Re: [PATCH] Overload std::distance and std::advance for path::iterator

2018-12-13 Thread Jonathan Wakely 

On 12/12/18 16:14 +, Jonathan Wakely wrote:

+void
+test04()
+{
+  std::filesystem::path p = "/a/b/c/d/e/f/g";
+  VERIFY( std::distance(p.begin(), p.end()) == 8);
+  auto it = p.begin();
+  std::advance(it, 1);
+  VERIFY( std::distance(p.begin(), it) == 1 );
+  VERIFY( it->native() == "a" );
+  std::advance(it, 3);
+  VERIFY( std::distance(p.begin(), it) == 4 );
+  VERIFY( it->native() == "d" );
+  std::advance(it, -2);
+  VERIFY( std::distance(p.begin(), it) == 2 );
+  VERIFY( it->native() == "b" );


This fails on Windows because native() returns a wide string.

Fixed like so, committed to trunk.


commit 499376d36d7f792174f9080cbd59e7482f7e18b0
Author: Jonathan Wakely 
Date:   Thu Dec 13 12:07:43 2018 +

Fix test to work when path::native() returns wstring

* testsuite/27_io/filesystem/path/itr/traversal.cc: Fix test for
mingw.

diff --git a/libstdc++-v3/testsuite/27_io/filesystem/path/itr/traversal.cc b/libstdc++-v3/testsuite/27_io/filesystem/path/itr/traversal.cc
index 55760e82a9a..d77e613ee53 100644
--- a/libstdc++-v3/testsuite/27_io/filesystem/path/itr/traversal.cc
+++ b/libstdc++-v3/testsuite/27_io/filesystem/path/itr/traversal.cc
@@ -144,13 +144,13 @@ test04()
   auto it = p.begin();
   std::advance(it, 1);
   VERIFY( std::distance(p.begin(), it) == 1 );
-  VERIFY( it->native() == "a" );
+  VERIFY( it->string() == "a" );
   std::advance(it, 3);
   VERIFY( std::distance(p.begin(), it) == 4 );
-  VERIFY( it->native() == "d" );
+  VERIFY( it->string() == "d" );
   std::advance(it, -2);
   VERIFY( std::distance(p.begin(), it) == 2 );
-  VERIFY( it->native() == "b" );
+  VERIFY( it->string() == "b" );
 }
 
 int

[PATCH] Overload std::distance and std::advance for path::iterator

2018-12-12 Thread Jonathan Wakely 

Although filesystem::path::iterator is only a bidirectional iterator,
the underlying sequence has random access iterators (specifically, raw
pointers). This means std::distance and std::advance can be implemented
more efficiently than the generic versions which apply ++ and --
repeatedly.

PR libstdc++/71044 (partial)
* include/bits/fs_path.h (__path_iter_distance, __path_iter_advance):
New friend functions to implement std::distance and std::advance more
efficiently.
(distance, advance): Add overloads for path::iterator.
* testsuite/27_io/filesystem/path/itr/components.cc: Test new
overload.

Tested x86_64-linux, committed to trunk.

commit 994dfa1a5ca5ddd4e8d280873ef376ee6ab8352b
Author: Jonathan Wakely 
Date:   Fri Nov 30 16:33:24 2018 +

Overload std::distance and std::advance for path::iterator

Although filesystem::path::iterator is only a bidirectional iterator,
the underlying sequence has random access iterators (specifically, raw
pointers). This means std::distance and std::advance can be implemented
more efficiently than the generic versions which apply ++ and --
repeatedly.

PR libstdc++/71044 (partial)
* include/bits/fs_path.h (__path_iter_distance, 
__path_iter_advance):
New friend functions to implement std::distance and std::advance 
more
efficiently.
(distance, advance): Add overloads for path::iterator.
* testsuite/27_io/filesystem/path/itr/components.cc: Test new
overload.

diff --git a/libstdc++-v3/include/bits/fs_path.h 
b/libstdc++-v3/include/bits/fs_path.h
index cbaea7343a3..075b3ab5ef8 100644
--- a/libstdc++-v3/include/bits/fs_path.h
+++ b/libstdc++-v3/include/bits/fs_path.h
@@ -733,6 +733,37 @@ _GLIBCXX_BEGIN_NAMESPACE_CXX11
   private:
 friend class path;
 
+bool _M_is_multi() const { return _M_path->_M_type == _Type::_Multi; }
+
+friend difference_type
+__path_iter_distance(const iterator& __first, const iterator& __last)
+{
+  __glibcxx_assert(__first._M_path != nullptr);
+  __glibcxx_assert(__first._M_path == __last._M_path);
+  if (__first._M_is_multi())
+   return std::distance(__first._M_cur, __last._M_cur);
+  else if (__first._M_at_end == __last._M_at_end)
+   return 0;
+  else
+   return __first._M_at_end ? -1 : 1;
+}
+
+friend void
+__path_iter_advance(iterator& __i, difference_type __n)
+{
+  if (__n == 1)
+   ++__i;
+  else if (__n == -1)
+   --__i;
+  else if (__n != 0)
+   {
+ __glibcxx_assert(__i._M_path != nullptr);
+ __glibcxx_assert(__i._M_is_multi());
+ // __glibcxx_assert(__i._M_path->_M_cmpts.end() - __i._M_cur >= __n);
+ __i._M_cur += __n;
+   }
+}
+
 iterator(const path* __path, path::_List::const_iterator __iter)
 : _M_path(__path), _M_cur(__iter), _M_at_end()
 { }
@@ -1160,6 +1191,15 @@ _GLIBCXX_BEGIN_NAMESPACE_CXX11
 _GLIBCXX_END_NAMESPACE_CXX11
 } // namespace filesystem
 
+inline ptrdiff_t
+distance(filesystem::path::iterator __first, filesystem::path::iterator __last)
+{ return __path_iter_distance(__first, __last); }
+
+template
+  void
+  advance(filesystem::path::iterator& __i, _Distance __n)
+  { __path_iter_advance(__i, static_cast(__n)); }
+
 extern template class __shared_ptr;
 
 _GLIBCXX_END_NAMESPACE_VERSION
diff --git a/libstdc++-v3/testsuite/27_io/filesystem/path/itr/traversal.cc 
b/libstdc++-v3/testsuite/27_io/filesystem/path/itr/traversal.cc
index 4852c03c78e..55760e82a9a 100644
--- a/libstdc++-v3/testsuite/27_io/filesystem/path/itr/traversal.cc
+++ b/libstdc++-v3/testsuite/27_io/filesystem/path/itr/traversal.cc
@@ -136,10 +136,28 @@ test03()
 }
 }
 
+void
+test04()
+{
+  std::filesystem::path p = "/a/b/c/d/e/f/g";
+  VERIFY( std::distance(p.begin(), p.end()) == 8);
+  auto it = p.begin();
+  std::advance(it, 1);
+  VERIFY( std::distance(p.begin(), it) == 1 );
+  VERIFY( it->native() == "a" );
+  std::advance(it, 3);
+  VERIFY( std::distance(p.begin(), it) == 4 );
+  VERIFY( it->native() == "d" );
+  std::advance(it, -2);
+  VERIFY( std::distance(p.begin(), it) == 2 );
+  VERIFY( it->native() == "b" );
+}
+
 int
 main()
 {
   test01();
   test02();
   test03();
+  test04();
 }