completed merge

2014-06-09 23:15:57 +02:00
parent 89da38cfa4 570ec97eda
commit 5e3159f800
53 changed files with 11633 additions and 1982 deletions
--- a/src/copy/pvCopy.cpp
+++ b/src/copy/pvCopy.cpp
@@ -0,0 +1,644 @@
+/* pvCopy.cpp */
+/**
+ * Copyright - See the COPYRIGHT that is included with this distribution.
+ * EPICS pvData is distributed subject to a Software License Agreement found
+ * in file LICENSE that is included with this distribution.
+ */
+/**
+ * @author Marty Kraimer
+ * @date 2013.04
+ */
+#include <string>
+#include <stdexcept>
+#include <memory>
+#include <sstream>
+
+#include <pv/thread.h>
+
+#include <pv/pvCopy.h>
+#include <pv/convert.h>
+
+
+namespace epics { namespace pvData { 
+
+using namespace epics::pvData;
+using std::tr1::static_pointer_cast;
+using std::tr1::dynamic_pointer_cast;
+using std::size_t;
+using std::cout;
+using std::endl;
+
+static PVCopyPtr NULLPVCopy;
+static FieldConstPtr NULLField;
+static StructureConstPtr NULLStructure;
+static PVStructurePtr NULLPVStructure;
+static CopyNodePtr NULLCopyNode;
+static CopyMasterNodePtr NULLCopyMasterNode;
+
+struct CopyNode {
+    CopyNode()
+    : isStructure(false),
+      structureOffset(0),
+      nfields(0)
+    {}
+    bool isStructure;
+    size_t structureOffset; // In the copy
+    size_t nfields;
+    PVStructurePtr options;
+};
+    
+struct CopyMasterNode : public CopyNode{
+    PVFieldPtr masterPVField;
+};
+
+typedef std::vector<CopyNodePtr> CopyNodePtrArray;
+typedef std::tr1::shared_ptr<CopyNodePtrArray> CopyNodePtrArrayPtr;
+    
+struct CopyStructureNode : public  CopyNode {
+    CopyNodePtrArrayPtr nodes;
+};
+
+PVCopyPtr PVCopy::create(
+    PVStructurePtr const &pvMaster, 
+    PVStructurePtr const &pvRequest, 
+    String const & structureName)
+{
+    PVStructurePtr pvStructure(pvRequest);
+    if(structureName.size()>0) {
+        if(pvRequest->getStructure()->getNumberFields()>0) {
+            pvStructure = pvRequest->getStructureField(structureName);
+            if(pvStructure.get()==NULL) return NULLPVCopy;
+        }
+    } else if(pvStructure->getSubField("field")!=NULL) {
+        pvStructure = pvRequest->getStructureField("field");
+    }
+    PVCopyPtr pvCopy = PVCopyPtr(new PVCopy(pvMaster));
+    bool result = pvCopy->init(pvStructure);
+    if(!result) pvCopy.reset();
+    return pvCopy;
+}
+
+PVCopy::PVCopy(
+    PVStructurePtr const &pvMaster)
+: pvMaster(pvMaster)
+{
+}
+
+void PVCopy::destroy()
+{
+    headNode.reset();
+}
+
+PVStructurePtr PVCopy::getPVMaster()
+{
+    return pvMaster;
+}
+
+void PVCopy::traverseMaster(CopyNodePtr const &innode, PVCopyTraverseMasterCallbackPtr const & callback)
+{
+    CopyNodePtr node = innode;
+    if(!node->isStructure) {
+        CopyMasterNodePtr masterNode = static_pointer_cast<CopyMasterNode>(node);
+        callback->nextMasterPVField(masterNode->masterPVField);
+        return;
+    }
+    CopyStructureNodePtr structNode = static_pointer_cast<CopyStructureNode>(node);
+    CopyNodePtrArrayPtr nodes = structNode->nodes;
+    for(size_t i=0; i< nodes->size(); i++) {
+        node = (*nodes)[i];
+        traverseMaster(node,callback);
+    }
+}
+
+StructureConstPtr PVCopy::getStructure()
+{
+    return structure;
+}
+
+PVStructurePtr PVCopy::createPVStructure()
+{
+    if(cacheInitStructure.get()!=NULL) {
+        PVStructurePtr save = cacheInitStructure;
