150 lines
6.4 KiB
C
150 lines
6.4 KiB
C
/* FriBidi
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* fribidi-bidi.h - bidirectional algorithm
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*
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* $Id: fribidi-bidi.h,v 1.15 2005/11/03 01:39:01 behdad Exp $
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* $Author: behdad $
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* $Date: 2005/11/03 01:39:01 $
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* $Revision: 1.15 $
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* $Source: /cvs/fribidi/fribidi2/lib/fribidi-bidi.h,v $
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*
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* Authors:
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* Behdad Esfahbod, 2001, 2002, 2004
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* Dov Grobgeld, 1999, 2000
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*
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* Copyright (C) 2004 Sharif FarsiWeb, Inc
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* Copyright (C) 2001,2002 Behdad Esfahbod
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* Copyright (C) 1999,2000 Dov Grobgeld
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*
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* This library is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Lesser General Public
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* License as published by the Free Software Foundation; either
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* version 2.1 of the License, or (at your option) any later version.
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*
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* This library is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public License
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* along with this library, in a file named COPYING; if not, write to the
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* Free Software Foundation, Inc., 59 Temple Place, Suite 330,
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* Boston, MA 02111-1307, USA
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*
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* For licensing issues, contact <license@farsiweb.info>.
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*/
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#ifndef _FRIBIDI_BIDI_H
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#define _FRIBIDI_BIDI_H
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#include "fribidi-common.h"
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#include "fribidi-types.h"
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#include "fribidi-flags.h"
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#include "fribidi-bidi-types.h"
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#include "fribidi-begindecls.h"
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#define fribidi_get_par_embedding_levels FRIBIDI_NAMESPACE(get_par_embedding_levels)
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/* fribidi_get_par_direction - get base paragraph direction
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*
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* This function finds the base direction of a single paragraph,
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* as defined by rule P2 of the Unicode Bidirectional Algorithm available at
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* http://www.unicode.org/reports/tr9/#P2.
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*
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* You typically do not need this function as
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* fribidi_get_par_embedding_levels() knows how to compute base direction
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* itself, but you may need this to implement a more sophisticated paragraph
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* direction handling. Note that you can pass more than a paragraph to this
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* function and the direction of the first non-neutral paragraph is returned,
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* which is a very good heuristic to set direction of the neutral paragraphs
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* at the beginning of text. For other neutral paragraphs, you better use the
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* direction of the previous paragraph.
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*
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* Returns: Base pargraph direction. No weak paragraph direction is returned,
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* only LTR, RTL, or ON.
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*/
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FRIBIDI_ENTRY FriBidiParType fribidi_get_par_direction (
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const FriBidiCharType *bidi_types, /* input list of bidi types as returned by
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fribidi_get_bidi_types() */
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const FriBidiStrIndex len /* input string length */
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);
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#define fribidi_get_par_embedding_levels FRIBIDI_NAMESPACE(get_par_embedding_levels)
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/* fribidi_get_par_embedding_levels - get bidi embedding levels of a paragraph
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*
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* This function finds the bidi embedding levels of a single paragraph,
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* as defined by the Unicode Bidirectional Algorithm available at
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* http://www.unicode.org/reports/tr9/. This function implements rules P2 to
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* I1 inclusive, and parts 1 to 3 of L1, except for rule X9 which is
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* implemented in fribidi_remove_bidi_marks(). Part 4 of L1 is implemented
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* in fribidi_reorder_line().
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*
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* There are a few macros defined in fribidi-bidi-types.h to work with this
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* embedding levels.
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*
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* Returns: Maximum level found plus one, or zero if any error occured
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* (memory allocation failure most probably).
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*/
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FRIBIDI_ENTRY FriBidiLevel
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fribidi_get_par_embedding_levels (
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const FriBidiCharType *bidi_types, /* input list of bidi types as returned by
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fribidi_get_bidi_types() */
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const FriBidiStrIndex len, /* input string length of the paragraph */
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FriBidiParType *pbase_dir, /* requested and resolved paragraph
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* base direction */
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FriBidiLevel *embedding_levels /* output list of embedding levels */
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) FRIBIDI_GNUC_WARN_UNUSED;
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#define fribidi_reorder_line FRIBIDI_NAMESPACE(reorder_line)
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/* fribidi_reorder_line - reorder a line of logical string to visual
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*
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* This function reorders the characters in a line of text from logical to
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* final visual order. This function implements part 4 of rule L1, and rules
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* L2 and L3 of the Unicode Bidirectional Algorithm available at
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* http://www.unicode.org/reports/tr9/#Reordering_Resolved_Levels.
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*
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* As a side effect it also sets position maps if not NULL.
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*
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* You should provide the resolved paragraph direction and embedding levels as
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* set by fribidi_get_par_embedding_levels(). Also note that the embedding
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* levels may change a bit. To be exact, the embedding level of any sequence
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* of white space at the end of line is reset to the paragraph embedding level
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* (That is part 4 of rule L1).
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*
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* Note that the bidi types and embedding levels are not reordered. You can
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* reorder these (or any other) arrays using the map later. The user is
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* responsible to initialize map to something sensible, like an identity
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* mapping, or pass NULL if no map is needed.
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*
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* There is an optional part to this function, which is whether non-spacing
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* marks for right-to-left parts of the text should be reordered to come after
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* their base characters in the visual string or not. Most rendering engines
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* expect this behavior, but console-based systems for example do not like it.
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* This is controlled by the FRIBIDI_FLAG_REORDER_NSM flag. The flag is on
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* in FRIBIDI_FLAGS_DEFAULT.
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*
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* Returns: Maximum level found in this line plus one, or zero if any error
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* occured (memory allocation failure most probably).
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*/
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FRIBIDI_ENTRY FriBidiLevel fribidi_reorder_line (
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FriBidiFlags flags, /* reorder flags */
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const FriBidiCharType *bidi_types, /* input list of bidi types as returned by
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fribidi_get_bidi_types() */
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const FriBidiStrIndex len, /* input length of the line */
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const FriBidiStrIndex off, /* input offset of the beginning of the line
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in the paragraph */
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const FriBidiParType base_dir, /* resolved paragraph base direction */
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FriBidiLevel *embedding_levels, /* input list of embedding levels,
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as returned by
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fribidi_get_par_embedding_levels */
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FriBidiChar *visual_str, /* visual string to reorder */
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FriBidiStrIndex *map /* a map of string indices which is reordered
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* to reflect where each glyph ends up. */
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) FRIBIDI_GNUC_WARN_UNUSED;
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#include "fribidi-enddecls.h"
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#endif /* !_FRIBIDI_BIDI_H */
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/* Editor directions:
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* vim:textwidth=78:tabstop=8:shiftwidth=2:autoindent:cindent
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*/
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