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gecko-dev/layout/base/nsBidi.h

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/* -*- Mode: C; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
*
* ***** BEGIN LICENSE BLOCK *****
* Version: MPL 1.1/GPL 2.0/LGPL 2.1
*
* The contents of this file are subject to the Mozilla Public License Version
* 1.1 (the "License"); you may not use this file except in compliance with
* the License. You may obtain a copy of the License at
* http://www.mozilla.org/MPL/
*
* Software distributed under the License is distributed on an "AS IS" basis,
* WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
* for the specific language governing rights and limitations under the
* License.
*
* The Original Code is mozilla.org code.
*
* The Initial Developer of the Original Code is
* IBM Corporation.
* Portions created by the Initial Developer are Copyright (C) 2000
* the Initial Developer. All Rights Reserved.
*
* Contributor(s):
* Simon Montagu
*
* Alternatively, the contents of this file may be used under the terms of
* either of the GNU General Public License Version 2 or later (the "GPL"),
* or the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
* in which case the provisions of the GPL or the LGPL are applicable instead
* of those above. If you wish to allow use of your version of this file only
* under the terms of either the GPL or the LGPL, and not to allow others to
* use your version of this file under the terms of the MPL, indicate your
* decision by deleting the provisions above and replace them with the notice
* and other provisions required by the GPL or the LGPL. If you do not delete
* the provisions above, a recipient may use your version of this file under
* the terms of any one of the MPL, the GPL or the LGPL.
*
* ***** END LICENSE BLOCK ***** */
#ifndef nsBidi_h__
#define nsBidi_h__
#include "nsCOMPtr.h"
#include "nsString.h"
// Bidi reordering engine from ICU
/*
* javadoc-style comments are intended to be transformed into HTML
* using DOC++ - see
* http://www.zib.de/Visual/software/doc++/index.html .
*
* The HTML documentation is created with
* doc++ -H nsIBidi.h
*/
/**
* @mainpage BIDI algorithm for Mozilla (from ICU)
*
* <h2>BIDI algorithm for Mozilla</h2>
*
* This is an implementation of the Unicode Bidirectional algorithm.
* The algorithm is defined in the
* <a href="http://www.unicode.org/unicode/reports/tr9/">Unicode Technical Report 9</a>,
* version 5, also described in The Unicode Standard, Version 3.0 .<p>
*
* <h3>General remarks about the API:</h3>
*
* The <quote>limit</quote> of a sequence of characters is the position just after their
* last character, i.e., one more than that position.<p>
*
* Some of the API functions provide access to <quote>runs</quote>.
* Such a <quote>run</quote> is defined as a sequence of characters
* that are at the same embedding level
* after performing the BIDI algorithm.<p>
*
* @author Markus W. Scherer. Ported to Mozilla by Simon Montagu
* @version 1.0
*/
/**
* nsBidiLevel is the type of the level values in this
* Bidi implementation.
* It holds an embedding level and indicates the visual direction
* by its bit 0 (even/odd value).<p>
*
* It can also hold non-level values for the
* <code>aParaLevel</code> and <code>aEmbeddingLevels</code>
* arguments of <code>SetPara</code>; there:
* <ul>
* <li>bit 7 of an <code>aEmbeddingLevels[]</code>
* value indicates whether the using application is
* specifying the level of a character to <i>override</i> whatever the
* Bidi implementation would resolve it to.</li>
* <li><code>aParaLevel</code> can be set to the
* pseudo-level values <code>NSBIDI_DEFAULT_LTR</code>
* and <code>NSBIDI_DEFAULT_RTL</code>.</li></ul>
*
* @see nsIBidi::SetPara
*
* <p>The related constants are not real, valid level values.
* <code>NSBIDI_DEFAULT_XXX</code> can be used to specify
* a default for the paragraph level for
* when the <code>SetPara</code> function
* shall determine it but there is no
* strongly typed character in the input.<p>
*
* Note that the value for <code>NSBIDI_DEFAULT_LTR</code> is even
* and the one for <code>NSBIDI_DEFAULT_RTL</code> is odd,
* just like with normal LTR and RTL level values -
* these special values are designed that way. Also, the implementation
* assumes that NSBIDI_MAX_EXPLICIT_LEVEL is odd.
*
* @see NSBIDI_DEFAULT_LTR
* @see NSBIDI_DEFAULT_RTL
* @see NSBIDI_LEVEL_OVERRIDE
* @see NSBIDI_MAX_EXPLICIT_LEVEL
*/
typedef PRUint8 nsBidiLevel;
/** Paragraph level setting.
* If there is no strong character, then set the paragraph level to 0 (left-to-right).
*/
#define NSBIDI_DEFAULT_LTR 0xfe
/** Paragraph level setting.
* If there is no strong character, then set the paragraph level to 1 (right-to-left).
*/
#define NSBIDI_DEFAULT_RTL 0xff
/**
* Maximum explicit embedding level.
* (The maximum resolved level can be up to <code>NSBIDI_MAX_EXPLICIT_LEVEL+1</code>).
