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Diffstat (limited to 'contrib/llvm/tools/clang/lib/Format/Encoding.h')
-rw-r--r-- | contrib/llvm/tools/clang/lib/Format/Encoding.h | 144 |
1 files changed, 144 insertions, 0 deletions
diff --git a/contrib/llvm/tools/clang/lib/Format/Encoding.h b/contrib/llvm/tools/clang/lib/Format/Encoding.h new file mode 100644 index 0000000..356334d --- /dev/null +++ b/contrib/llvm/tools/clang/lib/Format/Encoding.h @@ -0,0 +1,144 @@ +//===--- Encoding.h - Format C++ code -------------------------------------===// +// +// The LLVM Compiler Infrastructure +// +// This file is distributed under the University of Illinois Open Source +// License. See LICENSE.TXT for details. +// +//===----------------------------------------------------------------------===// +/// +/// \file +/// \brief Contains functions for text encoding manipulation. Supports UTF-8, +/// 8-bit encodings and escape sequences in C++ string literals. +/// +//===----------------------------------------------------------------------===// + +#ifndef LLVM_CLANG_FORMAT_ENCODING_H +#define LLVM_CLANG_FORMAT_ENCODING_H + +#include "clang/Basic/LLVM.h" +#include "llvm/Support/ConvertUTF.h" +#include "llvm/Support/Unicode.h" + +namespace clang { +namespace format { +namespace encoding { + +enum Encoding { + Encoding_UTF8, + Encoding_Unknown // We treat all other encodings as 8-bit encodings. +}; + +/// \brief Detects encoding of the Text. If the Text can be decoded using UTF-8, +/// it is considered UTF8, otherwise we treat it as some 8-bit encoding. +inline Encoding detectEncoding(StringRef Text) { + const UTF8 *Ptr = reinterpret_cast<const UTF8 *>(Text.begin()); + const UTF8 *BufEnd = reinterpret_cast<const UTF8 *>(Text.end()); + if (::isLegalUTF8String(&Ptr, BufEnd)) + return Encoding_UTF8; + return Encoding_Unknown; +} + +inline unsigned getCodePointCountUTF8(StringRef Text) { + unsigned CodePoints = 0; + for (size_t i = 0, e = Text.size(); i < e; i += getNumBytesForUTF8(Text[i])) { + ++CodePoints; + } + return CodePoints; +} + +/// \brief Gets the number of code points in the Text using the specified +/// Encoding. +inline unsigned getCodePointCount(StringRef Text, Encoding Encoding) { + switch (Encoding) { + case Encoding_UTF8: + return getCodePointCountUTF8(Text); + default: + return Text.size(); + } +} + +/// \brief Returns the number of columns required to display the \p Text on a +/// generic Unicode-capable terminal. Text is assumed to use the specified +/// \p Encoding. +inline unsigned columnWidth(StringRef Text, Encoding Encoding) { + if (Encoding == Encoding_UTF8) { + int ContentWidth = llvm::sys::unicode::columnWidthUTF8(Text); + if (ContentWidth >= 0) + return ContentWidth; + } + return Text.size(); +} + +/// \brief Returns the number of columns required to display the \p Text, +/// starting from the \p StartColumn on a terminal with the \p TabWidth. The +/// text is assumed to use the specified \p Encoding. +inline unsigned columnWidthWithTabs(StringRef Text, unsigned StartColumn, + unsigned TabWidth, Encoding Encoding) { + unsigned TotalWidth = 0; + StringRef Tail = Text; + for (;;) { + StringRef::size_type TabPos = Tail.find('\t'); + if (TabPos == StringRef::npos) + return TotalWidth + columnWidth(Tail, Encoding); + int Width = columnWidth(Tail.substr(0, TabPos), Encoding); + assert(Width >= 0); + TotalWidth += Width; + TotalWidth += TabWidth - (TotalWidth + StartColumn) % TabWidth; + Tail = Tail.substr(TabPos + 1); + } +} + +/// \brief Gets the number of bytes in a sequence representing a single +/// codepoint and starting with FirstChar in the specified Encoding. +inline unsigned getCodePointNumBytes(char FirstChar, Encoding Encoding) { + switch (Encoding) { + case Encoding_UTF8: + return getNumBytesForUTF8(FirstChar); + default: + return 1; + } +} + +inline bool isOctDigit(char c) { return '0' <= c && c <= '7'; } + +inline bool isHexDigit(char c) { + return ('0' <= c && c <= '9') || ('a' <= c && c <= 'f') || + ('A' <= c && c <= 'F'); +} + +/// \brief Gets the length of an escape sequence inside a C++ string literal. +/// Text should span from the beginning of the escape sequence (starting with a +/// backslash) to the end of the string literal. +inline unsigned getEscapeSequenceLength(StringRef Text) { + assert(Text[0] == '\\'); + if (Text.size() < 2) + return 1; + + switch (Text[1]) { + case 'u': + return 6; + case 'U': + return 10; + case 'x': { + unsigned I = 2; // Point after '\x'. + while (I < Text.size() && isHexDigit(Text[I])) + ++I; + return I; + } + default: + if (isOctDigit(Text[1])) { + unsigned I = 1; + while (I < Text.size() && I < 4 && isOctDigit(Text[I])) + ++I; + return I; + } + return 2; + } +} + +} // namespace encoding +} // namespace format +} // namespace clang + +#endif // LLVM_CLANG_FORMAT_ENCODING_H |