gecko/intl/unicharutil/util/nsBidiUtils.cpp

/* -*- 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):
 *   Maha Abou El Rous <mahar@eg.ibm.com>
 *   Lina Kemmel <lkemmel@il.ibm.com>
 *   Simon Montagu <smontagu@netscape.com>
 *   Roozbeh Pournader <roozbeh@sharif.edu>
 *   Ehsan Akhgari <ehsan.akhgari@gmail.com>
 *
 * 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
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 * ***** END LICENSE BLOCK ***** */
#include "nsBidiUtils.h"
#include "symmtable.h"
#include "bidicattable.h"
#include "nsCharTraits.h"

static nsCharType ebc2ucd[15] = {
  eCharType_OtherNeutral, /* Placeholder -- there will never be a 0 index value */
  eCharType_LeftToRight,
  eCharType_RightToLeft,
  eCharType_RightToLeftArabic,
  eCharType_ArabicNumber,
  eCharType_EuropeanNumber,
  eCharType_EuropeanNumberSeparator,
  eCharType_EuropeanNumberTerminator,
  eCharType_CommonNumberSeparator,
  eCharType_OtherNeutral,
  eCharType_DirNonSpacingMark,
  eCharType_BoundaryNeutral,
  eCharType_BlockSeparator,
  eCharType_SegmentSeparator,
  eCharType_WhiteSpaceNeutral
};

static nsCharType cc2ucd[5] = {
  eCharType_LeftToRightEmbedding,
  eCharType_RightToLeftEmbedding,
  eCharType_PopDirectionalFormat,
  eCharType_LeftToRightOverride,
  eCharType_RightToLeftOverride
};

#define ARABIC_TO_HINDI_DIGIT_INCREMENT (START_HINDI_DIGITS - START_ARABIC_DIGITS)
#define PERSIAN_TO_HINDI_DIGIT_INCREMENT (START_HINDI_DIGITS - START_FARSI_DIGITS)
#define ARABIC_TO_PERSIAN_DIGIT_INCREMENT (START_FARSI_DIGITS - START_ARABIC_DIGITS)
#define NUM_TO_ARABIC(c) \
  ((((c)>=START_HINDI_DIGITS) && ((c)<=END_HINDI_DIGITS)) ? \
   ((c) - (PRUint16)ARABIC_TO_HINDI_DIGIT_INCREMENT) : \
   ((((c)>=START_FARSI_DIGITS) && ((c)<=END_FARSI_DIGITS)) ? \
    ((c) - (PRUint16)ARABIC_TO_PERSIAN_DIGIT_INCREMENT) : \
     (c)))
#define NUM_TO_HINDI(c) \
  ((((c)>=START_ARABIC_DIGITS) && ((c)<=END_ARABIC_DIGITS)) ? \
   ((c) + (PRUint16)ARABIC_TO_HINDI_DIGIT_INCREMENT): \
   ((((c)>=START_FARSI_DIGITS) && ((c)<=END_FARSI_DIGITS)) ? \
    ((c) + (PRUint16)PERSIAN_TO_HINDI_DIGIT_INCREMENT) : \
     (c)))
#define NUM_TO_PERSIAN(c) \
  ((((c)>=START_HINDI_DIGITS) && ((c)<=END_HINDI_DIGITS)) ? \
   ((c) - (PRUint16)PERSIAN_TO_HINDI_DIGIT_INCREMENT) : \
   ((((c)>=START_ARABIC_DIGITS) && ((c)<=END_ARABIC_DIGITS)) ? \
    ((c) + (PRUint16)ARABIC_TO_PERSIAN_DIGIT_INCREMENT) : \
     (c)))

PRUnichar HandleNumberInChar(PRUnichar aChar, PRBool aPrevCharArabic, PRUint32 aNumFlag)
{
  // IBMBIDI_NUMERAL_NOMINAL *
  // IBMBIDI_NUMERAL_REGULAR
  // IBMBIDI_NUMERAL_HINDICONTEXT
  // IBMBIDI_NUMERAL_ARABIC
  // IBMBIDI_NUMERAL_HINDI