*
*/
#define NSBIDI_MAX_EXPLICIT_LEVEL 61
/** Bit flag for level input.
* Overrides directional properties.
*/
#define NSBIDI_LEVEL_OVERRIDE 0x80
/**
* <code>nsBidiDirection</code> values indicate the text direction.
*/
enum nsBidiDirection {
/** All left-to-right text This is a 0 value. */
NSBIDI_LTR,
/** All right-to-left text This is a 1 value. */
NSBIDI_RTL,
/** Mixed-directional text. */
NSBIDI_MIXED
};
typedef enum nsBidiDirection nsBidiDirection;
/* miscellaneous definitions ------------------------------------------------ */
/**
* Read ftp://ftp.unicode.org/Public/UNIDATA/ReadMe-Latest.txt
* section BIDIRECTIONAL PROPERTIES
* for the detailed definition of the following categories
*
* The values here must match the equivalents in %map in
* mozilla/intl/unicharutil/tools/genbidicattable.pl
*/
typedef enum {
eBidiCat_Undefined,
eBidiCat_L, /* Left-to-Right */
eBidiCat_R, /* Right-to-Left */
eBidiCat_AL, /* Right-to-Left Arabic */
eBidiCat_AN, /* Arabic Number */
eBidiCat_EN, /* European Number */
eBidiCat_ES, /* European Number Separator */
eBidiCat_ET, /* European Number Terminator */
eBidiCat_CS, /* Common Number Separator */
eBidiCat_ON, /* Other Neutrals */
eBidiCat_NSM, /* Non-Spacing Mark */
eBidiCat_BN, /* Boundary Neutral */
eBidiCat_B, /* Paragraph Separator */
eBidiCat_S, /* Segment Separator */
eBidiCat_WS, /* Whitespace */
eBidiCat_CC = 0xf, /* Control Code */
/* (internal use only - will never be outputed) */
eBidiCat_LRE = 0x2a, /* Left-to-Right Embedding */
eBidiCat_RLE = 0x2b, /* Right-to-Left Embedding */
eBidiCat_PDF = 0x2c, /* Pop Directional Formatting */
eBidiCat_LRO = 0x2d, /* Left-to-Right Override */
eBidiCat_RLO = 0x2e /* Right-to-Left Override */
} eBidiCategory;
enum nsCharType {
eCharType_LeftToRight = 0,
eCharType_RightToLeft = 1,
eCharType_EuropeanNumber = 2,
eCharType_EuropeanNumberSeparator = 3,
eCharType_EuropeanNumberTerminator = 4,
eCharType_ArabicNumber = 5,
eCharType_CommonNumberSeparator = 6,
eCharType_BlockSeparator = 7,
eCharType_SegmentSeparator = 8,
eCharType_WhiteSpaceNeutral = 9,
eCharType_OtherNeutral = 10,
eCharType_LeftToRightEmbedding = 11,
eCharType_LeftToRightOverride = 12,
eCharType_RightToLeftArabic = 13,
eCharType_RightToLeftEmbedding = 14,
eCharType_RightToLeftOverride = 15,
eCharType_PopDirectionalFormat = 16,
eCharType_DirNonSpacingMark = 17,
eCharType_BoundaryNeutral = 18,
eCharType_CharTypeCount
};
/**
* This specifies the language directional property of a character set.
*/
typedef enum nsCharType nsCharType;
/**
* definitions of bidirection character types by category
*/
#define CHARTYPE_IS_RTL(val) ( ( (val) == eCharType_RightToLeft) || ( (val) == eCharType_RightToLeftArabic) )
#define CHARTYPE_IS_WEAK(val) ( ( (val) == eCharType_EuropeanNumberSeparator) \
|| ( (val) == eCharType_EuropeanNumberTerminator) \
|| ( ( (val) > eCharType_ArabicNumber) && ( (val) != eCharType_RightToLeftArabic) ) )
/** option flags for WriteReverse() */
/**
* option bit for WriteReverse():
* keep combining characters after their base characters in RTL runs
*
* @see WriteReverse
*/
#define NSBIDI_KEEP_BASE_COMBINING 1
/**
* option bit for WriteReverse():
* replace characters with the "mirrored" property in RTL runs
* by their mirror-image mappings
*
* @see WriteReverse
*/
#define NSBIDI_DO_MIRRORING 2
/**
* option bit for WriteReverse():
* remove Bidi control characters
*
* @see WriteReverse
*/
#define NSBIDI_REMOVE_BIDI_CONTROLS 8
/* helper macros for each allocated array member */
#define GETDIRPROPSMEMORY(length) \
GetMemory((void **)&mDirPropsMemory, &mDirPropsSize, \
mMayAllocateText, (length))
#define GETLEVELSMEMORY(length) \
GetMemory((void **)&mLevelsMemory, &mLevelsSize, \
mMayAllocateText, (length))
#define GETRUNSMEMORY(length) \
GetMemory((void **)&mRunsMemory, &mRunsSize, \
mMayAllocateRuns, (length)*sizeof(Run))
/* additional macros used by constructor - always allow allocation */
#define GETINITIALDIRPROPSMEMORY(length) \
GetMemory((void **)&mDirPropsMemory, &mDirPropsSize, \
PR_TRUE, (length))
#define GETINITIALLEVELSMEMORY(length) \
GetMemory((void **)&mLevelsMemory, &mLevelsSize, \
PR_TRUE, (length))
#define GETINITIALRUNSMEMORY(length) \
GetMemory((void **)&mRunsMemory, &mRunsSize, \
PR_TRUE, (length)*sizeof(Run))
/*
* Sometimes, bit values are more appropriate
* to deal with directionality properties.
