mirror of
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928 lines
36 KiB
C++
928 lines
36 KiB
C++
/* -*- Mode: C; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
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*
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* ***** BEGIN LICENSE BLOCK *****
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* Version: MPL 1.1/GPL 2.0/LGPL 2.1
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*
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* The contents of this file are subject to the Mozilla Public License Version
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* 1.1 (the "License"); you may not use this file except in compliance with
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* the License. You may obtain a copy of the License at
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* http://www.mozilla.org/MPL/
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*
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* Software distributed under the License is distributed on an "AS IS" basis,
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* WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
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* for the specific language governing rights and limitations under the
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* License.
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*
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* The Original Code is mozilla.org code.
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*
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* The Initial Developer of the Original Code is
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* IBM Corporation.
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* Portions created by the Initial Developer are Copyright (C) 2000
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* the Initial Developer. All Rights Reserved.
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*
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* Contributor(s):
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* Simon Montagu
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*
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* Alternatively, the contents of this file may be used under the terms of
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* either of the GNU General Public License Version 2 or later (the "GPL"),
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* or the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
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* in which case the provisions of the GPL or the LGPL are applicable instead
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* of those above. If you wish to allow use of your version of this file only
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* under the terms of either the GPL or the LGPL, and not to allow others to
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* use your version of this file under the terms of the MPL, indicate your
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* decision by deleting the provisions above and replace them with the notice
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* and other provisions required by the GPL or the LGPL. If you do not delete
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* the provisions above, a recipient may use your version of this file under
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* the terms of any one of the MPL, the GPL or the LGPL.
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*
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* ***** END LICENSE BLOCK ***** */
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#ifndef nsBidi_h__
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#define nsBidi_h__
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#include "nsCOMPtr.h"
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#include "nsString.h"
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#include "nsBidiUtils.h"
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// Bidi reordering engine from ICU
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/*
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* javadoc-style comments are intended to be transformed into HTML
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* using DOC++ - see
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* http://www.zib.de/Visual/software/doc++/index.html .
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*
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* The HTML documentation is created with
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* doc++ -H nsIBidi.h
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*/
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/**
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* @mainpage BIDI algorithm for Mozilla (from ICU)
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*
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* <h2>BIDI algorithm for Mozilla</h2>
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*
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* This is an implementation of the Unicode Bidirectional algorithm.
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* The algorithm is defined in the
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* <a href="http://www.unicode.org/unicode/reports/tr9/">Unicode Technical Report 9</a>,
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* version 5, also described in The Unicode Standard, Version 3.0 .<p>
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*
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* <h3>General remarks about the API:</h3>
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*
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* The <quote>limit</quote> of a sequence of characters is the position just after their
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* last character, i.e., one more than that position.<p>
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*
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* Some of the API functions provide access to <quote>runs</quote>.
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* Such a <quote>run</quote> is defined as a sequence of characters
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* that are at the same embedding level
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* after performing the BIDI algorithm.<p>
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*
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* @author Markus W. Scherer. Ported to Mozilla by Simon Montagu
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* @version 1.0
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*/
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/**
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* nsBidiLevel is the type of the level values in this
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* Bidi implementation.
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* It holds an embedding level and indicates the visual direction
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* by its bit 0 (even/odd value).<p>
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*
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* It can also hold non-level values for the
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* <code>aParaLevel</code> and <code>aEmbeddingLevels</code>
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* arguments of <code>SetPara</code>; there:
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* <ul>
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* <li>bit 7 of an <code>aEmbeddingLevels[]</code>
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* value indicates whether the using application is
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* specifying the level of a character to <i>override</i> whatever the
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* Bidi implementation would resolve it to.</li>
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* <li><code>aParaLevel</code> can be set to the
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* pseudo-level values <code>NSBIDI_DEFAULT_LTR</code>
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* and <code>NSBIDI_DEFAULT_RTL</code>.</li></ul>
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*
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* @see nsIBidi::SetPara
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*
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* <p>The related constants are not real, valid level values.
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* <code>NSBIDI_DEFAULT_XXX</code> can be used to specify
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* a default for the paragraph level for
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* when the <code>SetPara</code> function
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* shall determine it but there is no
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* strongly typed character in the input.<p>
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*
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* Note that the value for <code>NSBIDI_DEFAULT_LTR</code> is even
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* and the one for <code>NSBIDI_DEFAULT_RTL</code> is odd,
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* just like with normal LTR and RTL level values -
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* these special values are designed that way. Also, the implementation
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* assumes that NSBIDI_MAX_EXPLICIT_LEVEL is odd.
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*
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* @see NSBIDI_DEFAULT_LTR
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* @see NSBIDI_DEFAULT_RTL
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* @see NSBIDI_LEVEL_OVERRIDE
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* @see NSBIDI_MAX_EXPLICIT_LEVEL
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*/
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typedef PRUint8 nsBidiLevel;
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/** Paragraph level setting.
