fixed iterator category and added test to test sort and partial buffer search via stl algorithms

Author: vinitjames

circular_buffer.h

@@ -124,7 +124,7 @@ class CircularBuffer {
 	struct  BufferIterator{
 	public:
 		friend class CircularBuffer<T>;
-		typedef std::forward_iterator_tag iterator_category;
+		typedef std::random_access_iterator_tag iterator_category;
 		typedef ptrdiff_t difference_type;
 		typedef T value_type;
 		typedef typename std::conditional<isConst, const value_type&, value_type&>::type reference;
@@ -160,8 +160,9 @@ class CircularBuffer {
 		pointer  operator->() { return &(operator*()); }
 
 		reference operator[](size_type index){
-			this->_index += index;
-			return this->operator*();
+			BufferIterator iter = *this;
+			iter._index += index;
+			return *iter;
 		}
 
 		BufferIterator& operator++(){
@@ -207,6 +208,11 @@ class CircularBuffer {
 			return lhsiter;
 		}
 
+		friend difference_type operator-(const BufferIterator& lhsiter, const BufferIterator& rhsiter){
+			
+			return lhsiter._index - rhsiter._index;
+		}
+
 		BufferIterator& operator-=(difference_type n){
 			_index -= n;
 			return *this;

tests/iterator_test.cpp

@@ -12,75 +12,88 @@ class CircularBufferTest : public ::testing::Test{
 
 protected:
 
-	CircularBuffer<std::string> test_buff{TEST_BUFFER_SIZE};
-	
+	CircularBuffer<std::string> test_str_buff{TEST_BUFFER_SIZE};
+	CircularBuffer<int> test_int_buff{TEST_BUFFER_SIZE};
 };
 
 TEST_F(CircularBufferTest, IteratorBasedLoopTest){	
 	//create full buffer
 	for(int i=0; i<TEST_BUFFER_SIZE; i++)
-		test_buff.push_back("string" + std::to_string(i));
+		test_str_buff.push_back("string" + std::to_string(i));
     int i = 0;
-	for(auto it = test_buff.begin(); it!=test_buff.end(); it++)
+	for(auto it = test_str_buff.begin(); it!=test_str_buff.end(); it++)
 		EXPECT_EQ(*it, "string" + std::to_string(i++));
 	//partially fill buffers
-	test_buff.clear();
+	test_str_buff.clear();
 	for(int i=0; i<TEST_BUFFER_SIZE/2; i++)
-		test_buff.push_back("string" + std::to_string(i));
+		test_str_buff.push_back("string" + std::to_string(i));
 	//test begin and end on partially full buffer
 	i = 0;
-	for(auto it = test_buff.begin(); it!=test_buff.end(); it++)
+	for(auto it = test_str_buff.begin(); it!=test_str_buff.end(); it++)
 		EXPECT_EQ(*it, "string" + std::to_string(i++));
 	//test size with increment variable
 	EXPECT_EQ(i, TEST_BUFFER_SIZE/2);
-	
-
 }
 
 TEST_F(CircularBufferTest, RangeBasedLoopTest){	
 	//create full buffer
 	for(int i=0; i<TEST_BUFFER_SIZE; i++)
-		test_buff.push_back("string" + std::to_string(i));
+		test_str_buff.push_back("string" + std::to_string(i));
 	int i = 0;
 	//copied elements 
-    for(auto buff_elem : test_buff)
+    for(auto buff_elem : test_str_buff)
 		EXPECT_EQ(buff_elem, "string" + std::to_string(i++));
 	//auto reference
 	i = 0;
-    for(auto& buff_elem : test_buff)
+    for(auto& buff_elem : test_str_buff)
 		EXPECT_EQ(buff_elem, "string" + std::to_string(i++));	
 	//auto const reference
 	i = 0;
-    for(const auto& buff_elem : test_buff)
+    for(const auto& buff_elem : test_str_buff)
 		EXPECT_EQ(buff_elem, "string" + std::to_string(i++));
 	//check iterators after modifications
 	for(int i = 0; i<REDUCE_SIZE; i++)
-		test_buff.pop_front();
+		test_str_buff.pop_front();
 	i = 0;
-    for(const auto& buff_elem : test_buff)
+    for(const auto& buff_elem : test_str_buff)
 		EXPECT_EQ(buff_elem, "string" + std::to_string(i++));
 	EXPECT_EQ(i, TEST_BUFFER_SIZE - REDUCE_SIZE);
 }
 
 TEST_F(CircularBufferTest, FindTest){	
 	//create full buffer
 	for(int i=0; i<TEST_BUFFER_SIZE; i++)
-		test_buff.push_back("string" + std::to_string(i));
-	auto result = std::find(test_buff.cbegin(), test_buff.cend(), "string50");
+		test_str_buff.push_back("string" + std::to_string(i));
+	auto result = std::find(test_str_buff.cbegin(), test_str_buff.cend(), "string50");
 	EXPECT_EQ(*result, "string50");
-	result  = std::find(test_buff.cbegin(), test_buff.cend(), "string100");
-	EXPECT_EQ(result, test_buff.cend());	
+	result  = std::find(test_str_buff.cbegin(), test_str_buff.cend(), "string100");
+	EXPECT_EQ(result, test_str_buff.cend());
+	//partial buffer search
+	result  = std::find(test_str_buff.cbegin(), test_str_buff.cbegin() + 50, "string30");
+	EXPECT_EQ(*result, "string30");
+	result  = std::find(test_str_buff.cbegin(), test_str_buff.cbegin() + 50, "string51");
+	EXPECT_EQ(result, test_str_buff.cbegin() + 50);
 }
 
 TEST_F(CircularBufferTest, ForEachTest){	
 	//create full buffer
 	for(int i=0; i<TEST_BUFFER_SIZE; i++)
-		test_buff.push_back("string" + std::to_string(i));
-	std::for_each(test_buff.begin(), test_buff.end(), [](std::string& elem){ elem = elem + "modified";});
+		test_str_buff.push_back("string" + std::to_string(i));
+	std::for_each(test_str_buff.begin(), test_str_buff.end(), [](std::string& elem){ elem = elem + "modified";});
 	int i=0;
-	for(const auto& elem: test_buff)
+	for(const auto& elem: test_str_buff)
 		EXPECT_EQ(elem, "string" + std::to_string(i++) + "modified");	
 }
 
+TEST_F(CircularBufferTest, SortTest){	
+	//create full buffer
+	for(int i=0; i<TEST_BUFFER_SIZE; i++)
+		test_int_buff.push_back(i);
+	std::sort(test_int_buff.begin(), test_int_buff.end(), std::greater<int>());
+	int i = 99;
+	for(const auto& elem: test_int_buff)
+		EXPECT_EQ(elem, i--);
+}
+