Feature (contd.): Variable Fields - AbstractProtocol now caches fieldFrameBitOffset unless the subclass says not to

common/abstractprotocol.cpp

@@ -79,6 +79,7 @@ AbstractProtocol::AbstractProtocol(StreamBase *stream, AbstractProtocol *parent)
     _frameVariableCount = -1;
     protoSize = -1;
     _hasPayload = true;
+    _cacheFlags |= FieldFrameBitOffsetCache;
 }
 
 /*!
@@ -363,11 +364,24 @@ int AbstractProtocol::fieldFrameBitOffset(int index, int streamIndex) const
     if ((index < 0) || (index >= frameFieldCount()))
         return -1;
 
-    // TODO: we should cache the return value
+    // Lookup Cache; if not available calculate and cache (if enabled)
-    for (int i = 0; i < index; i++)
-        ofs += fieldData(i, FieldBitSize, streamIndex).toInt();
 
-    qDebug("======> index: %d, ofs: %d", index, ofs);
+    if (_fieldFrameBitOffset.contains(index)) {
+        ofs = _fieldFrameBitOffset.value(index);
+        goto _exit;
+    }
+
+    for (int i = 0; i < index; i++) {
+        if (_cacheFlags.testFlag(FieldFrameBitOffsetCache)
+                && !_fieldFrameBitOffset.contains(i))
+            _fieldFrameBitOffset.insert(i, ofs);
+        ofs += fieldData(i, FieldBitSize, streamIndex).toInt();
+    }
+    if (_cacheFlags.testFlag(FieldFrameBitOffsetCache))
+        _fieldFrameBitOffset.insert(index, ofs);
+
+_exit:
+    qDebug("======> ffbo index: %d, ofs: %d", index, ofs);
     return ofs;
 }
 

common/abstractprotocol.h

@@ -20,11 +20,12 @@ along with this program.  If not, see <http://www.gnu.org/licenses/>
 #ifndef _ABSTRACT_PROTOCOL_H
 #define _ABSTRACT_PROTOCOL_H
 
+#include <QByteArray>
+#include <QFlags>
+#include <QHash>
+#include <QLinkedList>
 #include <QString>
 #include <QVariant>
-#include <QByteArray>
-#include <QLinkedList>
-#include <QFlags>
 #include <qendian.h>
 
 //#include "../rpc/pbhelper.h"
@@ -50,6 +51,7 @@ private:
     mutable int _frameVariableCount;
     mutable int protoSize;
     mutable QString protoAbbr;
+    mutable QHash<int, int> _fieldFrameBitOffset;
     OstProto::Protocol _data;
 
 protected:
@@ -61,6 +63,13 @@ protected:
     //! Is protocol typically followed by payload or another protocol
     bool _hasPayload;
 
+    //! Caching Control Flags
+    enum CacheFlag {
+        FieldFrameBitOffsetCache = 0x1
+    };
+    Q_DECLARE_FLAGS(CacheFlags, CacheFlag);
+    CacheFlags _cacheFlags;
+
 public:
     //! Properties of a field, can be OR'd
     enum FieldFlag {
@@ -170,6 +179,7 @@ private:
     void varyProtocolFrameValue(QByteArray &buf, int frameIndex,
                                 const OstProto::VariableField &varField) const;
 };
+Q_DECLARE_OPERATORS_FOR_FLAGS(AbstractProtocol::CacheFlags);
 Q_DECLARE_OPERATORS_FOR_FLAGS(AbstractProtocol::FieldFlags);
 
 #endif

common/gmp.cpp

@@ -25,6 +25,8 @@ QHash<int, int> GmpProtocol::frameFieldCountMap;
 GmpProtocol::GmpProtocol(StreamBase *stream, AbstractProtocol *parent)
     : AbstractProtocol(stream, parent)
 {
+    // field count may change based on msgType - so don't cache field offsets
+    _cacheFlags &= ~FieldFrameBitOffsetCache;
 }
 
 GmpProtocol::~GmpProtocol()

common/icmp.cpp

@@ -27,6 +27,8 @@ IcmpProtocol::IcmpProtocol(StreamBase *stream, AbstractProtocol *parent)
 
 IcmpProtocol::~IcmpProtocol()
 {
+    // field count may change based on msgType - so don't cache field offsets
+    _cacheFlags &= ~FieldFrameBitOffsetCache;
 }
 
 AbstractProtocol* IcmpProtocol::createInstance(StreamBase *stream,