fix undefined behavior in unit tests

17 files changed, 95 insertions, 209 deletions

diff --git a/fnet/src/tests/frt/method_pt/method_pt.cpp b/fnet/src/tests/frt/method_pt/method_pt.cpp
index 3ce3c3062af..bc42a31d91b 100644
--- a/fnet/src/tests/frt/method_pt/method_pt.cpp
+++ b/fnet/src/tests/frt/method_pt/method_pt.cpp
@@ -6,14 +6,8 @@
 #include <vespa/fnet/frt/rpcrequest.h>
 class Test;
 class SimpleHandler;
-
-class MediumHandler1;
-class MediumHandler2;
-class MediumHandler3;
-
-class ComplexHandler1;
-class ComplexHandler2;
-class ComplexHandler3;
+class MediumHandler;
+class ComplexHandler;
 
 //-------------------------------------------------------------
 
@@ -23,12 +17,8 @@ std::unique_ptr<fnet::frt::StandaloneFRT> _server;
 FRT_Supervisor   *_supervisor;
 FRT_Target       *_target;
 SimpleHandler    *_simpleHandler;
-MediumHandler1   *_mediumHandler1;
-MediumHandler2   *_mediumHandler2;
-MediumHandler3   *_mediumHandler3;
-ComplexHandler1  *_complexHandler1;
-ComplexHandler2  *_complexHandler2;
-ComplexHandler3  *_complexHandler3;
+MediumHandler    *_mediumHandler;
+ComplexHandler   *_complexHandler;
 
 bool              _mediumHandlerOK;
 bool              _complexHandlerOK;
@@ -115,31 +105,9 @@ public:
 
 //-------------------------------------------------------------
 
-class MediumHandler1 : public FRT_Invokable,
-                       public MediumA,
-                       public MediumB
-{
-public:
-    void foo() override {}
-    void bar() override {}
-    void RPC_Method(FRT_RPCRequest *req);
-};
-
-
-class MediumHandler2 : public MediumA,
-                       public FRT_Invokable,
-                       public MediumB
-{
-public:
-    void foo() override {}
-    void bar() override {}
-    void RPC_Method(FRT_RPCRequest *req);
-};
-
-
-class MediumHandler3 : public MediumA,
-                       public MediumB,
-                       public FRT_Invokable
+class MediumHandler : public FRT_Invokable,
+                      public MediumA,
+                      public MediumB
 {
 public:
     void foo() override {}
@@ -149,31 +117,9 @@ public:
 
 //-------------------------------------------------------------
 
-class ComplexHandler1 : public FRT_Invokable,
-                        public ComplexA,
-                        public ComplexB
-{
-public:
-    void foo() override {}
-    void bar() override {}
-    void RPC_Method(FRT_RPCRequest *req);
-};
-
-
-class ComplexHandler2 : public ComplexA,
-                        public FRT_Invokable,
-                        public ComplexB
-{
-public:
-    void foo() override {}
-    void bar() override {}
-    void RPC_Method(FRT_RPCRequest *req);
-};
-
-
-class ComplexHandler3 : public ComplexA,
-                        public ComplexB,
-                        public FRT_Invokable
+class ComplexHandler : public FRT_Invokable,
+                       public ComplexA,
+                       public ComplexB
 {
 public:
     void foo() override {}
@@ -187,21 +133,13 @@ void initTest() {
     _server = std::make_unique<fnet::frt::StandaloneFRT>();
   _supervisor      = &_server->supervisor();
   _simpleHandler   = new SimpleHandler();
-  _mediumHandler1  = new MediumHandler1();
-  _mediumHandler2  = new MediumHandler2();
-  _mediumHandler3  = new MediumHandler3();
-  _complexHandler1 = new ComplexHandler1();
-  _complexHandler2 = new ComplexHandler2();
-  _complexHandler3 = new ComplexHandler3();
+  _mediumHandler   = new MediumHandler();
+  _complexHandler  = new ComplexHandler();
 