+        cacheInitStructure.reset();
+        return save;
+    }
+    PVStructurePtr pvStructure = 
+        getPVDataCreate()->createPVStructure(structure);
+    return pvStructure;
+}
+
+PVStructurePtr PVCopy::getOptions(std::size_t fieldOffset)
+{
+    if(fieldOffset==0) return headNode->options;
+    CopyNodePtr node = headNode;
+    while(true) {
+        if(!node->isStructure) {
+            if(node->structureOffset==fieldOffset) return node->options;
+            return NULLPVStructure;
+        }
+        CopyStructureNodePtr structNode = static_pointer_cast<CopyStructureNode>(node);
+        CopyNodePtrArrayPtr nodes = structNode->nodes;
+        boolean okToContinue = false;
+        for(size_t i=0; i< nodes->size(); i++) {
+            node = (*nodes)[i];
+            size_t soff = node->structureOffset;
+            if(fieldOffset>=soff && fieldOffset<soff+node->nfields) {
+                if(fieldOffset==soff) return node->options;
+                if(!node->isStructure) {
+                    return NULLPVStructure;
+                }
+                okToContinue = true;
+                break;
+            }
+        }
+        if(okToContinue) continue;
+        throw std::invalid_argument("fieldOffset not valid");
+    }
+}
+
+size_t PVCopy::getCopyOffset(PVFieldPtr const &masterPVField)
+{
+    if(masterPVField->getFieldOffset()==0) return 0;
+    if(!headNode->isStructure) {
+        CopyMasterNodePtr masterNode = static_pointer_cast<CopyMasterNode>(headNode);
+        if((masterNode->masterPVField.get())==masterPVField.get()) {
+             return headNode->structureOffset;
+        }
+        PVStructure * parent = masterPVField->getParent();
+        size_t offsetParent = parent->getFieldOffset();
+        size_t off = masterPVField->getFieldOffset();
+        size_t offdiff = off -offsetParent;
+        if(offdiff<masterNode->nfields) return headNode->structureOffset + offdiff;
+        return String::npos;
+    }
+    CopyStructureNodePtr node = static_pointer_cast<CopyStructureNode>(headNode);
+    CopyMasterNodePtr masterNode = getCopyOffset(node,masterPVField);
+    if(masterNode.get()!=NULL) return masterNode->structureOffset;
+    return String::npos;
+}
+
+size_t PVCopy::getCopyOffset(
+    PVStructurePtr const  &masterPVStructure,
+    PVFieldPtr const  &masterPVField)
+{
+    CopyMasterNodePtr masterNode;
+    if(!headNode->isStructure) {
+        masterNode = static_pointer_cast<CopyMasterNode>(headNode);
+        if(masterNode->masterPVField.get()!=masterPVStructure.get()) return String::npos;
+    } else {
+        CopyStructureNodePtr node = static_pointer_cast<CopyStructureNode>(headNode);
+        masterNode = getCopyOffset(node,masterPVField);
+    }
+    if(masterNode.get()==NULL) return String::npos;
+    size_t diff = masterPVField->getFieldOffset()
+        - masterPVStructure->getFieldOffset();
+    return masterNode->structureOffset + diff;
+}
+
+PVFieldPtr PVCopy::getMasterPVField(size_t structureOffset)
+{
+    CopyMasterNodePtr masterNode;
+    if(!headNode->isStructure) {
+        masterNode = static_pointer_cast<CopyMasterNode>(headNode);
+    } else {
+        CopyStructureNodePtr node = static_pointer_cast<CopyStructureNode>(headNode);
+        masterNode = getMasterNode(node,structureOffset);
+    }
+    if(masterNode.get()==NULL) {