* Abbreviations in these macro names refer to names
* used in the Bidi algorithm.
*/
typedef PRUint8 DirProp;
#define DIRPROP_FLAG(dir) (1UL<<(dir))
/* special flag for multiple runs from explicit embedding codes */
#define DIRPROP_FLAG_MULTI_RUNS (1UL<<31)
/* are there any characters that are LTR or RTL? */
#define MASK_LTR (DIRPROP_FLAG(L)|DIRPROP_FLAG(EN)|DIRPROP_FLAG(AN)|DIRPROP_FLAG(LRE)|DIRPROP_FLAG(LRO))
#define MASK_RTL (DIRPROP_FLAG(R)|DIRPROP_FLAG(AL)|DIRPROP_FLAG(RLE)|DIRPROP_FLAG(RLO))
/* explicit embedding codes */
#define MASK_LRX (DIRPROP_FLAG(LRE)|DIRPROP_FLAG(LRO))
#define MASK_RLX (DIRPROP_FLAG(RLE)|DIRPROP_FLAG(RLO))
#define MASK_OVERRIDE (DIRPROP_FLAG(LRO)|DIRPROP_FLAG(RLO))
#define MASK_EXPLICIT (MASK_LRX|MASK_RLX|DIRPROP_FLAG(PDF))
#define MASK_BN_EXPLICIT (DIRPROP_FLAG(BN)|MASK_EXPLICIT)
/* paragraph and segment separators */
#define MASK_B_S (DIRPROP_FLAG(B)|DIRPROP_FLAG(S))
/* all types that are counted as White Space or Neutral in some steps */
#define MASK_WS (MASK_B_S|DIRPROP_FLAG(WS)|MASK_BN_EXPLICIT)
#define MASK_N (DIRPROP_FLAG(O_N)|MASK_WS)
/* all types that are included in a sequence of European Terminators for (W5) */
#define MASK_ET_NSM_BN (DIRPROP_FLAG(ET)|DIRPROP_FLAG(NSM)|MASK_BN_EXPLICIT)
/* types that are neutrals or could becomes neutrals in (Wn) */
#define MASK_POSSIBLE_N (DIRPROP_FLAG(CS)|DIRPROP_FLAG(ES)|DIRPROP_FLAG(ET)|MASK_N)
/*
* These types may be changed to "e",
* the embedding type (L or R) of the run,
* in the Bidi algorithm (N2)
*/
#define MASK_EMBEDDING (DIRPROP_FLAG(NSM)|MASK_POSSIBLE_N)
/* the dirProp's L and R are defined to 0 and 1 values in nsCharType */
#define GET_LR_FROM_LEVEL(level) ((DirProp)((level)&1))
#define IS_DEFAULT_LEVEL(level) (((level)&0xfe)==0xfe)
/* handle surrogate pairs --------------------------------------------------- */
#define IS_FIRST_SURROGATE(uchar) (((uchar)&0xfc00)==0xd800)
#define IS_SECOND_SURROGATE(uchar) (((uchar)&0xfc00)==0xdc00)
/* get the UTF-32 value directly from the surrogate pseudo-characters */
#define SURROGATE_OFFSET ((0xd800<<10UL)+0xdc00-0x10000)
#define GET_UTF_32(first, second) (((first)<<10UL)+(second)-SURROGATE_OFFSET)
#define UTF_ERROR_VALUE 0xffff
/* definitions with forward iteration --------------------------------------- */
/*
* all the macros that go forward assume that
* the initial offset is 0<=i<length;
* they update the offset
*/
/* fast versions, no error-checking */
#define UTF16_APPEND_CHAR_UNSAFE(s, i, c){ \
if((PRUint32)(c)<=0xffff) { \
(s)[(i)++]=(PRUnichar)(c); \
} else { \
(s)[(i)++]=(PRUnichar)((c)>>10)+0xd7c0; \
(s)[(i)++]=(PRUnichar)(c)&0x3ff|0xdc00; \
} \
}
/* safe versions with error-checking and optional regularity-checking */
#define UTF16_APPEND_CHAR_SAFE(s, i, length, c) { \
if((PRUInt32)(c)<=0xffff) { \
(s)[(i)++]=(PRUnichar)(c); \
} else if((PRUInt32)(c)<=0x10ffff) { \
if((i)+1<(length)) { \
(s)[(i)++]=(PRUnichar)((c)>>10)+0xd7c0; \
(s)[(i)++]=(PRUnichar)(c)&0x3ff|0xdc00; \
} else /* not enough space */ { \
(s)[(i)++]=UTF_ERROR_VALUE; \
} \
} else /* c>0x10ffff, write error value */ { \
(s)[(i)++]=UTF_ERROR_VALUE; \
} \
}
/* definitions with backward iteration -------------------------------------- */
/*
* all the macros that go backward assume that
* the valid buffer range starts at offset 0
* and that the initial offset is 0<i<=length;
* they update the offset
*/
/* fast versions, no error-checking */
/*
* Get a single code point from an offset that points behind the last
* of the code units that belong to that code point.