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* If there is no strong character, then set the paragraph level to 0 (left-to-right).
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*/
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#define NSBIDI_DEFAULT_LTR 0xfe
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/** Paragraph level setting.
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* If there is no strong character, then set the paragraph level to 1 (right-to-left).
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*/
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#define NSBIDI_DEFAULT_RTL 0xff
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/**
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* Maximum explicit embedding level.
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* (The maximum resolved level can be up to <code>NSBIDI_MAX_EXPLICIT_LEVEL+1</code>).
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*
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*/
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#define NSBIDI_MAX_EXPLICIT_LEVEL 61
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/** Bit flag for level input.
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* Overrides directional properties.
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*/
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#define NSBIDI_LEVEL_OVERRIDE 0x80
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/**
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* <code>nsBidiDirection</code> values indicate the text direction.
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*/
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enum nsBidiDirection {
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/** All left-to-right text This is a 0 value. */
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NSBIDI_LTR,
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/** All right-to-left text This is a 1 value. */
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NSBIDI_RTL,
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/** Mixed-directional text. */
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NSBIDI_MIXED
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};
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typedef enum nsBidiDirection nsBidiDirection;
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/* miscellaneous definitions ------------------------------------------------ */
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/** option flags for WriteReverse() */
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/**
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* option bit for WriteReverse():
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* keep combining characters after their base characters in RTL runs
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*
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* @see WriteReverse
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*/
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#define NSBIDI_KEEP_BASE_COMBINING 1
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/**
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* option bit for WriteReverse():
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* replace characters with the "mirrored" property in RTL runs
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* by their mirror-image mappings
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*
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* @see WriteReverse
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*/
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#define NSBIDI_DO_MIRRORING 2
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/**
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* option bit for WriteReverse():
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* remove Bidi control characters
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*
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* @see WriteReverse
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*/
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#define NSBIDI_REMOVE_BIDI_CONTROLS 8
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/* helper macros for each allocated array member */
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#define GETDIRPROPSMEMORY(length) \
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GetMemory((void **)&mDirPropsMemory, &mDirPropsSize, \
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mMayAllocateText, (length))
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#define GETLEVELSMEMORY(length) \
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GetMemory((void **)&mLevelsMemory, &mLevelsSize, \
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mMayAllocateText, (length))
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#define GETRUNSMEMORY(length) \
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GetMemory((void **)&mRunsMemory, &mRunsSize, \
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mMayAllocateRuns, (length)*sizeof(Run))
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/* additional macros used by constructor - always allow allocation */
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#define GETINITIALDIRPROPSMEMORY(length) \
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GetMemory((void **)&mDirPropsMemory, &mDirPropsSize, \
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PR_TRUE, (length))
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#define GETINITIALLEVELSMEMORY(length) \
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GetMemory((void **)&mLevelsMemory, &mLevelsSize, \
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PR_TRUE, (length))
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#define GETINITIALRUNSMEMORY(length) \
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GetMemory((void **)&mRunsMemory, &mRunsSize, \
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PR_TRUE, (length)*sizeof(Run))
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/*
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* Sometimes, bit values are more appropriate
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* to deal with directionality properties.
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* Abbreviations in these macro names refer to names
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* used in the Bidi algorithm.
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*/
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typedef PRUint8 DirProp;
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#define DIRPROP_FLAG(dir) (1UL<<(dir))
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/* special flag for multiple runs from explicit embedding codes */
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#define DIRPROP_FLAG_MULTI_RUNS (1UL<<31)
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/* are there any characters that are LTR or RTL? */
