Provided by: libpalm-perl_1.012-2_all 
NAME
Palm::PDB - Parse Palm database files.
SYNOPSIS
use Palm::PDB;
use SomeHelperClass;
$pdb = new Palm::PDB;
$pdb->Load("myfile.pdb");
# Manipulate records in $pdb
$pdb->Write("myotherfile.pdb");
(Note: yes, you do want to use "Palm::PDB", even if you're dealing with some other type of
database. $pdb will be reblessed to the appropriate type by "$pdb->Load".)
DESCRIPTION
The Palm::PDB module provides a framework for reading and writing database files for use
on PalmOS devices such as the PalmPilot. It can read and write both Palm Database (".pdb")
and Palm Resource (".prc") files.
By itself, the PDB module is not terribly useful; it is intended to be used in conjunction
with supplemental modules for specific types of databases, such as Palm::Raw or
Palm::Memo.
The Palm::PDB module encapsulates the common work of parsing the structure of a Palm
database. The Load() function reads the file, then passes the individual chunks (header,
records, etc.) to application-specific functions for processing. Similarly, the Write()
function calls application-specific functions to get the individual chunks, then writes
them to a file.
METHODS
new
$new = new Palm::PDB();
Creates a new PDB. $new is a reference to an anonymous hash. Some of its elements have
special significance. See Load().
RegisterPDBHandlers
&Palm::PDB::RegisterPDBHandlers("classname", typespec...);
Typically:
&Palm::PDB::RegisterPDBHandlers(__PACKAGE__,
[ "FooB", "DATA" ],
);
The $pdb->Load() method acts as a virtual constructor. When it reads the header of a
".pdb" file, it looks up the file's creator and type in a set of tables, and reblesses
$pdb into a class capable of parsing the application-specific parts of the file (AppInfo
block, records, etc.)
RegisterPDBHandlers() adds entries to these tables; it says that any file whose creator
and/or type match any of the typespecs (there may be several) should be reblessed into the
class classname.
Note that RegisterPDBHandlers() applies only to record databases (".pdb" files). For
resource databases, see RegisterPRCHandlers().
RegisterPDBHandlers() is typically called in the import() function of a helper class. In
this case, the class is registering itself, and it is simplest just to use "__PACKAGE__"
for the package name:
package PalmFoo;
use Palm::PDB;
sub import
{
&Palm::PDB::RegisterPDBHandlers(__PACKAGE__,
[ "FooZ", "DATA" ]
);
}
A typespec can be either a string, or an anonymous array with two elements. If it is an
anonymous array, then the first element is the file's creator; the second element is its
type. If a typespec is a string, it is equivalent to specifying that string as the
database's creator, and a wildcard as its type.
The creator and type should be either four-character strings, or the empty string. An
empty string represents a wildcard. Thus:
&Palm::PDB::RegisterPDBHandlers("MyClass",
[ "fOOf", "DATA" ],
[ "BarB", "" ],
[ "", "BazQ" ],
"Fred"
);
Class MyClass will handle:
Databases whose creator is "fOOf" and whose type is "DATA".
Databases whose creator is "BarB", of any type.
Databases with any creator whose type is "BazQ".
Databases whose creator is "Fred", of any type.
RegisterPRCHandlers
&Palm::PDB::RegisterPRCHandlers("classname", typespec...);
Typically:
&Palm::PDB::RegisterPRCHandlers(__PACKAGE__,
[ "FooZ", "CODE" ],
);
RegisterPRCHandlers() is similar to RegisterPDBHandlers(), but specifies a class to handle
resource database (".prc") files.
A class for parsing applications should begin with:
package PalmApps;
use Palm::PDB;
sub import
{
&Palm::PDB::RegisterPRCHandlers(__PACKAGE__,
[ "", "appl" ]
);
}
Load
$pdb->Load($filename);
Reads the file $filename, parses it, reblesses $pdb to the appropriate class, and invokes
appropriate methods to parse the application-specific parts of the database (see "HELPER
CLASSES").
$filename may also be an open file handle (as long as it's seekable). This allows for
manipulating databases in memory structures.
Load() uses the typespecs given to RegisterPDBHandlers() and RegisterPRCHandlers() when
deciding how to rebless $pdb. For record databases, it uses the typespecs passed to
RegisterPDBHandlers(), and for resource databases, it uses the typespecs passed to
RegisterPRCHandlers().
Load() looks for matching typespecs in the following order, from most to least specific:
1. A typespec that specifies both the database's creator and its type exactly.
2. A typespec that specifies the database's type and has a wildcard for the creator (this
is rarely used).
