/* * This is an implementation of wcwidth() and wcswidth() (defined in * IEEE Std 1002.1-2001) for Unicode. * * http://www.opengroup.org/onlinepubs/007904975/functions/wcwidth.html * http://www.opengroup.org/onlinepubs/007904975/functions/wcswidth.html * * In fixed-width output devices, Latin characters all occupy a single * "cell" position of equal width, whereas ideographic CJK characters * occupy two such cells. Interoperability between terminal-line * applications and (teletype-style) character terminals using the * UTF-8 encoding requires agreement on which character should advance * the cursor by how many cell positions. No established formal * standards exist at present on which Unicode character shall occupy * how many cell positions on character terminals. These routines are * a first attempt of defining such behavior based on simple rules * applied to data provided by the Unicode Consortium. * * For some graphical characters, the Unicode standard explicitly * defines a character-cell width via the definition of the East Asian * FullWidth (F), Wide (W), Half-width (H), and Narrow (Na) classes. * In all these cases, there is no ambiguity about which width a * terminal shall use. For characters in the East Asian Ambiguous (A) * class, the width choice depends purely on a preference of backward * compatibility with either historic CJK or Western practice. * Choosing single-width for these characters is easy to justify as * the appropriate long-term solution, as the CJK practice of * displaying these characters as double-width comes from historic * implementation simplicity (8-bit encoded characters were displayed * single-width and 16-bit ones double-width, even for Greek, * Cyrillic, etc.) and not any typographic considerations. * * Much less clear is the choice of width for the Not East Asian * (Neutral) class. Existing practice does not dictate a width for any * of these characters. It would nevertheless make sense * typographically to allocate two character cells to characters such * as for instance EM SPACE or VOLUME INTEGRAL, which cannot be * represented adequately with a single-width glyph. The following * routines at present merely assign a single-cell width to all * neutral characters, in the interest of simplicity. This is not * entirely satisfactory and should be reconsidered before * establishing a formal standard in this area. At the moment, the * decision which Not East Asian (Neutral) characters should be * represented by double-width glyphs cannot yet be answered by * applying a simple rule from the Unicode database content. Setting * up a proper standard for the behavior of UTF-8 character terminals * will require a careful analysis not only of each Unicode character, * but also of each presentation form, something the author of these * routines has avoided to do so far. * * http://www.unicode.org/unicode/reports/tr11/ * * Markus Kuhn -- 2007-05-26 (Unicode 5.0) * * Permission to use, copy, modify, and distribute this software * for any purpose and without fee is hereby granted. The author * disclaims all warranties with regard to this software. * * Latest version: http://www.cl.cam.ac.uk/~mgk25/ucs/wcwidth.c */ #include #include "putty.h" /* for prototypes */ struct interval { unsigned int first; unsigned int last; }; /* auxiliary function for binary search in interval table */ static bool bisearch(unsigned int ucs, const struct interval *table, int max) { int min = 0; int mid; if (ucs < table[0].first || ucs > table[max].last) return false; while (max >= min) { mid = (min + max) / 2; if (ucs > table[mid].last) min = mid + 1; else if (ucs < table[mid].first) max = mid - 1; else return true; } return false; } /* The following two functions define the column width of an ISO 10646 * character as follows: * * - The null character (U+0000) has a column width of 0. * * - Other C0/C1 control characters and DEL will lead to a return * value of -1. * * - Non-spacing and enclosing combining characters (general * category code Mn or Me in the Unicode database) have a * column width of 0. * * - SOFT HYPHEN (U+00AD) has a column width of 1. * * - Other format characters (general category code Cf in the Unicode * database) and ZERO WIDTH SPACE (U+200B) have a column width of 0. * * - Hangul Jamo medial vowels and final consonants (U+1160-U+11FF) * have a column width of 0. * * - Spacing characters in the East Asian Wide (W) or East Asian * Full-width (F) category as defined in Unicode Technical * Report #11 have a column width of 2. * * - All remaining characters (including all printable * ISO 8859-1 and WGL4 characters, Unicode control characters, * etc.) have a column width of 1. * * This implementation assumes that wchar_t characters are encoded * in ISO 10646. */ int mk_wcwidth(unsigned int ucs) { /* sorted list of non-overlapping intervals of non-spacing characters */ static const struct interval combining[] = { #include "unicode/nonspacing_chars.h" }; /* A sorted list of intervals of double-width characters */ static const struct interval wide[] = { #include "unicode/wide_chars.h" }; /* test for 8-bit control characters */ if (ucs == 0) return 0; if (ucs < 32 || (ucs >= 0x7f && ucs < 0xa0)) return -1; /* binary search in table of non-spacing characters */ if (bisearch(ucs, combining, sizeof(combining) / sizeof(struct interval) - 1)) return 0; /* if we arrive here, ucs is not a combining or C0/C1 control character */ /* binary search in table of double-width characters */ if (bisearch(ucs, wide, sizeof(wide) / sizeof(struct interval) - 1)) return 2; /* normal width character */ return 1; } int mk_wcswidth(const unsigned int *pwcs, size_t n) { int w, width = 0; for (;*pwcs && n-- > 0; pwcs++) if ((w = mk_wcwidth(*pwcs)) < 0) return -1; else width += w; return width; } /* * The following functions are the same as mk_wcwidth() and * mk_wcswidth(), except that spacing characters in the East Asian * Ambiguous (A) category as defined in Unicode Technical Report #11 * have a column width of 2. This variant might be useful for users of * CJK legacy encodings who want to migrate to UCS without changing * the traditional terminal character-width behaviour. It is not * otherwise recommended for general use. */ int mk_wcwidth_cjk(unsigned int ucs) { /* A sorted list of intervals of ambiguous width characters */ static const struct interval ambiguous[] = { #include "unicode/ambiguous_wide_chars.h" }; /* binary search in table of non-spacing characters */ if (bisearch(ucs, ambiguous, sizeof(ambiguous) / sizeof(struct interval) - 1)) return 2; return mk_wcwidth(ucs); } int mk_wcswidth_cjk(const unsigned int *pwcs, size_t n) { int w, width = 0; for (;*pwcs && n-- > 0; pwcs++) if ((w = mk_wcwidth_cjk(*pwcs)) < 0) return -1; else width += w; return width; }