intl/unicharutil/util/nsBidiUtils.cpp

   1 /* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
   2  *
   3  * This Source Code Form is subject to the terms of the Mozilla Public
   4  * License, v. 2.0. If a copy of the MPL was not distributed with this
   5  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
   6 #include "nsBidiUtils.h"
   7
   8 #define ARABIC_TO_HINDI_DIGIT_INCREMENT (START_HINDI_DIGITS - START_ARABIC_DIGITS)
   9 #define PERSIAN_TO_HINDI_DIGIT_INCREMENT (START_HINDI_DIGITS - START_FARSI_DIGITS)
  10 #define ARABIC_TO_PERSIAN_DIGIT_INCREMENT (START_FARSI_DIGITS - START_ARABIC_DIGITS)
  11 #define NUM_TO_ARABIC(c) \
  12   ((((c)>=START_HINDI_DIGITS) && ((c)<=END_HINDI_DIGITS)) ? \
  13    ((c) - (uint16_t)ARABIC_TO_HINDI_DIGIT_INCREMENT) : \
  14    ((((c)>=START_FARSI_DIGITS) && ((c)<=END_FARSI_DIGITS)) ? \
  15     ((c) - (uint16_t)ARABIC_TO_PERSIAN_DIGIT_INCREMENT) : \
  16      (c)))
  17 #define NUM_TO_HINDI(c) \
  18   ((((c)>=START_ARABIC_DIGITS) && ((c)<=END_ARABIC_DIGITS)) ? \
  19    ((c) + (uint16_t)ARABIC_TO_HINDI_DIGIT_INCREMENT): \
  20    ((((c)>=START_FARSI_DIGITS) && ((c)<=END_FARSI_DIGITS)) ? \
  21     ((c) + (uint16_t)PERSIAN_TO_HINDI_DIGIT_INCREMENT) : \
  22      (c)))
  23 #define NUM_TO_PERSIAN(c) \
  24   ((((c)>=START_HINDI_DIGITS) && ((c)<=END_HINDI_DIGITS)) ? \
  25    ((c) - (uint16_t)PERSIAN_TO_HINDI_DIGIT_INCREMENT) : \
  26    ((((c)>=START_ARABIC_DIGITS) && ((c)<=END_ARABIC_DIGITS)) ? \
  27     ((c) + (uint16_t)ARABIC_TO_PERSIAN_DIGIT_INCREMENT) : \
  28      (c)))
  29
  30 char16_t HandleNumberInChar(char16_t aChar, bool aPrevCharArabic, uint32_t aNumFlag)
  31 {
  32   // IBMBIDI_NUMERAL_NOMINAL *
  33   // IBMBIDI_NUMERAL_REGULAR
  34   // IBMBIDI_NUMERAL_HINDICONTEXT
  35   // IBMBIDI_NUMERAL_ARABIC
  36   // IBMBIDI_NUMERAL_HINDI
  37
  38   switch (aNumFlag) {
  39     case IBMBIDI_NUMERAL_HINDI:
  40       return NUM_TO_HINDI(aChar);
  41     case IBMBIDI_NUMERAL_ARABIC:
  42       return NUM_TO_ARABIC(aChar);
  43     case IBMBIDI_NUMERAL_PERSIAN:
  44       return NUM_TO_PERSIAN(aChar);
  45     case IBMBIDI_NUMERAL_REGULAR:
  46     case IBMBIDI_NUMERAL_HINDICONTEXT:
  47     case IBMBIDI_NUMERAL_PERSIANCONTEXT:
  48       // for clipboard handling
  49       //XXX do we really want to convert numerals when copying text?
  50       if (aPrevCharArabic) {
  51         if (aNumFlag == IBMBIDI_NUMERAL_PERSIANCONTEXT)
  52           return NUM_TO_PERSIAN(aChar);
  53         else
  54           return NUM_TO_HINDI(aChar);
  55       }
  56       else
  57         return NUM_TO_ARABIC(aChar);
  58     case IBMBIDI_NUMERAL_NOMINAL:
  59     default:
  60       return aChar;
  61   }
  62 }
  63
  64 nsresult HandleNumbers(char16_t* aBuffer, uint32_t aSize, uint32_t aNumFlag)
  65 {
  66   uint32_t i;
  67
  68   switch (aNumFlag) {
  69     case IBMBIDI_NUMERAL_HINDI:
  70     case IBMBIDI_NUMERAL_ARABIC:
  71     case IBMBIDI_NUMERAL_PERSIAN:
  72     case IBMBIDI_NUMERAL_REGULAR:
  73     case IBMBIDI_NUMERAL_HINDICONTEXT:
  74     case IBMBIDI_NUMERAL_PERSIANCONTEXT:
  75       for (i=0;i<aSize;i++)
  76         aBuffer[i] = HandleNumberInChar(aBuffer[i], !!(i>0 ? aBuffer[i-1] : 0), aNumFlag);
  77       break;
  78     case IBMBIDI_NUMERAL_NOMINAL:
  79     default:
  80       break;
  81   }
  82   return NS_OK;
  83 }
  84
  85 bool HasRTLChars(const nsAString& aString)
  86 {
  87 // This is used to determine whether to enable bidi if a string has
  88 // right-to-left characters. To simplify things, anything that could be a
  89 // surrogate or RTL presentation form is covered just by testing >= 0xD800).
  90 // It's fine to enable bidi in rare cases where it actually isn't needed.
  91   int32_t length = aString.Length();
  92   for (int32_t i = 0; i < length; i++) {
  93     char16_t ch = aString.CharAt(i);
  94     if (ch >= 0xD800 || IS_IN_BMP_RTL_BLOCK(ch)) {
  95       return true;
  96     }
  97   }
  98   return false;
  99 }