NAME
Bitmask::Data - Handle bitmasks in an easy and flexible way
SYNOPSIS
# Create a simple bitmask class
packacke MyBitmask;
use base qw(Bitmask::Data);
__PACKAGE__->bitmask_length(18);
__PACKAGE__->bitmask_default(0b000000000000000011);
__PACKAGE__->init(
'value1' => 0b000000000000000001,
'value2' => 0b000000000000000010,
'value2' => 0b000000000000000100,
'value4' => 0b000000000000001000,
'value5' => 0b000000000000010000,
...
);
## Somewhere else in your code
use MyBitmask;
my $bm = MyBitmask->new('value1','value3');
$bm->mask;
DESCRIPTION
This package helps you dealing with bitmasks. First you need to subclass
Bitmask::Data and set the bitmask values and length. (If you are only
working with a single bitmask in a simple application you might also
initialize the bitmask directly in the Bitmask::Data module).
After the initialization you can create an arbitrary number of bitmask
objects which can be accessed and manipulated with convenient methods.
METHODS
Class Methods
bitmask_length
Set/Get the length of the bitmask. Changing this value after the
initialization is not recommended.
Default: 16
bitmask_default
Set/Get the default bitmask for empty Bitmask::Data objects.
Default: undef
bitmask_complex
Boolean value that enables/disables checks for composed bitmasks. If
false init will only accept bitmask bit values that are powers of 2.
Default: 0
Complex bitmask also allow the creation of overlapping bitmask values:
packacke LocaleBitmask;
use base qw(Bitmask::Data);
__PACKAGE__->bitmask_length(8); # 8 bits
__PACKAGE__->bitmask_complex(1); # enable overlapping bitmasks
__PACKAGE__->init(
AT => 0b000_00001, # Austria
CH => 0b000_00010, # Switzerland
DE => 0b000_00100, # Germany
FR => 0b000_01000, # France
IT => 0b000_10000, # Italy
de => 0b001_00000, # German
fr => 0b010_00000, # French
it => 0b100_00000, # Italian
de_AT => 0b001_00001, # German / Austria
de_CH => 0b001_00010, # German / Switzerland
de_DE => 0b001_00100, # German / Germany
fr_CH => 0b010_00010, # French / Germany
fr_FR => 0b010_01000, # French / France
it_CH => 0b100_00010, # Italian / Germany
it_IT => 0b100_10000, # Italian / Italy
);
# Somewhere else
LocaleBitmask->new('de')->hasany('de'); # true
LocaleBitmask->new('de')->hasany('de_DE'); # true
LocaleBitmask->new('de')->hasall('de_DE'); # false
LocaleBitmask->new('de_DE','de_AT','de_CH')->hasexact('de','AT','DE','CH'); # true
LocaleBitmask->new('de_DE','de_AT','de_CH')->list # de,DE,de_DE,de_AT,AT,de_CH,CH
bitmask_lazyinit
Boolean value that enables/disables warnings for lazy initialization. (
Lazy initialization = call of init without bitmask bit values)
Default: 0
bitmask_items
HASHREF of all bitmask items. Don't mess around here unless you know
what you are doing.
init
CLASS->init(LIST of VALUES);
Initializes the bitmask class. You can supply a list of possible values.
Optionally you can also specify the bits for the mask by adding bit
values after the value.
CLASS->init(
'value1' => 0b000001,
'value2' => 0b000010,
'value3' => 0b001000,
'value4' => 0b010000,
);
With "bitmask_lazyinit" enabled you can also skip the bitmask bit values
CLASS->bitmask_lazyinit(1);
CLASS->init(
'value1',
'value2',
'value3',
'value4',
);
data2bit
CLASS->data2bit(VALUE);
Returns the corresponding bit for the given value.
bit2data
CLASS->bit2data(BIT);
Returns the corresponding value for the given bit.
bm2data
CLASS->bm2data(BITMASK);
Returns all the value for the given bitmask.
any2data
CLASS->any2data(124); # Bitmask
CLASS->any2data('de_DE'); # Value
CLASS->any2data(0b110001001); # Bitmask in bit notation
CLASS->any2data('0B110001001'); # Bitmask string
CLASS->any2data('0b111000001'); # Bitmask string
Turns a single value (bit, bitmask,value, bitmask string) into a value.
_parse_params
CLASS->_parse_params(LIST)
Helper method for parsing params passed to various methods.
Public Methods
new
my $bm = MyBitmask->new();
my $bm = MyBitmask->new('value1');
my $bm = MyBitmask->new('value2', 'value3');
my $bm = MyBitmask->new('0b00010000010000');
my $bm = MyBitmask->new(124);
my $bm = MyBitmask->new(0b00010000010000);
my $bm = MyBitmask->new(0x2);
my $bm = MyBitmask->new([32, 'value1', 0b00010000010000]);
Create a new bitmask object. You can supply almost any combination of
bits, bitmasks and values, even mix different types.
