1 //===- llvm/Support/Unicode.h - Unicode character properties -*- C++ -*-=====// 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 // 9 // This file defines functions that allow querying certain properties of Unicode 10 // characters. 11 // 12 //===----------------------------------------------------------------------===// 13 14 #ifndef LLVM_SUPPORT_UNICODE_H 15 #define LLVM_SUPPORT_UNICODE_H 16 17 namespace llvm { 18 class StringRef; 19 20 namespace sys { 21 namespace unicode { 22 23 enum ColumnWidthErrors { 24 ErrorInvalidUTF8 = -2, 25 ErrorNonPrintableCharacter = -1 26 }; 27 28 /// Determines if a character is likely to be displayed correctly on the 29 /// terminal. Exact implementation would have to depend on the specific 30 /// terminal, so we define the semantic that should be suitable for generic case 31 /// of a terminal capable to output Unicode characters. 32 /// 33 /// All characters from the Unicode code point range are considered printable 34 /// except for: 35 /// * C0 and C1 control character ranges; 36 /// * default ignorable code points as per 5.21 of 37 /// http://www.unicode.org/versions/Unicode6.2.0/UnicodeStandard-6.2.pdf 38 /// except for U+00AD SOFT HYPHEN, as it's actually displayed on most 39 /// terminals; 40 /// * format characters (category = Cf); 41 /// * surrogates (category = Cs); 42 /// * unassigned characters (category = Cn). 43 /// \return true if the character is considered printable. 44 bool isPrintable(int UCS); 45 46 /// Gets the number of positions the UTF8-encoded \p Text is likely to occupy 47 /// when output on a terminal ("character width"). This depends on the 48 /// implementation of the terminal, and there's no standard definition of 49 /// character width. 50 /// 51 /// The implementation defines it in a way that is expected to be compatible 52 /// with a generic Unicode-capable terminal. 53 /// 54 /// \return Character width: 55 /// * ErrorNonPrintableCharacter (-1) if \p Text contains non-printable 56 /// characters (as identified by isPrintable); 57 /// * 0 for each non-spacing and enclosing combining mark; 58 /// * 2 for each CJK character excluding halfwidth forms; 59 /// * 1 for each of the remaining characters. 60 int columnWidthUTF8(StringRef Text); 61 62 /// Fold input unicode character according the Simple unicode case folding 63 /// rules. 64 int foldCharSimple(int C); 65 66 } // namespace unicode 67 } // namespace sys 68 } // namespace llvm 69 70 #endif 71