reference, declarationdefinition
definition → references, declarations, derived classes, virtual overrides
reference to multiple definitions → definitions
unreferenced
    1
    2
    3
    4
    5
    6
    7
    8
    9
   10
   11
   12
   13
   14
   15
   16
   17
   18
   19
   20
   21
   22
   23
   24
   25
   26
   27
   28
   29
   30
   31
   32
   33
   34
   35
   36
   37
   38
   39
   40
   41
   42
   43
   44
   45
   46
   47
   48
   49
   50
   51
   52
   53
   54
   55
   56
   57
   58
   59
   60
   61
   62
   63
   64
   65
   66
   67
   68
   69
   70
//===- llvm/Support/Unicode.h - Unicode character properties  -*- C++ -*-=====//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
//
// This file defines functions that allow querying certain properties of Unicode
// characters.
//
//===----------------------------------------------------------------------===//

#ifndef LLVM_SUPPORT_UNICODE_H
#define LLVM_SUPPORT_UNICODE_H

namespace llvm {
class StringRef;

namespace sys {
namespace unicode {

enum ColumnWidthErrors {
  ErrorInvalidUTF8 = -2,
  ErrorNonPrintableCharacter = -1
};

/// Determines if a character is likely to be displayed correctly on the
/// terminal. Exact implementation would have to depend on the specific
/// terminal, so we define the semantic that should be suitable for generic case
/// of a terminal capable to output Unicode characters.
///
/// All characters from the Unicode code point range are considered printable
/// except for:
///   * C0 and C1 control character ranges;
///   * default ignorable code points as per 5.21 of
///     http://www.unicode.org/versions/Unicode6.2.0/UnicodeStandard-6.2.pdf
///     except for U+00AD SOFT HYPHEN, as it's actually displayed on most
///     terminals;
///   * format characters (category = Cf);
///   * surrogates (category = Cs);
///   * unassigned characters (category = Cn).
/// \return true if the character is considered printable.
bool isPrintable(int UCS);

/// Gets the number of positions the UTF8-encoded \p Text is likely to occupy
/// when output on a terminal ("character width"). This depends on the
/// implementation of the terminal, and there's no standard definition of
/// character width.
///
/// The implementation defines it in a way that is expected to be compatible
/// with a generic Unicode-capable terminal.
///
/// \return Character width:
///   * ErrorNonPrintableCharacter (-1) if \p Text contains non-printable
///     characters (as identified by isPrintable);
///   * 0 for each non-spacing and enclosing combining mark;
///   * 2 for each CJK character excluding halfwidth forms;
///   * 1 for each of the remaining characters.
int columnWidthUTF8(StringRef Text);

/// Fold input unicode character according the Simple unicode case folding
/// rules.
int foldCharSimple(int C);

} // namespace unicode
} // namespace sys
} // namespace llvm

#endif