3. A typespec that specifies the database's creator and has a wildcard for the type.
4. A typespec that has wildcards for both the creator and type.
Thus, if the database has creator "FooZ" and type "DATA", Load() will first look for
"FooZ"/"DATA", then ""/"DATA", then "FooZ"/"", and finally will fall back on ""/"" (the
universal default).
After Load() returns, $pdb may contain the following fields:
$pdb->{"name"}
The name of the database.
$pdb->{"attributes"}{"ResDB"}
$pdb->{"attributes"}{"ReadOnly"}
$pdb->{"attributes"}{"AppInfoDirty"}
$pdb->{"attributes"}{"Backup"}
$pdb->{"attributes"}{"OKToInstallNewer"}
$pdb->{"attributes"}{"ResetAfterInstall"}
$pdb->{"attributes"}{"CopyPrevention"}
$pdb->{"attributes"}{"Stream"}
$pdb->{"attributes"}{"Hidden"}
$pdb->{"attributes"}{"LaunchableData"}
$pdb->{"attributes"}{"Recyclable"}
$pdb->{"attributes"}{"Bundle"}
$pdb->{"attributes"}{"Open"}
These are the attribute flags from the database header. Each is true iff the
corresponding flag is set.
The "LaunchableData" attribute is set on PQAs.
$pdb->{"version"}
The database's version number. An integer.
$pdb->{"ctime"}
$pdb->{"mtime"}
$pdb->{"baktime"}
The database's creation time, last modification time, and time of last backup, in Unix
"time_t" format (seconds since Jan. 1, 1970).
$pdb->{"modnum"}
The database's modification number. An integer.
$pdb->{"type"}
The database's type. A four-character string.
$pdb->{"creator"}
The database's creator. A four-character string.
$pdb->{"uniqueIDseed"}
The database's unique ID seed. An integer.
$pdb->{"2NULs"}
The two NUL bytes that appear after the record index and the AppInfo block. Included
here because every once in a long while, they are not NULs, for some reason.
$pdb->{"appinfo"}
The AppInfo block, as returned by the $pdb->ParseAppInfoBlock() helper method.
$pdb->{"sort"}
The sort block, as returned by the $pdb->ParseSortBlock() helper method.
@{$pdb->{"records"}}
The list of records in the database, as returned by the $pdb->ParseRecord() helper
method. Resource databases do not have this.
@{$pdb->{"resources"}}
The list of resources in the database, as returned by the $pdb->ParseResource() helper
method. Record databases do not have this.
All of these fields may be set by hand, but should conform to the format given above.
Write
$pdb->Write($filename);
Invokes methods in helper classes to get the application-specific parts of the database,
then writes the database to the file $filename.
$filename may also be an open file handle (as long as it's seekable). This allows for
manipulating databases in memory structures.
Write() uses the following helper methods:
PackAppInfoBlock()
PackSortBlock()
PackResource() or PackRecord()
See also "HELPER CLASSES".
new_Record
$record = Palm::PDB->new_Record();
$record = new_Record Palm::PDB;
Creates a new record, with the bare minimum needed:
$record->{'category'}
$record->{'attributes'}{'Dirty'}
$record->{'id'}
The ``Dirty'' attribute is originally set, since this function will usually be called to
create records to be added to a database.
"new_Record" does not add the new record to a PDB. For that, you want "append_Record".
is_Dirty
$pdb->Write( $fname ) if $pdb->is_Dirty();
Returns non-zero if any of the in-memory elements of the database have been changed. This
includes changes via function calls (any call that changes the $pdb's "last modification"
time) as well as testing the "dirty" status of attributes where possible (i.e. AppInfo,
records, but not resource entries).
append_Record
$record = $pdb->append_Record;
$record2 = $pdb->append_Record($record1);
If called without any arguments, creates a new record with new_Record(), and appends it to
$pdb.
If given a reference to a record, appends that record to @{$pdb->{records}}.
Returns a reference to the newly-appended record.
This method updates $pdb's "last modification" time.
new_Resource
$resource = Palm::PDB->new_Resource();
$resource = new_Resource Palm::PDB;
Creates a new resource and initializes
$resource->{type}
$resource->{id}
append_Resource
$resource = $pdb->append_Resource;
$resource2 = $pdb->append_Resource($resource1);
If called without any arguments, creates a new resource with new_Resource(), and appends
it to $pdb.
If given a reference to a resource, appends that resource to @{$pdb->{resources}}.
Returns a reference to the newly-appended resource.
This method updates $pdb's "last modification" time.
findRecordByID
$record = $pdb->findRecordByID($id);
Looks through the list of records in $pdb, and returns a reference to the record with ID
$id, or the undefined value if no such record was found.
delete_Record
$pdb->delete_Record($record, $expunge);
Marks $record for deletion, so that it will be deleted from the database at the next sync.