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#define MASK_LTR (DIRPROP_FLAG(L)|DIRPROP_FLAG(EN)|DIRPROP_FLAG(AN)|DIRPROP_FLAG(LRE)|DIRPROP_FLAG(LRO))
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#define MASK_RTL (DIRPROP_FLAG(R)|DIRPROP_FLAG(AL)|DIRPROP_FLAG(RLE)|DIRPROP_FLAG(RLO))
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/* explicit embedding codes */
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#define MASK_LRX (DIRPROP_FLAG(LRE)|DIRPROP_FLAG(LRO))
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#define MASK_RLX (DIRPROP_FLAG(RLE)|DIRPROP_FLAG(RLO))
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#define MASK_OVERRIDE (DIRPROP_FLAG(LRO)|DIRPROP_FLAG(RLO))
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#define MASK_EXPLICIT (MASK_LRX|MASK_RLX|DIRPROP_FLAG(PDF))
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#define MASK_BN_EXPLICIT (DIRPROP_FLAG(BN)|MASK_EXPLICIT)
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/* paragraph and segment separators */
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#define MASK_B_S (DIRPROP_FLAG(B)|DIRPROP_FLAG(S))
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/* all types that are counted as White Space or Neutral in some steps */
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#define MASK_WS (MASK_B_S|DIRPROP_FLAG(WS)|MASK_BN_EXPLICIT)
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#define MASK_N (DIRPROP_FLAG(O_N)|MASK_WS)
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/* all types that are included in a sequence of European Terminators for (W5) */
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#define MASK_ET_NSM_BN (DIRPROP_FLAG(ET)|DIRPROP_FLAG(NSM)|MASK_BN_EXPLICIT)
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/* types that are neutrals or could becomes neutrals in (Wn) */
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#define MASK_POSSIBLE_N (DIRPROP_FLAG(CS)|DIRPROP_FLAG(ES)|DIRPROP_FLAG(ET)|MASK_N)
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/*
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* These types may be changed to "e",
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* the embedding type (L or R) of the run,
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* in the Bidi algorithm (N2)
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*/
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#define MASK_EMBEDDING (DIRPROP_FLAG(NSM)|MASK_POSSIBLE_N)
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/* the dirProp's L and R are defined to 0 and 1 values in nsCharType */
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#define GET_LR_FROM_LEVEL(level) ((DirProp)((level)&1))
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#define IS_DEFAULT_LEVEL(level) (((level)&0xfe)==0xfe)
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/* handle surrogate pairs --------------------------------------------------- */
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#define IS_FIRST_SURROGATE(uchar) (((uchar)&0xfc00)==0xd800)
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#define IS_SECOND_SURROGATE(uchar) (((uchar)&0xfc00)==0xdc00)
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/* get the UTF-32 value directly from the surrogate pseudo-characters */
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#define SURROGATE_OFFSET ((0xd800<<10UL)+0xdc00-0x10000)
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#define GET_UTF_32(first, second) (((first)<<10UL)+(second)-SURROGATE_OFFSET)
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#define UTF_ERROR_VALUE 0xffff
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/* definitions with forward iteration --------------------------------------- */
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/*
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* all the macros that go forward assume that
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* the initial offset is 0<=i<length;
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* they update the offset
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*/
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/* fast versions, no error-checking */
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#define UTF16_APPEND_CHAR_UNSAFE(s, i, c){ \
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if((PRUint32)(c)<=0xffff) { \
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(s)[(i)++]=(PRUnichar)(c); \
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} else { \
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(s)[(i)++]=(PRUnichar)((c)>>10)+0xd7c0; \
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(s)[(i)++]=(PRUnichar)(c)&0x3ff|0xdc00; \
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} \
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}
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/* safe versions with error-checking and optional regularity-checking */
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#define UTF16_APPEND_CHAR_SAFE(s, i, length, c) { \
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if((PRUInt32)(c)<=0xffff) { \
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(s)[(i)++]=(PRUnichar)(c); \
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} else if((PRUInt32)(c)<=0x10ffff) { \
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if((i)+1<(length)) { \
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(s)[(i)++]=(PRUnichar)((c)>>10)+0xd7c0; \
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(s)[(i)++]=(PRUnichar)(c)&0x3ff|0xdc00; \
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} else /* not enough space */ { \
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(s)[(i)++]=UTF_ERROR_VALUE; \
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} \
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} else /* c>0x10ffff, write error value */ { \
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(s)[(i)++]=UTF_ERROR_VALUE; \
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} \
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}
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/* definitions with backward iteration -------------------------------------- */
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/*
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* all the macros that go backward assume that
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* the valid buffer range starts at offset 0
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* and that the initial offset is 0<i<=length;
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* they update the offset
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*/
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/* fast versions, no error-checking */
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/*
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* Get a single code point from an offset that points behind the last
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* of the code units that belong to that code point.
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* Assume 0<=i<length.
