/* 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

 **********************************************************/