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String­Bytevector­Conversion­Cowan

cowan
2012-11-23 01:32:32
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This proposal extends the (scheme base) procedures utf8->string and string->utf8 to additional encodings, providing procedures that translate between strings and bytevectors that encode those strings using the UTF-16, UTF-16LE, and UTF-16BE encodings.

Procedures

(utf16->string bytevector start end)

(utf16le->string bytevector start end)

(utf16be->string bytevector start end)

Decodes the bytes of bytevector between start and end and returns the corresponding string. It is an error for bytevector to contain byte sequences representing characters which are forbidden in strings. If the first two bytes of the bytevector are either #xFE #xFF or #xFF #xFE, then utf16->string interprets them as a byte order mark, and uses that to interpret the rest of the bytevector as little-endian or big-endian respectively. If no byte order mark is present, the assumed byte order is implementation-defined. The other two procedures always interpret the encoded form as little-endian or big-endian respectively, and do not recognize any byte order mark.

(string->utf16 string start end)

(string->utf16le string start end)

(string->utf16be string start end)

Encodes the characters of string between start and end and returns the corresponding bytevector. String->utf16 always generates a byte order mark, but the byte order it generates is implementation-defined. The other two procedures always generate the encoded form as little-endian or big-endian respectively, and do not generate any byte order mark.