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*/
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#define UTF16_PREV_CHAR_UNSAFE(s, i, c) { \
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(c)=(s)[--(i)]; \
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if(IS_SECOND_SURROGATE(c)) { \
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(c)=GET_UTF_32((s)[--(i)], (c)); \
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} \
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}
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#define UTF16_BACK_1_UNSAFE(s, i) { \
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if(IS_SECOND_SURROGATE((s)[--(i)])) { \
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--(i); \
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} \
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}
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#define UTF16_BACK_N_UNSAFE(s, i, n) { \
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PRInt32 __N=(n); \
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while(__N>0) { \
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UTF16_BACK_1_UNSAFE(s, i); \
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--__N; \
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} \
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}
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/* safe versions with error-checking and optional regularity-checking */
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#define UTF16_PREV_CHAR_SAFE(s, start, i, c, strict) { \
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(c)=(s)[--(i)]; \
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if(IS_SECOND_SURROGATE(c)) { \
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PRUnichar __c2; \
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if((i)>(start) && IS_FIRST_SURROGATE(__c2=(s)[(i)-1])) { \
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--(i); \
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(c)=GET_UTF_32(__c2, (c)); \
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/* strict: ((c)&0xfffe)==0xfffe is caught by UTF_IS_ERROR() */ \
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} else if(strict) {\
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/* unmatched second surrogate */ \
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(c)=UTF_ERROR_VALUE; \
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} \
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} else if(strict && IS_FIRST_SURROGATE(c)) { \
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/* unmatched first surrogate */ \
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(c)=UTF_ERROR_VALUE; \
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/* else strict: (c)==0xfffe is caught by UTF_IS_ERROR() */ \
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} \
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}
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#define UTF16_BACK_1_SAFE(s, start, i) { \
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if(IS_SECOND_SURROGATE((s)[--(i)]) && (i)>(start) && IS_FIRST_SURROGATE((s)[(i)-1])) { \
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--(i); \
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} \
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}
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#define UTF16_BACK_N_SAFE(s, start, i, n) { \
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PRInt32 __N=(n); \
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while(__N>0 && (i)>(start)) { \
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UTF16_BACK_1_SAFE(s, start, i); \
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--__N; \
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} \
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}
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#define UTF_PREV_CHAR_UNSAFE(s, i, c) UTF16_PREV_CHAR_UNSAFE(s, i, c)
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#define UTF_PREV_CHAR_SAFE(s, start, i, c, strict) UTF16_PREV_CHAR_SAFE(s, start, i, c, strict)
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#define UTF_BACK_1_UNSAFE(s, i) UTF16_BACK_1_UNSAFE(s, i)
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#define UTF_BACK_1_SAFE(s, start, i) UTF16_BACK_1_SAFE(s, start, i)
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#define UTF_BACK_N_UNSAFE(s, i, n) UTF16_BACK_N_UNSAFE(s, i, n)
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#define UTF_BACK_N_SAFE(s, start, i, n) UTF16_BACK_N_SAFE(s, start, i, n)
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#define UTF_APPEND_CHAR_UNSAFE(s, i, c) UTF16_APPEND_CHAR_UNSAFE(s, i, c)
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#define UTF_APPEND_CHAR_SAFE(s, i, length, c) UTF16_APPEND_CHAR_SAFE(s, i, length, c)
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#define UTF_PREV_CHAR(s, start, i, c) UTF_PREV_CHAR_SAFE(s, start, i, c, PR_FALSE)
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#define UTF_BACK_1(s, start, i) UTF_BACK_1_SAFE(s, start, i)
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#define UTF_BACK_N(s, start, i, n) UTF_BACK_N_SAFE(s, start, i, n)
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#define UTF_APPEND_CHAR(s, i, length, c) UTF_APPEND_CHAR_SAFE(s, i, length, c)
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/* Run structure for reordering --------------------------------------------- */
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typedef struct Run {
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PRInt32 logicalStart, /* first character of the run; b31 indicates even/odd level */
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visualLimit; /* last visual position of the run +1 */
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} Run;
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/* in a Run, logicalStart will get this bit set if the run level is odd */
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#define INDEX_ODD_BIT (1UL<<31)
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#define MAKE_INDEX_ODD_PAIR(index, level) (index|((PRUint32)level<<31))
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#define ADD_ODD_BIT_FROM_LEVEL(x, level) ((x)|=((PRUint32)level<<31))
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#define REMOVE_ODD_BIT(x) ((x)&=~INDEX_ODD_BIT)
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#define GET_INDEX(x) (x&~INDEX_ODD_BIT)
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#define GET_ODD_BIT(x) ((PRUint32)x>>31)
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#define IS_ODD_RUN(x) ((x&INDEX_ODD_BIT)!=0)
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#define IS_EVEN_RUN(x) ((x&INDEX_ODD_BIT)==0)
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typedef PRUint32 Flags;
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/**
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* This class holds information about a paragraph of text
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* with Bidi-algorithm-related details, or about one line of
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* such a paragraph.<p>
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* Reordering can be done on a line, or on a paragraph which is
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* then interpreted as one single line.<p>
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*
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* On construction, the class is initially empty. It is assigned
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* the Bidi properties of a paragraph by <code>SetPara</code>
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* or the Bidi properties of a line of a paragraph by
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* <code>SetLine</code>.<p>
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* A Bidi class can be reused for as long as it is not deallocated
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* by calling its destructor.<p>
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* <code>SetPara</code> will allocate additional memory for
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* internal structures as necessary.
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*/
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class nsBidi
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{
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public:
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/** @brief Default constructor.
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*
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* The nsBidi object is initially empty. It is assigned
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* the Bidi properties of a paragraph by <code>SetPara()</code>
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* or the Bidi properties of a line of a paragraph by
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* <code>GetLine()</code>.<p>
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* This object can be reused for as long as it is not destroyed.<p>
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* <code>SetPara()</code> will allocate additional memory for
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* internal structures as necessary.
