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      1 //===--- UnicodeCharRanges.h - Types and functions for character ranges ---===//
      2 //
      3 //                     The LLVM Compiler Infrastructure
      4 //
      5 // This file is distributed under the University of Illinois Open Source
      6 // License. See LICENSE.TXT for details.
      7 //
      8 //===----------------------------------------------------------------------===//
      9 #ifndef LLVM_SUPPORT_UNICODECHARRANGES_H
     10 #define LLVM_SUPPORT_UNICODECHARRANGES_H
     11 
     12 #include "llvm/ADT/ArrayRef.h"
     13 #include "llvm/ADT/SmallPtrSet.h"
     14 #include "llvm/Support/Compiler.h"
     15 #include "llvm/Support/Debug.h"
     16 #include "llvm/Support/Mutex.h"
     17 #include "llvm/Support/MutexGuard.h"
     18 #include "llvm/Support/raw_ostream.h"
     19 #include <algorithm>
     20 
     21 #define DEBUG_TYPE "unicode"
     22 
     23 namespace llvm {
     24 namespace sys {
     25 
     26 /// \brief Represents a closed range of Unicode code points [Lower, Upper].
     27 struct UnicodeCharRange {
     28   uint32_t Lower;
     29   uint32_t Upper;
     30 };
     31 
     32 inline bool operator<(uint32_t Value, UnicodeCharRange Range) {
     33   return Value < Range.Lower;
     34 }
     35 inline bool operator<(UnicodeCharRange Range, uint32_t Value) {
     36   return Range.Upper < Value;
     37 }
     38 
     39 /// \brief Holds a reference to an ordered array of UnicodeCharRange and allows
     40 /// to quickly check if a code point is contained in the set represented by this
     41 /// array.
     42 class UnicodeCharSet {
     43 public:
     44   typedef ArrayRef<UnicodeCharRange> CharRanges;
     45 
     46   /// \brief Constructs a UnicodeCharSet instance from an array of
     47   /// UnicodeCharRanges.
     48   ///
     49   /// Array pointed by \p Ranges should have the lifetime at least as long as
     50   /// the UnicodeCharSet instance, and should not change. Array is validated by
     51   /// the constructor, so it makes sense to create as few UnicodeCharSet
     52   /// instances per each array of ranges, as possible.
     53 #ifdef NDEBUG
     54 
     55   // FIXME: This could use constexpr + static_assert. This way we
     56   // may get rid of NDEBUG in this header. Unfortunately there are some
     57   // problems to get this working with MSVC 2013. Change this when
     58   // the support for MSVC 2013 is dropped.
     59   constexpr UnicodeCharSet(CharRanges Ranges) : Ranges(Ranges) {}
     60 #else
     61   UnicodeCharSet(CharRanges Ranges) : Ranges(Ranges) {
     62     assert(rangesAreValid());
     63   }
     64 #endif
     65 
     66   /// \brief Returns true if the character set contains the Unicode code point
     67   /// \p C.
     68   bool contains(uint32_t C) const {
     69     return std::binary_search(Ranges.begin(), Ranges.end(), C);
     70   }
     71 
     72 private:
     73   /// \brief Returns true if each of the ranges is a proper closed range
     74   /// [min, max], and if the ranges themselves are ordered and non-overlapping.
     75   bool rangesAreValid() const {
     76     uint32_t Prev = 0;
     77     for (CharRanges::const_iterator I = Ranges.begin(), E = Ranges.end();
     78          I != E; ++I) {
     79       if (I != Ranges.begin() && Prev >= I->Lower) {
     80         DEBUG(dbgs() << "Upper bound 0x");
     81         DEBUG(dbgs().write_hex(Prev));
     82         DEBUG(dbgs() << " should be less than succeeding lower bound 0x");
     83         DEBUG(dbgs().write_hex(I->Lower) << "\n");
     84         return false;
     85       }
     86       if (I->Upper < I->Lower) {
     87         DEBUG(dbgs() << "Upper bound 0x");
     88         DEBUG(dbgs().write_hex(I->Lower));
     89         DEBUG(dbgs() << " should not be less than lower bound 0x");
     90         DEBUG(dbgs().write_hex(I->Upper) << "\n");
     91         return false;
     92       }
     93       Prev = I->Upper;
     94     }
     95 
     96     return true;
     97   }
     98 
     99   const CharRanges Ranges;
    100 };
    101 
    102 } // namespace sys
    103 } // namespace llvm
    104 
    105 #undef DEBUG_TYPE // "unicode"
    106 
    107 #endif // LLVM_SUPPORT_UNICODECHARRANGES_H
    108