   ASSERT_TRUE(_supervisor != nullptr);
   ASSERT_TRUE(_simpleHandler != nullptr);
-  ASSERT_TRUE(_mediumHandler1 != nullptr);
-  ASSERT_TRUE(_mediumHandler2 != nullptr);
-  ASSERT_TRUE(_mediumHandler3 != nullptr);
-  ASSERT_TRUE(_complexHandler1 != nullptr);
-  ASSERT_TRUE(_complexHandler2 != nullptr);
-  ASSERT_TRUE(_complexHandler3 != nullptr);
+  ASSERT_TRUE(_mediumHandler != nullptr);
+  ASSERT_TRUE(_complexHandler != nullptr);
 
   ASSERT_TRUE(_supervisor->Listen(0));
   std::string spec = vespalib::make_string("tcp/localhost:%d",
@@ -219,31 +157,15 @@ void initTest() {
 
   //-------------------------------------------------------------------
 
-  rb.DefineMethod("mediumMethod1", "", "",
-                  FRT_METHOD(MediumHandler1::RPC_Method),
-                  _mediumHandler1);
-
-  rb.DefineMethod("mediumMethod2", "", "",
-                  FRT_METHOD(MediumHandler2::RPC_Method),
-                  _mediumHandler2);
-
-  rb.DefineMethod("mediumMethod3", "", "",
-                  FRT_METHOD(MediumHandler3::RPC_Method),
-                  _mediumHandler3);
+  rb.DefineMethod("mediumMethod", "", "",
+                  FRT_METHOD(MediumHandler::RPC_Method),
+                  _mediumHandler);
 
   //-------------------------------------------------------------------
 
-  rb.DefineMethod("complexMethod1", "", "",
-                  FRT_METHOD(ComplexHandler1::RPC_Method),
-                  _complexHandler1);
-
-  rb.DefineMethod("complexMethod2", "", "",
-                  FRT_METHOD(ComplexHandler2::RPC_Method),
-                  _complexHandler2);
-
-  rb.DefineMethod("complexMethod3", "", "",
-                  FRT_METHOD(ComplexHandler3::RPC_Method),
-                  _complexHandler3);
+  rb.DefineMethod("complexMethod", "", "",
+                  FRT_METHOD(ComplexHandler::RPC_Method),
+                  _complexHandler);
 
   //-------------------------------------------------------------------
 
@@ -253,12 +175,8 @@ void initTest() {
 
 
 void finiTest() {
-  delete _complexHandler1;
-  delete _complexHandler2;
-  delete _complexHandler3;
-  delete _mediumHandler1;
-  delete _mediumHandler2;
-  delete _mediumHandler3;
+  delete _complexHandler;
+  delete _mediumHandler;
   delete _simpleHandler;
   _target->SubRef();
   _server.reset();
@@ -275,19 +193,7 @@ TEST("method pt") {
 
   req->SubRef();
   req = _supervisor->AllocRPCRequest();
-  req->SetMethodName("mediumMethod1");
-  _target->InvokeSync(req, 60.0);
-  EXPECT_TRUE(!req->IsError());
-
-  req->SubRef();
-  req = _supervisor->AllocRPCRequest();
-  req->SetMethodName("mediumMethod2");
-  _target->InvokeSync(req, 60.0);
-  EXPECT_TRUE(!req->IsError());
-
-  req->SubRef();
-  req = _supervisor->AllocRPCRequest();
-  req->SetMethodName("mediumMethod3");
+  req->SetMethodName("mediumMethod");
   _target->InvokeSync(req, 60.0);
   EXPECT_TRUE(!req->IsError());
 
@@ -295,19 +201,7 @@ TEST("method pt") {
 
   req->SubRef();
   req = _supervisor->AllocRPCRequest();
-  req->SetMethodName("complexMethod1");
-  _target->InvokeSync(req, 60.0);
-  EXPECT_TRUE(!req->IsError());
-
-  req->SubRef();
-  req = _supervisor->AllocRPCRequest();
-  req->SetMethodName("complexMethod2");
-  _target->InvokeSync(req, 60.0);
-  EXPECT_TRUE(!req->IsError());
-
-  req->SubRef();
-  req = _supervisor->AllocRPCRequest();
-  req->SetMethodName("complexMethod3");
+  req->SetMethodName("complexMethod");
   _target->InvokeSync(req, 60.0);
   EXPECT_TRUE(!req->IsError());
 
