Index: src/libchcore/TDataBuffer.cpp
===================================================================
diff -u -N -r409a0af1e9fdea72ca016118d76a5a95e53496e8 -r6f082e25ab71169e9e631f139a2eddc4ef45d2e9
--- src/libchcore/TDataBuffer.cpp	(.../TDataBuffer.cpp)	(revision 409a0af1e9fdea72ca016118d76a5a95e53496e8)
+++ src/libchcore/TDataBuffer.cpp	(.../TDataBuffer.cpp)	(revision 6f082e25ab71169e9e631f139a2eddc4ef45d2e9)
@@ -228,7 +228,7 @@
 	// first the user-facing buffer size
 	if(stBufferSize == 0)
 	{
-		stBufferSize = DefaultMaxMemory;
+		stBufferSize = DefaultBufferSize;
 		bResult = false;
 	}
 	else
@@ -262,13 +262,13 @@
 		stMaxMemory = std::max(DefaultMaxMemory, RoundUp(DefaultMaxMemory, stPageSize));
 		bResult = false;
 	}
-	else if(stMaxMemory < stPageSize)
+	else
 	{
-		size_t stNewSize = RoundUp(stMaxMemory, stBufferSize);
-		if(stNewSize != stMaxMemory)
+		size_t stNewSize = RoundUp(stMaxMemory, stPageSize);
+		if(stMaxMemory != stNewSize)
 		{
+			stMaxMemory = stNewSize;
 			bResult = false;
-			stMaxMemory = stPageSize;
 		}
 	}
 
@@ -313,7 +313,7 @@
 
 bool TDataBufferManager::CheckResizeSize(size_t& stNewMaxSize)
 {
-	if(m_stPageSize == 0 || m_stMaxMemory == 0 || m_stBufferSize == 0)
+	if(!IsInitialized())
 	{
 		stNewMaxSize = 0;
 		return false;
@@ -362,11 +362,21 @@
 	}
 }
 
+size_t TDataBufferManager::GetRealAllocatedMemorySize() const
+{
+	return m_stPageSize * (m_vAllocBlocksToFree.size() + m_vVirtualAllocBlocks.size());
+}
+
 bool TDataBufferManager::HasFreeBuffer() const
 {
 	return !m_listUnusedBuffers.empty();
 }
 
+size_t TDataBufferManager::GetCountOfFreeBuffers() const
+{
+	return m_listUnusedBuffers.size();
+}
+
 bool TDataBufferManager::CanAllocPage() const
 {
 	if(!IsInitialized())
@@ -445,6 +455,7 @@
 	{
 		m_vAllocBlocksToFree.push_back(spAllocBlock);
 	}
+	m_stMaxMemory -= m_stPageSize;
 }
 
 bool TDataBufferManager::GetFreeBuffer(TSimpleDataBuffer& rSimpleBuffer)
Index: src/libchcore/TDataBuffer.h
===================================================================
diff -u -N -r409a0af1e9fdea72ca016118d76a5a95e53496e8 -r6f082e25ab71169e9e631f139a2eddc4ef45d2e9
--- src/libchcore/TDataBuffer.h	(.../TDataBuffer.h)	(revision 409a0af1e9fdea72ca016118d76a5a95e53496e8)
+++ src/libchcore/TDataBuffer.h	(.../TDataBuffer.h)	(revision 6f082e25ab71169e9e631f139a2eddc4ef45d2e9)
@@ -127,8 +127,11 @@
 	size_t GetPageSize() const { return m_stPageSize; }
 	size_t GetSimpleBufferSize() const { return m_stBufferSize; }
 
+	size_t GetRealAllocatedMemorySize() const;
+
 	// buffer retrieval
 	bool HasFreeBuffer() const;		// checks if a buffer is available without allocating any new memory
+	size_t GetCountOfFreeBuffers() const;	// how many free buffers are there that can be used without allocating additional memory
 
 	bool GetFreeBuffer(TSimpleDataBuffer& rSimpleBuffer);
 	void ReleaseBuffer(TSimpleDataBuffer& rSimpleBuffer);
Index: tests/libchcore_test/src/TDataBufferManagerTest.cpp
===================================================================
diff -u -N -r409a0af1e9fdea72ca016118d76a5a95e53496e8 -r6f082e25ab71169e9e631f139a2eddc4ef45d2e9
--- tests/libchcore_test/src/TDataBufferManagerTest.cpp	(.../TDataBufferManagerTest.cpp)	(revision 409a0af1e9fdea72ca016118d76a5a95e53496e8)
+++ tests/libchcore_test/src/TDataBufferManagerTest.cpp	(.../TDataBufferManagerTest.cpp)	(revision 6f082e25ab71169e9e631f139a2eddc4ef45d2e9)
@@ -37,4 +37,105 @@
 }
 
