1 files changed, 95 insertions, 0 deletions
diff --git a/lib/uniwidth/width.c b/lib/uniwidth/width.c
new file mode 100644
index 0000000..c9d4d1d
--- /dev/null
+++ b/lib/uniwidth/width.c
@@ -0,0 +1,95 @@
+/* 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;
+}