93 lines
3.1 KiB
C++
93 lines
3.1 KiB
C++
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/*
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* Copyright (C) 2017 The Android Open Source Project
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* * Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* * Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in
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* the documentation and/or other materials provided with the
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* distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
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* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
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* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
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* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
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* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
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* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
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* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
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* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
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* OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*/
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#include <wchar.h>
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#include "private/icu.h"
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int wcwidth(wchar_t wc) {
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// Fast-path ASCII.
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if (wc >= 0x20 && wc < 0x7f) return 1;
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// ASCII NUL is a special case.
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if (wc == 0) return 0;
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// C0.
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if (wc < ' ' || (wc >= 0x7f && wc <= 0xa0)) return -1;
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// Now for the i18n part. This isn't defined or standardized, so a lot of the choices are
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// pretty arbitrary. See https://www.cl.cam.ac.uk/~mgk25/ucs/wcwidth.c for more details.
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// Fancy unicode control characters?
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switch (__icu_charType(wc)) {
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case -1:
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// No icu4c available; give up.
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return -1;
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case U_CONTROL_CHAR:
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return -1;
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case U_NON_SPACING_MARK:
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case U_ENCLOSING_MARK:
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case U_FORMAT_CHAR:
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return 0;
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}
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if (__icu_hasBinaryProperty(wc, UCHAR_DEFAULT_IGNORABLE_CODE_POINT, nullptr)) return 0;
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// Medial and final jamo render as zero width when used correctly.
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switch (__icu_getIntPropertyValue(wc, UCHAR_HANGUL_SYLLABLE_TYPE)) {
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case U_HST_VOWEL_JAMO:
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case U_HST_TRAILING_JAMO:
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return 0;
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case U_HST_LEADING_JAMO:
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case U_HST_LV_SYLLABLE:
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case U_HST_LVT_SYLLABLE:
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return 2;
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}
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if (wc >= 0x3248 && wc <= 0x4dff) {
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// Circled two-digit CJK "speed sign" numbers. EastAsianWidth is ambiguous,
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// but wide makes more sense.
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if (wc <= 0x324f) return 2;
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// Hexagrams. EastAsianWidth is neutral, but wide seems better.
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if (wc >= 0x4dc0) return 2;
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}
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// The EastAsianWidth property is at least defined by the Unicode standard!
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switch (__icu_getIntPropertyValue(wc, UCHAR_EAST_ASIAN_WIDTH)) {
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case U_EA_AMBIGUOUS:
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case U_EA_HALFWIDTH:
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case U_EA_NARROW:
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case U_EA_NEUTRAL:
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return 1;
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case U_EA_FULLWIDTH:
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case U_EA_WIDE:
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return 2;
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}
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return 0;
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}
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