IMPORTANT: Project has moved to github because of power of Git :-)

What is metatable?

metatable aims to provide simple interface to store and retrieve data. It is written entirely in PHP and uses only basic PHP functions, so no extensions are needed. But still metatable should be fast enough to be used as storage backend in some sort of applications. Data are stored in binary file in metatable's own format.

Data representation

metatable is big hashmap, which associates (row : string, column : string) pair to value. Currently supported value types are: string, int (32bit) and boolean. string is uninterpreted, so other types may be stored in their binary form as string. Maximal lengths of row and col are 124 bytes.

metatable file is composed from frames and structure of frames written at the end of file. Frames are named, name of frame consists from 4 bytes (there is possibility to have at most 2^32 frames). Data itself are stored as sorted set of fixed-size records in data frame. Values of type string are stored in another frame called strs. The last basic frame is indx where „indexes“ are stored.

Basic usage

To open up metatable file use metatable::open():

```

$table = metatable::open('foo'); ```

Either FALSE or newly created instance of metatable is returned. metatable object has only a few public methods – get(), set(), index(), unindex() and close(). get() and set() are used to retrieve and store values. When passing NULL to set() as value, record is deleted.

``` $table->set('foo', 'bar', 5);

$table->get('foo', 'bar'); // => array('foo' => array('bar' => 5))

$table->set('foo', 'bar', NULL);

$table->get('foo', 'bar'); // => array() ```

index() and unindex() creates and drops indexes. Index is precomputed saved value, where data are stored in data frame. Indexes can be created only of there are some values to index.

The last method close() saves structure informations and closes metatable file. metatable is constructed in way that each instance is „transaction“ – all operations are performed or none of them – data integrity is assured.

Advanced usage

metatable::open() flags

metatable::open() takes two arguments – $filename and $flags, where $flags is integer – or-ed list of flags defined in metatable class constants. Possible flags are:

• READONLY – metatable is opened readonly, cannot do set() and is not saved on closing (defautly turned off)
• READWRITE – all operations are possible (defaulty on)
• STRINGS_GC – strings are garbage collected (defaultly on)
• AUTOCLOSE – automatically saved on instance destruction (defaultly off)

What next?

That is all of metatable. If you want to try, go to download section.