+        throw std::invalid_argument(
+            "PVCopy::getMasterPVField: setstructureOffset not valid");
+    }
+    size_t diff = structureOffset - masterNode->structureOffset;
+    PVFieldPtr pvMasterField = masterNode->masterPVField;
+    if(diff==0) return pvMasterField;
+    PVStructurePtr pvStructure
+        = static_pointer_cast<PVStructure>(pvMasterField);
+    return pvStructure->getSubField(
+        pvMasterField->getFieldOffset() + diff);
+}
+
+void PVCopy::initCopy(
+    PVStructurePtr const  &copyPVStructure,
+    BitSetPtr const  &bitSet)
+{
+    bitSet->clear();
+    bitSet->set(0);
+    updateCopyFromBitSet(copyPVStructure,bitSet);
+}
+
+void PVCopy::updateCopySetBitSet(
+    PVStructurePtr const  &copyPVStructure,
+    BitSetPtr const  &bitSet)
+{
+    if(headNode->isStructure) {
+        CopyStructureNodePtr node = static_pointer_cast<CopyStructureNode>(headNode);
+        updateStructureNodeSetBitSet(copyPVStructure,node,bitSet);
+    } else {
+        CopyMasterNodePtr masterNode = static_pointer_cast<CopyMasterNode>(headNode);
+        PVFieldPtr pvMasterField= masterNode->masterPVField;
+        PVFieldPtr copyPVField = copyPVStructure;
+        PVFieldPtr pvField = pvMasterField;
+        if(pvField->getField()->getType()==epics::pvData::structure) {
+            updateSubFieldSetBitSet(copyPVField,pvMasterField,bitSet);
+            return;
+        }
+        ConvertPtr convert = getConvert();
+        bool isEqual = convert->equals(copyPVField,pvField);
+        if(!isEqual) {
+            convert->copy(pvField, copyPVField);
+            bitSet->set(copyPVField->getFieldOffset());
+        }
+    }
+}
+
+void PVCopy::updateCopyFromBitSet(
+    PVStructurePtr const  &copyPVStructure,
+    BitSetPtr const  &bitSet)
+{
+    bool doAll = bitSet->get(0);
+    if(headNode->isStructure) {
+        CopyStructureNodePtr node = static_pointer_cast<CopyStructureNode>(headNode);
+        updateStructureNodeFromBitSet(copyPVStructure,node,bitSet,true,doAll);
+    } else {
+        CopyMasterNodePtr masterNode = static_pointer_cast<CopyMasterNode>(headNode);
+        updateSubFieldFromBitSet(copyPVStructure, masterNode->masterPVField,bitSet, true,doAll);
+    }
+}
+
+void PVCopy::updateMaster(
+    PVStructurePtr const  &copyPVStructure,
+    BitSetPtr const  &bitSet)
+{
+    bool doAll = bitSet->get(0);
+    if(headNode->isStructure) {
+        CopyStructureNodePtr node =
+            static_pointer_cast<CopyStructureNode>(headNode);
+        updateStructureNodeFromBitSet(
+            copyPVStructure,node,bitSet,false,doAll);
+    } else {
+        CopyMasterNodePtr masterNode =
+            static_pointer_cast<CopyMasterNode>(headNode);
+        updateSubFieldFromBitSet( copyPVStructure,masterNode->masterPVField,bitSet,false,doAll);
+    }
+}
+
+epics::pvData::String PVCopy::dump()
+{
+    String builder;
+    dump(&builder,headNode,0);
+    return builder;
+}
+
+void PVCopy::dump(String *builder,CopyNodePtr const &node,int indentLevel)
+{
+    getConvert()->newLine(builder,indentLevel);
+    std::stringstream ss;
+    ss << (node->isStructure ? "structureNode" : "masterNode");
+    ss << " structureOffset " << node->structureOffset;
+    ss << " nfields " << node->nfields;
+    *builder +=  ss.str();
+    PVStructurePtr options = node->options;
+    if(options.get()!=NULL) {
+        getConvert()->newLine(builder,indentLevel +1);
