Quick reference

// Encoding
$text = TextStringObject::create('hello');
$int = UnsignedIntegerObject::create(42);
$list = ListObject::create([$text, $int]);
$map = MapObject::create()->add($text, $int);
$tagged = TimestampTag::create($int);
$encoded = (string) $map;

// Decoding
$decoder = Decoder::create();
$stream = StringStream::create($encoded);
$object = $decoder->decode($stream);
$phpValue = $object->normalize();

// Tags
$timestamp = TimestampTag::create(UnsignedIntegerObject::create(time()));
$decimal = DecimalFractionTag::createFromFloat(3.14);
$datetime = DatetimeTag::create(TextStringObject::create('2024-01-15T10:30:00Z'));

The classes, by major type

Type	Class	Definite and indefinite
0	UnsignedIntegerObject	—
1	NegativeIntegerObject	—
2	ByteStringObject	IndefiniteLengthByteStringObject
3	TextStringObject	IndefiniteLengthTextStringObject
4	ListObject	IndefiniteLengthListObject
5	MapObject	IndefiniteLengthMapObject
6	a subclass of Tag	—
7	TrueObject, FalseObject, NullObject, UndefinedObject, the float objects	—

The calls you need

What	How
Build any object	SomeObject::create(…)
Encode	(string) $object
Decode	Decoder::create()->decode(StringStream::create($bytes))
Limit the nesting	Decoder::create(null, null, 32)
To a PHP value	$object->normalize()
The object a tag wraps	$tag->getValue()
A tag number	TagClass::getTagId()
Register your tags	Decoder::create(TagManager::create([…]))
Count a list or a map	count($object)
Read a map entry	$map->get('key'), $map->has('key')

The tag numbers the library implements are listed in the IANA registry.