@@ -338,57 +232,21 @@ SimpleHandler::RPC_Method(FRT_RPCRequest *req)
 //-------------------------------------------------------------
 
 void
-MediumHandler1::RPC_Method(FRT_RPCRequest *req)
-{
-  (void) req;
-  _mediumHandlerOK = (_mediumHandlerOK &&
-                      this == _mediumHandler1);
-}
-
-
-void
-MediumHandler2::RPC_Method(FRT_RPCRequest *req)
+MediumHandler::RPC_Method(FRT_RPCRequest *req)
 {
   (void) req;
   _mediumHandlerOK = (_mediumHandlerOK &&
-                      this == _mediumHandler2);
-}
-
-
-void
-MediumHandler3::RPC_Method(FRT_RPCRequest *req)
-{
-  (void) req;
-  _mediumHandlerOK = (_mediumHandlerOK &&
-                      this == _mediumHandler3);
+                      this == _mediumHandler);
 }
 
 //-------------------------------------------------------------
 
 void
-ComplexHandler1::RPC_Method(FRT_RPCRequest *req)
-{
-  (void) req;
-  _complexHandlerOK = (_complexHandlerOK &&
-                       this == _complexHandler1);
-}
-
-
-void
-ComplexHandler2::RPC_Method(FRT_RPCRequest *req)
-{
-  (void) req;
-  _complexHandlerOK = (_complexHandlerOK &&
-                       this == _complexHandler2);
-}
-
-
-void
-ComplexHandler3::RPC_Method(FRT_RPCRequest *req)
+ComplexHandler::RPC_Method(FRT_RPCRequest *req)
 {
   (void) req;
   _complexHandlerOK = (_complexHandlerOK &&
-                       this == _complexHandler3);
+                       this == _complexHandler);
 }
 
 //-------------------------------------------------------------
diff --git a/fnet/src/tests/frt/rpc/sharedblob.cpp b/fnet/src/tests/frt/rpc/sharedblob.cpp
index 90cfa63fbdb..2ccb44d03cb 100644
--- a/fnet/src/tests/frt/rpc/sharedblob.cpp
+++ b/fnet/src/tests/frt/rpc/sharedblob.cpp
@@ -29,20 +29,28 @@ struct Data
     uint32_t len;
 
