Ed Chester <[EMAIL PROTECTED]> [2003:09:19:11:15:38+0100] scribed: <snip />
> > Here's the problem:
> > Got a large file (>1Mb) containing binary data.
> > Bytes are in the correct order.
> > Each byte is in low-endian order (lsb first).
> > Want write an output file with bytes in the same order, but with
> > each byte big-endianed.
> >
> > Sounds simple. So I broke out my old friend Bit::Vector, and
> > here's what I did (surrounding stuffs snipped):
> >
> > while (read LL, my $b, 1) {
> > my $h = unpack "H*", $b;
> > my $b_h = Bit::Vector -> new_Hex(8,$h) -> to_Bin;
> > my $r = reverse($b_h);
> > print OF pack "H*", Bit::Vector -> new_Bin(8,$r) -> to_Hex;
> > }
> >
> > LL is my filehandle, $b is current byte, OF is output filehandle,
> > $r the byte in the order I want it for output.
<snip />
Is this what you want?
==================== BEGIN ====================
#! /usr/bin/perl -w
use strict;
# Determine the endianness of your system
my $is_little_endian = unpack( 'c', pack( 's', 1 ) );
print $is_little_endian ? "little" : "BIG", " endian\n";
# Try different size chunk's
my $chunk = 32768;
my $infile = shift || "/home/mds/binary";
my $outfile = "./test.out";
-s $outfile && unlink $outfile;
open IN, "$infile"
or die "\n\tERROR: Cannot read \'$infile\' : $? : $! \n\n";
binmode(IN);
open OUT, ">>$outfile"
or die "\n\tERROR: Cannot create \'$outfile\' : $? : $! \n\n";
while (read IN, my $b, $chunk) {
print OUT pack('H*', unpack( 'h*', $b ))
}
close IN;
close OUT;
exit 0;
==================== END ====================
# ls -al
total 2088
drwxr-sr-x 3 mds mds 4096 Sep 19 22:52 .
drwxr-sr-x 12 mds mds 4096 Sep 19 17:03 ..
-rwxr-xr-x 1 mds mds 1037480 Jul 18 09:51 test.in
-rw-r--r-- 1 mds mds 1037480 Sep 19 22:52 test.out
# time ~/endian.plx ./test.in
little endian
real 0m0.338s
user 0m0.130s
sys 0m0.030s
hth
--
Best Regards,
mds
mds resource
877.596.8237
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Dare to fix things before they break . . .
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Our capacity for understanding is inversely proportional to how much
we think we know. The more I know, the more I know I don't know . . .
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