You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
129 lines
4.1 KiB
129 lines
4.1 KiB
//===--- Encoding.h - Format C++ code ---------------------------*- 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
|
|
//
|
|
//===----------------------------------------------------------------------===//
|
|
///
|
|
/// \file
|
|
/// Contains functions for text encoding manipulation. Supports UTF-8,
|
|
/// 8-bit encodings and escape sequences in C++ string literals.
|
|
///
|
|
//===----------------------------------------------------------------------===//
|
|
|
|
#ifndef LLVM_CLANG_LIB_FORMAT_ENCODING_H
|
|
#define LLVM_CLANG_LIB_FORMAT_ENCODING_H
|
|
|
|
#include "clang/Basic/LLVM.h"
|
|
#include "llvm/ADT/StringRef.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.
|
|
};
|
|
|
|
/// 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 llvm::UTF8 *Ptr = reinterpret_cast<const llvm::UTF8 *>(Text.begin());
|
|
const llvm::UTF8 *BufEnd = reinterpret_cast<const llvm::UTF8 *>(Text.end());
|
|
if (llvm::isLegalUTF8String(&Ptr, BufEnd))
|
|
return Encoding_UTF8;
|
|
return Encoding_Unknown;
|
|
}
|
|
|
|
/// 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);
|
|
// FIXME: Figure out the correct way to handle this in the presence of both
|
|
// printable and unprintable multi-byte UTF-8 characters. Falling back to
|
|
// returning the number of bytes may cause problems, as columnWidth suddenly
|
|
// becomes non-additive.
|
|
if (ContentWidth >= 0)
|
|
return ContentWidth;
|
|
}
|
|
return Text.size();
|
|
}
|
|
|
|
/// 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);
|
|
TotalWidth += columnWidth(Tail.substr(0, TabPos), Encoding);
|
|
if (TabWidth)
|
|
TotalWidth += TabWidth - (TotalWidth + StartColumn) % TabWidth;
|
|
Tail = Tail.substr(TabPos + 1);
|
|
}
|
|
}
|
|
|
|
/// 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 llvm::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');
|
|
}
|
|
|
|
/// 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 1 + llvm::getNumBytesForUTF8(Text[1]);
|
|
}
|
|
}
|
|
|
|
} // namespace encoding
|
|
} // namespace format
|
|
} // namespace clang
|
|
|
|
#endif
|