Skip site navigation (1)Skip section navigation (2)

FreeBSD Manual Pages

  
 
  

home | help
Data::Hexdumper(3)    User Contributed Perl Documentation   Data::Hexdumper(3)

NAME
       Data::Hexdumper - Make binary data human-readable

SYNOPSIS
	   use Data::Hexdumper qw(hexdump);
	   print hexdump(
	     data	    => $data, #	what to	dump
	     # NB number_format	is deprecated
	     number_format  => 'S',   #	display	as unsigned 'shorts'
	     start_position => 100,   #	start at this offset ...
	     end_position   => 148    #	... and	end at this offset
	   );
	   print hexdump(
	     "abcdefg",
	     { output_format =>	'%4a : %C %S< %L> : %d'	}
	   );

DESCRIPTION
       "Data::Hexdumper" provides a simple way to format arbitrary binary data
       into a nice human-readable format, somewhat similar to the Unix
       'hexdump' utility.

       It gives	the programmer a considerable degree of	flexibility in how the
       data is formatted, with sensible	defaults.  It is envisaged that	it
       will primarily be of use	for those wrestling alligators in the swamp of
       binary file formats, which is why it was	written	in the first place.

SUBROUTINES
       The following subroutines are exported by default, although this	is
       deprecated and will be removed in some future version.  Please pretend
       that you	need to	ask the	module to export them to you.

       If you do assume	that the module	will always export them, then you may
       also assume that	your code will break at	some point after 1 Aug 2012.

   hexdump
       Does everything.	 Takes a hash of parameters, one of which is
       mandatory, the rest having sensible defaults if not specified.
       Available parameters are:

       data
	   A scalar containing the binary data we're interested	in.  This is
	   mandatory.

       start_position
	   An integer telling us where in "data" to start dumping.  Defaults
	   to the beginning of "data".

       end_position
	   An integer telling us where in "data" to stop dumping.  Defaults to
	   the end of "data".

       number_format
	   This	is deprecated.	See 'INCOMPATIBLE CHANGES' below.  If you use
	   this	your data will be padded with NULLs to be an integer multiple
	   of 16 bytes.	 You can expect	number_format to be removed at some
	   point in 2014 or later.

	   A string specifying how to format the data.	It can be any of the
	   following, which you	will notice have the same meanings as they do
	   to perl's "pack" function:

	   C - unsigned	char
	   S - unsigned	16-bit,	native endianness
	   v or	S< - unsigned 16-bit, little-endian
	   n or	S> - unsigned 16-bit, big-endian
	   L - unsigned	32-bit,	native endianness
	   V or	L< - unsigned 32-bit, little-endian
	   N or	L> - unsigned 32-bit, big-endian
	   Q - unsigned	64-bit,	native endianness
	   Q< -	unsigned 64-bit, little-endian
	   Q> -	unsigned 64-bit, big-endian

	   Note	that 64-bit formats are	*always* available, even if your perl
	   is only 32-bit.  Similarly, using < and > on	the S and L formats
	   always works, even if you're	using a	pre 5.10.0 perl.  That's
	   because this	code doesn't use "pack()".

       output_format
	   This	is an alternative and much more	flexible (but more complex)
	   method of specifying	the output format.  Instead of specifying a
	   single format for all your output, you can specify formats like:

	     %4a : %C %S %L> %Q	: %d

	   which will, on each line, display first the address (consisting of
	   '0x'	and 4 hexadecimal digits, zero-padded if necessary), then a
	   space, then a colon,	then a single byte of data, then a space, then
	   an unsigned 16-bit value in native endianness, then a space,	then
	   an unsigned 32-bit big-endian value,	... then a colon, a space,
	   then	the characters representing your 15 byte record.

	   You can use exactly the same	characters and character sequences as
	   are specified above for number_format, plus 'a' for the address,
	   and 'd' for the data.  To output a literal %	character, use %% as
	   is normal with formats - see	sprintf	for details.  To output	a
	   literal < or	> character where it may be confused with any of the
	   {S,L,Q}{<,>}	sequences, use %< or %>.  So, for example, to output a
	   16-bit value	in native endianness followed by <, use	%S%<.

	   %a takes an optional	base-ten number	between	the % and the a
	   signifying the number of hexadecimal	digits.	 This defaults to 4.

	   %{C,S,L,Q} also take	an optional base-ten number between the	% and
	   the letter, signifying the number of	repeats.  These	will be
	   separated by	spaces in the output.  So '%4C'	is equivalent to '%C
	   %C %C %C'.