     Data(const char *pt, uint32_t l) : buf(new char[l]), len(l) {
-        memcpy(buf, pt, len);
+        if (len > 0) {
+            memcpy(buf, pt, len);
+        }
     }
     Data(uint32_t l, char c) : buf(new char[l]), len(l) {
-        memset(buf, c, len);
+        if (len > 0) {
+            memset(buf, c, len);
+        }
     }
     Data(const Data &rhs) : buf(new char[rhs.len]), len(rhs.len) {
-        memcpy(buf, rhs.buf, len);
+        if (len > 0) {
+            memcpy(buf, rhs.buf, len);
+        }
     }
     Data &operator=(const Data &rhs) {
         if (this != &rhs) {
             delete [] buf;
             buf = new char[rhs.len];
             len = rhs.len;
-            memcpy(buf, rhs.buf, len);
+            if (len > 0) {
+                memcpy(buf, rhs.buf, len);
+            }
         }
         return *this;
     }
diff --git a/searchcore/src/vespa/searchcore/proton/documentmetastore/documentmetastore.cpp b/searchcore/src/vespa/searchcore/proton/documentmetastore/documentmetastore.cpp
index c0d291ca695..b1b5f45a8fa 100644
--- a/searchcore/src/vespa/searchcore/proton/documentmetastore/documentmetastore.cpp
+++ b/searchcore/src/vespa/searchcore/proton/documentmetastore/documentmetastore.cpp
@@ -74,10 +74,10 @@ private:
 public:
     Reader(std::unique_ptr<FastOS_FileInterface> datFile)
         : _datFile(std::move(datFile)),
-          _lidReader(_datFile.file()),
-          _gidReader(_datFile.file()),
-          _bucketUsedBitsReader(_datFile.file()),
-          _timestampReader(_datFile.file()),
+          _lidReader(&_datFile.file()),
+          _gidReader(&_datFile.file()),
+          _bucketUsedBitsReader(&_datFile.file()),
+          _timestampReader(&_datFile.file()),
           _docIdLimit(0)
     {
         _docIdLimit = _datFile.header().getTag(DOCID_LIMIT).asInteger();
diff --git a/searchlib/src/tests/attribute/tensorattribute/tensorattribute_test.cpp b/searchlib/src/tests/attribute/tensorattribute/tensorattribute_test.cpp
index ee1680bbd9a..bf0b74b0003 100644
--- a/searchlib/src/tests/attribute/tensorattribute/tensorattribute_test.cpp
+++ b/searchlib/src/tests/attribute/tensorattribute/tensorattribute_test.cpp
@@ -100,7 +100,7 @@ private:
 public:
     MockIndexLoader(int& index_value, FastOS_FileInterface& file)
         : _index_value(index_value),
-          _reader(file)
+          _reader(&file)
     {}
     bool load_next() override {
         _index_value = _reader.readHostOrder();
diff --git a/searchlib/src/tests/sortspec/multilevelsort.cpp b/searchlib/src/tests/sortspec/multilevelsort.cpp
index 005fe6bd9d5..82bdf99ab2c 100644
--- a/searchlib/src/tests/sortspec/multilevelsort.cpp
+++ b/searchlib/src/tests/sortspec/multilevelsort.cpp
@@ -56,7 +56,7 @@ private:
     T getRandomValue() {
         T min = std::numeric_limits<T>::min();
         T max = std::numeric_limits<T>::max();
-        return min + static_cast<T>(double(max - min) * (((float)rand() / (float)RAND_MAX)));
+        return static_cast<T>(double(min) + (double(max) - double(min)) * (double(rand()) / double(RAND_MAX)));
     }
     template<typename T>
     void fill(IntegerAttribute *attr, uint32_t size, uint32_t unique = 0);
diff --git a/searchlib/src/vespa/searchlib/attribute/primitivereader.h b/searchlib/src/vespa/searchlib/attribute/primitivereader.h
index 12eac275f8a..613065260ad 100644
--- a/searchlib/src/vespa/searchlib/attribute/primitivereader.h
+++ b/searchlib/src/vespa/searchlib/attribute/primitivereader.h
@@ -13,7 +13,7 @@ namespace search {
     public:
         PrimitiveReader(AttributeVector &attr)
             : ReaderBase(attr),
-              _datReader(_datFile.file())
+              _datReader(&_datFile.file())
         { }
 