 ///////////////////////////////////////////////////////////////////////////////
-// TSimpleDataBuffer
+// TDataBufferManager
+
+TEST(TDataBufferManager, CheckBufferConfigBase)
+{
+	// only max mem - default values
+	size_t stMaxMem(0);
+	EXPECT_EQ(chcore::TDataBufferManager::CheckBufferConfig(stMaxMem), false);
+	EXPECT_EQ(stMaxMem, chcore::TDataBufferManager::DefaultMaxMemory);
+
+	const size_t stTestSize = 103145;
+	stMaxMem = stTestSize;
+	EXPECT_EQ(chcore::TDataBufferManager::CheckBufferConfig(stMaxMem), false);
+	EXPECT_LE(stTestSize, stMaxMem);
+}
+
+TEST(TDataBufferManager, CheckBufferConfigExt)
+{
+	// detailed config - default values
+	size_t stMaxMem = 0;
+	size_t stPageSize(0);
+	size_t stChunkSize(0);
+	EXPECT_EQ(chcore::TDataBufferManager::CheckBufferConfig(stMaxMem, stPageSize, stChunkSize), false);
+	EXPECT_EQ(stMaxMem, chcore::TDataBufferManager::DefaultMaxMemory);
+	EXPECT_EQ(stPageSize, chcore::TDataBufferManager::DefaultPageSize);
+	EXPECT_EQ(stChunkSize, chcore::TDataBufferManager::DefaultBufferSize);
+
+	const size_t stTestMaxSize = 1237645;
+	const size_t stTestPageSize = 34563;
+	const size_t stTestBufferSize = 120;
+	stMaxMem = stTestMaxSize;
+	stPageSize = stTestPageSize;
+	stChunkSize = stTestBufferSize;
+	EXPECT_EQ(chcore::TDataBufferManager::CheckBufferConfig(stMaxMem, stPageSize, stChunkSize), false);
+	EXPECT_LE(stTestMaxSize, stMaxMem);
+	EXPECT_LE(stTestPageSize, stPageSize);
+	EXPECT_LE(stTestBufferSize, stChunkSize);
+}
+
+TEST(TDataBufferManager, FailedInitializations)
+{
+	chcore::TDataBufferManager tBufferManager;
+
+	// failed initializations
+	EXPECT_THROW(tBufferManager.Initialize(chcore::TDataBufferManager::DefaultMaxMemory - 1), chcore::TCoreException);
+	EXPECT_EQ(tBufferManager.IsInitialized(), false);
+
+	EXPECT_THROW(tBufferManager.Initialize(chcore::TDataBufferManager::DefaultMaxMemory, chcore::TDataBufferManager::DefaultPageSize - 1, 
+		chcore::TDataBufferManager::DefaultBufferSize), chcore::TCoreException);
+	EXPECT_EQ(tBufferManager.IsInitialized(), false);
+
+	// succeeded initialization
+	EXPECT_NO_FATAL_FAILURE(tBufferManager.Initialize(chcore::TDataBufferManager::DefaultPageSize));
+	EXPECT_EQ(tBufferManager.IsInitialized(), true);
+	EXPECT_EQ(tBufferManager.GetMaxMemorySize(), chcore::TDataBufferManager::DefaultPageSize);
+}
+
+class TInitializedBufferManager : public ::testing::Test
+{
+protected:
+	virtual void SetUp()
+	{
+		size_t stMaxMemory = 1048034;
+
+		chcore::TDataBufferManager::CheckBufferConfig(stMaxMemory);
+		tBufferManager.Initialize(stMaxMemory);
+	}
+
+	chcore::TDataBufferManager tBufferManager;
+};
+
+TEST_F(TInitializedBufferManager, FailedResize)
+{
+	EXPECT_TRUE(tBufferManager.IsInitialized());
+
+	size_t stCurrentMaxSize = tBufferManager.GetMaxMemorySize();
+	size_t stCurrentPageSize = tBufferManager.GetPageSize();
+	size_t stCurrentBufferSize = tBufferManager.GetSimpleBufferSize();
+
+	// try to change to something useless, check if nothing breaks inside
+	EXPECT_THROW(tBufferManager.ChangeMaxMemorySize(0), chcore::TCoreException);
+	EXPECT_EQ(stCurrentMaxSize ,tBufferManager.GetMaxMemorySize());
+	EXPECT_EQ(stCurrentPageSize, tBufferManager.GetPageSize());
+	EXPECT_EQ(stCurrentBufferSize, tBufferManager.GetSimpleBufferSize());
+}
+
+TEST_F(TInitializedBufferManager, ResizeWithSimpleBufferChecks)
+{
+	EXPECT_TRUE(tBufferManager.IsInitialized());
+	EXPECT_EQ((tBufferManager.GetMaxMemorySize() / tBufferManager.GetSimpleBufferSize()), tBufferManager.GetCountOfFreeBuffers());
+
+	size_t stCurrentMaxSize = tBufferManager.GetMaxMemorySize();
+
+	// try to change to something useless, check if nothing breaks inside
+	size_t stNewBufferSize = stCurrentMaxSize / 2;
+	tBufferManager.CheckResizeSize(stNewBufferSize);	// can't assume that it will return true here, since we don't really know what's the buffer size now...
+
+	EXPECT_NO_FATAL_FAILURE(tBufferManager.ChangeMaxMemorySize(stNewBufferSize));
+	EXPECT_EQ(tBufferManager.GetMaxMemorySize(), stNewBufferSize);
+
+	EXPECT_TRUE(tBufferManager.HasFreeBuffer());
+	EXPECT_EQ((tBufferManager.GetMaxMemorySize() / tBufferManager.GetSimpleBufferSize()), tBufferManager.GetCountOfFreeBuffers());
+}