StdAppInfo(3) User Contributed Perl Documentation StdAppInfo(3)NAME
Palm::StdAppInfo - Handles standard AppInfo block (categories)
SYNOPSIS
Usually:
package MyPDBHandler;
use Palm::StdAppInfo(); # Note the parentheses
@ISA = qw( Palm::StdAppInfo );
use constant APPINFO_PADDING = 1;
sub ParseAppInfoBlock {
my $self = shift;
my $data = shift;
my $appinfo = {};
&Palm::StdAppInfo::parse_StdAppInfo($appinfo, $data);
$app_specific_data = $appinfo->{other};
}
sub PackAppInfoBlock {
my $self = shift;
my $retval;
$self->{appinfo}{other} = <pack application-specific data>;
$retval = &Palm::StdAppInfo::pack_StdAppInfo($self->{appinfo});
return $retval;
}
Or as a standalone "PDB" helper class:
use Palm::StdAppInfo;
DESCRIPTION
Many Palm applications use a common format for keeping track of
categories. The "Palm::StdAppInfo" class deals with this common
format:
$pdb = new Palm::PDB;
$pdb->Load("myfile.pdb");
@categories = @{$pdb->{appinfo}{categories}};
$lastUniqueID = $pdb->{appinfo}{lastUniqueID};
$other = $pdb->{appinfo}{other};
where:
@categories is an array of references-to-hash:
"$cat = $categories[0];"
"$cat->{name}"
The name of the category, a string of at most 16 characters.
"$cat->{id}"
The category ID, an integer in the range 0-255. Each category has a
unique ID. By convention, 0 is reserved for the "Unfiled" category;
IDs assigned by the Palm are in the range 1-127, and IDs assigned
by the desktop are in the range 128-255.
"$cat->{renamed}"
A boolean. This field is true iff the category has been renamed
since the last sync.
$lastUniqueID is (I think) the last category ID that was assigned.
$other is any data that follows the category list in the AppInfo block.
If you're writing a helper class for a PDB that includes a category
list, you should parse this field to get any data that follows the
category list; you should also make sure that this field is initialized
before you call &Palm::StdAppInfo::pack_AppInfo.
APPINFO_PADDING
Normally, the AppInfo block includes a byte of padding at the end, to
bring its length to an even number. However, some databases use this
byte for data.
If your database uses the padding byte for data, then your
&ParseAppInfoBlock method (see "SYNOPSIS") should call
&parse_StdAppInfo with a true $nopadding argument.
If, for whatever reason, you wish to inherit
&StdAppInfo::ParseAppInfoBlock, then add
use constant APPINFO_PADDING => 0;
to your handler package, to tell it that the padding byte is really
data.
FUNCTIONS
seed_StdAppInfo
&Palm::StdAppInfo::seed_StdAppInfo(\%appinfo);
Creates the standard fields in an existing AppInfo hash. Usually used
to ensure that a newly-created AppInfo block contains an initialized
category array:
my $appinfo = {};
&Palm::StdAppInfo::seed_StdAppInfo($appinfo);
Note: this is not a method.
newStdAppInfo
$appinfo = Palm::StdAppInfo->newStdAppInfo;
Like "seed_StdAppInfo", but creates an AppInfo hash and returns a
reference to it.
new
$pdb = new Palm::StdAppInfo;
Create a new PDB, initialized with nothing but a standard AppInfo
block.
There are very few reasons to use this, and even fewer good ones. If
you're writing a helper class to parse some PDB format that contains a
category list, then you should make that helper class a subclass of
"Palm::StdAppInfo".
parse_StdAppInfo
$len = &Palm::StdAppInfo::parse_StdAppInfo(\%appinfo, $data, $nopadding);
This function (this is not a method) is intended to be called from
within a PDB helper class's "ParseAppInfoBlock" method.
"parse_StdAppInfo()" parses a standard AppInfo block from the raw data
$data and fills in the fields in %appinfo. It returns the number of
bytes parsed.
$nopadding is optional, and defaults to false. Normally, the AppInfo
block includes a padding byte at the end. If $nopadding is true, then
&parse_StdAppInfo assumes that the padding byte is application data,
and includes it in $appinfo{'other'}, so that the caller can parse it.
ParseAppInfoBlock
$pdb = new Palm::StdAppInfo;
$pdb->ParseAppInfoBlock($data);
If your application's AppInfo block contains standard category support
and nothing else, you may choose to just inherit this method instead of
writing your own "ParseAppInfoBlock" method. Otherwise, see the example
in "SYNOPSIS".
pack_StdAppInfo
$data = &Palm::StdAppInfo::pack_StdAppInfo(\%appinfo);
This function (this is not a method) is intended to be called from
within a PDB helper class's "PackAppInfoBlock" method.
"pack_StdAppInfo" takes an AppInfo hash and packs it as a string of raw
data that can be written to a PDB.
Note that if you're using this inside a helper class's
"PackAppInfoBlock" method, you should make sure that $appinfo{other} is
properly initialized before you call
&Palm::StdAppInfo::pack_StdAppInfo.
$nopadding is optional, and defaults to false. Normally, the AppInfo
block includes a byte of padding at the end. If $nopadding is true,
then &pack_StdAppInfo doesn't include this byte of padding, so that the
application can use it.
PackAppInfoBlock
$pdb = new Palm::StdAppInfo;
$data = $pdb->PackAppInfoBlock();
If your application's AppInfo block contains standard category support
and nothing else, you may choose to just inherit this method instead of
writing your own "PackAppInfoBlock" method. Otherwise, see the example
in "SYNOPSIS".
addCategory
$pdb->addCategory($name [, $id [, $renamed]]);
Adds a category to $pdb.
The $name argument specifies the new category's name.
The optional $id argument specifies the new category's numeric ID; if
omitted or undefined, &addCategory will pick one.
The optional $renamed argument is a boolean value indicating whether
the new category should be marked as having been modified. This
defaults to true since, conceptually, &addCategory doesn't really add a
category: it finds one whose name happens to be empty, and renames it.
Returns a true value if successful, false otherwise. In case of
failure, &addCategory sets $Palm::StdAppInfo::error to an error
message.
deleteCategory
$pdb->deleteCategory($name);
Deletes the category with name $name. Actually, though, it doesn't
delete the category: it just changes its name to the empty string, and
marks the category as renamed.
renameCategory
$pdb->renameCategory($oldname, $newname);
Renames the category named $oldname to $newname.
If successful, returns a true value. If there is no category named
$oldname, returns a false value and sets $Palm::StdAppInfo::error to an
error message.
SOURCE CONTROL
The source is in Github:
http://github.com/briandfoy/p5-Palm/tree/master
AUTHOR
Alessandro Zummo, "<a.zummo@towertech.it>"
Currently maintained by brian d foy, "<bdfoy@cpan.org>"
SEE ALSOPalm::PDB(3)perl v5.14.0 2010-02-23 StdAppInfo(3)