If $expunge is false or omitted, the record will be marked for deletion with archival. If
$expunge is true, the record will be marked for deletion without archival.
This method updates $pdb's "last modification" time.
remove_Record
for (@{$pdb->{'records'}})
{
$pdb->remove_Record( $_ ) if $_->{attributes}{deleted};
}
Removes $record from the database. This differs from "delete_Record" in that it's an
actual deletion rather than just setting a flag.
This method updates $pdb's "last modification" time.
HELPER CLASSES
$pdb->Load() reblesses $pdb into a new class. This helper class is expected to convert raw
data from the database into parsed representations of it, and vice-versa.
A helper class must have all of the methods listed below. The Palm::Raw class is useful if
you don't want to define all of the required methods.
ParseAppInfoBlock
$appinfo = $pdb->ParseAppInfoBlock($buf);
$buf is a string of raw data. ParseAppInfoBlock() should parse this data and return it,
typically in the form of a reference to an object or to an anonymous hash.
This method will not be called if the database does not have an AppInfo block.
The return value from ParseAppInfoBlock() will be accessible as $pdb->{appinfo}.
PackAppInfoBlock
$buf = $pdb->PackAppInfoBlock();
This is the converse of ParseAppInfoBlock(). It takes $pdb's AppInfo block,
$pdb->{appinfo}, and returns a string of binary data that can be written to the database
file.
ParseSortBlock
$sort = $pdb->ParseSortBlock($buf);
$buf is a string of raw data. ParseSortBlock() should parse this data and return it,
typically in the form of a reference to an object or to an anonymous hash.
This method will not be called if the database does not have a sort block.
The return value from ParseSortBlock() will be accessible as $pdb->{sort}.
PackSortBlock
$buf = $pdb->PackSortBlock();
This is the converse of ParseSortBlock(). It takes $pdb's sort block, $pdb->{sort}, and
returns a string of raw data that can be written to the database file.
ParseRecord
$record = $pdb->ParseRecord(
offset => $offset, # Record's offset in file
attributes => # Record attributes
{
expunged => bool, # True iff expunged
dirty => bool, # True iff dirty
deleted => bool, # True iff deleted
private => bool, # True iff private
archive => bool, # True iff to be archived
},
category => $category, # Record's category number
id => $id, # Record's unique ID
data => $buf, # Raw record data
);
ParseRecord() takes the arguments listed above and returns a parsed representation of the
record, typically as a reference to a record object or anonymous hash.
The output from ParseRecord() will be appended to @{$pdb->{records}}. The records appear
in this list in the same order as they appear in the file.
$offset argument is not normally useful, but is included for completeness.
The fields in %$attributes are boolean values. They are true iff the record has the
corresponding flag set.
$category is an integer in the range 0-15, which indicates which category the record
belongs to. This is normally an index into a table given at the beginning of the AppInfo
block.
A typical ParseRecord() method has this general form:
sub ParseRecord
{
my $self = shift
my %record = @_;
# Parse $self->{data} and put the fields into new fields in
# $self.
delete $record{data}; # No longer useful
return \%record;
}
PackRecord
$buf = $pdb->PackRecord($record);
The converse of ParseRecord(). PackRecord() takes a record as returned by ParseRecord()
and returns a string of raw data that can be written to the database file.
PackRecord() is never called when writing a resource database.
ParseResource
$record = $pdb->ParseResource(
type => $type, # Resource type
id => $id, # Resource ID
offset => $offset, # Resource's offset in file
data => $buf, # Raw resource data
);
ParseResource() takes the arguments listed above and returns a parsed representation of
the resource, typically as a reference to a resource object or anonymous hash.
The output from ParseResource() will be appended to @{$pdb->{resources}}. The resources
appear in this list in the same order as they appear in the file.
$type is a four-character string giving the resource's type.
$id is an integer that uniquely identifies the resource amongst others of its type.
$offset is not normally useful, but is included for completeness.
PackResource
$buf = $pdb->PackResource($resource);
The converse of ParseResource(). PackResource() takes a resource as returned by
PackResource() and returns a string of raw data that can be written to the database file.
PackResource() is never called when writing a record database.
BUGS
These functions die too easily. They should return an error code.
Database manipulation is still an arcane art.
It may be possible to parse sort blocks further.
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 ALSO
Palm::Raw(3)
Palm::Address(3)
Palm::Datebook(3)
Palm::Mail(3)
Palm::Memo(3)
Palm::ToDo(3)
Palm Database Files, in the ColdSync distribution.
The Virtual Constructor (aka Factory Method) pattern is described in Design Patterns, by
Erich Gamma et al., Addison-Wesley.