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