tor-browser

WordBreaker.cpp (6250B)

---

/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/. */

#include "mozilla/intl/WordBreaker.h"

#include "icu4x/WordSegmenter.hpp"
#include "mozilla/CheckedInt.h"
#include "mozilla/intl/UnicodeProperties.h"
#include "mozilla/StaticPrefs_intl.h"
#include "mozilla/StaticPrefs_layout.h"
#include "nsComplexBreaker.h"
#include "nsTArray.h"
#include "nsUnicharUtils.h"
#include "nsUnicodeProperties.h"

using mozilla::intl::Script;
using mozilla::intl::UnicodeProperties;
using mozilla::intl::WordBreaker;
using mozilla::intl::WordRange;
using mozilla::unicode::GetGenCategory;

#define ASCII_IS_ALPHA(c) \
 ((('a' <= (c)) && ((c) <= 'z')) || (('A' <= (c)) && ((c) <= 'Z')))
#define ASCII_IS_DIGIT(c) (('0' <= (c)) && ((c) <= '9'))
#define ASCII_IS_SPACE(c) \
 ((' ' == (c)) || ('\t' == (c)) || ('\r' == (c)) || ('\n' == (c)))
#define IS_ALPHABETICAL_SCRIPT(c) ((c) < 0x2E80)

// we change the beginning of IS_HAN from 0x4e00 to 0x3400 to relfect
// Unicode 3.0
#define IS_HAN(c) \
 ((0x3400 <= (c)) && ((c) <= 0x9fff)) || ((0xf900 <= (c)) && ((c) <= 0xfaff))
#define IS_KATAKANA(c) ((0x30A0 <= (c)) && ((c) <= 0x30FF))
#define IS_HIRAGANA(c) ((0x3040 <= (c)) && ((c) <= 0x309F))
#define IS_HALFWIDTHKATAKANA(c) ((0xFF60 <= (c)) && ((c) <= 0xFF9F))

/* static */
WordBreaker::WordBreakClass WordBreaker::GetClass(char16_t c) {
 // begin of the hack

 if (IS_ALPHABETICAL_SCRIPT(c)) {
   if (IS_ASCII(c)) {
     if (ASCII_IS_SPACE(c)) {
       return kWbClassSpace;
     }
     if (ASCII_IS_ALPHA(c) || ASCII_IS_DIGIT(c) ||
         (c == '_' && !StaticPrefs::layout_word_select_stop_at_underscore())) {
       return kWbClassAlphaLetter;
     }
     return kWbClassPunct;
   }
   if (c == 0x00A0 /*NBSP*/) {
     return kWbClassSpace;
   }
   if (GetGenCategory(c) == nsUGenCategory::kPunctuation) {
     return kWbClassPunct;
   }
   if (UnicodeProperties::IsScriptioContinua(c)) {
     return kWbClassScriptioContinua;
   }
   return kWbClassAlphaLetter;
 }
 if (IS_HAN(c)) {
   return kWbClassHanLetter;
 }
 if (IS_KATAKANA(c)) {
   return kWbClassKatakanaLetter;
 }
 if (IS_HIRAGANA(c)) {
   return kWbClassHiraganaLetter;
 }
 if (IS_HALFWIDTHKATAKANA(c)) {
   return kWbClassHWKatakanaLetter;
 }
 if (GetGenCategory(c) == nsUGenCategory::kPunctuation) {
   return kWbClassPunct;
 }
 if (UnicodeProperties::IsScriptioContinua(c)) {
   return kWbClassScriptioContinua;
 }
 return kWbClassAlphaLetter;
}

WordRange WordBreaker::FindWord(const nsAString& aText, uint32_t aPos,
                               const FindWordOptions aOptions) {
 const CheckedInt<uint32_t> len = aText.Length();
 MOZ_RELEASE_ASSERT(len.isValid());

 if (aPos >= len.value()) {
   return {len.value(), len.value()};
 }

 WordRange range{0, len.value()};

 if (StaticPrefs::intl_icu4x_segmenter_enabled()) {
   auto segmenter = icu4x::WordSegmenter::create_auto();
   auto iterator = segmenter->segment16(
       std::u16string_view(aText.BeginReading(), aText.Length()));

   uint32_t previousPos = 0;
   while (true) {
     const int32_t nextPos = iterator->next();
     if (nextPos < 0) {
       range.mBegin = previousPos;
       range.mEnd = len.value();
       break;
     }
     if ((uint32_t)nextPos > aPos) {
       range.mBegin = previousPos;
       range.mEnd = (uint32_t)nextPos;
       break;
     }

     previousPos = nextPos;
   }

   if (aOptions != FindWordOptions::StopAtPunctuation) {
     return range;
   }

   for (uint32_t i = range.mBegin; i < range.mEnd; i++) {
     if (mozilla::IsPunctuationForWordSelect(aText[i])) {
       if (i > aPos) {
         range.mEnd = i;
         break;
       }
       if (i == aPos) {
         range.mBegin = i;
         range.mEnd = i + 1;
         break;
       }
       if (i < aPos) {
         range.mBegin = i + 1;
       }
     }
   }

   return range;
 }

 WordBreakClass c = GetClass(aText[aPos]);

 // Scan forward
 for (uint32_t i = aPos + 1; i < len.value(); i++) {
   if (c != GetClass(aText[i])) {
     range.mEnd = i;
     break;
   }
 }

 // Scan backward
 for (uint32_t i = aPos; i > 0; i--) {
   if (c != GetClass(aText[i - 1])) {
     range.mBegin = i;
     break;
   }
 }

 if (kWbClassScriptioContinua == c) {
   // we pass the whole text segment to the complex word breaker to find a
   // shorter answer
   AutoTArray<uint8_t, 256> breakBefore;
   breakBefore.SetLength(range.mEnd - range.mBegin);
   ComplexBreaker::GetBreaks(aText.BeginReading() + range.mBegin,
                             range.mEnd - range.mBegin,
                             breakBefore.Elements());

   // Scan forward
   for (uint32_t i = aPos + 1; i < range.mEnd; i++) {
     if (breakBefore[i - range.mBegin]) {
       range.mEnd = i;
       break;
     }
   }

   // Scan backward
   for (uint32_t i = aPos; i > range.mBegin; i--) {
     if (breakBefore[i - range.mBegin]) {
       range.mBegin = i;
       break;
     }
   }
 }
 return range;
}

int32_t WordBreaker::Next(const char16_t* aText, uint32_t aLen, uint32_t aPos) {
 MOZ_ASSERT(aText);

 if (aPos >= aLen) {
   return NS_WORDBREAKER_NEED_MORE_TEXT;
 }

 const WordBreakClass posClass = GetClass(aText[aPos]);
 uint32_t nextBreakPos;
 for (nextBreakPos = aPos + 1; nextBreakPos < aLen; ++nextBreakPos) {
   if (posClass != GetClass(aText[nextBreakPos])) {
     break;
   }
 }

 if (kWbClassScriptioContinua == posClass) {
   // We pass the whole text segment to the complex word breaker to find a
   // shorter answer.
   const char16_t* segStart = aText + aPos;
   const uint32_t segLen = nextBreakPos - aPos + 1;
   AutoTArray<uint8_t, 256> breakBefore;
   breakBefore.SetLength(segLen);
   ComplexBreaker::GetBreaks(segStart, segLen, breakBefore.Elements());

   for (uint32_t i = aPos + 1; i < nextBreakPos; ++i) {
     if (breakBefore[i - aPos]) {
       nextBreakPos = i;
       break;
     }
   }
 }

 MOZ_ASSERT(nextBreakPos != aPos);
 return nextBreakPos;
}