1 | //===- LineIterator.h - Iterator to read a text buffer's lines --*- 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 | #ifndef LLVM_SUPPORT_LINEITERATOR_H |
10 | #define LLVM_SUPPORT_LINEITERATOR_H |
11 | |
12 | #include "llvm/ADT/StringRef.h" |
13 | #include "llvm/Support/DataTypes.h" |
14 | #include "llvm/Support/MemoryBufferRef.h" |
15 | #include <iterator> |
16 | #include <optional> |
17 | |
18 | namespace llvm { |
19 | |
20 | class MemoryBuffer; |
21 | |
22 | /// A forward iterator which reads text lines from a buffer. |
23 | /// |
24 | /// This class provides a forward iterator interface for reading one line at |
25 | /// a time from a buffer. When default constructed the iterator will be the |
26 | /// "end" iterator. |
27 | /// |
28 | /// The iterator is aware of what line number it is currently processing. It |
29 | /// strips blank lines by default, and comment lines given a comment-starting |
30 | /// character. |
31 | /// |
32 | /// Note that this iterator requires the buffer to be nul terminated. |
33 | class line_iterator { |
34 | std::optional<MemoryBufferRef> Buffer; |
35 | char = '\0'; |
36 | bool SkipBlanks = true; |
37 | |
38 | unsigned LineNumber = 1; |
39 | StringRef CurrentLine; |
40 | |
41 | public: |
42 | using iterator_category = std::forward_iterator_tag; |
43 | using value_type = StringRef; |
44 | using difference_type = std::ptrdiff_t; |
45 | using pointer = value_type *; |
46 | using reference = value_type &; |
47 | |
48 | /// Default construct an "end" iterator. |
49 | line_iterator() = default; |
50 | |
51 | /// Construct a new iterator around an unowned memory buffer. |
52 | explicit line_iterator(const MemoryBufferRef &Buffer, bool SkipBlanks = true, |
53 | char = '\0'); |
54 | |
55 | /// Construct a new iterator around some memory buffer. |
56 | explicit line_iterator(const MemoryBuffer &Buffer, bool SkipBlanks = true, |
57 | char = '\0'); |
58 | |
59 | /// Return true if we've reached EOF or are an "end" iterator. |
60 | bool is_at_eof() const { return !Buffer; } |
61 | |
62 | /// Return true if we're an "end" iterator or have reached EOF. |
63 | bool is_at_end() const { return is_at_eof(); } |
64 | |
65 | /// Return the current line number. May return any number at EOF. |
66 | int64_t line_number() const { return LineNumber; } |
67 | |
68 | /// Advance to the next (non-empty, non-comment) line. |
69 | line_iterator &operator++() { |
70 | advance(); |
71 | return *this; |
72 | } |
73 | line_iterator operator++(int) { |
74 | line_iterator tmp(*this); |
75 | advance(); |
76 | return tmp; |
77 | } |
78 | |
79 | /// Get the current line as a \c StringRef. |
80 | StringRef operator*() const { return CurrentLine; } |
81 | const StringRef *operator->() const { return &CurrentLine; } |
82 | |
83 | friend bool operator==(const line_iterator &LHS, const line_iterator &RHS) { |
84 | return LHS.Buffer == RHS.Buffer && |
85 | LHS.CurrentLine.begin() == RHS.CurrentLine.begin(); |
86 | } |
87 | |
88 | friend bool operator!=(const line_iterator &LHS, const line_iterator &RHS) { |
89 | return !(LHS == RHS); |
90 | } |
91 | |
92 | private: |
93 | /// Advance the iterator to the next line. |
94 | void advance(); |
95 | }; |
96 | } |
97 | |
98 | #endif |
99 | |