/* Pango
* pango-emoji.c: Emoji handling
*
* Copyright (C) 2017 Google, Inc.
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Library General Public
* License as published by the Free Software Foundation; either
* version 2 of the License, or (at your option) any later version.
*
* This library 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
* Library General Public License for more details.
*
* You should have received a copy of the GNU Library General Public
* License along with this library; if not, write to the
* Free Software Foundation, Inc., 59 Temple Place - Suite 330,
* Boston, MA 02111-1307, USA.
*
* Implementation of pango_emoji_iter is derived from Chromium:
*
* https://cs.chromium.org/chromium/src/third_party/WebKit/Source/platform/fonts/FontFallbackPriority.h
* https://cs.chromium.org/chromium/src/third_party/WebKit/Source/platform/text/CharacterEmoji.cpp
* https://cs.chromium.org/chromium/src/third_party/WebKit/Source/platform/fonts/SymbolsIterator.cpp
*
* // Copyright 2015 The Chromium Authors. All rights reserved.
* // Use of this source code is governed by a BSD-style license that can be
* // found in the LICENSE file.
*/
#include "config.h"
#include <stdlib.h>
#include <string.h>
#include "pango-emoji-private.h"
#include "pango-emoji-table.h"
static int
interval_compare (const void *key, const void *elt)
{
gunichar c = GPOINTER_TO_UINT (key);
struct Interval *interval = (struct Interval *)elt;
if (c < interval->start)
return -1;
if (c > interval->end)
return +1;
return 0;
}
#define DEFINE_pango_Is_(name) \
static gboolean \
_pango_Is_##name (gunichar ch) \
{ \
/* bsearch() is declared attribute(nonnull(1)) so we can't validly search \
* for a NULL key */ \
/* \
if (G_UNLIKELY (ch == 0)) \
return FALSE; \
*/ \
\
if (bsearch (GUINT_TO_POINTER (ch), \
_pango_##name##_table, \
G_N_ELEMENTS (_pango_##name##_table), \
sizeof _pango_##name##_table[0], \
interval_compare)) \
return TRUE; \
\
return FALSE; \
}
DEFINE_pango_Is_(Emoji)
DEFINE_pango_Is_(Emoji_Presentation)
DEFINE_pango_Is_(Emoji_Modifier)
DEFINE_pango_Is_(Emoji_Modifier_Base)
static gboolean
_pango_Is_Emoji_Text_Default (gunichar ch)
{
return _pango_Is_Emoji (ch) && !_pango_Is_Emoji_Presentation (ch);
}
static gboolean
_pango_Is_Emoji_Emoji_Default (gunichar ch)
{
return _pango_Is_Emoji_Presentation (ch);
}
static gboolean
_pango_Is_Emoji_Keycap_Base (gunichar ch)
{
return (ch >= '0' && ch <= '9') || ch == '#' || ch == '*';
}
static gboolean
_pango_Is_Regional_Indicator (gunichar ch)
{
return (ch >= 0x1F1E6 && ch <= 0x1F1FF);
}
const gunichar kCombiningEnclosingCircleBackslashCharacter = 0x20E0;
const gunichar kCombiningEnclosingKeycapCharacter = 0x20E3;
const gunichar kEyeCharacter = 0x1F441;
const gunichar kFemaleSignCharacter = 0x2640;
const gunichar kLeftSpeechBubbleCharacter = 0x1F5E8;
const gunichar kMaleSignCharacter = 0x2642;
const gunichar kRainbowCharacter = 0x1F308;
const gunichar kStaffOfAesculapiusCharacter = 0x2695;
const gunichar kVariationSelector15Character = 0xFE0E;
const gunichar kVariationSelector16Character = 0xFE0F;
const gunichar kWavingWhiteFlagCharacter = 0x1F3F3;
const gunichar kZeroWidthJoinerCharacter = 0x200D;
typedef enum {
PANGO_EMOJI_TYPE_INVALID,
PANGO_EMOJI_TYPE_TEXT, /* For regular non-symbols text */
PANGO_EMOJI_TYPE_EMOJI_TEXT, /* For emoji in text presentaiton */
PANGO_EMOJI_TYPE_EMOJI_EMOJI /* For emoji in emoji presentation */
} PangoEmojiType;
static PangoEmojiType
_pango_get_emoji_type (gunichar codepoint)
{
/* Those should only be Emoji presentation as combinations of two. */
if (_pango_Is_Emoji_Keycap_Base (codepoint) ||
_pango_Is_Regional_Indicator (codepoint))
return PANGO_EMOJI_TYPE_TEXT;
if (codepoint == kCombiningEnclosingKeycapCharacter)
return PANGO_EMOJI_TYPE_EMOJI_EMOJI;
