I would like to convert some data in binary using Perl. The data needs to be output in 8 bits binary. The original data comes in this format:
137.0000
136.0000
133.0000
136.0000
10.0000
134.0000
0.0000
132.0000
132.0000
To do so, I transformed the data to suppress the ".0000" then I use the pack
function with the option C*
(this format correspond to an "unsigned character (usually 8 bits)" according to the documentation).
I called this file txt2bin.pl
:
my $file = $ARGV[0];
my $fileout = $file.".bin";
if($file eq "-h" or $file eq "-help" or $file eq "")
{
print "Usage : txt2bin.pl file_in\n";
print " file_out = file_in.bin\n";
print "This script converts a txt file to a binary file\n";
}
else
{
print "File in = $file\n";
print "File out = $fileout\n";
open(FILE,"<$file") or die $!;
open(FILEOUT,">$fileout") or die $!;
binmode FILEOUT;
while(defined(my $line=<FILE>))
{
chomp($line);
$line =~ s/\.0000//;
syswrite FILEOUT, pack("C*",$line);
}
close(FILE);
close(FILEOUT);
}
I also need to be able to do the reverse operation, so, I created another file bin2txt.pl
:
my $file = $ARGV[0];
my $fileout = $file.".txt";
if($file eq "-h" or $file eq "-help" or $file eq "")
{
print "Usage : bin2txt.pl file_in\n";
print " file_out = file_in.txt\n";
print "This script converts a binairy file to a txt file\n";
}
else
{
print "File in = $file\n";
print "File out = $fileout\n";
my $file = "<$file";
# undef $/ to read whole file in one go
undef $/;
open(FILE,$file) or die $!;
open(FILEOUT,">$fileout") or die $!;
# binmode FILE to supress conversion of line endings
binmode FILE;
my $data = <FILE>;
$data =~ s/(.{1})/unpack("C*",$1).".0000 \n"/eg;
syswrite FILEOUT, $data;
}
However, when I execute the first program txt2bin.pl
, then the second, I should get:
137.0000
136.0000
133.0000
136.0000
10.0000
134.0000
0.0000
132.0000
132.0000
Instead, of that, I get this:
137.0000
136.0000
133.0000
136.0000
134.0000
0.0000
132.0000
132.0000
The 10.0000
does not show up, do you guys have any idea about this ?
Thanks for helping.
You need to add the s
modifier to the regexp substitution in order to match a 10 (newline) :
$data =~ s/(.{1})/unpack("C*",$1).".0000 \n"/seg;
From perldoc perlre :
s
Treat the string as single line. That is, change "." to match any character whatsoever, even a newline, which normally it would not match.