text: /**
   * Licensed to the Apache Software Foundation (ASF) under one
   * or more contributor license agreements.  See the NOTICE file
   * distributed with this work for additional information
   * regarding copyright ownership.  The ASF licenses this file
   * to you under the Apache License, Version 2.0 (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.apache.org/licenses/LICENSE-2.0
   *
   * Unless required by applicable law or agreed to in writing,
   * software distributed under the License is distributed on an
   * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
   * KIND, either express or implied.  See the License for the
   * specific language governing permissions and limitations
   * under the License.
   */
  #pragma once
  
  #include <stdint.h>
  #include <unicode/utypes.h>
  
  namespace JSC { namespace Yarr {
  
  // This set of data provides information for each UCS2 code point as to the set of code points
  // that it should match under the ES6 case insensitive RegExp matching rules, specified in 21.2.2.8.2.
  // The non-Unicode tables are autogenerated using YarrCanonicalize.js into YarrCanonicalize.cpp.
  // The Unicode tables are autogenerated using the python script generateYarrCanonicalizeUnicode
  // which creates YarrCanonicalizeUnicode.cpp.
  enum UCS2CanonicalizationType {
      CanonicalizeUnique,               // No canonically equal values, e.g. 0x0.
      CanonicalizeSet,                  // Value indicates a set in characterSetInfo.
      CanonicalizeRangeLo,              // Value is positive delta to pair, E.g. 0x41 has value 0x20, -> 0x61.
      CanonicalizeRangeHi,              // Value is positive delta to pair, E.g. 0x61 has value 0x20, -> 0x41.
      CanonicalizeAlternatingAligned,   // Aligned consequtive pair, e.g. 0x1f4,0x1f5.
      CanonicalizeAlternatingUnaligned, // Unaligned consequtive pair, e.g. 0x241,0x242.
  };
  struct CanonicalizationRange {
      UChar32 begin;
      UChar32 end;
      UChar32 value;
      UCS2CanonicalizationType type;
  };
  
  extern const size_t UCS2_CANONICALIZATION_RANGES;
  extern const UChar32* const ucs2CharacterSetInfo[];
  extern const CanonicalizationRange ucs2RangeInfo[];
  
  extern const size_t UNICODE_CANONICALIZATION_RANGES;
  extern const UChar32* const unicodeCharacterSetInfo[];
  extern const CanonicalizationRange unicodeRangeInfo[];
  
  enum class CanonicalMode { UCS2, Unicode };
  
  inline const UChar32* canonicalCharacterSetInfo(unsigned index, CanonicalMode canonicalMode)
  {
      const UChar32* const* rangeInfo = canonicalMode == CanonicalMode::UCS2 ? ucs2CharacterSetInfo : unicodeCharacterSetInfo;
      return rangeInfo[index];
  }
  
  // This searches in log2 time over ~400-600 entries, so should typically result in 9 compares.
  inline const CanonicalizationRange* canonicalRangeInfoFor(UChar32 ch, CanonicalMode canonicalMode = CanonicalMode::UCS2)
  {
      const CanonicalizationRange* info = canonicalMode == CanonicalMode::UCS2 ? ucs2RangeInfo : unicodeRangeInfo;
      size_t entries = canonicalMode == CanonicalMode::UCS2 ? UCS2_CANONICALIZATION_RANGES : UNICODE_CANONICALIZATION_RANGES;
  
      while (true) {
          size_t candidate = entries >> 1;
          const CanonicalizationRange* candidateInfo = info + candidate;
          if (ch < candidateInfo->begin)
              entries = candidate;
          else if (ch <= candidateInfo->end)
              return candidateInfo;
          else {
              info = candidateInfo + 1;
              entries -= (candidate + 1);
          }
      }
  }
  
  // Should only be called for characters that have one canonically matching value.
  inline UChar32 getCanonicalPair(const CanonicalizationRange* info, UChar32 ch)
  {
      ASSERT(ch >= info->begin && ch <= info->end);
      switch (info->type) {
      case CanonicalizeRangeLo:
          return ch + info->value;
      case CanonicalizeRangeHi:
          return ch - info->value;
      case CanonicalizeAlternatingAligned:
          return ch ^ 1;
      case CanonicalizeAlternatingUnaligned:
          return ((ch - 1) ^ 1) + 1;
      default:
          RELEASE_ASSERT_NOT_REACHED();
      }
      RELEASE_ASSERT_NOT_REACHED();
      return 0;
  }
  
  // Returns true if no other UCS2 codepoint can match this value.
  inline bool isCanonicallyUnique(UChar32 ch, CanonicalMode canonicalMode = CanonicalMode::UCS2)
  {
      return canonicalRangeInfoFor(ch, canonicalMode)->type == CanonicalizeUnique;
  }
  
  // Returns true if values are equal, under the canonicalization rules.
  inline bool areCanonicallyEquivalent(UChar32 a, UChar32 b, CanonicalMode canonicalMode = CanonicalMode::UCS2)
  {
      const CanonicalizationRange* info = canonicalRangeInfoFor(a, canonicalMode);
      switch (info->type) {
      case CanonicalizeUnique:
          return a == b;
      case CanonicalizeSet: {
          for (const UChar32* set = canonicalCharacterSetInfo(info->value, canonicalMode); (a = *set); ++set) {
              if (a == b)
                  return true;
          }
          return false;
      }
      case CanonicalizeRangeLo:
          return (a == b) || (a + info->value == b);
      case CanonicalizeRangeHi:
          return (a == b) || (a - info->value == b);
      case CanonicalizeAlternatingAligned:
          return (a | 1) == (b | 1);
      case CanonicalizeAlternatingUnaligned:
          return ((a - 1) | 1) == ((b - 1) | 1);
      }
  
      RELEASE_ASSERT_NOT_REACHED();
      return false;
  }
  
  } } // JSC::Yarr
  