From e5aae1bb97d5f73703287358f841c6d957101dfd Mon Sep 17 00:00:00 2001
From: Boris Kolpackov <boris@codesynthesis.com>
Date: Sun, 19 Jul 2015 12:06:57 +0200
Subject: Implement path iterator decrement operator

---
 butl/path             | 25 +++++++++++++++++++++++--
 tests/path/driver.cxx | 39 +++++++++++++++++++++++++++++++++++----
 2 files changed, 58 insertions(+), 6 deletions(-)

diff --git a/butl/path b/butl/path
index db77563..c667378 100644
--- a/butl/path
+++ b/butl/path
@@ -388,9 +388,9 @@ namespace butl
     {
       typedef string_type value_type;
       typedef string_type* pointer;
-      typedef string_type& reference;
+      typedef string_type reference;
       typedef std::ptrdiff_t difference_type;
-      typedef std::forward_iterator_tag iterator_category;
+      typedef std::bidirectional_iterator_tag iterator_category;
 
       typedef typename string_type::size_type size_type;
 
@@ -409,9 +409,30 @@ namespace butl
         return *this;
       }
 
+      iterator&
+      operator-- ()
+      {
+        e_ = b_;
+
+        if (e_ != 0)
+        {
+          b_ = e_ == string_type::npos ?
+            traits::rfind_separator (*p_) /* Rigtmost component */ :
+            --e_ > 0 ? traits::rfind_separator (*p_, e_ - 1) :
+            string_type::npos /* Leftmost empty component */;
+
+          b_ = b_ == string_type::npos ? 0 : b_ + 1;
+        }
+
+        return *this;
+      }
+
       iterator
       operator++ (int) {iterator r (*this); operator++ (); return r;}
 
+      iterator
+      operator-- (int) {iterator r (*this); operator-- (); return r;}
+
       string_type operator* () const
       {
         return string_type (*p_, b_, (e_ != string_type::npos ? e_ - b_ : e_));
diff --git a/tests/path/driver.cxx b/tests/path/driver.cxx
index 30933ea..a0fe18d 100644
--- a/tests/path/driver.cxx
+++ b/tests/path/driver.cxx
@@ -92,12 +92,22 @@ main ()
     assert (p.begin () == p.end ());
   }
   {
+    path p;
+    assert (p.rbegin () == p.rend ());
+  }
+  {
     path p ("foo");
     path::iterator i (p.begin ());
     assert (i != p.end () && *i == "foo");
     assert (++i == p.end ());
   }
   {
+    path p ("foo");
+    path::reverse_iterator i (p.rbegin ());
+    assert (i != p.rend () && *i == "foo");
+    assert (++i == p.rend ());
+  }
+  {
     path p ("foo/bar");
     path::iterator i (p.begin ());
     assert (i != p.end () && *i == "foo");
@@ -105,6 +115,13 @@ main ()
     assert (++i == p.end ());
   }
   {
+    path p ("foo/bar");
+    path::reverse_iterator i (p.rbegin ());
+    assert (i != p.rend () && *i == "bar");
+    assert (++i != p.rend () && *i == "foo");
+    assert (++i == p.rend ());
+  }
+  {
     path p ("/foo/bar");
     path::iterator i (p.begin ());
     assert (i != p.end () && *i == "");
@@ -112,6 +129,14 @@ main ()
     assert (++i != p.end () && *i == "bar");
     assert (++i == p.end ());
   }
+  {
+    path p ("/foo/bar");
+    path::reverse_iterator i (p.rbegin ());
+    assert (i != p.rend () && *i == "bar");
+    assert (++i != p.rend () && *i == "foo");
+    assert (++i != p.rend () && *i == "");
+    assert (++i == p.rend ());
+  }
 #ifndef _WIN32
   {
     path p ("/");
@@ -119,6 +144,12 @@ main ()
     assert (i != p.end () && *i == "");
     assert (++i == p.end ());
   }
+  {
+    path p ("/");
+    path::reverse_iterator i (p.rbegin ());
+    assert (i != p.rend () && *i == "");
+    assert (++i == p.rend ());
+  }
 #endif
 
   // iterator range construction
@@ -197,11 +228,11 @@ main ()
 
   // comparison
   //
-  assert (path ("./foo") == path("./foo"));
-  assert (path ("./boo") < path("./foo"));
+  assert (path ("./foo") == path ("./foo"));
+  assert (path ("./boo") < path ("./foo"));
 #ifdef _WIN32
-  assert (path (".\\foo") == path("./FoO"));
-  assert (path (".\\boo") < path(".\\Foo"));
+  assert (path (".\\foo") == path ("./FoO"));
+  assert (path (".\\boo") < path (".\\Foo"));
 #endif
 
   // posix_string
-- 
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