         virtual ~PrimitiveReader() { }
diff --git a/searchlib/src/vespa/searchlib/attribute/readerbase.cpp b/searchlib/src/vespa/searchlib/attribute/readerbase.cpp
index d023d9b56b1..8dd1a466fb5 100644
--- a/searchlib/src/vespa/searchlib/attribute/readerbase.cpp
+++ b/searchlib/src/vespa/searchlib/attribute/readerbase.cpp
@@ -32,9 +32,9 @@ ReaderBase::ReaderBase(AttributeVector &attr)
                   attribute::LoadUtils::openWeight(attr) : std::unique_ptr<Fast_BufferedFile>()),
       _idxFile(attr.hasMultiValue() ?
                attribute::LoadUtils::openIDX(attr) : std::unique_ptr<Fast_BufferedFile>()),
-      _weightReader(_weightFile.file()),
-      _idxReader(_idxFile.file()),
-      _enumReader(_datFile.file()),
+      _weightReader(_weightFile.valid() ? &_weightFile.file() : nullptr),
+      _idxReader(_idxFile.valid() ? &_idxFile.file() : nullptr),
+      _enumReader(&_datFile.file()),
       _currIdx(0),
       _createSerialNum(0u),
       _fixedWidth(attr.getFixedWidth()),
diff --git a/searchlib/src/vespa/searchlib/docstore/chunkformat.cpp b/searchlib/src/vespa/searchlib/docstore/chunkformat.cpp
index 9e3e6c9e46c..79a6742f9da 100644
--- a/searchlib/src/vespa/searchlib/docstore/chunkformat.cpp
+++ b/searchlib/src/vespa/searchlib/docstore/chunkformat.cpp
@@ -38,8 +38,8 @@ ChunkFormat::pack(uint64_t lastSerial, vespalib::DataBuffer & compressed, const
         compressed.getData()[oldPos] = type;
     }
     if (includeSerializedSize()) {
-        const uint32_t serializedSize = compressed.getDataLen()+4;
-        *reinterpret_cast<uint32_t *>(compressed.getData() + serializedSizePos) = htonl(serializedSize);
+        const uint32_t serializedSize = htonl(compressed.getDataLen()+4);
+        memcpy(compressed.getData() + serializedSizePos, &serializedSize, sizeof(serializedSize));
     }
     uint32_t crc = computeCrc(compressed.getData(), compressed.getDataLen());
     compressed.writeInt32(crc);
diff --git a/searchlib/src/vespa/searchlib/parsequery/stackdumpiterator.cpp b/searchlib/src/vespa/searchlib/parsequery/stackdumpiterator.cpp
index f625a2b7fd2..ae1d2c16960 100644
--- a/searchlib/src/vespa/searchlib/parsequery/stackdumpiterator.cpp
+++ b/searchlib/src/vespa/searchlib/parsequery/stackdumpiterator.cpp
@@ -48,17 +48,19 @@ SimpleQueryStackDumpIterator::read_stringref(const char *&p)
 uint64_t
 SimpleQueryStackDumpIterator::readUint64(const char *&p)
 {
-    uint64_t l = vespalib::nbo::n2h(*(const uint64_t *)(const void *)p);
-    p += sizeof(uint64_t);
-    return l;
+    uint64_t value;
+    memcpy(&value, p, sizeof(value));
+    p += sizeof(value);
+    return vespalib::nbo::n2h(value);
 }
 
 double
 SimpleQueryStackDumpIterator::read_double(const char *&p)
 {
-    double result = vespalib::nbo::n2h(*reinterpret_cast<const double *>(p));
-    p += sizeof(double);
-    return result;
+    double value;
+    memcpy(&value, p, sizeof(value));
+    p += sizeof(value);
+    return vespalib::nbo::n2h(value);
 }
 
 uint64_t
diff --git a/searchlib/src/vespa/searchlib/tensor/blob_sequence_reader.h b/searchlib/src/vespa/searchlib/tensor/blob_sequence_reader.h
index 45fcf5524d2..adad87d8cfe 100644
--- a/searchlib/src/vespa/searchlib/tensor/blob_sequence_reader.h
+++ b/searchlib/src/vespa/searchlib/tensor/blob_sequence_reader.h
@@ -17,7 +17,7 @@ private:
 public:
     BlobSequenceReader(AttributeVector &attr)
         : ReaderBase(attr),
-          _sizeReader(_datFile.file())
+          _sizeReader(&_datFile.file())
     { }
     uint32_t getNextSize() { return _sizeReader.readHostOrder(); }
     void readBlob(void *buf, size_t len);
diff --git a/searchlib/src/vespa/searchlib/tensor/hnsw_index.cpp b/searchlib/src/vespa/searchlib/tensor/hnsw_index.cpp
index 24bfacb8c5a..e82f31df38e 100644
--- a/searchlib/src/vespa/searchlib/tensor/hnsw_index.cpp
+++ b/searchlib/src/vespa/searchlib/tensor/hnsw_index.cpp
@@ -685,7 +685,7 @@ HnswIndex::make_loader(FastOS_FileInterface& file)
     assert(get_entry_docid() == 0); // cannot load after index has data
     using ReaderType = FileReader<uint32_t>;
     using LoaderType = HnswIndexLoader<ReaderType>;
-    return std::make_unique<LoaderType>(_graph, std::make_unique<ReaderType>(file));
+    return std::make_unique<LoaderType>(_graph, std::make_unique<ReaderType>(&file));
 }
 
 struct NeighborsByDocId {
diff --git a/searchlib/src/vespa/searchlib/transactionlog/translogserver.h b/searchlib/src/vespa/searchlib/transactionlog/translogserver.h
index 7f17adc99f7..f7ea80c9248 100644
--- a/searchlib/src/vespa/searchlib/transactionlog/translogserver.h
+++ b/searchlib/src/vespa/searchlib/transactionlog/translogserver.h
@@ -18,7 +18,7 @@ namespace search::transactionlog {
 class TransLogServerExplorer;
 class Domain;
 
