kc3-lang/gnulib/lib/uniwidth/width.c

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• Hash : 32a72f45
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  Date : 2023-01-01T01:14:21
  

  maint: run 'make update-copyright'
  

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• lib/uniwidth/width.c

• /* Determine display width of Unicode character.
     Copyright (C) 2001-2002, 2006-2023 Free Software Foundation, Inc.
     Written by Bruno Haible <bruno@clisp.org>, 2002.
  
     This file is free software: you can redistribute it and/or modify
     it under the terms of the GNU Lesser General Public License as
     published by the Free Software Foundation; either version 2.1 of the
     License, or (at your option) any later version.
  
     This file is distributed in the hope that it will be useful,
     but WITHOUT ANY WARRANTY; without even the implied warranty of
     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
     GNU Lesser General Public License for more details.
  
     You should have received a copy of the GNU Lesser General Public License
     along with this program.  If not, see <https://www.gnu.org/licenses/>.  */
  
  #include <config.h>
  
  /* Specification.  */
  #include "uniwidth.h"
  
  #include "cjk.h"
  
  /* The non-spacing attribute table consists of:
     * Non-spacing characters; generated from PropList.txt or
       "grep '^[^;]*;[^;]*;[^;]*;[^;]*;NSM;' UnicodeData.txt"
     * Format control characters; generated from
       "grep '^[^;]*;[^;]*;Cf;' UnicodeData.txt"
     * Zero width characters; generated from
       "grep '^[^;]*;ZERO WIDTH ' UnicodeData.txt"
     * Hangul Jamo characters that have conjoining behaviour:
         - jungseong = syllable-middle vowels
         - jongseong = syllable-final consonants
       Rationale:
       1) These characters act like combining characters. They have no
       equivalent in legacy character sets. Therefore the EastAsianWidth.txt
       file does not really matter for them; UAX #11 East Asian Width
       <https://www.unicode.org/reports/tr11/> makes it clear that it focus
       is on compatibility with traditional Japanese layout.
       By contrast, the same glyphs without conjoining behaviour are available
       in the U+3130..U+318F block, and these characters are mapped to legacy
       character sets, and traditional Japanese layout matters for them.
       2) glibc does the same thing, see
       <https://sourceware.org/bugzilla/show_bug.cgi?id=21750>
       <https://sourceware.org/bugzilla/show_bug.cgi?id=26120>
   */
  #include "uniwidth/width0.h"
  
  #include "uniwidth/width2.h"
  #include "unictype/bitmap.h"
  
  #define SIZEOF(a) (sizeof(a) / sizeof(a[0]))
  
  
  /* Determine number of column positions required for UC.  */
  int
  uc_width (ucs4_t uc, const char *encoding)
  {
    /* Test for non-spacing or control character.  */
    if ((uc >> 9) < SIZEOF (nonspacing_table_ind))
      {
        int ind = nonspacing_table_ind[uc >> 9];
        if (ind >= 0)
          if ((nonspacing_table_data[64*ind + ((uc >> 3) & 63)] >> (uc & 7)) & 1)
            {
              if (uc > 0 && uc < 0xa0)
                return -1;
              else
                return 0;
            }
      }
    else if ((uc >> 9) == (0xe0000 >> 9))
      {
        if (uc >= 0xe0100)
          {
            if (uc <= 0xe01ef)
              return 0;
          }
        else
          {
            if (uc >= 0xe0020 ? uc <= 0xe007f : uc == 0xe0001)
              return 0;
          }
      }
    /* Test for double-width character.  */
    if (bitmap_lookup (&u_width2, uc))
      return 2;
    /* In ancient CJK encodings, Cyrillic and most other characters are
       double-width as well.  */
    if (uc >= 0x00A1 && uc < 0xFF61 && uc != 0x20A9
        && is_cjk_encoding (encoding))
      return 2;
    return 1;
  }
  

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