1 //===-- llvm/ADT/iterator - Portable wrapper around <iterator> --*- C++ -*-===//
3 // The LLVM Compiler Infrastructure
5 // This file was developed by the LLVM research group and is distributed under
6 // the University of Illinois Open Source License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 // This file provides a wrapper around the mysterious <iterator> header file.
11 // In GCC 2.95.3, the file defines a bidirectional_iterator class (and other
12 // friends), instead of the standard iterator class. In GCC 3.1, the
13 // bidirectional_iterator class got moved out and the new, standards compliant,
14 // iterator<> class was added. Because there is nothing that we can do to get
15 // correct behavior on both compilers, we have this header with #ifdef's. Gross
18 // By #includ'ing this file, you get the contents of <iterator> plus the
19 // following classes in the global namespace:
21 // 1. bidirectional_iterator
22 // 2. forward_iterator
24 // The #if directives' expressions are filled in by Autoconf.
26 //===----------------------------------------------------------------------===//
28 #ifndef LLVM_ADT_ITERATOR
29 #define LLVM_ADT_ITERATOR
33 #undef HAVE_BI_ITERATOR
34 #undef HAVE_STD_ITERATOR
35 #undef HAVE_FWD_ITERATOR
38 # define HAVE_BI_ITERATOR 0
39 # define HAVE_STD_ITERATOR 1
40 # define HAVE_FWD_ITERATOR 0
44 # if HAVE_STD_ITERATOR
45 /// If the bidirectional iterator is not defined, we attempt to define it in
46 /// terms of the C++ standard iterator. Otherwise, we import it with a "using"
49 template<class Ty, class PtrDiffTy>
50 struct bidirectional_iterator
51 : public std::iterator<std::bidirectional_iterator_tag, Ty, PtrDiffTy> {
54 # error "Need to have standard iterator to define bidirectional iterator!"
57 using std::bidirectional_iterator;
60 #if !HAVE_FWD_ITERATOR
61 # if HAVE_STD_ITERATOR
62 /// If the forward iterator is not defined, attempt to define it in terms of
63 /// the C++ standard iterator. Otherwise, we import it with a "using" statement.
65 template<class Ty, class PtrDiffTy>
66 struct forward_iterator
67 : public std::iterator<std::forward_iterator_tag, Ty, PtrDiffTy> {
70 # error "Need to have standard iterator to define forward iterator!"
73 using std::forward_iterator;