+        options->toString(builder);
+        getConvert()->newLine(builder,indentLevel);
+    }
+    if(!node->isStructure) {
+        CopyMasterNodePtr masterNode = static_pointer_cast<CopyMasterNode>(node);
+        String name = masterNode->masterPVField->getFullName();
+        *builder += " masterField " + name;
+        return;
+    }
+    CopyStructureNodePtr structureNode =
+        static_pointer_cast<CopyStructureNode>(node);
+    CopyNodePtrArrayPtr nodes = structureNode->nodes;
+    for(size_t i=0; i<nodes->size(); ++i) {
+        if((*nodes)[i].get()==NULL) {
+            getConvert()->newLine(builder,indentLevel +1);
+            ss.str("");
+            ss << "node[" << i << "] is null";
+            *builder += ss.str();
+            continue;
+        }
+        dump(builder,(*nodes)[i],indentLevel+1);
+    }
+}
+
+bool PVCopy::init(epics::pvData::PVStructurePtr const &pvRequest)
+{
+    PVStructurePtr pvMasterStructure = pvMaster;
+    size_t len = pvRequest->getPVFields().size();
+    bool entireMaster = false;
+    if(len==String::npos) entireMaster = true;
+    if(len==0) entireMaster = true;
+    PVStructurePtr pvOptions;
+    if(len==1 && pvRequest->getSubField("_options")!=NULL) {
+        pvOptions = pvRequest->getStructureField("_options");
+    }
+    if(entireMaster) {
+        structure = pvMasterStructure->getStructure();
+        CopyMasterNodePtr masterNode(new CopyMasterNode());
+        headNode = masterNode;
+        masterNode->options = pvOptions;
+        masterNode->isStructure = false;
+        masterNode->structureOffset = 0;
+        masterNode->masterPVField = pvMasterStructure;
+        masterNode->nfields = pvMasterStructure->getNumberFields();
+        return true;
+    }
+    structure = createStructure(pvMasterStructure,pvRequest);
+    if(structure==NULL) return false;
+    cacheInitStructure = createPVStructure();
+    headNode = createStructureNodes(
+        pvMaster,
+        pvRequest,
+        cacheInitStructure);
+    return true;
+}
+
+epics::pvData::String PVCopy::dump(
+    String const &value,
+    CopyNodePtr const &node,
+    int indentLevel)
+{
+    throw std::logic_error(String("Not Implemented"));
+}
+
+
+StructureConstPtr PVCopy::createStructure(
+    PVStructurePtr const &pvMaster,
+    PVStructurePtr const  &pvFromRequest)
+{
+    if(pvFromRequest->getStructure()->getNumberFields()==0) {
+        return pvMaster->getStructure();
+    }
+    PVFieldPtrArray const &pvFromRequestFields = pvFromRequest->getPVFields();
+    StringArray const &fromRequestFieldNames = pvFromRequest->getStructure()->getFieldNames();
+    size_t length = pvFromRequestFields.size();
+    if(length==0) return NULLStructure;
+    FieldConstPtrArray fields; fields.reserve(length);
+    StringArray fieldNames; fields.reserve(length);
+    for(size_t i=0; i<length; ++i) {
+        String const &fieldName = fromRequestFieldNames[i];
+        PVFieldPtr pvMasterField = pvMaster->getSubField(fieldName);
+        if(pvMasterField==NULL) continue;
+        FieldConstPtr field = pvMasterField->getField();
+        if(field->getType()==epics::pvData::structure) {
+            PVStructurePtr pvRequestStructure = static_pointer_cast<PVStructure>(
+                pvFromRequestFields[i]);
+            if(pvRequestStructure->getNumberFields()>0) {
