The data model

A CBOR data item is one of eight major types, numbered 0 to 7. Every one of them has a class in this library, and some have two: one for the definite-length encoding, one for the indefinite-length form.

Type	Description	PHP classes
0	Unsigned integer	UnsignedIntegerObject
1	Negative integer	NegativeIntegerObject
2	Byte string	ByteStringObject, IndefiniteLengthByteStringObject
3	Text string	TextStringObject, IndefiniteLengthTextStringObject
4	Array	ListObject, IndefiniteLengthListObject
5	Map	MapObject, IndefiniteLengthMapObject
6	Tag	subclasses of Tag, see tags
7	Simple value or float	TrueObject, FalseObject, NullObject, the float objects

Every class lives in the CBOR namespace, the tags in CBOR\Tag, and the simple values and floats in CBOR\OtherObject.

The hierarchy of classes

CBORObject (interface)
└── AbstractCBORObject (abstract)
    ├── UnsignedIntegerObject
    ├── NegativeIntegerObject
    ├── ByteStringObject
    ├── IndefiniteLengthByteStringObject
    ├── TextStringObject
    ├── IndefiniteLengthTextStringObject
    ├── ListObject
    ├── IndefiniteLengthListObject
    ├── MapObject
    ├── IndefiniteLengthMapObject
    ├── Tag (abstract)
    │   ├── DatetimeTag
    │   ├── TimestampTag
    │   ├── DecimalFractionTag
    │   ├── BigFloatTag
    │   ├── CoseSign1Tag, UuidTag, SetTag…
    │   ├── … the other built-in tags
    │   └── GenericTag
    └── OtherObject (abstract)
        ├── TrueObject
        ├── FalseObject
        ├── NullObject
        ├── UndefinedObject
        ├── DoublePrecisionFloatObject
        └── …

Two things are true of every object of that tree, whatever its type:

• it is built by a static create() method, never by new;
• casting it to a string encodes it, because each one implements __toString().

Most of them also implement Normalizable, which turns a decoded object into a native PHP value. That is the subject of normalization.