Make iterator bounds behave as expected

meaning ++ from an end() iterator results in an end() iterator and -- from a begin() iterator results in a begin() iterator
kafka399 · Jan 1, 2012 · 591f089 · 591f089
1 parent 433a652
commit 591f089
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Showing 2 changed files with 21 additions and 15 deletions.
diff --git a/src/array_hash.h b/src/array_hash.h
@@ -19,8 +19,6 @@
  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  */
 
-// TODO backwards iteration
-
 #ifndef ARRAY_HASH_H
 #define ARRAY_HASH_H
 
@@ -29,10 +27,6 @@
 #include <utility>
 #include <iterator>
 
-// TODO
-#include <iostream>
-using namespace std;
-
 namespace stx {
 
 /**
@@ -123,15 +117,15 @@ class array_hash_traits
  };
  */
 
-template<class T>
+template <class T>
 class array_hash
 {
 };
 
 /**
  * Hash table container for unsorted strings.
  */
-template<>
+template <>
 class array_hash<std::string>
 {
 private:
@@ -162,7 +156,7 @@ class array_hash<std::string>
     /**
      * Iterator range constructor.
      */
-    template<class Iterator>
+    template <class Iterator>
     array_hash(Iterator first, const Iterator& last,
             const array_hash_traits& traits = array_hash_traits()) :
             _traits(traits)
@@ -506,6 +500,8 @@ class array_hash<std::string>
         /**
          * Move this iterator forward to the next element in the table.
          *
+         * Calling this function on an end() iterator does nothing.
+         *
          * @return  self-reference
          */
         iterator& operator++()
@@ -535,6 +531,8 @@ class array_hash<std::string>
         /**
          * Move this iterator backward to the previous element in the table.
          *
+         * Calling this function on a begin iterator does nothing.
+         *
          * @return  self-reference
          */
         iterator& operator--()
@@ -553,6 +551,7 @@ class array_hash<std::string>
                     _p = prev;
                 } else {
                     // Move back to the previous occupied slot
+                    int tmp = _slot;
                     --_slot;
                     while (_slot >= 0 && _data[_slot] == NULL) {
                         --_slot;
@@ -561,10 +560,7 @@ class array_hash<std::string>
                     if (_slot < 0) {
                         // We are at the beginning. Make this a begin
                         // iterator
-                        while (_data[_slot] == NULL) {
-                            ++_slot;
-                        }
-                        _p = _data[_slot] + sizeof(size_type);
+                        _slot = tmp;
                         return *this;
                     }
                 }

diff --git a/test/array_hash_test.cpp b/test/array_hash_test.cpp
@@ -172,10 +172,9 @@ CASE(testInsert)
 
 CASE(testReverseIteration)
 {
-    stack<string> st;
-
     // Initialize the stack
     array_hash<string> ah(data.begin(), data.end());
+    stack<string> st;
     for (array_hash<string>::iterator it = ah.begin(); it != ah.end(); ++it) {
         st.push(*it);
     }
@@ -188,6 +187,17 @@ CASE(testReverseIteration)
     }
 }
 
+CASE(testIteratorBounds)
+{
+    array_hash<string> ah(data.begin(), data.end());
+    array_hash<string>::const_iterator it = ah.begin();
+    --it;
+    BOOST_CHECK(it == ah.begin());
+    it = ah.end();
+    ++it;
+    BOOST_CHECK(it == ah.end());
+}
+
 CASE(testEquality)
 {
     array_hash<string> a(data.begin(), data.end());