+                 StringArray const &names = pvRequestStructure->getStructure()->
+                     getFieldNames();
+                 size_t num = names.size();
+                 if(num>0 && names[0].compare("_options")==0) --num;
+                 if(num>0) {
+                     if(pvMasterField->getField()->getType()!=epics::pvData::structure) continue;
+                     fieldNames.push_back(fieldName);
+                     fields.push_back(createStructure(
+                         static_pointer_cast<PVStructure>(pvMasterField),
+                         pvRequestStructure));
+                     continue;
+                 }
+            }
+        }
+        fieldNames.push_back(fieldName);
+        fields.push_back(field);
+    }
+    size_t numsubfields = fields.size();
+    if(numsubfields==0) return NULLStructure;
+    return getFieldCreate()->createStructure(fieldNames, fields);
+}
+
+CopyNodePtr PVCopy::createStructureNodes(
+    PVStructurePtr const &pvMasterStructure,
+    PVStructurePtr const &pvFromRequest,
+    PVStructurePtr const &pvFromCopy)
+{
+    PVFieldPtrArray const & copyPVFields = pvFromCopy->getPVFields();
+    PVStructurePtr pvOptions;
+    PVFieldPtr pvField = pvFromRequest->getSubField("_options");
+    if(pvField!=NULL) pvOptions = static_pointer_cast<PVStructure>(pvField);
+    size_t number = copyPVFields.size();
+    CopyNodePtrArrayPtr nodes(new CopyNodePtrArray());
+    nodes->reserve(number);
+    for(size_t i=0; i<number; i++) {
+        PVFieldPtr copyPVField = copyPVFields[i];
+        String fieldName = copyPVField->getFieldName();
+        
+        PVStructurePtr requestPVStructure = static_pointer_cast<PVStructure>(
+              pvFromRequest->getSubField(fieldName));
+        PVStructurePtr pvSubFieldOptions;
+        PVFieldPtr pvField = requestPVStructure->getSubField("_options");
+        if(pvField!=NULL) pvSubFieldOptions = static_pointer_cast<PVStructure>(pvField);
+        PVFieldPtr pvMasterField;
+        PVFieldPtrArray const & pvMasterFields = pvMasterStructure->getPVFields();
+        for(size_t j=0; i<pvMasterFields.size(); j++ ) {
+            if(pvMasterFields[j]->getFieldName().compare(fieldName)==0) {
+                pvMasterField = pvMasterFields[j];
+                break;
+            }
+        }
+        size_t numberRequest = requestPVStructure->getPVFields().size();
+        if(pvSubFieldOptions!=NULL) numberRequest--;
+        if(numberRequest>0) {
+            nodes->push_back(createStructureNodes(
+                static_pointer_cast<PVStructure>(pvMasterField),
+                requestPVStructure,
+                static_pointer_cast<PVStructure>(copyPVField)));
+            continue;
+        }
+        CopyMasterNodePtr masterNode(new CopyMasterNode());
+        masterNode->options = pvSubFieldOptions;
+        masterNode->isStructure = false;
+        masterNode->masterPVField = pvMasterField;
+        masterNode->nfields = copyPVField->getNumberFields();
+        masterNode->structureOffset = copyPVField->getFieldOffset();
+        nodes->push_back(masterNode);
+    }
+    CopyStructureNodePtr structureNode(new CopyStructureNode());
+    structureNode->isStructure = true;
+    structureNode->nodes = nodes;
+    structureNode->structureOffset = pvFromCopy->getFieldOffset();
+    structureNode->nfields = pvFromCopy->getNumberFields();