-class TransLogServer : public document::Runnable, private FRT_Invokable, public WriterFactory
+class TransLogServer : private FRT_Invokable, public document::Runnable, public WriterFactory
 {
 public:
     friend class TransLogServerExplorer;
diff --git a/searchlib/src/vespa/searchlib/util/fileutil.cpp b/searchlib/src/vespa/searchlib/util/fileutil.cpp
index e85e792f492..7d65e298767 100644
--- a/searchlib/src/vespa/searchlib/util/fileutil.cpp
+++ b/searchlib/src/vespa/searchlib/util/fileutil.cpp
@@ -109,9 +109,9 @@ FileUtil::loadFile(const vespalib::string &fileName)
 void FileReaderBase::handleError(ssize_t numRead, size_t wanted)
 {
     if (numRead == 0) {
-        throw std::runtime_error(vespalib::make_string("Trying to read past EOF of file %s", _file.GetFileName()));
+        throw std::runtime_error(vespalib::make_string("Trying to read past EOF of file %s", _file->GetFileName()));
     } else {
-        throw std::runtime_error(vespalib::make_string("Partial read(%zd of %zu) of file %s", numRead, wanted, _file.GetFileName()));
+        throw std::runtime_error(vespalib::make_string("Partial read(%zd of %zu) of file %s", numRead, wanted, _file->GetFileName()));
     }
 }
 
@@ -126,7 +126,7 @@ void FileWriterBase::handleError(ssize_t numRead, size_t wanted)
 
 ssize_t
 FileReaderBase::read(void *buf, size_t sz) {
-    ssize_t numRead = _file.Read(buf, sz);
+    ssize_t numRead = _file->Read(buf, sz);
     if (numRead != ssize_t(sz)) {
         handleError(numRead, sz);
     }
diff --git a/searchlib/src/vespa/searchlib/util/fileutil.h b/searchlib/src/vespa/searchlib/util/fileutil.h
index 8271265aa33..bb74aa47484 100644
--- a/searchlib/src/vespa/searchlib/util/fileutil.h
+++ b/searchlib/src/vespa/searchlib/util/fileutil.h
@@ -73,11 +73,11 @@ public:
 class FileReaderBase
 {
 public:
-    FileReaderBase(FastOS_FileInterface & file) : _file(file) { }
+    FileReaderBase(FastOS_FileInterface * file) : _file(file) { }
     ssize_t read(void *buf, size_t sz);
 private:
     void handleError(ssize_t numRead, size_t wanted);
-    FastOS_FileInterface & _file;
+    FastOS_FileInterface * _file;
 };
 
