/*FUNCTION	<<wcwidth>>---number of column positions of a wide-character code	INDEX	wcwidth SYNOPSIS	#include <wchar.h>	int wcwidth(const wint_t <[wc]>); DESCRIPTION	The <<wcwidth>> function shall determine the number of column	positions required for the wide character <[wc]>. The application	shall ensure that the value of <[wc]> is a character representable	as a wint_t (combining Unicode surrogate pairs into single 21-bit	Unicode code points), and is a wide-character code corresponding to a	valid character in the current locale. RETURNS	The <<wcwidth>> function shall either return 0 (if <[wc]> is a null	wide-character code), or return the number of column positions to	be occupied by the wide-character code <[wc]>, or return -1 (if <[wc]>	does not correspond to a printable wide-character code). PORTABILITY<<wcwidth>> has been introduced in the Single UNIX Specification Volume 2.<<wcwidth>> has been marked as an extension in the Single UNIX Specification Volume 3.*/ /* * This is an implementation of wcwidth() (defined in * IEEE Std 1002.1-2001) for Unicode. * * http://www.opengroup.org/onlinepubs/007904975/functions/wcwidth.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 <_ansi.h>#include <wchar.h>#ifndef _MB_CAPABLE#include <wctype.h> /* iswprint, iswcntrl */#endif#include "local.h" #ifdef _MB_CAPABLEstruct interval{  int first;  int last;}; /* auxiliary function for binary search in interval table */static intbisearch(wint_t ucs, const struct interval *table, int max){  int min = 0;  int mid;   if (ucs < table[0].first || ucs > table[max].last)    return 0;  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 1;    }   return 0;}#endif /* _MB_CAPABLE */ /* The following function defines 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. * *    - If the current language is recognized as a language usually using *      CJK fonts, spacing characters in the East Asian Ambiguous (A) *      category as defined in Unicode Technical Report #11 have a column *      width of 2. * *    - 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 wint_t characters are encoded * in ISO 10646. */ int__wcwidth (const wint_t ucs){#ifdef _MB_CAPABLE  /* sorted list of non-overlapping intervals of East Asian Ambiguous chars */  static const struct interval ambiguous[] =#include "ambiguous.t"   /* sorted list of non-overlapping intervals of non-spacing characters */  static const struct interval combining[] =#include "combining.t"   /* sorted list of non-overlapping intervals of wide characters,     ranges extended to Blocks where possible   */  static const struct interval wide[] =#include "wide.t"   /* Test for NUL character */  if (ucs == 0)    return 0;   /* Test for printable ASCII characters */  if (ucs >= 0x20 && ucs < 0x7f)    return 1;   /* Test for control characters */  if (ucs < 0xa0)    return -1;   /* Test for surrogate pair values. */  if (ucs >= 0xd800 && ucs <= 0xdfff)    return -1;   /* check CJK width mode (1: ambiguous-wide, 0: normal, -1: disabled) */  int cjk_lang = __locale_cjk_lang ();   /* binary search in table of ambiguous characters */  if (cjk_lang > 0      && bisearch(ucs, ambiguous,		  sizeof(ambiguous) / sizeof(struct interval) - 1))    return 2;   /* 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 wide character codes */  if (cjk_lang >= 0      && bisearch(ucs, wide,	       sizeof(wide) / sizeof(struct interval) - 1))    return 2;  else    return 1;#else /* !_MB_CAPABLE */  if (iswprint (ucs))    return 1;  if (iswcntrl (ucs) || ucs == L'\0')    return 0;  return -1;#endif /* _MB_CAPABLE */} intwcwidth (const wint_t wc){  wint_t wi = wc; #ifdef _MB_CAPABLE  wi = _jp2uc (wi);#endif /* _MB_CAPABLE */  return __wcwidth (wi);}