+    structureNode->options = pvOptions;
+    return structureNode;
+}
+
+void PVCopy::updateStructureNodeSetBitSet(
+    PVStructurePtr const &pvCopy,
+    CopyStructureNodePtr const &structureNode,
+    epics::pvData::BitSetPtr const &bitSet)
+{
+    for(size_t i=0; i<structureNode->nodes->size(); i++) {
+        CopyNodePtr node = (*structureNode->nodes)[i];
+        PVFieldPtr pvField = pvCopy->getSubField(node->structureOffset);
+        if(node->isStructure) {
+            PVStructurePtr xxx = static_pointer_cast<PVStructure>(pvField);
+            CopyStructureNodePtr yyy =
+                static_pointer_cast<CopyStructureNode>(node);
+            updateStructureNodeSetBitSet(xxx,yyy,bitSet); 
+        } else {
+            CopyMasterNodePtr masterNode =
+                static_pointer_cast<CopyMasterNode>(node);
+            updateSubFieldSetBitSet(pvField,masterNode->masterPVField,bitSet);
+        }
+    }
+}
+
+void PVCopy::updateSubFieldSetBitSet(
+    PVFieldPtr const &pvCopy,
+    PVFieldPtr const &pvMaster,
+    BitSetPtr const &bitSet)
+{
+    FieldConstPtr field = pvCopy->getField();
+    Type type = field->getType();
+    if(type!=epics::pvData::structure) {
+        ConvertPtr convert = getConvert();
+        bool isEqual = convert->equals(pvCopy,pvMaster);
+    	if(isEqual) {
+    	    if(type==structureArray) {
+    	        // always act as though a change occurred.
+    	        // Note that array elements are shared.
+		bitSet->set(pvCopy->getFieldOffset());
+    	    }
+    	}
+        if(isEqual) return;
+        convert->copy(pvMaster, pvCopy);
+        bitSet->set(pvCopy->getFieldOffset());
+        return;
+    }
+    PVStructurePtr pvCopyStructure = static_pointer_cast<PVStructure>(pvCopy);
+    PVFieldPtrArray const & pvCopyFields = pvCopyStructure->getPVFields();
+    PVStructurePtr pvMasterStructure =
+        static_pointer_cast<PVStructure>(pvMaster);
+    PVFieldPtrArray const & pvMasterFields =
+        pvMasterStructure->getPVFields();
+    size_t length = pvCopyFields.size();
+    for(size_t i=0; i<length; i++) {
+        updateSubFieldSetBitSet(pvCopyFields[i],pvMasterFields[i],bitSet);
+    }
+}
+
+void PVCopy::updateStructureNodeFromBitSet(
+    PVStructurePtr const &pvCopy,
+    CopyStructureNodePtr const &structureNode,
+    BitSetPtr const &bitSet,
+    bool toCopy,
+    bool doAll)
+{
+    size_t offset = structureNode->structureOffset;
+    if(!doAll) {
+        size_t nextSet = bitSet->nextSetBit(offset);
+        if(nextSet==String::npos) return;
+    }
+    if(offset>=pvCopy->getNextFieldOffset()) return;
+    if(!doAll) doAll = bitSet->get(offset);
+    CopyNodePtrArrayPtr  nodes = structureNode->nodes;
+    for(size_t i=0; i<nodes->size(); i++) {
+        CopyNodePtr node = (*nodes)[i];
+        PVFieldPtr pvField = pvCopy->getSubField(node->structureOffset);
+        if(node->isStructure) {
+            PVStructurePtr xxx = static_pointer_cast<PVStructure>(pvField);
+            CopyStructureNodePtr subStructureNode =
+                static_pointer_cast<CopyStructureNode>(node);
+            updateStructureNodeFromBitSet(
+                 xxx,subStructureNode,bitSet,toCopy,doAll);
+        } else {
+            CopyMasterNodePtr masterNode =
+                static_pointer_cast<CopyMasterNode>(node);
+            updateSubFieldFromBitSet(