 class FileWriterBase
@@ -95,7 +95,7 @@ template <typename T>
 class FileReader : public FileReaderBase
 {
 public:
-    FileReader(FastOS_FileInterface & file) : FileReaderBase(file) { }
+    FileReader(FastOS_FileInterface * file) : FileReaderBase(file) { }
     T readHostOrder() {
         T result;
         read(&result, sizeof(result));
diff --git a/vespalib/src/vespa/vespalib/data/databuffer.cpp b/vespalib/src/vespa/vespalib/data/databuffer.cpp
index 8640a369267..313fbe58fab 100644
--- a/vespalib/src/vespa/vespalib/data/databuffer.cpp
+++ b/vespalib/src/vespa/vespalib/data/databuffer.cpp
@@ -77,7 +77,9 @@ DataBuffer::shrink(size_t newsize)
     if (newsize != 0) {
         newbuf = static_cast<char *>(newBuf.get());
         newdata = newbuf + padbefore(_alignment, newbuf);
-        memcpy(newdata, _datapt, getDataLen());
+        if (getDataLen() > 0) {
+            memcpy(newdata, _datapt, getDataLen());
+        }
     }
     _buffer.swap(newBuf);
     _bufstart = newbuf;
@@ -101,7 +103,9 @@ DataBuffer::pack(size_t needbytes)
         Alloc newBuf(_buffer.create(bufsize));
         char *newbuf = static_cast<char *>(newBuf.get());
         char *newdata = newbuf + padbefore(_alignment, newbuf);
-        memcpy(newdata, _datapt, dataLen);
+        if (dataLen > 0) {
+            memcpy(newdata, _datapt, dataLen);
+        }
         _bufstart = newbuf;
         _datapt   = newdata;
         _freept   = newdata + dataLen;
@@ -109,7 +113,9 @@ DataBuffer::pack(size_t needbytes)
         _buffer.swap(newBuf);
     } else {
         char *datapt = _bufstart + padbefore(_alignment, _bufstart);
-        memmove(datapt, _datapt, dataLen);
+        if (dataLen > 0) {
+            memmove(datapt, _datapt, dataLen);
+        }
         _datapt = datapt;
         _freept = _datapt + dataLen;
     }
@@ -119,8 +125,12 @@ DataBuffer::pack(size_t needbytes)
 bool
 DataBuffer::equals(DataBuffer *other)
 {
-    if (getDataLen() != other->getDataLen())
+    if (getDataLen() != other->getDataLen()) {
         return false;
+    }
+    if (getDataLen() == 0) {
+        return true;
+    }
     return memcmp(getData(), other->getData(), getDataLen()) == 0;
 }
 
diff --git a/vespalib/src/vespa/vespalib/objects/nbostream.cpp b/vespalib/src/vespa/vespalib/objects/nbostream.cpp
index c4af25efcac..a369bd21c56 100644
--- a/vespalib/src/vespa/vespalib/objects/nbostream.cpp
+++ b/vespalib/src/vespa/vespalib/objects/nbostream.cpp
@@ -60,7 +60,9 @@ nbostream::nbostream(const nbostream & rhs) :
 {
     extend(rhs.size());
     _wp = rhs.size();
-    memcpy(_wbuf.data(), &rhs._rbuf[rhs._rp], _wp);
+    if (_wp > 0) {
+        memcpy(_wbuf.data(), &rhs._rbuf[rhs._rp], _wp);
+    }
 }
 
 nbostream::nbostream(nbostream && rhs) noexcept
@@ -76,7 +78,9 @@ nbostream::nbostream(nbostream && rhs) noexcept
     rhs._rbuf = ConstBufferRef();
     if (!_longLivedBuffer && (_wbuf.capacity() == 0)) {
         _wbuf.resize(roundUp2inN(_rbuf.size()));
-        memcpy(_wbuf.data(), &_rbuf[_rp], size());
+        if (size() > 0) {
+            memcpy(_wbuf.data(), &_rbuf[_rp], size());
+        }
         _wp = size();
         _rp = 0;
         _rbuf = ConstBufferRef(_wbuf.data(), _wbuf.capacity());
@@ -120,7 +124,9 @@ void nbostream::reserve(size_t sz)
 
 void nbostream::compact()
 {
-    memmove(_wbuf.data(), &_rbuf[_rp], left());
+    if (left() > 0) {
+        memmove(_wbuf.data(), &_rbuf[_rp], left());
+    }
     _wp = left();
     _rp = 0;
 }
diff --git a/vespalib/src/vespa/vespalib/objects/nbostream.h b/vespalib/src/vespa/vespalib/objects/nbostream.h
index e7bed8d59ff..12d4fac04cc 100644
--- a/vespalib/src/vespa/vespalib/objects/nbostream.h
+++ b/vespalib/src/vespa/vespalib/objects/nbostream.h
@@ -159,7 +159,9 @@ public:
         if (__builtin_expect(space() < sz, false)) {
             extend(sz);
         }
-        memcpy(&_wbuf[_wp], v, sz);
+        if (sz > 0) {
+            memcpy(&_wbuf[_wp], v, sz);
+        }
         _wp += sz;
     }
     void read(void *v, size_t sz) {