1//===- LineIterator.h - Iterator to read a text buffer's lines --*- 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#ifndef LLVM_SUPPORT_LINEITERATOR_H
11#define LLVM_SUPPORT_LINEITERATOR_H
12
13#include "llvm/ADT/StringRef.h"
14#include "llvm/Support/DataTypes.h"
15#include <iterator>
16
17namespace llvm {
18
19class MemoryBuffer;
20
21/// \brief A forward iterator which reads text lines from a buffer.
22///
23/// This class provides a forward iterator interface for reading one line at
24/// a time from a buffer. When default constructed the iterator will be the
25/// "end" iterator.
26///
27/// The iterator is aware of what line number it is currently processing. It
28/// strips blank lines by default, and comment lines given a comment-starting
29/// character.
30///
31/// Note that this iterator requires the buffer to be nul terminated.
32class line_iterator
33    : public std::iterator<std::forward_iterator_tag, StringRef> {
34  const MemoryBuffer *Buffer;
35  char CommentMarker;
36  bool SkipBlanks;
37
38  unsigned LineNumber;
39  StringRef CurrentLine;
40
41public:
42  /// \brief Default construct an "end" iterator.
43  line_iterator() : Buffer(nullptr) {}
44
45  /// \brief Construct a new iterator around some memory buffer.
46  explicit line_iterator(const MemoryBuffer &Buffer, bool SkipBlanks = true,
47                         char CommentMarker = '\0');
48
49  /// \brief Return true if we've reached EOF or are an "end" iterator.
50  bool is_at_eof() const { return !Buffer; }
51
52  /// \brief Return true if we're an "end" iterator or have reached EOF.
53  bool is_at_end() const { return is_at_eof(); }
54
55  /// \brief Return the current line number. May return any number at EOF.
56  int64_t line_number() const { return LineNumber; }
57
58  /// \brief Advance to the next (non-empty, non-comment) line.
59  line_iterator &operator++() {
60    advance();
61    return *this;
62  }
63  line_iterator operator++(int) {
64    line_iterator tmp(*this);
65    advance();
66    return tmp;
67  }
68
69  /// \brief Get the current line as a \c StringRef.
70  StringRef operator*() const { return CurrentLine; }
71  const StringRef *operator->() const { return &CurrentLine; }
72
73  friend bool operator==(const line_iterator &LHS, const line_iterator &RHS) {
74    return LHS.Buffer == RHS.Buffer &&
75           LHS.CurrentLine.begin() == RHS.CurrentLine.begin();
76  }
77
78  friend bool operator!=(const line_iterator &LHS, const line_iterator &RHS) {
79    return !(LHS == RHS);
80  }
81
82private:
83  /// \brief Advance the iterator to the next line.
84  void advance();
85};
86}
87
88#endif
89