* Assume 0<=i<length.
*/
#define UTF16_PREV_CHAR_UNSAFE(s, i, c) { \
(c)=(s)[--(i)]; \
if(IS_SECOND_SURROGATE(c)) { \
(c)=GET_UTF_32((s)[--(i)], (c)); \
} \
}
#define UTF16_BACK_1_UNSAFE(s, i) { \
if(IS_SECOND_SURROGATE((s)[--(i)])) { \
--(i); \
} \
}
#define UTF16_BACK_N_UNSAFE(s, i, n) { \
PRInt32 __N=(n); \
while(__N>0) { \
UTF16_BACK_1_UNSAFE(s, i); \
--__N; \
} \
}
/* safe versions with error-checking and optional regularity-checking */
#define UTF16_PREV_CHAR_SAFE(s, start, i, c, strict) { \
(c)=(s)[--(i)]; \
if(IS_SECOND_SURROGATE(c)) { \
PRUnichar __c2; \
if((i)>(start) && IS_FIRST_SURROGATE(__c2=(s)[(i)-1])) { \
--(i); \
(c)=GET_UTF_32(__c2, (c)); \
/* strict: ((c)&0xfffe)==0xfffe is caught by UTF_IS_ERROR() */ \
} else if(strict) {\
/* unmatched second surrogate */ \
(c)=UTF_ERROR_VALUE; \
} \
} else if(strict && IS_FIRST_SURROGATE(c)) { \
/* unmatched first surrogate */ \
(c)=UTF_ERROR_VALUE; \
/* else strict: (c)==0xfffe is caught by UTF_IS_ERROR() */ \
} \
}
#define UTF16_BACK_1_SAFE(s, start, i) { \
if(IS_SECOND_SURROGATE((s)[--(i)]) && (i)>(start) && IS_FIRST_SURROGATE((s)[(i)-1])) { \
--(i); \
} \
}
#define UTF16_BACK_N_SAFE(s, start, i, n) { \
PRInt32 __N=(n); \
while(__N>0 && (i)>(start)) { \
UTF16_BACK_1_SAFE(s, start, i); \
--__N; \
} \
}
#define UTF_PREV_CHAR_UNSAFE(s, i, c) UTF16_PREV_CHAR_UNSAFE(s, i, c)
#define UTF_PREV_CHAR_SAFE(s, start, i, c, strict) UTF16_PREV_CHAR_SAFE(s, start, i, c, strict)
#define UTF_BACK_1_UNSAFE(s, i) UTF16_BACK_1_UNSAFE(s, i)
#define UTF_BACK_1_SAFE(s, start, i) UTF16_BACK_1_SAFE(s, start, i)
#define UTF_BACK_N_UNSAFE(s, i, n) UTF16_BACK_N_UNSAFE(s, i, n)
#define UTF_BACK_N_SAFE(s, start, i, n) UTF16_BACK_N_SAFE(s, start, i, n)
#define UTF_APPEND_CHAR_UNSAFE(s, i, c) UTF16_APPEND_CHAR_UNSAFE(s, i, c)
#define UTF_APPEND_CHAR_SAFE(s, i, length, c) UTF16_APPEND_CHAR_SAFE(s, i, length, c)
#define UTF_PREV_CHAR(s, start, i, c) UTF_PREV_CHAR_SAFE(s, start, i, c, PR_FALSE)
#define UTF_BACK_1(s, start, i) UTF_BACK_1_SAFE(s, start, i)
#define UTF_BACK_N(s, start, i, n) UTF_BACK_N_SAFE(s, start, i, n)
#define UTF_APPEND_CHAR(s, i, length, c) UTF_APPEND_CHAR_SAFE(s, i, length, c)
/* Run structure for reordering --------------------------------------------- */
typedef struct Run {
PRInt32 logicalStart, /* first character of the run; b31 indicates even/odd level */
visualLimit; /* last visual position of the run +1 */
} Run;
/* in a Run, logicalStart will get this bit set if the run level is odd */
#define INDEX_ODD_BIT (1UL<<31)
#define MAKE_INDEX_ODD_PAIR(index, level) (index|((PRUint32)level<<31))
#define ADD_ODD_BIT_FROM_LEVEL(x, level) ((x)|=((PRUint32)level<<31))
#define REMOVE_ODD_BIT(x) ((x)&=~INDEX_ODD_BIT)
#define GET_INDEX(x) (x&~INDEX_ODD_BIT)
#define GET_ODD_BIT(x) ((PRUint32)x>>31)
#define IS_ODD_RUN(x) ((x&INDEX_ODD_BIT)!=0)
#define IS_EVEN_RUN(x) ((x&INDEX_ODD_BIT)==0)
typedef PRUint32 Flags;
/**
* This class holds information about a paragraph of text
* with Bidi-algorithm-related details, or about one line of
* such a paragraph.<p>
* Reordering can be done on a line, or on a paragraph which is
* then interpreted as one single line.<p>
*
* On construction, the class is initially empty. It is assigned
* the Bidi properties of a paragraph by <code>SetPara</code>
* or the Bidi properties of a line of a paragraph by
* <code>SetLine</code>.<p>
* A Bidi class can be reused for as long as it is not deallocated
* by calling its destructor.<p>
* <code>SetPara</code> will allocate additional memory for
* internal structures as necessary.
