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 Optional<MemoryBufferRef> Buffer; 35 char CommentMarker = '\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 CommentMarker = '\0'); 54 55 /// Construct a new iterator around some memory buffer. 56 explicit line_iterator(const MemoryBuffer &Buffer, bool SkipBlanks = true, 57 char CommentMarker = '\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