intl/lwbrk/LineBreaker.h

   1 /* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
   2 /* This Source Code Form is subject to the terms of the Mozilla Public
   3  * License, v. 2.0. If a copy of the MPL was not distributed with this
   4  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
   5 #ifndef mozilla_intl_LineBreaker_h__
   6 #define mozilla_intl_LineBreaker_h__
   7
   8 #include <cstdint>
   9
  10 #define NS_LINEBREAKER_NEED_MORE_TEXT -1
  11
  12 namespace mozilla {
  13 namespace intl {
  14 enum class LineBreakRule : uint8_t;
  15 enum class WordBreakRule : uint8_t;
  16
  17 class LineBreaker final {
  18  public:
  19   // LineBreaker is a utility class with only static methods. No need to
  20   // instantiate it.
  21   LineBreaker() = delete;
  22   ~LineBreaker() = delete;
  23
  24   // Find the next line break opportunity starting from aPos + 1. It can return
  25   // aLen if there's no break opportunity between [aPos + 1, aLen - 1].
  26   //
  27   // If aPos is already at the end of aText or beyond, i.e. aPos >= aLen, return
  28   // NS_LINEBREAKER_NEED_MORE_TEXT.
  29   //
  30   // DEPRECATED: Use LineBreakIteratorUtf16 instead.
  31   static int32_t Next(const char16_t* aText, uint32_t aLen, uint32_t aPos);
  32
  33   // Call this on a word with whitespace at either end. We will apply JISx4051
  34   // rules to find breaks inside the word. aBreakBefore is set to the break-
  35   // before status of each character; aBreakBefore[0] will always be false
  36   // because we never return a break before the first character.
  37   // aLength is the length of the aText array and also the length of the
  38   // aBreakBefore output array.
  39   static void ComputeBreakPositions(const char16_t* aText, uint32_t aLength,
  40                                     WordBreakRule aWordBreak,
  41                                     LineBreakRule aLevel,
  42                                     bool aIsChineseOrJapanese,
  43                                     uint8_t* aBreakBefore);
  44   static void ComputeBreakPositions(const uint8_t* aText, uint32_t aLength,
  45                                     WordBreakRule aWordBreak,
  46                                     LineBreakRule aLevel,
  47                                     bool aIsChineseOrJapanese,
  48                                     uint8_t* aBreakBefore);
  49 };
  50
  51 static inline bool NS_IsSpace(char16_t u) {
  52   return u == 0x0020 ||                   // SPACE
  53          u == 0x0009 ||                   // CHARACTER TABULATION
  54          u == 0x000D ||                   // CARRIAGE RETURN
  55          (0x2000 <= u && u <= 0x2006) ||  // EN QUAD, EM QUAD, EN SPACE,
  56                                           // EM SPACE, THREE-PER-EM SPACE,
  57                                           // FOUR-PER-SPACE, SIX-PER-EM SPACE,
  58          (0x2008 <= u && u <= 0x200B) ||  // PUNCTUATION SPACE, THIN SPACE,
  59                                           // HAIR SPACE, ZERO WIDTH SPACE
  60          u == 0x1361 ||                   // ETHIOPIC WORDSPACE
  61          u == 0x1680 ||                   // OGHAM SPACE MARK
  62          u == 0x205F;                     // MEDIUM MATHEMATICAL SPACE
  63 }
  64
  65 static inline bool NS_NeedsPlatformNativeHandling(char16_t aChar) {
  66   return
  67 #if ANDROID || XP_WIN  // Bug 1647377/1736393: no "platform native" support for
  68                        // Tibetan; better to just use our class-based breaker.
  69       (0x0e01 <= aChar && aChar <= 0x0eff) ||  // Thai, Lao
  70 #else
  71       // Routing Tibetan to the platform-native breaker currently results in
  72       // WPT failures in a few css3-text-line-break-opclns-* testcases that mix
  73       // a Tibetan character with other-script context.
  74       (0x0e01 <= aChar && aChar <= 0x0fff) ||  // Thai, Lao, Tibetan
  75 #endif
  76       (0x1780 <= aChar && aChar <= 0x17ff);  // Khmer
  77 }
  78
  79 }  // namespace intl
  80 }  // namespace mozilla
  81
  82 #endif /* mozilla_intl_LineBreaker_h__ */