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*
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*/
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nsBidi();
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/** @brief Destructor. */
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virtual ~nsBidi();
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/**
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* Perform the Unicode Bidi algorithm. It is defined in the
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* <a href="http://www.unicode.org/unicode/reports/tr9/">Unicode Technical Report 9</a>,
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* version 5,
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* also described in The Unicode Standard, Version 3.0 .<p>
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*
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* This function takes a single plain text paragraph with or without
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* externally specified embedding levels from <quote>styled</quote> text
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* and computes the left-right-directionality of each character.<p>
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*
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* If the entire paragraph consists of text of only one direction, then
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* the function may not perform all the steps described by the algorithm,
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* i.e., some levels may not be the same as if all steps were performed.
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* This is not relevant for unidirectional text.<br>
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* For example, in pure LTR text with numbers the numbers would get
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* a resolved level of 2 higher than the surrounding text according to
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* the algorithm. This implementation may set all resolved levels to
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* the same value in such a case.<p>
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*
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* The text must be externally split into separate paragraphs (rule P1).
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* Paragraph separators (B) should appear at most at the very end.
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*
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* @param aText is a pointer to the single-paragraph text that the
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* Bidi algorithm will be performed on
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* (step (P1) of the algorithm is performed externally).
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* <strong>The text must be (at least) <code>aLength</code> long.</strong>
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*
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* @param aLength is the length of the text; if <code>aLength==-1</code> then
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* the text must be zero-terminated.
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*
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* @param aParaLevel specifies the default level for the paragraph;
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* it is typically 0 (LTR) or 1 (RTL).
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* If the function shall determine the paragraph level from the text,
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* then <code>aParaLevel</code> can be set to
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* either <code>NSBIDI_DEFAULT_LTR</code>
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* or <code>NSBIDI_DEFAULT_RTL</code>;
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* if there is no strongly typed character, then
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* the desired default is used (0 for LTR or 1 for RTL).
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* Any other value between 0 and <code>NSBIDI_MAX_EXPLICIT_LEVEL</code> is also valid,
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* with odd levels indicating RTL.
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*
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* @param aEmbeddingLevels (in) may be used to preset the embedding and override levels,
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* ignoring characters like LRE and PDF in the text.
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* A level overrides the directional property of its corresponding
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* (same index) character if the level has the
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* <code>NSBIDI_LEVEL_OVERRIDE</code> bit set.<p>
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* Except for that bit, it must be
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* <code>aParaLevel<=aEmbeddingLevels[]<=NSBIDI_MAX_EXPLICIT_LEVEL</code>.<p>
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* <strong>Caution: </strong>A copy of this pointer, not of the levels,
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* will be stored in the <code>nsBidi</code> object;
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* the <code>aEmbeddingLevels</code> array must not be
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* deallocated before the <code>nsBidi</code> object is destroyed or reused,
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* and the <code>aEmbeddingLevels</code>
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* should not be modified to avoid unexpected results on subsequent Bidi operations.
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* However, the <code>SetPara</code> and
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* <code>SetLine</code> functions may modify some or all of the levels.<p>
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* After the <code>nsBidi</code> object is reused or destroyed, the caller
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* must take care of the deallocation of the <code>aEmbeddingLevels</code> array.<p>
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* <strong>The <code>aEmbeddingLevels</code> array must be
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* at least <code>aLength</code> long.</strong>
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*/
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nsresult SetPara(const PRUnichar *aText, PRInt32 aLength, nsBidiLevel aParaLevel, nsBidiLevel *aEmbeddingLevels);
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/**
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* Get the directionality of the text.
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*
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* @param aDirection receives a <code>NSBIDI_XXX</code> value that indicates if the entire text
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* represented by this object is unidirectional,
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* and which direction, or if it is mixed-directional.
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*
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* @see nsBidiDirection
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*/
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nsresult GetDirection(nsBidiDirection* aDirection);
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#ifdef FULL_BIDI_ENGINE
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/**
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* <code>SetLine</code> sets an <code>nsBidi</code> to
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* contain the reordering information, especially the resolved levels,
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* for all the characters in a line of text. This line of text is
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* specified by referring to an <code>nsBidi</code> object representing
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* this information for a paragraph of text, and by specifying
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* a range of indexes in this paragraph.<p>
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* In the new line object, the indexes will range from 0 to <code>aLimit-aStart</code>.<p>
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*
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* This is used after calling <code>SetPara</code>
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* for a paragraph, and after line-breaking on that paragraph.
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* It is not necessary if the paragraph is treated as a single line.<p>
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*
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* After line-breaking, rules (L1) and (L2) for the treatment of
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* trailing WS and for reordering are performed on
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* an <code>nsBidi</code> object that represents a line.<p>
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*
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* <strong>Important:</strong> the line <code>nsBidi</code> object shares data with
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* <code>aParaBidi</code>.
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* You must destroy or reuse this object before <code>aParaBidi</code>.
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* In other words, you must destroy or reuse the <code>nsBidi</code> object for a line
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* before the object for its parent paragraph.
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*
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* @param aParaBidi is the parent paragraph object.
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*
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* @param aStart is the line's first index into the paragraph text.
