IsUTF16CharValid function

In unit LazUTF16

Returns True if the specified values are a valid UTF-16 character (codepoint).

Declaration

pascal

function IsUTF16CharValid(AChar: WideChar; ANextChar: WideChar)
: Boolean

Arguments

`AChar`	First UTF-16 code examined in the method.
`ANextChar`	Next UTF-16 code examined in the method.

Function result

Returns False if AChar is #0 or AChar and ANextChar are unpaired surrogates.

Description

Based on the specification defined by the Unicode consortium, at:

https://unicode.org/faq/utf_bom.html#utf16-7

Q: Are there any 16-bit values that are invalid?

A: Unpaired surrogates are invalid in UTFs. These include any value in the range D800 to DBFF not followed by a value in the range DC00 to DFFF, or any value in the range DC00 to DFFF not preceded by a value in the range D800 to DBFF. [AF]

If ANextChar is set to #0 there is no next character.

An experiment, built from development snapshots. Not the official Free Pascal or Lazarus documentation.