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Extended Unix Code (EUC) is a multibyte character encoding system used primarily for Japanese, Korean, and simplified Chinese. The structure of EUC is based on the ISO-2022 standard, which specifies a way to represent character sets containing a maximum of 94 characters, or 8836 (942) characters, or 830584 (943) characters, as sequences of 7-bit codes. Only ISO-2022 compliant character sets can have EUC forms. Up to four coded character sets (referred to as G0, G1, G2, and G3 or as code sets 0, 1, 2, and 3) can be represented with the EUC scheme. G0 is almost always an ISO-646 compliant coded character set (e.g. US-ASCII/KS X 1003/ISO 646:KR in EUC-KR and US-ASCII/the ''lower half'' of JIS X 0201 in EUC-JP) that is invoked on GL (i.e. with the most significant bit cleared). To get the EUC form of an ISO-2022 character, the most significant bit of each 7-bit byte of the original ISO 2022 codes is set (by adding 128 to each of these original 7-bit codes); this allows software to easily distinguish whether a particular byte in a character string belongs to the ISO-646 code or the ISO-2022 (EUC) code. The most commonly used EUC codes are variable-width encodings with a character belonging to G0 (ISO-646 compliant coded character set) taking one byte and a character belonging to G1 (taken by a 94x94 coded character set) represented in two bytes. The EUC-CN form of GB2312 and EUC-KR are examples of such two-byte EUC codes. EUC-JP includes characters represented by up to three bytes whereas a single character in EUC-TW can take up to four bytes. Modern applications are more likely to use UTF-8, which supports all of the glyphs of the EUC codes, and more, and is generally more portable with fewer vendor deviations and errors. ==EUC-CN== EUC-CN is the usual way to use the GB2312 standard for simplified Chinese characters. Unlike the case of Japanese, the ISO-2022 form of GB2312 is not normally used, though a variant form called HZ was sometimes used on USENET. EUC-CN can also be used to encode the Unicode-based GB18030 character encoding, which includes traditional characters, although GB18030 is more frequently used without EUC encoding, since GB18030 is already a Unicode encoding. However, GB18030 encoded in EUC-CN is a variable-width encoding, because GB18030 contains more than 8836 (94×94) characters. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Extended Unix Code」の詳細全文を読む スポンサード リンク
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