+                pvField,masterNode->masterPVField,bitSet,toCopy,doAll);
+        }
+    }
+}
+
+void PVCopy::updateSubFieldFromBitSet(
+    PVFieldPtr const &pvCopy,
+    PVFieldPtr const &pvMasterField,
+    BitSetPtr const &bitSet,
+    bool toCopy,
+    bool doAll)
+{
+    if(!doAll) {
+        doAll = bitSet->get(pvCopy->getFieldOffset());
+    }
+    if(!doAll) {
+        size_t offset = pvCopy->getFieldOffset();
+        size_t nextSet = bitSet->nextSetBit(offset);
+        if(nextSet==String::npos) return;
+        if(nextSet>=pvCopy->getNextFieldOffset()) return;
+    }
+    ConvertPtr convert = getConvert();
+    if(pvCopy->getField()->getType()==epics::pvData::structure) {
+        PVStructurePtr pvCopyStructure =
+            static_pointer_cast<PVStructure>(pvCopy);
+        PVFieldPtrArray const & pvCopyFields = pvCopyStructure->getPVFields();
+        if(pvMasterField->getField()->getType() !=epics::pvData::structure)
+        {
+            throw std::logic_error(String("Logic error"));
+        }
+        PVStructurePtr pvMasterStructure = 
+            static_pointer_cast<PVStructure>(pvMasterField);
+        PVFieldPtrArray const & pvMasterFields =
+            pvMasterStructure->getPVFields();
+        for(size_t i=0; i<pvCopyFields.size(); i++) {
+            updateSubFieldFromBitSet(
+                pvCopyFields[i],
+                pvMasterFields[i],
+                bitSet,toCopy,doAll);
+        }
+    } else {
+        if(toCopy) {
+            convert->copy(pvMasterField, pvCopy);
+        } else {
+            convert->copy(pvCopy, pvMasterField);
+        }
+    }
+}
+
+CopyMasterNodePtr PVCopy::getCopyOffset(
+        CopyStructureNodePtr const &structureNode,
+        PVFieldPtr const &masterPVField)
+{
+    size_t offset = masterPVField->getFieldOffset();
+    CopyNodePtrArrayPtr nodes = structureNode->nodes;
+    for(size_t i=0; i< nodes->size(); i++) {
+        CopyNodePtr node = (*nodes)[i];
+        if(!node->isStructure) {
+            CopyMasterNodePtr masterNode =
+                static_pointer_cast<CopyMasterNode>(node);
+            size_t off = masterNode->masterPVField->getFieldOffset();
+            size_t nextOffset = masterNode->masterPVField->getNextFieldOffset(); 
+            if(offset>= off && offset<nextOffset) return masterNode;
+        } else {
+            CopyStructureNodePtr subNode =
+                static_pointer_cast<CopyStructureNode>(node);
+            CopyMasterNodePtr masterNode =
+                getCopyOffset(subNode,masterPVField);
+            if(masterNode.get()!=NULL) return masterNode;
+        }
+    }
+    return NULLCopyMasterNode;
+}
+
+CopyMasterNodePtr PVCopy::getMasterNode(
+        CopyStructureNodePtr const &structureNode,
+        std::size_t structureOffset)
+{
+    CopyNodePtrArrayPtr nodes = structureNode->nodes;
+    for(size_t i=0; i< nodes->size(); i++) {
+        CopyNodePtr node = (*nodes)[i];
+        if(structureOffset>=(node->structureOffset + node->nfields)) continue;
+        if(!node->isStructure) {
+            CopyMasterNodePtr masterNode =
+                static_pointer_cast<CopyMasterNode>(node);
+            return masterNode;
+        }
+        CopyStructureNodePtr subNode =
+            static_pointer_cast<CopyStructureNode>(node);
+        return  getMasterNode(subNode,structureOffset);
+    }
+    return NULLCopyMasterNode;
+}
+
+}}