CHARACTER ENCODING
\kˈaɹɪktəɹ ɛnkˈə͡ʊdɪŋ], \kˈaɹɪktəɹ ɛnkˈəʊdɪŋ], \k_ˈa_ɹ_ɪ_k_t_ə_ɹ ɛ_n_k_ˈəʊ_d_ɪ_ŋ]\
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(Or "character encoding scheme") A mapping ofbinary values to code positions and back; generally a 1:1(bijective) mapping.In the case of ASCII, this is generally a f(x)=x mapping:code point 65 maps to the byte value 65, and vice versa. Thisis possible because ASCII uses only code positionsrepresentable as single bytes, i.e., values between 0 and 255,at most. (US-ASCII only uses values 0 to 127, in fact.)Unicode and many CJK coded character sets use many morethan 255 positions, requiring more complex mappings: sometimesthe characters are mapped onto pairs of bytes (see DBCS).In many cases, this breaks programs that assume a one-to-onemapping of bytes to characters, and so, for example, treat anyoccurrance of the byte value 13 as a carriage return. Toavoid this problem, character encodings such as UTF-8 weredevised.
By Denis Howe
Word of the day
Platidiam
- An inorganic water-soluble platinum complex. After undergoing hydrolysis, it reacts DNA produce both intra interstrand crosslinks. These crosslinks appear to impair replication and transcription of DNA. The cytotoxicity cisplatin correlates with cellular arrest in G2 phase cell cycle.