UTF16LE

UTF-16 Little Endian (UTF-16LE) is a Unicode encoding form that uses 16-bit code units to represent Unicode scalar values. It is a variant of UTF-16 that stores the least significant byte first in each 16-bit unit, i.e., little-endian order.

In UTF-16LE, code points in the Basic Multilingual Plane (U+0000 to U+FFFF) are encoded as a single 16-bit unit. Code points above U+FFFF (up to U+10FFFF) require a surrogate pair, consisting of a high surrogate in the range U+D800 to U+DBFF followed by a low surrogate in the range U/DC00 to U+DFFF.

The bytes within each 16-bit unit are stored in little-endian order, so the low byte comes first. For example, the character 'A' (U+0041) becomes 41 00 in UTF-16LE. The character U+1D11E (musical symbol G clef) is encoded as the surrogate pair 0xD834 0xDD1E, yielding the byte sequence 34 D8 1E DD in UTF-16LE.

A Byte Order Mark (BOM) can be used to signal endianness when UTF-16 is used in contexts where endianness might be ambiguous. For UTF-16LE, the BOM would be the bytes FF FE. The BOM is optional; when the encoding is explicitly specified as UTF-16LE, the BOM may be omitted.

UTF-16LE is widely used in Windows environments and in various programming APIs for internal string representation. It can be more compact than UTF-8 for many non-ASCII scripts, but it introduces complexity due to surrogate pairs and makes random access by code points more involved compared to fixed-width encodings.