if (_pango_Is_Emoji_Emoji_Default (codepoint) ||
_pango_Is_Emoji_Modifier_Base (codepoint) ||
_pango_Is_Emoji_Modifier (codepoint))
return PANGO_EMOJI_TYPE_EMOJI_EMOJI;
if (_pango_Is_Emoji_Text_Default (codepoint))
return PANGO_EMOJI_TYPE_EMOJI_TEXT;
return PANGO_EMOJI_TYPE_TEXT;
}
PangoEmojiIter *
_pango_emoji_iter_init (PangoEmojiIter *iter,
const char *text,
int length)
{
iter->text_start = text;
if (length >= 0)
iter->text_end = text + length;
else
iter->text_end = text + strlen (text);
iter->start = text;
iter->end = text;
iter->is_emoji = (gboolean) 2; /* HACK */
_pango_emoji_iter_next (iter);
return iter;
}
void
_pango_emoji_iter_fini (PangoEmojiIter *iter)
{
}
#define PANGO_EMOJI_TYPE_IS_EMOJI(typ) ((typ) == PANGO_EMOJI_TYPE_EMOJI_EMOJI)
gboolean
_pango_emoji_iter_next (PangoEmojiIter *iter)
{
PangoEmojiType current_emoji_type = PANGO_EMOJI_TYPE_INVALID;
if (iter->end == iter->text_end)
return FALSE;
iter->start = iter->end;
for (; iter->end < iter->text_end; iter->end = g_utf8_next_char (iter->end))
{
gunichar ch = g_utf8_get_char (iter->end);
/* Except at the beginning, ZWJ just carries over the emoji or neutral
* text type, VS15 & VS16 we just carry over as well, since we already
* resolved those through lookahead. Also, don't downgrade to text
* presentation for emoji that are part of a ZWJ sequence, example
* U+1F441 U+200D U+1F5E8, eye (text presentation) + ZWJ + left speech
* bubble, see below. */
if ((!(ch == kZeroWidthJoinerCharacter && !iter->is_emoji) &&
ch != kVariationSelector15Character &&
ch != kVariationSelector16Character &&
ch != kCombiningEnclosingCircleBackslashCharacter &&
!_pango_Is_Regional_Indicator(ch) &&
!((ch == kLeftSpeechBubbleCharacter ||
ch == kRainbowCharacter ||
ch == kMaleSignCharacter ||
ch == kFemaleSignCharacter ||
ch == kStaffOfAesculapiusCharacter) &&
!iter->is_emoji)) ||
current_emoji_type == PANGO_EMOJI_TYPE_INVALID) {
current_emoji_type = _pango_get_emoji_type (ch);
}
if (g_utf8_next_char (iter->end) < iter->text_end) /* Optimize. */
{
gunichar peek_char = g_utf8_get_char (g_utf8_next_char (iter->end));
/* Variation Selectors */
if (current_emoji_type ==
PANGO_EMOJI_TYPE_EMOJI_EMOJI &&
peek_char == kVariationSelector15Character) {
current_emoji_type = PANGO_EMOJI_TYPE_EMOJI_TEXT;
}
if ((current_emoji_type ==
PANGO_EMOJI_TYPE_EMOJI_TEXT ||
_pango_Is_Emoji_Keycap_Base(ch)) &&
peek_char == kVariationSelector16Character) {
current_emoji_type = PANGO_EMOJI_TYPE_EMOJI_EMOJI;
}
/* Combining characters Keycap... */
if (_pango_Is_Emoji_Keycap_Base(ch) &&
peek_char == kCombiningEnclosingKeycapCharacter) {
current_emoji_type = PANGO_EMOJI_TYPE_EMOJI_EMOJI;
};
/* Regional indicators */
if (_pango_Is_Regional_Indicator(ch) &&
_pango_Is_Regional_Indicator(peek_char)) {
current_emoji_type = PANGO_EMOJI_TYPE_EMOJI_EMOJI;
}
/* Upgrade text presentation emoji to emoji presentation when followed by
* ZWJ, Example U+1F441 U+200D U+1F5E8, eye + ZWJ + left speech bubble. */
if ((ch == kEyeCharacter ||
ch == kWavingWhiteFlagCharacter) &&
peek_char == kZeroWidthJoinerCharacter) {
current_emoji_type = PANGO_EMOJI_TYPE_EMOJI_EMOJI;
}
}
if (iter->is_emoji == (gboolean) 2)
iter->is_emoji = !PANGO_EMOJI_TYPE_IS_EMOJI (current_emoji_type);
if (iter->is_emoji == PANGO_EMOJI_TYPE_IS_EMOJI (current_emoji_type))
{
iter->is_emoji = !PANGO_EMOJI_TYPE_IS_EMOJI (current_emoji_type);
/* Make sure we make progress. Weird sequences, like a VC15 followed
* by VC16, can trick us into stalling otherwise. */
if (iter->start == iter->end)
iter->end = g_utf8_next_char (iter->end);
return TRUE;
}
}
iter->is_emoji = PANGO_EMOJI_TYPE_IS_EMOJI (current_emoji_type);
return TRUE;
}
/**********************************************************
* End of code from Chromium
**********************************************************/