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*
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* @param aLimit is just behind the line's last index into the paragraph text
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* (its last index +1).<br>
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* It must be <code>0<=aStart<=aLimit<=</code>paragraph length.
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*
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* @see SetPara
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*/
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nsresult SetLine(nsIBidi* aParaBidi, PRInt32 aStart, PRInt32 aLimit);
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/**
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* Get the length of the text.
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*
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* @param aLength receives the length of the text that the nsBidi object was created for.
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*/
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nsresult GetLength(PRInt32* aLength);
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/**
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* Get the paragraph level of the text.
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*
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* @param aParaLevel receives a <code>NSBIDI_XXX</code> value indicating the paragraph level
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*
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* @see nsBidiLevel
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*/
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nsresult GetParaLevel(nsBidiLevel* aParaLevel);
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/**
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* Get the level for one character.
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*
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* @param aCharIndex the index of a character.
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*
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* @param aLevel receives the level for the character at aCharIndex.
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*
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* @see nsBidiLevel
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*/
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nsresult GetLevelAt(PRInt32 aCharIndex, nsBidiLevel* aLevel);
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/**
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* Get an array of levels for each character.<p>
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*
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* Note that this function may allocate memory under some
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* circumstances, unlike <code>GetLevelAt</code>.
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*
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* @param aLevels receives a pointer to the levels array for the text,
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* or <code>NULL</code> if an error occurs.
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*
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* @see nsBidiLevel
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*/
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nsresult GetLevels(nsBidiLevel** aLevels);
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#endif // FULL_BIDI_ENGINE
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/**
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* Get the bidirectional type for one character.
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*
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* @param aCharIndex the index of a character.
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*
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* @param aType receives the bidirectional type of the character at aCharIndex.
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*/
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nsresult GetCharTypeAt(PRInt32 aCharIndex, nsCharType* aType);
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/**
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* Get a logical run.
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* This function returns information about a run and is used
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* to retrieve runs in logical order.<p>
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* This is especially useful for line-breaking on a paragraph.
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*
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* @param aLogicalStart is the first character of the run.
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*
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* @param aLogicalLimit will receive the limit of the run.
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* The l-value that you point to here may be the
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* same expression (variable) as the one for
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* <code>aLogicalStart</code>.
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* This pointer can be <code>NULL</code> if this
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* value is not necessary.
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*
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* @param aLevel will receive the level of the run.
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* This pointer can be <code>NULL</code> if this
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* value is not necessary.
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*/
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nsresult GetLogicalRun(PRInt32 aLogicalStart, PRInt32* aLogicalLimit, nsBidiLevel* aLevel);
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/**
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* Get the number of runs.
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* This function may invoke the actual reordering on the
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* <code>nsBidi</code> object, after <code>SetPara</code>
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* may have resolved only the levels of the text. Therefore,
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* <code>CountRuns</code> may have to allocate memory,
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* and may fail doing so.
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*
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* @param aRunCount will receive the number of runs.
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*/
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nsresult CountRuns(PRInt32* aRunCount);
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/**
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* Get one run's logical start, length, and directionality,
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* which can be 0 for LTR or 1 for RTL.
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* In an RTL run, the character at the logical start is
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* visually on the right of the displayed run.
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* The length is the number of characters in the run.<p>
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* <code>CountRuns</code> should be called
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* before the runs are retrieved.
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*
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* @param aRunIndex is the number of the run in visual order, in the
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* range <code>[0..CountRuns-1]</code>.
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*
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* @param aLogicalStart is the first logical character index in the text.
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* The pointer may be <code>NULL</code> if this index is not needed.
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*
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* @param aLength is the number of characters (at least one) in the run.
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* The pointer may be <code>NULL</code> if this is not needed.
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*
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* @param aDirection will receive the directionality of the run,
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* <code>NSBIDI_LTR==0</code> or <code>NSBIDI_RTL==1</code>,
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* never <code>NSBIDI_MIXED</code>.
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*
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* @see CountRuns<p>
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*
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* Example:
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* @code
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* PRInt32 i, count, logicalStart, visualIndex=0, length;
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* nsBidiDirection dir;
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* pBidi->CountRuns(&count);
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* for(i=0; i<count; ++i) {
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* pBidi->GetVisualRun(i, &logicalStart, &length, &dir);
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* if(NSBIDI_LTR==dir) {
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* do { // LTR
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* show_char(text[logicalStart++], visualIndex++);
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* } while(--length>0);
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* } else {
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* logicalStart+=length; // logicalLimit
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* do { // RTL
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* show_char(text[--logicalStart], visualIndex++);
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* } while(--length>0);
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* }
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* }
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* @endcode
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*
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* Note that in right-to-left runs, code like this places
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* modifier letters before base characters and second surrogates
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* before first ones.