* LIST or ARRAYREF of values
* LIST or ARRAYREF of strings representing bits or bitmasks (starting
with '0b')
* LIST or ARRAYREF of bitmasks
* Any combination of the above
clone
$bm2 = $bm->clone();
Clones a bitmask object
set
$bm->set(ITEMS);
This method takes the same arguments as "new". It resets the current
bitmask and sets the supplied arguments.
Returns the object.
list
$bm->list()
In list context, this returns a list of the set values in scalar
context, this returns an array reference to the list of values.
length
$bm->length()
Number of set bitmask values.
first
$bm->first()
Returns the first set value (the order of the values is determied by the
sequence of the addition)
remove
$bm->remove(ITEMS);
This method takes the same arguments as "new". The values supplied in
the arguments will be unset.
Returns the object.
reset
$bm->reset();
Unsets all values, leaving an empty list.
Returns the object.
setall
$bm->setall();
Sets all values.
Returns the object.
add
$bm->add(ITEMS);
This method takes the same arguments as "new". The specified values will
be set.
Returns the object.
mask
$bm->mask();
Returns the integer representing the bitmask of all the set values.
string
$bm->string();
Retuns the string representing the bitmask.
sqlfilter_all
$bm->sqlfilter_all($field);
This method can be used for database searches in conjunction with
SQL::Abstract an POSTGRESQL (SQL::Abstract is used by "DBIx::Class" for
generating searches). The search will find all database rows with
bitmask that have at least the given values set. (use the "sql" method
for an exact match)
Example how to use sqlfilter with SQL::Abstract:
my($stmt, @bind) = $sql->select(
'mytable',
\@fields,
{
$bm->sqlfilter_all('mytable.bitmaskfield'),
}
);
Example how to use sqlfilter with DBIx::Class:
my $list = $resultset->search(
{
$bm->sqlfilter_all('me.bitmaskfield'),
},
);
sqlfilter
Shortcut for "sqlfilter_all"
sqlfilter_any
$bm->sqlfilter_any($field);
Works like "sqlfilter_all" but checks for any bit matching
hasall
$bm->hasall(ITEMS);
This method takes the same arguments as "new". Checks if all requestes
items are set and returns true or false.
hasexact
$bm->hasexact(ITEMS);
This method takes the same arguments as "new". Checks if the requestes
items exactly match the set values.
hasany
$bm->hasany(ITEMS);
This method takes the same arguments as "new". Checks if at least one
set value matches the supplied value list and returns true or false
CAVEATS
Since Bitmask::Data is very liberal with input data you cannot use
numbers as bitmask values.
Bitmask::Data also adds a considerable processing overhead (especially
when the bitmask_complex option is enabled) to bitmask manipulations.
SUBCLASSING
Bitmask::Data was designed to be subclassed.
package MyBitmask;
use base qw(Bitmask::Data);
__PACKAGE__->bitmask_length(20); # Default length is 16
__PACKAGE__->init(
'value1' => 0b000000000000000001,
'value2' => 0x2,
'value2' => 4,
'value4', # lazy initlialization
'value5', # lazy initlialization
);
WORKING WITH DATABASES
This module comes with support for POSTGRESQL databases (patches for
other database vendors are welcome).
First you need to create the correct column types:
CREATE TABLE bitmaskexample (
id integer DEFAULT nextval('pkey_seq'::regclass) NOT NULL,
bitmask bit(14),
otherfields character varying
);
The length of the bitmask field must match "CLASS->bitmask_length".
This module provides three convenient methods to work with databases:
* sqlfilter_all: Search for matching bitmasks
* sqlfilter_any: Search for bitmasks with matching bits
* string: Print the bitmask string as used by postgres database
If you are working with DBIx::Class you might also install de- and
inflators for Bitmask objects:
__PACKAGE__->inflate_column('fieldname',{
inflate => sub {
my $value = shift;
return MyBitmask->new($value);
},
deflate => sub {
my $value = shift;
undef $value
unless ref($value) && $value->isa('MyBitmask');
$value //= MyBitmask->new();
return $value->string;
},
});
SUPPORT
Please report any bugs or feature requests to
"bug-bitmask-data@rt.cpan.org", or through the web interface at
<http://rt.cpan.org/Public/Bug/Report.html?Queue=Bitmask::Data>. I will
be notified and then you'll automatically be notified of the progress on
your report as I make changes.
AUTHOR
Klaus Ita
koki [at] worstofall.com
Maroš Kollár
CPAN ID: MAROS
maros [at] k-1.com
L<http://www.revdev.at>
ACKNOWLEDGEMENTS
This module was originally written by Klaus Ita (Koki) for Revdev
<http://www.revdev.at>, a nice litte software company I (Maros) run with
Koki and Domm (<http://search.cpan.org/~domm/>).
COPYRIGHT
Bitmask::Data is Copyright (c) 2008 Klaus Ita, Maroš Kollár -
<http://www.revdev.at>
This program is free software; you can redistribute it and/or modify it
under the same terms as Perl itself.
The full text of the license can be found in the LICENSE file included
with this module.