Re: How to convert binary to hexadecimal

[zentara]

in reply to How to convert binary to hexadecimal

Update: Oops....got a decimal in there. Sorry.

Another snippet for your perusal:

#!/usr/bin/perl
use warnings;
use strict;

my $binary = '11101010101010101010101010101010';
my $int = unpack("N", pack("B32", substr("0" x 32 . $binary, -32)));
my $hex = sprintf("%x", $int );
print $hex,"\n";

[vaas_m]

Hi zentara and all, Thanx for the info. I got it done very easily using pack and unpack as suggested by zentara. Rgds, Kiran Polu

[Anonymous Monk]

THanks Ikigami . I was looking everywhere for that.

[Anonymous Monk]

this function works only for 32 bits, this will work for any binary length sub b2h { my $num=shift; my $WIDTH=32; my $index=length($num)-$WIDTH; print "index= $index\n"; my $hex=""; do { my $width=$WIDTH; if ($index<0) { $width+=$index; $index=0; } $cut_string=substr($num,$index,$width); print "index is $index width is $width Cut String is $cut_string\n"; $hex= sprintf('%X', oct("0b$cut_string")). $hex; $index-=$WIDTH; } while ($index>(-1*$WIDTH)); return $hex; }

[toolic]

Since the code Does What I Want (works even for bit widths > 32), I have made it readable by using perltidy. I have also made it strict and removed the print statements:

use warnings FATAL => 'all';
use strict;

for (
        qw(
            00
            1010
            1110
            010001
            01101011
        ),
        '1' x 33,
        '0101' x 16
) {
    my $h = b2h($_);
    print "$_ $h width=", length($_), "\n";
}
exit;


sub b2h {
    my $num   = shift;
    my $WIDTH = 32;
    my $index = length($num) - $WIDTH;
    my $hex = '';
    do {
        my $width = $WIDTH;
        if ($index < 0) {
            $width += $index;
            $index = 0;
        }
        my $cut_string = substr($num, $index, $width);
        $hex = sprintf('%X', oct("0b$cut_string")) . $hex;
        $index -= $WIDTH;
    } while ($index > (-1 * $WIDTH));
    return $hex;
}

__END__

Output:

00 0 width=2
1010 A width=4
1110 E width=4
010001 11 width=6
01101011 6B width=8
111111111111111111111111111111111 1FFFFFFFF width=33
0101010101010101010101010101010101010101010101010101010101010101 55555
[phone] width=64

I have also been attempting to implement this with pack and unpack, to no avail.

[Anonymous Monk]

hi, I wanted to convert a long binary string to a hexadecimal string. sprintf didn't work because the number was more than 32 bits and thr pack/unpack functions are very complicated for me to understand. hence, I converted it using a truth table. The code is

sub Bin2Hex{
              my %truth_table = ( 
               '0000' => '0' , 
               '0001' => '1' , 
               '0010' => '2' , 
               '0011' => '3' , 
               '0100' => '4' , 
               '0101' => '5' , 
               '0110' => '6' , 
               '0111' => '7' , 
               '1000' => '8' , 
               '1001' => '9' , 
               '1010' => 'A' , 
               '1011' => 'B' , 
               '1100' => 'C' , 
               '1101' => 'D' , 
               '1110' => 'E' , 
               '1111' => 'F' , 
                                );
              
              my $count = 0;
              my $hex_string = ''; 
              my $len = $#_ ; 
              #print "len $len" ;
              my $nibble = '' ; 
              my $abit ; 
              my $hex_len ;
               my $hex_nibble ;
              $hex_len = ceil($len/4)  ;    
              #print "hex len $hex_len \n" ; 
              for(my $i=0; $i < $hex_len ; $i++) {
                     for(my $j= 0 ; $j < 4; $j++){
                              $abit = pop(@_) ;
                              if (defined $abit) {
                                       $nibble = $abit.$nibble;  
                              }
                              else {
                                       $nibble = '0'.$nibble ;

                              }
                     }
                      $hex_nibble = $truth_table{$nibble} ; 
                      $hex_string = $hex_nibble.$hex_string ;     
                      $nibble = '' ;
              }
              #print "the converted hex : $hex_string" ;
              return $hex_string ;
 } 

the input to the function is binary string stored in list.