*/
class nsBidi
{
public:
/** @brief Default constructor.
*
* The nsBidi object is initially empty. It is assigned
* the Bidi properties of a paragraph by <code>SetPara()</code>
* or the Bidi properties of a line of a paragraph by
* <code>GetLine()</code>.<p>
* This object can be reused for as long as it is not destroyed.<p>
* <code>SetPara()</code> will allocate additional memory for
* internal structures as necessary.
*
*/
nsBidi();
/** @brief Preallocating constructor
* Allocate an <code>nsBidi</code>
* object with preallocated memory for internal structures. This
* constructor provides an <code>nsBidi</code> object like
* the default constructor, but it also
* preallocates memory for internal structures according to the sizings
* supplied by the caller.<p> Subsequent functions will not allocate
* any more memory, and are thus guaranteed not to fail because of lack
* of memory.<p> The preallocation can be limited to some of the
* internal memory by setting some values to 0 here. That means that
* if, e.g., <code>aMaxRunCount</code> cannot be reasonably
* predetermined and should not be set to <code>aMaxLength</code> (the
* only failproof value) to avoid wasting memory, then
* <code>aMaxRunCount</code> could be set to 0 here and the internal
* structures that are associated with it will be allocated on demand,
* just like with the default constructor.
*
* If sufficient memory could not be allocated, no exception is thrown.
* Test whether mDirPropsSize == aMaxLength and/or mRunsSize == aMaxRunCount.
*
* @param aMaxLength is the maximum paragraph or line length that internal memory
* will be preallocated for. An attempt to associate this object with a
* longer text will fail, unless this value is 0, which leaves the allocation
* up to the implementation.
*
* @param aMaxRunCount is the maximum anticipated number of same-level runs
* that internal memory will be preallocated for. An attempt to access
* visual runs on an object that was not preallocated for as many runs
* as the text was actually resolved to will fail,
* unless this value is 0, which leaves the allocation up to the implementation.<p>
* The number of runs depends on the actual text and maybe anywhere between
* 1 and <code>aMaxLength</code>. It is typically small.<p>
*/
nsBidi(PRUint32 aMaxLength, PRUint32 aMaxRunCount);
/** @brief Destructor. */
virtual ~nsBidi();
/**
* Perform the Unicode Bidi algorithm. It is defined in the
* <a href="http://www.unicode.org/unicode/reports/tr9/">Unicode Technical Report 9</a>,
* version 5,
* also described in The Unicode Standard, Version 3.0 .<p>
*
* This function takes a single plain text paragraph with or without
* externally specified embedding levels from <quote>styled</quote> text
* and computes the left-right-directionality of each character.<p>
*
* If the entire paragraph consists of text of only one direction, then
* the function may not perform all the steps described by the algorithm,
* i.e., some levels may not be the same as if all steps were performed.
* This is not relevant for unidirectional text.<br>
* For example, in pure LTR text with numbers the numbers would get
* a resolved level of 2 higher than the surrounding text according to
* the algorithm. This implementation may set all resolved levels to
* the same value in such a case.<p>
*
* The text must be externally split into separate paragraphs (rule P1).
* Paragraph separators (B) should appear at most at the very end.
*
* @param aText is a pointer to the single-paragraph text that the
* Bidi algorithm will be performed on
* (step (P1) of the algorithm is performed externally).
* <strong>The text must be (at least) <code>aLength</code> long.</strong>
*
* @param aLength is the length of the text; if <code>aLength==-1</code> then
* the text must be zero-terminated.
*
* @param aParaLevel specifies the default level for the paragraph;
* it is typically 0 (LTR) or 1 (RTL).
* If the function shall determine the paragraph level from the text,
* then <code>aParaLevel</code> can be set to
* either <code>NSBIDI_DEFAULT_LTR</code>
* or <code>NSBIDI_DEFAULT_RTL</code>;
* if there is no strongly typed character, then
* the desired default is used (0 for LTR or 1 for RTL).
* Any other value between 0 and <code>NSBIDI_MAX_EXPLICIT_LEVEL</code> is also valid,
* with odd levels indicating RTL.
*
* @param aEmbeddingLevels (in) may be used to preset the embedding and override levels,
* ignoring characters like LRE and PDF in the text.
