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