1 //===--- UnicodeCharRanges.h - Types and functions for character ranges ---===//
2 //
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6 //
7 //===----------------------------------------------------------------------===//
8 #ifndef LLVM_SUPPORT_UNICODECHARRANGES_H
9 #define LLVM_SUPPORT_UNICODECHARRANGES_H
10 
11 #include "llvm/ADT/ArrayRef.h"
12 #include "llvm/ADT/SmallPtrSet.h"
13 #include "llvm/Support/Compiler.h"
14 #include "llvm/Support/Debug.h"
15 #include "llvm/Support/Mutex.h"
16 #include "llvm/Support/MutexGuard.h"
17 #include "llvm/Support/raw_ostream.h"
18 #include <algorithm>
19 
20 #define DEBUG_TYPE "unicode"
21 
22 namespace llvm {
23 namespace sys {
24 
25 /// Represents a closed range of Unicode code points [Lower, Upper].
26 struct UnicodeCharRange {
27   uint32_t Lower;
28   uint32_t Upper;
29 };
30 
31 inline bool operator<(uint32_t Value, UnicodeCharRange Range) {
32   return Value < Range.Lower;
33 }
34 inline bool operator<(UnicodeCharRange Range, uint32_t Value) {
35   return Range.Upper < Value;
36 }
37 
38 /// Holds a reference to an ordered array of UnicodeCharRange and allows
39 /// to quickly check if a code point is contained in the set represented by this
40 /// array.
41 class UnicodeCharSet {
42 public:
43   typedef ArrayRef<UnicodeCharRange> CharRanges;
44 
45   /// Constructs a UnicodeCharSet instance from an array of
46   /// UnicodeCharRanges.
47   ///
48   /// Array pointed by \p Ranges should have the lifetime at least as long as
49   /// the UnicodeCharSet instance, and should not change. Array is validated by
50   /// the constructor, so it makes sense to create as few UnicodeCharSet
51   /// instances per each array of ranges, as possible.
52 #ifdef NDEBUG
53 
54   // FIXME: This could use constexpr + static_assert. This way we
55   // may get rid of NDEBUG in this header. Unfortunately there are some
56   // problems to get this working with MSVC 2013. Change this when
57   // the support for MSVC 2013 is dropped.
UnicodeCharSet(CharRanges Ranges)58   constexpr UnicodeCharSet(CharRanges Ranges) : Ranges(Ranges) {}
59 #else
UnicodeCharSet(CharRanges Ranges)60   UnicodeCharSet(CharRanges Ranges) : Ranges(Ranges) {
61     assert(rangesAreValid());
62   }
63 #endif
64 
65   /// Returns true if the character set contains the Unicode code point
66   /// \p C.
contains(uint32_t C)67   bool contains(uint32_t C) const {
68     return std::binary_search(Ranges.begin(), Ranges.end(), C);
69   }
70 
71 private:
72   /// Returns true if each of the ranges is a proper closed range
73   /// [min, max], and if the ranges themselves are ordered and non-overlapping.
rangesAreValid()74   bool rangesAreValid() const {
75     uint32_t Prev = 0;
76     for (CharRanges::const_iterator I = Ranges.begin(), E = Ranges.end();
77          I != E; ++I) {
78       if (I != Ranges.begin() && Prev >= I->Lower) {
79         LLVM_DEBUG(dbgs() << "Upper bound 0x");
80         LLVM_DEBUG(dbgs().write_hex(Prev));
81         LLVM_DEBUG(dbgs() << " should be less than succeeding lower bound 0x");
82         LLVM_DEBUG(dbgs().write_hex(I->Lower) << "\n");
83         return false;
84       }
85       if (I->Upper < I->Lower) {
86         LLVM_DEBUG(dbgs() << "Upper bound 0x");
87         LLVM_DEBUG(dbgs().write_hex(I->Lower));
88         LLVM_DEBUG(dbgs() << " should not be less than lower bound 0x");
89         LLVM_DEBUG(dbgs().write_hex(I->Upper) << "\n");
90         return false;
91       }
92       Prev = I->Upper;
93     }
94 
95     return true;
96   }
97 
98   const CharRanges Ranges;
99 };
100 
101 } // namespace sys
102 } // namespace llvm
103 
104 #undef DEBUG_TYPE // "unicode"
105 
106 #endif // LLVM_SUPPORT_UNICODECHARRANGES_H
107