The 'PUAA' table

General table information

The Private Use Area attribute table (tag name: 'PUAA') provides a method for specifying Unicode character properties for characters in the Unicode Private Use Area (code points E000-F8FF, F0000-FFFFD, and 100000-10FFFD).

This table is not part of the Unicode Standard and is not endorsed by the Unicode Consortium. The information included in this table should be considered informative only and is not expected to be used by any text rendering engine.

PUA Attribute Table Format

The table header gives the table version number, the number of properties defined, and the offset in bytes to the property name and subtable. The format of the table header is as follows:

Type	Name	Description
UInt16	version	The table version number. Set to 1.
UInt16	propertyCount	The number of properties defined.
PropertyRecord	propertyRecord[propertyCount]	The property records array.
variable	subtables	Property subtable headers.
variable	entryData	Subtable entry data.
variable	stringData	Character strings in UTF-8.

The property records array follows the table header. Each record consists of an offset to the property name and an offset to the subtable header. Here is the format of a PropertyRecord:

Type	Name	Description
UInt32	propertyNameOffset	Offset in bytes from the start of the table to the property name.
UInt32	subtableHeaderOffset	Offset in bytes from the start of the table to the subtable header.

Property records should be sorted in ascending order by property name.

Property Subtable Format

Each property record points to a property subtable header consisting of the number of entries and an array of entry records. The format of the subtable header is as follows:

Type	Name	Description
UInt16	entryCount	The number of entries in this subtable.
EntryRecord	entryRecord[entryCount]	The entry records array.

The entry records array follows the subtable header. Each record consists of a type, a range of code points, and a value or offset.

Type	Name	Description
UInt8	entryType	The type of the entry data.
UInt8	plane	The Unicode plane of the range of code points covered by this entry. One of 0, 15, or 16.
UInt16	firstCodePoint	The least significant 16 bits of the first code point covered by this entry.
UInt16	lastCodePoint	The least significant 16 bits of the last code point covered by this entry.
UInt32	entryData	Interpretation varies according to entryType.

The entryType field determines the interpretation of the entryData field:

Entry Type ID	Entry Type	Meaning
1	Single	The entryData field contains either an offset to a UTF-8 character string or a 0-4 byte ASCII character string.
2	Multiple	The entryData field contains an offset to an array of Single values, one for each code point.
3	Boolean	The entryData field contains zero for a false property value or nonzero for a true property value.
4	Decimal	The entryData field contains a plain integer value.
5	Hexadecimal	The entryData field contains a Unicode code point value.
6	HexMultiple	The entryData field contains an offset to an array of Hexadecimal values, one for each code point.
7	HexSequence	The entryData field contains an offset to an array of Unicode code point values.
8	CaseMapping	The entryData field contains an offset to an array of Unicode code point values, plus a Single value.
9	NameAlias	The entryData field contains an offset to an array of two Single values, one for a name and one for a name type.

TBC