* A level overrides the directional property of its corresponding
* (same index) character if the level has the
* <code>NSBIDI_LEVEL_OVERRIDE</code> bit set.<p>
* Except for that bit, it must be
* <code>aParaLevel<=aEmbeddingLevels[]<=NSBIDI_MAX_EXPLICIT_LEVEL</code>.<p>
* <strong>Caution: </strong>A copy of this pointer, not of the levels,
* will be stored in the <code>nsBidi</code> object;
* the <code>aEmbeddingLevels</code> array must not be
* deallocated before the <code>nsBidi</code> object is destroyed or reused,
* and the <code>aEmbeddingLevels</code>
* should not be modified to avoid unexpected results on subsequent Bidi operations.
* However, the <code>SetPara</code> and
* <code>SetLine</code> functions may modify some or all of the levels.<p>
* After the <code>nsBidi</code> object is reused or destroyed, the caller
* must take care of the deallocation of the <code>aEmbeddingLevels</code> array.<p>
* <strong>The <code>aEmbeddingLevels</code> array must be
* at least <code>aLength</code> long.</strong>
*/
nsresult SetPara(const PRUnichar *aText, PRInt32 aLength, nsBidiLevel aParaLevel, nsBidiLevel *aEmbeddingLevels);
#ifdef FULL_BIDI_ENGINE
/**
* <code>SetLine</code> sets an <code>nsBidi</code> to
* contain the reordering information, especially the resolved levels,
* for all the characters in a line of text. This line of text is
* specified by referring to an <code>nsBidi</code> object representing
* this information for a paragraph of text, and by specifying
* a range of indexes in this paragraph.<p>
* In the new line object, the indexes will range from 0 to <code>aLimit-aStart</code>.<p>
*
* This is used after calling <code>SetPara</code>
* for a paragraph, and after line-breaking on that paragraph.
* It is not necessary if the paragraph is treated as a single line.<p>
*
* After line-breaking, rules (L1) and (L2) for the treatment of
* trailing WS and for reordering are performed on
* an <code>nsBidi</code> object that represents a line.<p>
*
* <strong>Important:</strong> the line <code>nsBidi</code> object shares data with
* <code>aParaBidi</code>.
* You must destroy or reuse this object before <code>aParaBidi</code>.
* In other words, you must destroy or reuse the <code>nsBidi</code> object for a line
* before the object for its parent paragraph.
*
* @param aParaBidi is the parent paragraph object.
*
* @param aStart is the line's first index into the paragraph text.
*
* @param aLimit is just behind the line's last index into the paragraph text
* (its last index +1).<br>
* It must be <code>0<=aStart<=aLimit<=</code>paragraph length.
*
* @see SetPara
*/
nsresult SetLine(nsIBidi* aParaBidi, PRInt32 aStart, PRInt32 aLimit);
/**
* Get the directionality of the text.
*
* @param aDirection receives a <code>NSBIDI_XXX</code> value that indicates if the entire text
* represented by this object is unidirectional,
* and which direction, or if it is mixed-directional.
*
* @see nsBidiDirection
*/
nsresult GetDirection(nsBidiDirection* aDirection);
/**
* Get the length of the text.
*
* @param aLength receives the length of the text that the nsBidi object was created for.
*/
nsresult GetLength(PRInt32* aLength);
/**
* Get the paragraph level of the text.
*
* @param aParaLevel receives a <code>NSBIDI_XXX</code> value indicating the paragraph level
*
* @see nsBidiLevel
*/
nsresult GetParaLevel(nsBidiLevel* aParaLevel);
/**
* Get the level for one character.
*
* @param aCharIndex the index of a character.
*
* @param aLevel receives the level for the character at aCharIndex.
*
* @see nsBidiLevel
*/
nsresult GetLevelAt(PRInt32 aCharIndex, nsBidiLevel* aLevel);
/**
* Get an array of levels for each character.<p>
*
* Note that this function may allocate memory under some
* circumstances, unlike <code>GetLevelAt</code>.
*
* @param aLevels receives a pointer to the levels array for the text,
* or <code>NULL</code> if an error occurs.
*
* @see nsBidiLevel
*/
nsresult GetLevels(nsBidiLevel** aLevels);
#endif // FULL_BIDI_ENGINE
/**
* Get the bidirectional type for one character.
*
* @param aCharIndex the index of a character.
*
* @param aType receives the bidirectional type of the character at aCharIndex.
*/
nsresult GetCharTypeAt(PRInt32 aCharIndex, nsCharType* aType);
/**
* Get a logical run.
* This function returns information about a run and is used
* to retrieve runs in logical order.<p>
* This is especially useful for line-breaking on a paragraph.
*
* @param aLogicalStart is the first character of the run.
*
* @param aLogicalLimit will receive the limit of the run.
* The l-value that you point to here may be the
* same expression (variable) as the one for
* <code>aLogicalStart</code>.
* This pointer can be <code>NULL</code> if this
* value is not necessary.
*
* @param aLevel will receive the level of the run.
