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:

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 }
    );