Refactoring: replace Doxygen::groupSDict by Doxygen::groupLinkedMap

25 files changed, 226 insertions, 403 deletions

diff --git a/src/classdef.cpp b/src/classdef.cpp
index 4492f3e..c573d27 100644
--- a/src/classdef.cpp
+++ b/src/classdef.cpp
@@ -3903,15 +3903,15 @@ QCString ClassDefImpl::getOutputFileBase() const
   if (!Doxygen::generatingXmlOutput)
   {
     Definition *scope=0;
-    if (inlineGroupedClasses && partOfGroups()!=0)
+    if (inlineGroupedClasses && !partOfGroups().empty())
     {
       // point to the group that embeds this class
-      return partOfGroups()->at(0)->getOutputFileBase();
+      return partOfGroups().front()->getOutputFileBase();
     }
-    else if (inlineSimpleClasses && m_impl->isSimple && partOfGroups()!=0)
+    else if (inlineSimpleClasses && m_impl->isSimple && !partOfGroups().empty())
     {
       // point to simple struct inside a group
-      return partOfGroups()->at(0)->getOutputFileBase();
+      return partOfGroups().front()->getOutputFileBase();
     }
     else if (inlineSimpleClasses && m_impl->isSimple && (scope=getOuterScope()))
     {
@@ -4940,11 +4940,11 @@ bool ClassDefImpl::isEmbeddedInOuterScope() const
        );
 
   // inline because of INLINE_GROUPED_CLASSES=YES ?
-  bool b1 = (inlineGroupedClasses && partOfGroups()!=0); // a grouped class
+  bool b1 = (inlineGroupedClasses && !partOfGroups().empty()); // a grouped class
   // inline because of INLINE_SIMPLE_STRUCTS=YES ?
   bool b2 = (inlineSimpleClasses && m_impl->isSimple && // a simple class
              (containerLinkable || // in a documented container
-              partOfGroups()!=0    // or part of a group
+              !partOfGroups().empty()    // or part of a group
              )
            );
   //printf("%s::isEmbeddedInOuterScope(): inlineGroupedClasses=%d "
diff --git a/src/classlist.cpp b/src/classlist.cpp
index 2998ac4..5351cde 100644
--- a/src/classlist.cpp
+++ b/src/classlist.cpp
@@ -116,15 +116,15 @@ void ClassLinkedRefMap::writeDocumentation(OutputList &ol,const Definition * con
 
   for (const auto &cd : *this)
   {
-    //printf("%s:writeDocumentation() %p linkable=%d embedded=%d container=%p partOfGroups=%d\n",
+    //printf("%s:writeDocumentation() %p linkable=%d embedded=%d container=%p partOfGroups=%zu\n",
     //  cd->name().data(),cd->getOuterScope(),cd->isLinkableInProject(),cd->isEmbeddedInOuterScope(),
-    //  container,cd->partOfGroups() ? cd->partOfGroups()->count() : 0);
+    //  container,cd->partOfGroups()->size());
 
