1 //===- llvm/Support/Unicode.h - Unicode character properties -*- C++ -*-=====// 2 // 3 // The LLVM Compiler Infrastructure 4 // 5 // This file is distributed under the University of Illinois Open Source 6 // License. See LICENSE.TXT for details. 7 // 8 //===----------------------------------------------------------------------===// 9 // 10 // This file defines functions that allow querying certain properties of Unicode 11 // characters. 12 // 13 //===----------------------------------------------------------------------===// 14 15 #ifndef LLVM_SUPPORT_UNICODE_H 16 #define LLVM_SUPPORT_UNICODE_H 17 18 namespace llvm { 19 class StringRef; 20 21 namespace sys { 22 namespace unicode { 23 24 enum ColumnWidthErrors { 25 ErrorInvalidUTF8 = -2, 26 ErrorNonPrintableCharacter = -1 27 }; 28 29 /// Determines if a character is likely to be displayed correctly on the 30 /// terminal. Exact implementation would have to depend on the specific 31 /// terminal, so we define the semantic that should be suitable for generic case 32 /// of a terminal capable to output Unicode characters. 33 /// 34 /// All characters from the Unicode code point range are considered printable 35 /// except for: 36 /// * C0 and C1 control character ranges; 37 /// * default ignorable code points as per 5.21 of 38 /// http://www.unicode.org/versions/Unicode6.2.0/UnicodeStandard-6.2.pdf 39 /// except for U+00AD SOFT HYPHEN, as it's actually displayed on most 40 /// terminals; 41 /// * format characters (category = Cf); 42 /// * surrogates (category = Cs); 43 /// * unassigned characters (category = Cn). 44 /// \return true if the character is considered printable. 45 bool isPrintable(int UCS); 46 47 /// Gets the number of positions the UTF8-encoded \p Text is likely to occupy 48 /// when output on a terminal ("character width"). This depends on the 49 /// implementation of the terminal, and there's no standard definition of 50 /// character width. 51 /// 52 /// The implementation defines it in a way that is expected to be compatible 53 /// with a generic Unicode-capable terminal. 54 /// 55 /// \return Character width: 56 /// * ErrorNonPrintableCharacter (-1) if \p Text contains non-printable 57 /// characters (as identified by isPrintable); 58 /// * 0 for each non-spacing and enclosing combining mark; 59 /// * 2 for each CJK character excluding halfwidth forms; 60 /// * 1 for each of the remaining characters. 61 int columnWidthUTF8(StringRef Text); 62 63 } // namespace unicode 64 } // namespace sys 65 } // namespace llvm 66 67 #endif 68