Renamed from include/Support/iterator. Doxygenify comments; add autoconf substitution tags.

llvm-svn: 11754

llvm/include/Support/iterator.in

@@ -0,0 +1,66 @@
+//===-- Support/iterator - "Portable" wrapper around <iterator> -*- C++ -*-===//
+// 
+//                     The LLVM Compiler Infrastructure
+//
+// This file was developed by the LLVM research group and is distributed under
+// the University of Illinois Open Source License. See LICENSE.TXT for details.
+// 
+//===----------------------------------------------------------------------===//
+//
+// This file provides a wrapper around the mysterious <iterator> header file.
+// In GCC 2.95.3, the file defines a bidirectional_iterator class (and other
+// friends), instead of the standard iterator class.  In GCC 3.1, the
+// bidirectional_iterator class got moved out and the new, standards compliant,
+// iterator<> class was added.  Because there is nothing that we can do to get
+// correct behavior on both compilers, we have this header with #ifdef's.  Gross
+// huh?
+//
+// By #includ'ing this file, you get the contents of <iterator> plus the
+// following classes in the global namespace:
+//
+//   1. bidirectional_iterator
+//   2. forward_iterator
+//
+// The #if directives' expressions are filled in by Autoconf.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef SUPPORT_ITERATOR
+#define SUPPORT_ITERATOR
+
+#include <iterator>
+
+#if !@HAVE_BI_ITERATOR@
+# if @HAVE_STD_ITERATOR@
+/// If the bidirectional iterator is not defined, we attempt to define it in
+/// terms of the C++ standard iterator. Otherwise, we import it with a "using"
+/// statement.
+///
+template<class Ty, class PtrDiffTy>
+struct bidirectional_iterator
+  : public std::iterator<std::bidirectional_iterator_tag, Ty, PtrDiffTy> {
+};
+# else
+#  error "Need to have standard iterator to define bidirectional iterator!"
+# endif
+#else
+using std::bidirectional_iterator;
+#endif
+
+#if !@HAVE_FWD_ITERATOR@
+# if @HAVE_STD_ITERATOR@
+/// If the forward iterator is not defined, attempt to define it in terms of
+/// the C++ standard iterator. Otherwise, we import it with a "using" statement.
+///
+template<class Ty, class PtrDiffTy>
+struct forward_iterator
+  : public std::iterator<std::forward_iterator_tag, Ty, PtrDiffTy> {
+};
+# else
+#  error "Need to have standard iterator to define forward iterator!"
+# endif
+#else
+using std::forward_iterator;
+#endif
+
+#endif