* This pointer can be <code>NULL</code> if this
* value is not necessary.
*/
nsresult GetLogicalRun(PRInt32 aLogicalStart, PRInt32* aLogicalLimit, nsBidiLevel* aLevel);
/**
* Get the number of runs.
* This function may invoke the actual reordering on the
* <code>nsBidi</code> object, after <code>SetPara</code>
* may have resolved only the levels of the text. Therefore,
* <code>CountRuns</code> may have to allocate memory,
* and may fail doing so.
*
* @param aRunCount will receive the number of runs.
*/
nsresult CountRuns(PRInt32* aRunCount);
/**
* Get one run's logical start, length, and directionality,
* which can be 0 for LTR or 1 for RTL.
* In an RTL run, the character at the logical start is
* visually on the right of the displayed run.
* The length is the number of characters in the run.<p>
* <code>CountRuns</code> should be called
* before the runs are retrieved.
*
* @param aRunIndex is the number of the run in visual order, in the
* range <code>[0..CountRuns-1]</code>.
*
* @param aLogicalStart is the first logical character index in the text.
* The pointer may be <code>NULL</code> if this index is not needed.
*
* @param aLength is the number of characters (at least one) in the run.
* The pointer may be <code>NULL</code> if this is not needed.
*
* @param aDirection will receive the directionality of the run,
* <code>NSBIDI_LTR==0</code> or <code>NSBIDI_RTL==1</code>,
* never <code>NSBIDI_MIXED</code>.
*
* @see CountRuns<p>
*
* Example:
* @code
* PRInt32 i, count, logicalStart, visualIndex=0, length;
* nsBidiDirection dir;
* pBidi->CountRuns(&count);
* for(i=0; i<count; ++i) {
* pBidi->GetVisualRun(i, &logicalStart, &length, &dir);
* if(NSBIDI_LTR==dir) {
* do { // LTR
* show_char(text[logicalStart++], visualIndex++);
* } while(--length>0);
* } else {
* logicalStart+=length; // logicalLimit
* do { // RTL
* show_char(text[--logicalStart], visualIndex++);
* } while(--length>0);
* }
* }
* @endcode
*
* Note that in right-to-left runs, code like this places
* modifier letters before base characters and second surrogates
* before first ones.
*/
nsresult GetVisualRun(PRInt32 aRunIndex, PRInt32* aLogicalStart, PRInt32* aLength, nsBidiDirection* aDirection);
#ifdef FULL_BIDI_ENGINE
/**
* Get the visual position from a logical text position.
* If such a mapping is used many times on the same
* <code>nsBidi</code> object, then calling
* <code>GetLogicalMap</code> is more efficient.<p>
*
* Note that in right-to-left runs, this mapping places
* modifier letters before base characters and second surrogates
* before first ones.
*
* @param aLogicalIndex is the index of a character in the text.
*
* @param aVisualIndex will receive the visual position of this character.
*
* @see GetLogicalMap
* @see GetLogicalIndex
*/
nsresult GetVisualIndex(PRInt32 aLogicalIndex, PRInt32* aVisualIndex);
/**
* Get the logical text position from a visual position.
* If such a mapping is used many times on the same
* <code>nsBidi</code> object, then calling
* <code>GetVisualMap</code> is more efficient.<p>
*
* This is the inverse function to <code>GetVisualIndex</code>.
*
* @param aVisualIndex is the visual position of a character.
*
* @param aLogicalIndex will receive the index of this character in the text.
*
* @see GetVisualMap
* @see GetVisualIndex
*/
nsresult GetLogicalIndex(PRInt32 aVisualIndex, PRInt32* aLogicalIndex);
/**
* Get a logical-to-visual index map (array) for the characters in the nsBidi
* (paragraph or line) object.
*
* @param aIndexMap is a pointer to an array of <code>GetLength</code>
* indexes which will reflect the reordering of the characters.
* The array does not need to be initialized.<p>
* The index map will result in <code>aIndexMap[aLogicalIndex]==aVisualIndex</code>.<p>
*
* @see GetVisualMap
* @see GetVisualIndex
*/
nsresult GetLogicalMap(PRInt32 *aIndexMap);
/**
* Get a visual-to-logical index map (array) for the characters in the nsBidi
* (paragraph or line) object.
*
* @param aIndexMap is a pointer to an array of <code>GetLength</code>
* indexes which will reflect the reordering of the characters.
* The array does not need to be initialized.<p>
* The index map will result in <code>aIndexMap[aVisualIndex]==aLogicalIndex</code>.<p>
*
* @see GetLogicalMap
* @see GetLogicalIndex
*/
nsresult GetVisualMap(PRInt32 *aIndexMap);
/**
* This is a convenience function that does not use a nsBidi object.
* It is intended to be used for when an application has determined the levels
* of objects (character sequences) and just needs to have them reordered (L2).
* This is equivalent to using <code>GetLogicalMap</code> on a
* <code>nsBidi</code> object.
*
* @param aLevels is an array with <code>aLength</code> levels that have been determined by
* the application.
