[core] Define an iterator for the srt::FixedArray.

srtcore/buffer_rcv.cpp

@@ -92,14 +92,14 @@ CRcvBufferNew::CRcvBufferNew(int initSeqNo, size_t size, CUnitQueue* unitqueue,
 
 CRcvBufferNew::~CRcvBufferNew()
 {
-    for (size_t i = 0; i < m_szSize; ++i)
+    // Can be optimized by only iterating m_iMaxPosInc from m_iStartPos.
+    for (FixedArray<Entry>::iterator it = m_entries.begin(); it != m_entries.end(); ++it)
     {
-        CUnit* unit = m_entries[i].pUnit;
-        if (unit != NULL)
-        {
-            m_pUnitQueue->makeUnitFree(unit);
-            m_entries[i].pUnit = NULL;
-        }
+        if (!it->pUnit)
+            continue;
+
+        m_pUnitQueue->makeUnitFree(it->pUnit);
+        it->pUnit = NULL;
     }
 }
 

srtcore/utilities.h

@@ -462,7 +462,18 @@ class FixedArray
         return m_entries[index];
     }
 
-    size_t  size() const { return m_size; }
+    size_t size() const { return m_size; }
+
+    typedef T* iterator;
+    typedef const T* const_iterator;
+
+    iterator begin() { return m_entries; }
+    iterator end() { return m_entries + m_size; }
+
+    const_iterator cbegin() const { return m_entries; }
+    const_iterator cend() const { return m_entries + m_size; }
+
+    T* data() { return m_entries; }
 
 private:
     FixedArray(const FixedArray<T>& );