UTF16na

UTF16na is a character encoding that represents Unicode characters using two bytes per character. It is a variable-width encoding, meaning that some characters are represented by a single 16-bit unit, while others require two 16-bit units, known as surrogate pairs. This makes it capable of encoding all Unicode characters.

The name UTF16na is a portmanteau of "Unicode Transformation Format 16-bit" and "na" which likely stands for "not applicable" or a similar qualifier indicating a specific implementation or variant. UTF-16 itself is a widely used encoding, particularly in systems like Windows and Java.

UTF16na shares the fundamental characteristics of UTF-16. It uses a sequence of 16-bit code units. Code points in the Basic Multilingual Plane (BMP), which covers the first 65,536 Unicode characters, are represented by a single 16-bit unit. Characters outside the BMP, requiring code points above U+FFFF, are represented using surrogate pairs. A surrogate pair consists of a high surrogate unit followed by a low surrogate unit, both falling within specific reserved ranges.

The endianness of UTF-16 encoding can be specified, often indicated by a Byte Order Mark (BOM) at the beginning of the text. UTF16na would adhere to this, requiring awareness of the byte order when reading or writing data. The primary advantage of UTF-16, and by extension UTF16na, is its efficiency for East Asian languages, where most commonly used characters fall within the BMP. However, it can be less space-efficient than UTF-8 for languages primarily using ASCII characters.