and unpack the mode
## to determine byte order (endian)
read FIN, $record, 8;
($mode) = unpack "A2", $record;
if ($mode eq "MM") { # big endian
$header_template = "A2nN";
$idf_tag_template = "n";
$next_offset_template = "N";
} elsif ( $mode eq "II" ) { # little endian
$header_template = "A2SL";
$idf_tag_template = "S";
$next_offset_template = "L";
} else {
die "invalid file format or not a TIFF file ($_[0])";
}
## unpack the header
($mode, $magic, $offset) = unpack $header_template, $record;
print "\n(1) mode:$mode, magic:$magic, offset:$offset\n";
## count the pages (images)
while ( $offset ) {
$page_count++;
## Move the file pointer to the beginning of the first IDF,
## read the number of entries in the IDF, and unpack the number
print "\nSeek to IDF at offset $offset\n";
my $seek_ok = seek(FIN, $offset, 0);
if ($seek_ok == 0) {
print "Seek for IDF failed: $!\n";
} else {
print "Seek OK!\n";
}
...
<snip>
...
}
------
Sample output from *NON* JFS file system:
(1) mode:II, magic:10752, offset:3556769792
Seek to IDF at offset 3556769792
Seek for IDF failed: A system call received a parameter that is not valid.
------
Sample output from JFS file system:
(1) mode:II, magic:10752, offset:3556769792
Seek to IDF at offset 3556769792
Seek OK!
I have tried using binmode() but that makes no difference. Has anyone else
encountered anything like this? If so, how did you resolve it?
Regards,
Ashley
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