*
* @param aLength is the number of levels in the array, or, semantically,
* the number of objects to be reordered.
* It must be <code>aLength>0</code>.
*
* @param aIndexMap is a pointer to an array of <code>aLength</code>
* indexes which will reflect the reordering of the characters.
* The array does not need to be initialized.<p>
* The index map will result in <code>aIndexMap[aLogicalIndex]==aVisualIndex</code>.
*/
nsresult ReorderLogical(const nsBidiLevel *aLevels, PRInt32 aLength, PRInt32 *aIndexMap);
#endif // FULL_BIDI_ENGINE
/**
* This is a convenience function that does not use a nsBidi object.
* It is intended to be used for when an application has determined the levels
* of objects (character sequences) and just needs to have them reordered (L2).
* This is equivalent to using <code>GetVisualMap</code> on a
* <code>nsBidi</code> object.
*
* @param aLevels is an array with <code>aLength</code> levels that have been determined by
* the application.
*
* @param aLength is the number of levels in the array, or, semantically,
* the number of objects to be reordered.
* It must be <code>aLength>0</code>.
*
* @param aIndexMap is a pointer to an array of <code>aLength</code>
* indexes which will reflect the reordering of the characters.
* The array does not need to be initialized.<p>
* The index map will result in <code>aIndexMap[aVisualIndex]==aLogicalIndex</code>.
*/
nsresult ReorderVisual(const nsBidiLevel *aLevels, PRInt32 aLength, PRInt32 *aIndexMap);
#ifdef FULL_BIDI_ENGINE
/**
* Invert an index map.
* The one-to-one index mapping of the first map is inverted and written to
* the second one.
*
* @param aSrcMap is an array with <code>aLength</code> indexes
* which define the original mapping.
*
* @param aDestMap is an array with <code>aLength</code> indexes
* which will be filled with the inverse mapping.
*
* @param aLength is the length of each array.
*/
nsresult InvertMap(const PRInt32 *aSrcMap, PRInt32 *aDestMap, PRInt32 aLength);
#endif // FULL_BIDI_ENGINE
/**
* Reverse a Right-To-Left run of Unicode text.
*
* This function preserves the integrity of characters with multiple
* code units and (optionally) modifier letters.
* Characters can be replaced by mirror-image characters
* in the destination buffer. Note that "real" mirroring has
* to be done in a rendering engine by glyph selection
* and that for many "mirrored" characters there are no
* 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
* write more than <code>aSrcLength</code> characters to <code>aDest</code>.
*
* @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.
*
* @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);
/**
* Give a UTF-32 codepoint
* return PR_TRUE if the codepoint is a Bidi control character (LRE, RLE, PDF, LRO, RLO, LRM, RLM)
* return PR_FALSE, otherwise
*/
PRBool IsBidiControl(PRUint32 aChar);
protected:
/** length of the current text */
PRInt32 mLength;
/** memory sizes in bytes */
PRSize mDirPropsSize, mLevelsSize, mRunsSize;
/** allocated memory */
DirProp* mDirPropsMemory;
nsBidiLevel* mLevelsMemory;
Run* mRunsMemory;
/** indicators for whether memory may be allocated after construction */
PRBool mMayAllocateText, mMayAllocateRuns;
const DirProp* mDirProps;
nsBidiLevel* mLevels;
/** the paragraph level */
nsBidiLevel mParaLevel;
/** flags is a bit set for which directional properties are in the text */
Flags mFlags;
/** 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();
nsresult CheckExplicitLevels(nsBidiDirection *aDirection);
nsBidiDirection DirectionFromFlags(Flags aFlags);
void ResolveImplicitLevels(PRInt32 aStart, PRInt32 aLimit, DirProp aSOR, DirProp aEOR);
void AdjustWSLevels();
void SetTrailingWSStart();
PRBool GetRuns();
void GetSingleRun(nsBidiLevel aLevel);
void ReorderLine(nsBidiLevel aMinLevel, nsBidiLevel aMaxLevel);
PRBool PrepareReorder(const nsBidiLevel *aLevels, PRInt32 aLength, PRInt32 *aIndexMap, nsBidiLevel *aMinLevel, nsBidiLevel *aMaxLevel);
/**
* Give a UTF-32 codepoint, return an eBidiCategory
*/
eBidiCategory GetBidiCategory(PRUint32 aChar);
/**
* Give a UTF-32 codepoint and an eBidiCategory,
* return PR_TRUE if the codepoint is in that category,
* return PR_FALSE, otherwise
*/
PRBool IsBidiCategory(PRUint32 aChar, eBidiCategory aBidiCategory);
/**
* Give a UTF-32 codepoint, return a nsCharType (compatible with ICU)
*/
nsCharType GetCharType(PRUint32 aChar);
/**
* Give a Unicode character, return the symmetric equivalent
*/
PRUint32 SymmSwap(PRUint32 aChar);
PRInt32 doWriteReverse(const PRUnichar *src, PRInt32 srcLength,
PRUnichar *dest, PRUint16 options);
};
#endif // _nsBidi_h_
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