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