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llvm-mirror/include/llvm/Support/UnicodeCharRanges.h
Davide Italiano 59b56f0a89 [Support] Add comment to explain why we can't drop NDEBUG.
Discussed with: Benjamin Kramer.

llvm-svn: 251210
2015-10-24 22:15:32 +00:00

109 lines
3.3 KiB
C++

//===--- UnicodeCharRanges.h - Types and functions for character ranges ---===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
#ifndef LLVM_SUPPORT_UNICODECHARRANGES_H
#define LLVM_SUPPORT_UNICODECHARRANGES_H
#include "llvm/ADT/ArrayRef.h"
#include "llvm/ADT/SmallPtrSet.h"
#include "llvm/Support/Compiler.h"
#include "llvm/Support/Debug.h"
#include "llvm/Support/Mutex.h"
#include "llvm/Support/MutexGuard.h"
#include "llvm/Support/raw_ostream.h"
#include <algorithm>
namespace llvm {
namespace sys {
#define DEBUG_TYPE "unicode"
/// \brief Represents a closed range of Unicode code points [Lower, Upper].
struct UnicodeCharRange {
uint32_t Lower;
uint32_t Upper;
};
inline bool operator<(uint32_t Value, UnicodeCharRange Range) {
return Value < Range.Lower;
}
inline bool operator<(UnicodeCharRange Range, uint32_t Value) {
return Range.Upper < Value;
}
/// \brief Holds a reference to an ordered array of UnicodeCharRange and allows
/// to quickly check if a code point is contained in the set represented by this
/// array.
class UnicodeCharSet {
public:
typedef ArrayRef<UnicodeCharRange> CharRanges;
/// \brief Constructs a UnicodeCharSet instance from an array of
/// UnicodeCharRanges.
///
/// Array pointed by \p Ranges should have the lifetime at least as long as
/// the UnicodeCharSet instance, and should not change. Array is validated by
/// the constructor, so it makes sense to create as few UnicodeCharSet
/// instances per each array of ranges, as possible.
#ifdef NDEBUG
// FIXME: This could use constexpr + static_assert. This way we
// may get rid of NDEBUG in this header. Unfortunately there are some
// problems to get this working with MSVC 2013. Change this when
// the support for MSVC 2013 is dropped.
LLVM_CONSTEXPR UnicodeCharSet(CharRanges Ranges) : Ranges(Ranges) {}
#else
UnicodeCharSet(CharRanges Ranges) : Ranges(Ranges) {
assert(rangesAreValid());
}
#endif
/// \brief Returns true if the character set contains the Unicode code point
/// \p C.
bool contains(uint32_t C) const {
return std::binary_search(Ranges.begin(), Ranges.end(), C);
}
private:
/// \brief Returns true if each of the ranges is a proper closed range
/// [min, max], and if the ranges themselves are ordered and non-overlapping.
bool rangesAreValid() const {
uint32_t Prev = 0;
for (CharRanges::const_iterator I = Ranges.begin(), E = Ranges.end();
I != E; ++I) {
if (I != Ranges.begin() && Prev >= I->Lower) {
DEBUG(dbgs() << "Upper bound 0x");
DEBUG(dbgs().write_hex(Prev));
DEBUG(dbgs() << " should be less than succeeding lower bound 0x");
DEBUG(dbgs().write_hex(I->Lower) << "\n");
return false;
}
if (I->Upper < I->Lower) {
DEBUG(dbgs() << "Upper bound 0x");
DEBUG(dbgs().write_hex(I->Lower));
DEBUG(dbgs() << " should not be less than lower bound 0x");
DEBUG(dbgs().write_hex(I->Upper) << "\n");
return false;
}
Prev = I->Upper;
}
return true;
}
const CharRanges Ranges;
};
#undef DEBUG_TYPE // "unicode"
} // namespace sys
} // namespace llvm
#endif // LLVM_SUPPORT_UNICODECHARRANGES_H