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*/
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nsresult GetVisualRun(PRInt32 aRunIndex, PRInt32* aLogicalStart, PRInt32* aLength, nsBidiDirection* aDirection);
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#ifdef FULL_BIDI_ENGINE
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/**
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* Get the visual position from a logical text position.
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* If such a mapping is used many times on the same
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* <code>nsBidi</code> object, then calling
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* <code>GetLogicalMap</code> is more efficient.<p>
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*
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* Note that in right-to-left runs, this mapping places
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* modifier letters before base characters and second surrogates
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* before first ones.
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*
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* @param aLogicalIndex is the index of a character in the text.
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*
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* @param aVisualIndex will receive the visual position of this character.
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*
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* @see GetLogicalMap
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* @see GetLogicalIndex
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*/
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nsresult GetVisualIndex(PRInt32 aLogicalIndex, PRInt32* aVisualIndex);
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/**
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* Get the logical text position from a visual position.
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* If such a mapping is used many times on the same
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* <code>nsBidi</code> object, then calling
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* <code>GetVisualMap</code> is more efficient.<p>
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*
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* This is the inverse function to <code>GetVisualIndex</code>.
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*
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* @param aVisualIndex is the visual position of a character.
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*
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* @param aLogicalIndex will receive the index of this character in the text.
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*
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* @see GetVisualMap
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* @see GetVisualIndex
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*/
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nsresult GetLogicalIndex(PRInt32 aVisualIndex, PRInt32* aLogicalIndex);
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/**
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* Get a logical-to-visual index map (array) for the characters in the nsBidi
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* (paragraph or line) object.
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*
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* @param aIndexMap is a pointer to an array of <code>GetLength</code>
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* indexes which will reflect the reordering of the characters.
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* The array does not need to be initialized.<p>
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* The index map will result in <code>aIndexMap[aLogicalIndex]==aVisualIndex</code>.<p>
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*
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* @see GetVisualMap
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* @see GetVisualIndex
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*/
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nsresult GetLogicalMap(PRInt32 *aIndexMap);
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/**
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* Get a visual-to-logical index map (array) for the characters in the nsBidi
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* (paragraph or line) object.
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*
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* @param aIndexMap is a pointer to an array of <code>GetLength</code>
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* indexes which will reflect the reordering of the characters.
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* The array does not need to be initialized.<p>
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* The index map will result in <code>aIndexMap[aVisualIndex]==aLogicalIndex</code>.<p>
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*
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* @see GetLogicalMap
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* @see GetLogicalIndex
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*/
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nsresult GetVisualMap(PRInt32 *aIndexMap);
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/**
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* This is a convenience function that does not use a nsBidi object.
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* It is intended to be used for when an application has determined the levels
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* of objects (character sequences) and just needs to have them reordered (L2).
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* This is equivalent to using <code>GetLogicalMap</code> on a
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* <code>nsBidi</code> object.
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*
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* @param aLevels is an array with <code>aLength</code> levels that have been determined by
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* the application.
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*
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* @param aLength is the number of levels in the array, or, semantically,
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* the number of objects to be reordered.
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* It must be <code>aLength>0</code>.
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*
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* @param aIndexMap is a pointer to an array of <code>aLength</code>
|
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* indexes which will reflect the reordering of the characters.
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* The array does not need to be initialized.<p>
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* The index map will result in <code>aIndexMap[aLogicalIndex]==aVisualIndex</code>.
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*/
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static nsresult ReorderLogical(const nsBidiLevel *aLevels, PRInt32 aLength, PRInt32 *aIndexMap);
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#endif // FULL_BIDI_ENGINE
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/**
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* This is a convenience function that does not use a nsBidi object.
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* It is intended to be used for when an application has determined the levels
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* of objects (character sequences) and just needs to have them reordered (L2).
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* This is equivalent to using <code>GetVisualMap</code> on a
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* <code>nsBidi</code> object.
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*
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* @param aLevels is an array with <code>aLength</code> levels that have been determined by
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* the application.
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*
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* @param aLength is the number of levels in the array, or, semantically,
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* the number of objects to be reordered.
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* It must be <code>aLength>0</code>.
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*
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* @param aIndexMap is a pointer to an array of <code>aLength</code>
|
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* indexes which will reflect the reordering of the characters.
|
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* The array does not need to be initialized.<p>
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* The index map will result in <code>aIndexMap[aVisualIndex]==aLogicalIndex</code>.
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*/
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static nsresult ReorderVisual(const nsBidiLevel *aLevels, PRInt32 aLength, PRInt32 *aIndexMap);
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#ifdef FULL_BIDI_ENGINE
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/**
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* Invert an index map.
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* The one-to-one index mapping of the first map is inverted and written to
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* the second one.
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*
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* @param aSrcMap is an array with <code>aLength</code> indexes
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* which define the original mapping.
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*
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* @param aDestMap is an array with <code>aLength</code> indexes
|
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* which will be filled with the inverse mapping.
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*
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* @param aLength is the length of each array.
