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/Optional.h" 13 #include "llvm/ADT/StringRef.h" 14 #include "llvm/Support/DataTypes.h" 15 #include "llvm/Support/MemoryBufferRef.h" 16 #include <iterator> 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 : public std::iterator<std::forward_iterator_tag, StringRef> { 35 Optional<MemoryBufferRef> Buffer; 36 char CommentMarker = '\0'; 37 bool SkipBlanks = true; 38 39 unsigned LineNumber = 1; 40 StringRef CurrentLine; 41 42 public: 43 /// Default construct an "end" iterator. 44 line_iterator() = default; 45 46 /// Construct a new iterator around an unowned memory buffer. 47 explicit line_iterator(const MemoryBufferRef &Buffer, bool SkipBlanks = true, 48 char CommentMarker = '\0'); 49 50 /// Construct a new iterator around some memory buffer. 51 explicit line_iterator(const MemoryBuffer &Buffer, bool SkipBlanks = true, 52 char CommentMarker = '\0'); 53 54 /// Return true if we've reached EOF or are an "end" iterator. 55 bool is_at_eof() const { return !Buffer; } 56 57 /// Return true if we're an "end" iterator or have reached EOF. 58 bool is_at_end() const { return is_at_eof(); } 59 60 /// Return the current line number. May return any number at EOF. 61 int64_t line_number() const { return LineNumber; } 62 63 /// Advance to the next (non-empty, non-comment) line. 64 line_iterator &operator++() { 65 advance(); 66 return *this; 67 } 68 line_iterator operator++(int) { 69 line_iterator tmp(*this); 70 advance(); 71 return tmp; 72 } 73 74 /// Get the current line as a \c StringRef. 75 StringRef operator*() const { return CurrentLine; } 76 const StringRef *operator->() const { return &CurrentLine; } 77 78 friend bool operator==(const line_iterator &LHS, const line_iterator &RHS) { 79 return LHS.Buffer == RHS.Buffer && 80 LHS.CurrentLine.begin() == RHS.CurrentLine.begin(); 81 } 82 83 friend bool operator!=(const line_iterator &LHS, const line_iterator &RHS) { 84 return !(LHS == RHS); 85 } 86 87 private: 88 /// Advance the iterator to the next line. 89 void advance(); 90 }; 91 } 92 93 #endif 94