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/* Pango
* arabic-lang.c:
*
* Copyright (C) 2006 Red Hat Software
* Copyright (C) 2006 Sharif FarsiWeb, Inc.
* Authors: Behdad Esfahbod <besfahbo@redhat.com>
* Roozbeh Pournader <roozbeh@farsiweb.info>
*
* 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.
*/
#include <config.h>
#include <string.h>
#include "pango-engine.h"
#include "pango-break.h"
/* No extra fields needed */
typedef PangoEngineLang ArabicEngineLang;
typedef PangoEngineLangClass ArabicEngineLangClass ;
#define SCRIPT_ENGINE_NAME "ArabicScriptEngineLang"
#define RENDER_TYPE PANGO_RENDER_TYPE_NONE
static PangoEngineScriptInfo arabic_scripts[] = {
{ PANGO_SCRIPT_ARABIC, "*" },
};
static PangoEngineInfo script_engines[] = {
{
SCRIPT_ENGINE_NAME,
PANGO_ENGINE_TYPE_LANG,
RENDER_TYPE,
arabic_scripts, G_N_ELEMENTS(arabic_scripts)
}
};
#define ALEF_WITH_MADDA_ABOVE 0x0622
#define YEH_WITH_HAMZA_ABOVE 0x0626
#define ALEF 0x0627
#define WAW 0x0648
#define YEH 0x064A
#define MADDAH_ABOVE 0x0653
#define HAMZA_ABOVE 0x0654
#define HAMZA_BELOW 0x0655
/*
* Arabic characters with canonical decompositions that are not just
* ligatures. The characters U+06C0, U+06C2, and U+06D3 are intentionally
* excluded as they are marked as "not an independent letter" in Unicode
* Character Database's NamesList.txt
*/
#define IS_COMPOSITE(c) (ALEF_WITH_MADDA_ABOVE <= (c) && (c) <= YEH_WITH_HAMZA_ABOVE)
/* If a character is the second part of a composite Arabic character with an Alef */
#define IS_COMPOSITE_WITH_ALEF(c) (MADDAH_ABOVE <= (c) && (c) <= HAMZA_BELOW)
static void
arabic_engine_break (PangoEngineLang *engine,
const char *text,
int length,
PangoAnalysis *analysis,
PangoLogAttr *attrs,
int attrs_len)
{
int i;
const char *p;
gunichar prev_wc, this_wc;
/* See http://bugzilla.gnome.org/show_bug.cgi?id=350132 for issues this
* module tries to solve.
*/
for (p = text, i = 0, prev_wc = 0;
p < text + length;
p = g_utf8_next_char (p), i++, prev_wc = this_wc)
{
this_wc = g_utf8_get_char (p);
/*
* Unset backspace_deletes_character for various combinations.
*
* A few more combinations may need to be handled here, but are not
* handled yet, as expectations of users is not known or may differ
* among different languages or users:
* some letters combined with U+0658 ARABIC MARK NOON GHUNNA;
* combinations considered one letter in Azerbaijani (WAW+SUKUN and
* FARSI_YEH+HAMZA_ABOVE); combinations of YEH and ALEF_MAKSURA with
* HAMZA_BELOW (Qur'anic); TATWEEL+HAMZA_ABOVE (Qur'anic).
*
* FIXME: Ordering these in some other way may lower the time spent here, or not.
*/
if (G_UNLIKELY (
IS_COMPOSITE (this_wc) ||
(prev_wc == ALEF && IS_COMPOSITE_WITH_ALEF (this_wc)) ||
(this_wc == HAMZA_ABOVE && (prev_wc == WAW || prev_wc == YEH))
))
attrs[i+1].backspace_deletes_character = FALSE;
}
}
static void
arabic_engine_lang_class_init (PangoEngineLangClass *class)
{
class->script_break = arabic_engine_break;
}
PANGO_ENGINE_LANG_DEFINE_TYPE (ArabicEngineLang, arabic_engine_lang,
arabic_engine_lang_class_init, NULL)
void
PANGO_MODULE_ENTRY(init) (GTypeModule *module)
{
arabic_engine_lang_register_type (module);
}
void
PANGO_MODULE_ENTRY(exit) (void)
{
}
void
PANGO_MODULE_ENTRY(list) (PangoEngineInfo **engines,
int *n_engines)
{
*engines = script_engines;
*n_engines = G_N_ELEMENTS (script_engines);
}
PangoEngine *
PANGO_MODULE_ENTRY(create) (const char *id)
{
if (!strcmp (id, SCRIPT_ENGINE_NAME))
return g_object_new (arabic_engine_lang_type, NULL);
else
return NULL;
}
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