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*/
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nsresult InvertMap(const PRInt32 *aSrcMap, PRInt32 *aDestMap, PRInt32 aLength);
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#endif // FULL_BIDI_ENGINE
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/**
|
|
* Reverse a Right-To-Left run of Unicode text.
|
|
*
|
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* This function preserves the integrity of characters with multiple
|
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* code units and (optionally) modifier letters.
|
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* Characters can be replaced by mirror-image characters
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* in the destination buffer. Note that "real" mirroring has
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* to be done in a rendering engine by glyph selection
|
|
* and that for many "mirrored" characters there are no
|
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* Unicode characters as mirror-image equivalents.
|
|
* There are also options to insert or remove Bidi control
|
|
* characters; see the description of the <code>aDestSize</code>
|
|
* and <code>aOptions</code> parameters and of the option bit flags.
|
|
*
|
|
* Since no Bidi controls are inserted here, this function will never
|
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* write more than <code>aSrcLength</code> characters to <code>aDest</code>.
|
|
*
|
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* @param aSrc A pointer to the RTL run text.
|
|
*
|
|
* @param aSrcLength The length of the RTL run.
|
|
* If the <code>NSBIDI_REMOVE_BIDI_CONTROLS</code> option
|
|
* is set, then the destination length may be less than
|
|
* <code>aSrcLength</code>.
|
|
* If this option is not set, then the destination length
|
|
* will be exactly <code>aSrcLength</code>.
|
|
*
|
|
* @param aDest A pointer to where the reordered text is to be copied.
|
|
* <code>aSrc[aSrcLength]</code> and <code>aDest[aSrcLength]</code>
|
|
* must not overlap.
|
|
*
|
|
* @param aOptions A bit set of options for the reordering that control
|
|
* how the reordered text is written.
|
|
*
|
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* @param aDestSize will receive the number of characters that were written to <code>aDest</code>.
|
|
*/
|
|
nsresult WriteReverse(const PRUnichar *aSrc, PRInt32 aSrcLength, PRUnichar *aDest, PRUint16 aOptions, PRInt32 *aDestSize);
|
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|
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protected:
|
|
friend class nsBidiPresUtils;
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|
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/** length of the current text */
|
|
PRInt32 mLength;
|
|
|
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/** memory sizes in bytes */
|
|
PRSize mDirPropsSize, mLevelsSize, mRunsSize;
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|
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/** allocated memory */
|
|
DirProp* mDirPropsMemory;
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nsBidiLevel* mLevelsMemory;
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Run* mRunsMemory;
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|
|
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/** indicators for whether memory may be allocated after construction */
|
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PRBool mMayAllocateText, mMayAllocateRuns;
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|
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const DirProp* mDirProps;
|
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nsBidiLevel* mLevels;
|
|
|
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/** the paragraph level */
|
|
nsBidiLevel mParaLevel;
|
|
|
|
/** flags is a bit set for which directional properties are in the text */
|
|
Flags mFlags;
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|
|
|
/** the overall paragraph or line directionality - see nsBidiDirection */
|
|
nsBidiDirection mDirection;
|
|
|
|
/** characters after trailingWSStart are WS and are */
|
|
/* implicitly at the paraLevel (rule (L1)) - levels may not reflect that */
|
|
PRInt32 mTrailingWSStart;
|
|
|
|
/** fields for line reordering */
|
|
PRInt32 mRunCount; /* ==-1: runs not set up yet */
|
|
Run* mRuns;
|
|
|
|
/** for non-mixed text, we only need a tiny array of runs (no malloc()) */
|
|
Run mSimpleRuns[1];
|
|
|
|
private:
|
|
|
|
void Init();
|
|
|
|
PRBool GetMemory(void **aMemory, PRSize* aSize, PRBool aMayAllocate, PRSize aSizeNeeded);
|
|
|
|
void Free();
|
|
|
|
void GetDirProps(const PRUnichar *aText);
|
|
|
|
nsBidiDirection ResolveExplicitLevels();
|
|
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nsresult CheckExplicitLevels(nsBidiDirection *aDirection);
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nsBidiDirection DirectionFromFlags(Flags aFlags);
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void ResolveImplicitLevels(PRInt32 aStart, PRInt32 aLimit, DirProp aSOR, DirProp aEOR);
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void AdjustWSLevels();
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void SetTrailingWSStart();
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PRBool GetRuns();
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void GetSingleRun(nsBidiLevel aLevel);
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void ReorderLine(nsBidiLevel aMinLevel, nsBidiLevel aMaxLevel);
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static PRBool PrepareReorder(const nsBidiLevel *aLevels, PRInt32 aLength, PRInt32 *aIndexMap, nsBidiLevel *aMinLevel, nsBidiLevel *aMaxLevel);
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PRInt32 doWriteReverse(const PRUnichar *src, PRInt32 srcLength,
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PRUnichar *dest, PRUint16 options);
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};
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#endif // _nsBidi_h_
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