/ 
Devel-Size-Report-0.06
River stage zero No dependents
/ Devel::Size::Report

NAME

Devel::Size::Report - generate a size report for all elements in a structure

SYNOPSIS

	use Devel::Size::Report qw/report_size/;

        my $a = [ 8, 9, 7,
                  [ \"12",
                    2, 3,
                    { a => 'b',
                      size => 12.2,
                      h => ['a']
                    },
                    sub { 42; },
                  'rrr'
                  ] ];
	print report_size($a, { indend => "   " } );

This will print something like this:

	Size report v0.04 for 'ARRAY(0x815a430)':
	  Array 743 bytes (overhead: 84 bytes, 11.31%)
	     Scalar 16 bytes
	     Scalar 16 bytes
	     Scalar 16 bytes
	     Array 611 bytes (overhead: 96 bytes, 15.71%)
	        Scalar reference 27 bytes
	        Scalar 28 bytes
	        Scalar 28 bytes
        	Hash 308 bytes (overhead: 180 bytes, 58.44%)
	           'h' => Array 82 bytes (overhead: 56 bytes, 68.29%)
	              Scalar 26 bytes
	           'a' => Scalar 26 bytes
        	   'size' => Scalar 20 bytes
	        Code 92 bytes
        	Scalar 32 bytes
	Total: 743 bytes

DESCRIPTION

Devel::Size can only report the size of a single element or the total size of a structure (array, hash etc). This module enhances Devel::Size by giving you the ability to generate a full size report for each element in a structure.

You have full control over how the generated text report looks like, and where you want to output it. In addition, the method track_size allows you to get at the raw data that is used to generate the report for even more flexibility.

METHODS

report_size

my $record = report_size( $reference, $options ) . "\n";
print $record;

Walks the given reference recursively and returns text tree describing the size of each element. $options is a hash, containing the following optional keys:

	names	  ref to HASH mapping the types to names
		  This should map S_Scalar to something like "Scalar" etc
	indend	  string to indend different levels with, default is '  '
	left	  indend all text with this at the left side, default is ''
	inner	  indend inner text with this at the left side, default is '  '
	total	  if true, a total size will be printed as last line
	bytes	  name of the size unit, defaults to 'bytes'
	head	  header string, default 'Size report for'
		  Set to '' to supress header completely	
  	overhead  Format string for the overhead, first size in bytes, then
		  the bytes string (see above) and then the percentage.
		  The default is:
		  " (overhead: %i%s, %0.2f%%)"
	addr 	  if true, for each element the memory address will be output
	class	  if true, show the class each element was blessed in

entries_per_element

my $entries = entries_per_element();

Returns the number of entries per element that track_size() will generate.

track_size

@elements = track_size( $reference, $level);

Walk the given scalar or reference recursively and returns an array, containing entries_per_element entries for each element in the structure pointed to by $reference. $reference can also be a plain scalar.

The entries currently are:

level	  the indend level
type	  the type of the element, S_SCALAR, S_HASH, S_ARRAY etc
	  if (type & S_KEY) != 0, the element is a member of a hash
size	  size in bytes of the element
overhead  if the element is an ARRAY or HASH, contains the overhead
	  in bytes (size - sum(size of all elements)).
name	  if type & S_KEY != 0, this contains the name of the hash key
addr	  memory address of the element
class	  classname that the element was blessed into, or ''

track_size calls itself recursively for ARRAY and HASH references.

type_name

$type_number = type($type_name);

Maps a type name (like 'SCALAR') to a type number (lilke S_SCALAR).

WRAP YOUR OWN

If you want to create your own report with different formattings, please use track_size and create a report out of the data you get. Look at the source code for report_size how to do this - it is easy!

CAVEATS

  • The limitations of Devel::Size also apply to this module. This means that CODE refs and other "obscure" things might show wrong sizes, or unknown overhead. In addition, some sizes might be reported wrong.

  • A string representation of the passed argument will be inserted when generating a report with a header.

    If the passed argument is an object with overloaded magic, then the routine for stringification will be triggered. If this routine does actually modify the object (for instance, Math::String objects cache their string form upon first call to stringification, thus modifying themselves), the reported size will be different from a first report without a header.

BUGS

Apart from the problems with Devel::Size, none known so far.

AUTHOR

(c) 2004 by Tels http://bloodgate.com