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/* FriBidi
* fribidi-joining.h - Arabic joining algorithm
*
* $Id: fribidi-joining.c,v 1.6 2006/01/31 03:23:13 behdad Exp $
* $Author: behdad $
* $Date: 2006/01/31 03:23:13 $
* $Revision: 1.6 $
* $Source: /cvs/fribidi/fribidi2/lib/fribidi-joining.c,v $
*
* Authors:
* Behdad Esfahbod, 2004
*
* Copyright (C) 2004 Sharif FarsiWeb, Inc
* Copyright (C) 2004 Behdad Esfahbod
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 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
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public License
* along with this library, in a file named COPYING; if not, write to the
* Free Software Foundation, Inc., 59 Temple Place, Suite 330,
* Boston, MA 02111-1307, USA
*
* For licensing issues, contact <license@farsiweb.info>.
*/
#include "common.h"
#include <fribidi-joining.h>
#include "mem.h"
#include "bidi-types.h"
#include "joining-types.h"
#if DEBUG+0
/*======================================================================
* For debugging, define some functions for printing joining types and
* properties.
*----------------------------------------------------------------------*/
static void
print_joining_types (
/* input */
const FriBidiLevel *embedding_levels,
const FriBidiStrIndex len,
const FriBidiJoiningType *jtypes
)
{
register FriBidiStrIndex i;
fribidi_assert (jtypes);
MSG (" Join. types: ");
for (i = 0; i < len; i++)
MSG2 ("%c", fribidi_char_from_joining_type (jtypes[i],
!FRIBIDI_LEVEL_IS_RTL
(embedding_levels[i])));
MSG ("\n");
}
#endif /* DEBUG */
#define FRIBIDI_CONSISTENT_LEVEL(i) \
(FRIBIDI_IS_EXPLICIT_OR_BN (bidi_types[(i)]) \
? FRIBIDI_SENTINEL \
: embedding_levels[(i)])
#define FRIBIDI_LEVELS_MATCH(i, j) \
((i) == (j) || (i) == FRIBIDI_SENTINEL || (j) == FRIBIDI_SENTINEL)
FRIBIDI_ENTRY void
fribidi_join_arabic (
/* input */
const FriBidiCharType *bidi_types,
const FriBidiStrIndex len,
const FriBidiLevel *embedding_levels,
/* input and output */
FriBidiArabicProp *ar_props
)
{
if UNLIKELY
(len == 0) return;
DBG ("in fribidi_join_arabic");
fribidi_assert (bidi_types);
fribidi_assert (embedding_levels);
fribidi_assert (ar_props);
# if DEBUG
if UNLIKELY
(fribidi_debug_status ())
{
print_joining_types (embedding_levels, len, ar_props);
}
# endif /* DEBUG */
/* The joining algorithm turned out very very dirty :(. That's what happens
* when you follow the standard which has never been implemented closely
* before.
*/
/* 8.2 Arabic - Cursive Joining */
DBG ("Arabic cursive joining");
{
/* The following do not need to be initialized as long as joins is
* initialized to false. We just do to turn off compiler warnings. */
register FriBidiStrIndex saved = 0;
register FriBidiLevel saved_level = FRIBIDI_SENTINEL;
register fribidi_boolean saved_shapes = false;
register FriBidiArabicProp saved_joins_following_mask = 0;
register fribidi_boolean joins = false;
register FriBidiStrIndex i;
for (i = 0; i < len; i++)
if (!FRIBIDI_IS_JOINING_TYPE_G (ar_props[i]))
{
register fribidi_boolean disjoin = false;
register fribidi_boolean shapes = FRIBIDI_ARAB_SHAPES (ar_props[i]);
register FriBidiLevel level = FRIBIDI_CONSISTENT_LEVEL (i);
if (joins && !FRIBIDI_LEVELS_MATCH (saved_level, level))
{
disjoin = true;
joins = false;
}
if (!FRIBIDI_IS_JOIN_SKIPPED (ar_props[i]))
{
register const FriBidiArabicProp joins_preceding_mask =
FRIBIDI_JOINS_PRECEDING_MASK (level);
if (!joins)
{
if (shapes)
FRIBIDI_UNSET_BITS (ar_props[i], joins_preceding_mask);
}
else if (!FRIBIDI_TEST_BITS (ar_props[i], joins_preceding_mask))
{
disjoin = true;
}
else
{
register FriBidiStrIndex j;
/* This is a FriBidi extension: we set joining properties
* for skipped characters in between, so we can put NSMs on tatweel
* later if we want. Useful on console for example.
*/
for (j = saved + 1; j < i; j++)
FRIBIDI_SET_BITS (ar_props[j], joins_preceding_mask | saved_joins_following_mask);
}
}
if (disjoin && saved_shapes)
FRIBIDI_UNSET_BITS (ar_props[saved], saved_joins_following_mask);
if (!FRIBIDI_IS_JOIN_SKIPPED (ar_props[i]))
{
saved = i;
saved_level = level;
saved_shapes = shapes;
saved_joins_following_mask =
FRIBIDI_JOINS_FOLLOWING_MASK (level);
joins =
FRIBIDI_TEST_BITS (ar_props[i], saved_joins_following_mask);
}
}
if ((joins) && saved_shapes)
FRIBIDI_UNSET_BITS (ar_props[saved], saved_joins_following_mask);
}
# if DEBUG
if UNLIKELY
(fribidi_debug_status ())
{
print_joining_types (embedding_levels, len, ar_props);
}
# endif /* DEBUG */
DBG ("leaving fribidi_join_arabic");
}
/* Editor directions:
* vim:textwidth=78:tabstop=8:shiftwidth=2:autoindent:cindent
*/
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