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author | Chandler Carruth <chandlerc@gmail.com> | 2013-12-27 04:28:57 +0000 |
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committer | Chandler Carruth <chandlerc@gmail.com> | 2013-12-27 04:28:57 +0000 |
commit | 5ff21b411149095abb421c1e1263341360072cec (patch) | |
tree | d34de93b7beaf2c032c7f26de8e85291c9b30495 /include/llvm/Support | |
parent | 52b162375ad7f0e1d820ae959031ac70e254aa3b (diff) | |
download | llvm-5ff21b411149095abb421c1e1263341360072cec.tar.gz llvm-5ff21b411149095abb421c1e1263341360072cec.tar.bz2 llvm-5ff21b411149095abb421c1e1263341360072cec.tar.xz |
Introduce a simple line-by-line iterator type into the Support library.
This is an iterator which you can build around a MemoryBuffer. It will
iterate through the non-empty, non-comment lines of the buffer as
a forward iterator. It should be small and reasonably fast (although it
could be made much faster if anyone cares, I don't really...).
This will be used to more simply support the text-based sample
profile file format, and is largely based on the original patch by
Diego. I've re-worked the style of it and separated it from the work of
producing a MemoryBuffer from a file which both simplifies the interface
and makes it easier to test.
The style of the API follows the C++ standard naming conventions to fit
in better with iterators in general, much like the Path and FileSystem
interfaces follow standard-based naming conventions.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@198068 91177308-0d34-0410-b5e6-96231b3b80d8
Diffstat (limited to 'include/llvm/Support')
-rw-r--r-- | include/llvm/Support/LineIterator.h | 73 |
1 files changed, 73 insertions, 0 deletions
diff --git a/include/llvm/Support/LineIterator.h b/include/llvm/Support/LineIterator.h new file mode 100644 index 0000000000..861c19881f --- /dev/null +++ b/include/llvm/Support/LineIterator.h @@ -0,0 +1,73 @@ +//===- LineIterator.h - Iterator to read a text buffer's lines --*- C++ -*-===// +// +// The LLVM Compiler Infrastructure +// +// This file is distributed under the University of Illinois Open Source +// License. See LICENSE.TXT for details. +// +//===----------------------------------------------------------------------===// + +#include "llvm/ADT/StringRef.h" +#include <iterator> + +namespace llvm { + +class MemoryBuffer; + +/// \brief A forward iterator which reads non-blank text lines from a buffer. +/// +/// This class provides a forward iterator interface for reading one line at +/// a time from a buffer. When default constructed the iterator will be the +/// "end" iterator. +/// +/// The iterator also is aware of what line number it is currently processing +/// and can strip comment lines given the comment-starting character. +/// +/// Note that this iterator requires the buffer to be nul terminated. +class line_iterator + : public std::iterator<std::forward_iterator_tag, StringRef, ptrdiff_t> { + const MemoryBuffer *Buffer; + char CommentMarker; + + unsigned LineNumber; + StringRef CurrentLine; + +public: + /// \brief Default construct an "end" iterator. + line_iterator() : Buffer(0) {} + + /// \brief Construct a new iterator around some memory buffer. + explicit line_iterator(const MemoryBuffer &Buffer, char CommentMarker = '\0'); + + /// \brief Return true if we've reached EOF or are an "end" iterator. + bool is_at_eof() const { return !Buffer; } + + /// \brief Return true if we're an "end" iterator or have reached EOF. + bool is_at_end() const { return is_at_eof(); } + + /// \brief Return the current line number. May return any number at EOF. + int64_t line_number() const { return LineNumber; } + + /// \brief Advance to the next (non-empty, non-comment) line. + line_iterator &operator++() { + advance(); + return *this; + } + + /// \brief Get the current line as a \c StringRef. + StringRef operator*() const { return CurrentLine; } + + friend bool operator==(const line_iterator &LHS, const line_iterator &RHS) { + return LHS.Buffer == RHS.Buffer && + LHS.CurrentLine.begin() == RHS.CurrentLine.begin(); + } + + friend bool operator!=(const line_iterator &LHS, const line_iterator &RHS) { + return !(LHS == RHS); + } + +private: + /// \brief Advance the iterator to the next line. + void advance(); +}; +} |