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//===- llvm/Support/Unicode.h - Unicode character properties -*- C++ -*-=====//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file defines functions that allow querying certain properties of Unicode
// characters.
//
//===----------------------------------------------------------------------===//
#include "llvm/ADT/StringRef.h"
namespace llvm {
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);
} // namespace unicode
} // namespace sys
} // namespace llvm
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