  switch (aNumFlag) {
    case IBMBIDI_NUMERAL_HINDI:
      return NUM_TO_HINDI(aChar);
    case IBMBIDI_NUMERAL_ARABIC:
      return NUM_TO_ARABIC(aChar);
    case IBMBIDI_NUMERAL_PERSIAN:
      return NUM_TO_PERSIAN(aChar);
    case IBMBIDI_NUMERAL_REGULAR:
    case IBMBIDI_NUMERAL_HINDICONTEXT:
    case IBMBIDI_NUMERAL_PERSIANCONTEXT:
      // for clipboard handling
      //XXX do we really want to convert numerals when copying text?
      if (aPrevCharArabic) {
        if (aNumFlag == IBMBIDI_NUMERAL_PERSIANCONTEXT)
          return NUM_TO_PERSIAN(aChar);
        else
          return NUM_TO_HINDI(aChar);
      }
      else
        return NUM_TO_ARABIC(aChar);
    case IBMBIDI_NUMERAL_NOMINAL:
    default:
      return aChar;
  }
}

nsresult HandleNumbers(PRUnichar* aBuffer, PRUint32 aSize, PRUint32 aNumFlag)
{
  PRUint32 i;

  switch (aNumFlag) {
    case IBMBIDI_NUMERAL_HINDI:
    case IBMBIDI_NUMERAL_ARABIC:
    case IBMBIDI_NUMERAL_PERSIAN:
    case IBMBIDI_NUMERAL_REGULAR:
    case IBMBIDI_NUMERAL_HINDICONTEXT:
    case IBMBIDI_NUMERAL_PERSIANCONTEXT:
      for (i=0;i<aSize;i++)
        aBuffer[i] = HandleNumberInChar(aBuffer[i], !!(i>0 ? aBuffer[i-1] : 0), aNumFlag);
      break;
    case IBMBIDI_NUMERAL_NOMINAL:
    default:
      break;
  }
  return NS_OK;
}

PRUint32 SymmSwap(PRUint32 aChar)
{
  return Mirrored(aChar);
}

eBidiCategory GetBidiCategory(PRUint32 aChar)
{
  eBidiCategory oResult = GetBidiCat(aChar);
  if (eBidiCat_CC == oResult)
    oResult = (eBidiCategory)(aChar & 0xFF); /* Control codes have special treatment to keep the tables smaller */
  return oResult;
}

PRBool IsBidiCategory(PRUint32 aChar, eBidiCategory aBidiCategory)
{
  return (GetBidiCategory(aChar) == aBidiCategory);
}

#define LRM_CHAR 0x200e
PRBool IsBidiControl(PRUint32 aChar)
{
  // This method is used when stripping Bidi control characters for
  // display, so it will return TRUE for LRM and RLM as
  // well as the characters with category eBidiCat_CC
  return (eBidiCat_CC == GetBidiCat(aChar) || ((aChar)&0xfffffe)==LRM_CHAR);
}

PRBool HasRTLChars(const nsAString& aString)
{
// This is used to determine whether to enable bidi if a string has 
// right-to-left characters. To simplify things, anything that could be a
// surrogate or RTL presentation form is covered just by testing >= 0xD800).
// It's fine to enable bidi in rare cases where it actually isn't needed.
  PRInt32 length = aString.Length();
  for (PRInt32 i = 0; i < length; i++) {
    PRUnichar ch = aString.CharAt(i);
    if (ch >= 0xD800 || IS_IN_BMP_RTL_BLOCK(ch)) {
      return PR_TRUE;
    }
  }
  return PR_FALSE;
}

nsCharType GetCharType(PRUint32 aChar)
{
  nsCharType oResult;
  eBidiCategory bCat = GetBidiCat(aChar);
  if (eBidiCat_CC != bCat) {
    NS_ASSERTION((PRUint32) bCat < (sizeof(ebc2ucd)/sizeof(nsCharType)), "size mismatch");
    if((PRUint32) bCat < (sizeof(ebc2ucd)/sizeof(nsCharType)))
      oResult = ebc2ucd[bCat];
    else 
      oResult = ebc2ucd[0]; // something is very wrong, but we need to return a value
  } else {
    NS_ASSERTION((aChar-0x202a) < (sizeof(cc2ucd)/sizeof(nsCharType)), "size mismatch");
    if((aChar-0x202a) < (sizeof(cc2ucd)/sizeof(nsCharType)))
      oResult = cc2ucd[aChar - 0x202a];
    else 
      oResult = ebc2ucd[0]; // something is very wrong, but we need to return a value
  }
  return oResult;
}