CharConversionException

CharConversion is the process of converting text between different character encodings. In computing, it covers decoding byte sequences into characters and encoding characters back into byte sequences, as well as transcoding between encodings when data moves across systems that use different sets of characters. It also includes Unicode normalization, which transforms text into a canonical form to enable reliable comparison and processing.

Common encodings include ASCII, UTF-8, UTF-16, UTF-32, and legacy code pages such as ISO-8859-1, Windows-1252, Shift JIS, and GB18030. Tools and libraries implement decoding and encoding routines, often with support for streaming data via incremental decoders and encoders. When converting, programmers must decide how to handle invalid or unsupported input, with error modes such as strict (raise an error), replace (substitute a placeholder), or ignore (drop problematic bytes).

Unicode normalization forms (NFC, NFD, NFKC, NFKD) are frequently part of CharConversion, ensuring that visually identical strings have a consistent internal representation. This is important for text comparison, indexing, and search functionality, especially when combining marks and surrogate pairs are involved.

Practical challenges include detecting the correct source encoding when it is not specified, preserving data fidelity during transcoding, and maintaining performance for large or streaming datasets. Security considerations arise from encoding mismatches, which can lead to data corruption or injection vulnerabilities if inputs are mishandled or misdeclared. Best practices emphasize explicit charset declarations, validating input encodings, and preferring Unicode (UTF-8 or UTF-16) as a robust, interoperable standard.