	   Anything else will get printed literally.  This format will be
	   repeated for	as many	lines as necessary.  If	the amount of data
	   isn't enough	to completely fill the last line, it will be padded
	   with	NULL bytes.

	   To specify both number_format and output_format is a	fatal error.

	   If neither are given, output_format defaults	to:

	     '	%4a : %16C : %d'

	   which is equivalent to the old-style:

	     number_format => 'C'

       suppress_warnings
	   Make	this true if you want to suppress any warnings - such as that
	   your	data may have been padded with NULLs if	it didn't exactly fit
	   into	an integer number of words, or if you do something that	is
	   deprecated.

       space_as_space
	   Make	this true if you want spaces (ASCII character 0x20) to be
	   printed as spaces Otherwise,	spaces will be printed as full stops /
	   periods (ASCII 0x2E).

       Alternatively, you can supply the parameters as a scalar	chunk of data
       followed	by an optional hashref of the other options:

	   $results = hexdump($string);
	   $results = hexdump(
	     $string,
	     { start_position => 100, end_position   =>	148 }
	   );

SEE ALSO
       Data::Dumper

       Data::HexDump if	your needs are simple

       perldoc -f unpack

       perldoc -f pack

INCOMPATIBLE CHANGES
       'number_format' is now implemented in terms of 'output_format'.	Your
       data will be padded to a	multiple of 16 bytes.  Previously-silent code
       may now emit warnings.

       The mappings are:

	 'C'  => '  %4a	: %C %C	%C %C %C %C %C %C %C %C	%C %C %C %C %C %C : %d'
	 'S'  => '  %4a	: %S %S	%S %S %S %S %S %S	  : %d'
	 'S<' => '  %4a	: %S< %S< %S< %S< %S< %S< %S< %S<	  : %d'
	 'S>' => '  %4a	: %S> %S> %S> %S> %S> %S> %S> %S>	  : %d'
	 'L'  => '  %4a	: %L %L	%L %L		  : %d'
	 'L<' => '  %4a	: %L< %L< %L< %L<	      :	%d'
	 'L>' => '  %4a	: %L> %L> %L> %L>	      :	%d'
	 'Q'  => '  %4a	: %Q %Q		      :	%d'
	 'Q<' => '  %4a	: %Q< %Q<		: %d'
	 'Q>' => '  %4a	: %Q> %Q>		: %d'

       and of course:

	 'V' =>	'L<'
	 'N' =>	'L>'
	 'v' =>	'S<'
	 'n' =>	'S>'

BUGS/LIMITATIONS
       Behaviour of %a is not defined if your file is too big.

       Behaviour of %NNa is not	defined	if NN is too big for your sprintf
       implementation to handle	0x%0${NN}X.

FEEDBACK
       I welcome constructive criticism	and bug	reports.  Please report	bugs
       either by email or via RT:
	 <http://rt.cpan.org/Public/Dist/Display.html?Name=Data-Hexdumper>

       The best	bug reports contain a test file	that fails with	the current
       code, and will pass once	it has been fixed.  The	code repository	is on
       Github:
	 <git://github.com/DrHyde/perl-modules-Data-Hexdumper.git>

AUTHOR,	COPYRIGHT and LICENCE
       Copyright 2001 -	2012 David Cantrell <david@cantrell.org.uk>

       This software is	free-as-in-speech software, and	may be used,
       distributed, and	modified under the terms of either the GNU General
       Public Licence version 2	or the Artistic	Licence.  It's up to you which
       one you use.  The full text of the licences can be found	in the files
       GPL2.txt	and ARTISTIC.txt, respectively.

CONSPIRACY
       This module is also free-as-in-mason software.

THANKS TO ...
       MHX, for	reporting a bug	when dumping a single byte of data

       Stefan Siegl, for reporting a bug when dumping an ASCII 0

       Steffen Winkler,	for inspiring me to use	proper output formats

perl v5.32.1			  2012-05-29		    Data::Hexdumper(3)

NAME | SYNOPSIS | DESCRIPTION | SUBROUTINES | SEE ALSO | INCOMPATIBLE CHANGES | BUGS/LIMITATIONS | FEEDBACK | AUTHOR, COPYRIGHT and LICENCE | CONSPIRACY | THANKS TO ...

Want to link to this manual page? Use this URL:
<https://www.freebsd.org/cgi/man.cgi?query=Data::Hexdumper&sektion=3&manpath=FreeBSD+13.0-RELEASE+and+Ports>

home | help