initial checkin

MAC_SDK/Source/Shared/CircleBuffer.cpp

@@ -0,0 +1,89 @@
+#include "All.h"
+#include "CircleBuffer.h"
+
+CCircleBuffer::CCircleBuffer()
+{
+    m_pBuffer = NULL;
+    m_nTotal = 0;
+    m_nHead = 0;
+    m_nTail = 0;
+    m_nEndCap = 0;
+    m_nMaxDirectWriteBytes = 0;
+}
+
+CCircleBuffer::~CCircleBuffer()
+{
+    SAFE_ARRAY_DELETE(m_pBuffer)
+}
+
+void CCircleBuffer::CreateBuffer(int nBytes, int nMaxDirectWriteBytes)
+{
+    SAFE_ARRAY_DELETE(m_pBuffer)
+    
+    m_nMaxDirectWriteBytes = nMaxDirectWriteBytes;
+    m_nTotal = nBytes + 1 + nMaxDirectWriteBytes;
+    m_pBuffer = new unsigned char [m_nTotal];
+    m_nHead = 0;
+    m_nTail = 0;
+    m_nEndCap = m_nTotal;
+}
+
+int CCircleBuffer::MaxAdd()
+{
+    int nMaxAdd = (m_nTail >= m_nHead) ? (m_nTotal - 1 - m_nMaxDirectWriteBytes) - (m_nTail - m_nHead) : m_nHead - m_nTail - 1;
+    return nMaxAdd;
+}
+
+int CCircleBuffer::MaxGet()
+{
+    return (m_nTail >= m_nHead) ? m_nTail - m_nHead : (m_nEndCap - m_nHead) + m_nTail;
+}
+
+int CCircleBuffer::Get(unsigned char * pBuffer, int nBytes)
+{
+    int nTotalGetBytes = 0;
+
+    if (pBuffer != NULL && nBytes > 0)
+    {
+        int nHeadBytes = min(m_nEndCap - m_nHead, nBytes);
+        int nFrontBytes = nBytes - nHeadBytes;
+
+        memcpy(&pBuffer[0], &m_pBuffer[m_nHead], nHeadBytes);
+        nTotalGetBytes = nHeadBytes;
+
+        if (nFrontBytes > 0)
+        {
+            memcpy(&pBuffer[nHeadBytes], &m_pBuffer[0], nFrontBytes);
+            nTotalGetBytes += nFrontBytes;
+        }
+
+        RemoveHead(nBytes);
+    }
+
+    return nTotalGetBytes;
+}
+
+void CCircleBuffer::Empty()
+{
+    m_nHead = 0;
+    m_nTail = 0;
+    m_nEndCap = m_nTotal;
+}
+
+int CCircleBuffer::RemoveHead(int nBytes)
+{
+    nBytes = min(MaxGet(), nBytes);
+    m_nHead += nBytes;
+    if (m_nHead >= m_nEndCap)
+        m_nHead -= m_nEndCap;
+    return nBytes;
+}
+
+int CCircleBuffer::RemoveTail(int nBytes)
+{
+    nBytes = min(MaxGet(), nBytes);
+    m_nTail -= nBytes;
+    if (m_nTail < 0)
+        m_nTail += m_nEndCap;
+    return nBytes;
+}