Add CChan::TrimBuffer and have SetBufferCount call it.

Chan.cpp

@@ -112,6 +112,7 @@ bool CChan::SetBufferCount(unsigned int u, bool bForce) {
 	if (!bForce && u > CZNC::Get().GetMaxBufferSize())
 		return false;
 	m_uBufferCount = u;
+	TrimBuffer(m_uBufferCount);
 	return true;
 }
 
@@ -534,6 +535,12 @@ void CChan::ClearBuffer() {
 	m_vsBuffer.clear();
 }
 
+void CChan::TrimBuffer(const unsigned int uMax) {
+	if (m_vsBuffer.size() > uMax) {
+		m_vsBuffer.erase(m_vsBuffer.begin(), m_vsBuffer.begin() + (uMax - m_vsBuffer.size())); 
+	}
+}
+
 void CChan::SendBuffer(CClient* pClient) {
 	if (m_pUser && m_pUser->IsUserAttached()) {
 		const vector<CString>& vsBuffer = GetBuffer();

Chan.h

@@ -88,6 +88,7 @@ public:
 	// Buffer
 	int AddBuffer(const CString& sLine);
 	void ClearBuffer();
+	void TrimBuffer(const unsigned int uMax);
 	void SendBuffer(CClient* pClient);
 	// !Buffer