decodeutf8

Decodeutf8 refers to the process of converting a sequence of bytes encoded in UTF-8 into a Unicode string. UTF-8 is the dominant encoding for Unicode on the web and in many programming environments, using one to four bytes per character. Decoding UTF-8 involves reading the byte stream, interpreting multi-byte sequences, and producing the corresponding Unicode code points.

Input for a decodeutf8 operation is typically a byte array or binary string. The output is a text string containing Unicode characters. In many implementations, a leading Byte Order Mark (BOM) can be detected and discarded if present, and decoding may be performed in streaming fashion, where chunks of data are decoded as they arrive with attention to possible cut sequences at chunk boundaries.

Error handling varies. Strict decoders raise errors when encountering invalid UTF-8 sequences, overlong encodings, or code points outside the allowed range. Lenient decoders may substitute invalid sequences with a replacement character (U+FFFD) or ignore them. Correct decoding must also reject surrogate code points, which are not valid as independent characters in UTF-8.

In practice, decodeutf8 is provided by standard libraries under various names. In Python, for example, a byte sequence can be decoded with the utf-8 codec. Other languages expose similar functionality via encoding APIs or constructors that take "utf-8" as the target encoding. Proper use is essential when processing external data to avoid misinterpretation or security vulnerabilities.

See also: UTF-8, Unicode, encoding, decoding, BOM, replacement character.