     if (!cd->isAnonymous() &&
         cd->isLinkableInProject() &&
         cd->isEmbeddedInOuterScope() &&
         !cd->isAlias() &&
-        (container==0 || cd->partOfGroups()==0) // if container==0 -> show as part of the group docs, otherwise only show if not part of a group
+        (container==0 || cd->partOfGroups().empty()) // if container==0 -> show as part of the group docs, otherwise only show if not part of a group
        )
     {
       //printf("  showing class %s\n",cd->name().data());
diff --git a/src/context.cpp b/src/context.cpp
index 8e28077..f597200 100644
--- a/src/context.cpp
+++ b/src/context.cpp
@@ -2339,7 +2339,7 @@ class ClassContext::Private : public DefinitionContext<ClassContext::Private>
           if (!cd->isAnonymous() &&
               cd->isLinkableInProject() &&
               cd->isEmbeddedInOuterScope() &&
-              cd->partOfGroups()==0
+              cd->partOfGroups().empty()
              )
           {
             classList->append(ClassContext::alloc(cd));
@@ -2900,7 +2900,7 @@ class NamespaceContext::Private : public DefinitionContext<NamespaceContext::Pri
           if (!cd->isAnonymous() &&
               cd->isLinkableInProject() &&
               cd->isEmbeddedInOuterScope() &&
-              cd->partOfGroups()==0)
+              cd->partOfGroups().empty())
           {
             classList->append(ClassContext::alloc(cd));
           }
@@ -3344,7 +3344,7 @@ class FileContext::Private : public DefinitionContext<FileContext::Private>
           if (!cd->isAnonymous() &&
               cd->isLinkableInProject() &&
               cd->isEmbeddedInOuterScope() &&
-              cd->partOfGroups()==0)
+              cd->partOfGroups().empty())
           {
             classList->append(ClassContext::alloc(cd));
           }
@@ -5366,16 +5366,11 @@ class ModuleContext::Private : public DefinitionContext<ModuleContext::Private>
       if (!cache.modules)
       {
         TemplateList *moduleList = TemplateList::alloc();
-        if (m_groupDef->getSubGroups())
+        for (const auto &gd : m_groupDef->getSubGroups())
         {
-          GroupListIterator gli(*m_groupDef->getSubGroups());
-          const GroupDef *gd;
-          for (gli.toFirst();(gd=gli.current());++gli)
+          if (gd->isVisible())
           {
-            if (gd->isVisible())
-            {
-              moduleList->append(ModuleContext::alloc(gd));
-            }
+            moduleList->append(ModuleContext::alloc(gd));
           }
         }
         cache.modules.reset(moduleList);
@@ -5655,7 +5650,7 @@ class ModuleContext::Private : public DefinitionContext<ModuleContext::Private>
           if (!cd->isAnonymous() &&
               cd->isLinkableInProject() &&
               cd->isEmbeddedInOuterScope() &&
-              cd->partOfGroups()==0)
+              cd->partOfGroups().empty())
           {
             classList->append(ClassContext::alloc(cd));
           }
@@ -6395,9 +6390,9 @@ class NestingNodeContext::Private
     void addModules(ClassDefSet &visitedClasses)
     {
       const GroupDef *gd = toGroupDef(m_def);
-      if (gd && gd->getSubGroups())
+      if (gd && !gd->getSubGroups().empty())
       {
-        m_children->addModules(*gd->getSubGroups(),visitedClasses);
+        m_children->addModules(gd->getSubGroups(),visitedClasses);
       }
     }
   private:
@@ -6591,27 +6586,23 @@ class NestingContext::Private : public GenericNodeListContext
         addPage(pd,rootOnly,visitedClasses);
       }
     }
-    void addModules(const GroupSDict &groups,ClassDefSet &visitedClasses)
+    void addModules(const GroupLinkedMap &groups,ClassDefSet &visitedClasses)
     {
-      GroupSDict::Iterator gli(groups);
-      const GroupDef *gd;
-      for (gli.toFirst();(gd=gli.current());++gli)
+      for (const auto &gd : groups)
       {
-        static bool externalGroups = Config_getBool(EXTERNAL_GROUPS);
+        bool externalGroups = Config_getBool(EXTERNAL_GROUPS);
         if (!gd->isASubGroup() && gd->isVisible() &&
-             (!gd->isReference() || externalGroups)
+            (!gd->isReference() || externalGroups)
            )
         {
-          append(NestingNodeContext::alloc(m_parent,gd,m_index,m_level,FALSE,FALSE,FALSE,visitedClasses));
+          append(NestingNodeContext::alloc(m_parent,gd.get(),m_index,m_level,FALSE,FALSE,FALSE,visitedClasses));
           m_index++;
         }
       }
     }
-    void addModules(const GroupList &list,ClassDefSet &visitedClasses)
+    void addModules(const GroupList &groups,ClassDefSet &visitedClasses)
     {
-      GroupListIterator gli(list);
-      const GroupDef *gd;
-      for (gli.toFirst();(gd=gli.current());++gli)
+      for (const auto &gd : groups)
       {
         if (gd->isVisible())
         {
@@ -6760,7 +6751,7 @@ void NestingContext::addPages(const PageLinkedRefMap &pages,bool rootOnly,ClassD
   p->addPages(pages,rootOnly,visitedClasses);
 }
 
-void NestingContext::addModules(const GroupSDict &modules,ClassDefSet &visitedClasses)
+void NestingContext::addModules(const GroupLinkedMap &modules,ClassDefSet &visitedClasses)
 {
   p->addModules(modules,visitedClasses);
 }
@@ -7533,13 +7524,11 @@ class ModuleListContext::Private : public GenericNodeListContext
   public:
     void addModules()
     {
-      GroupSDict::Iterator gli(*Doxygen::groupSDict);
-      const GroupDef *gd;
-      for (gli.toFirst();(gd=gli.current());++gli)
+      for (const auto &gd : *Doxygen::groupLinkedMap)
       {
         if (!gd->isReference())
         {
-          append(ModuleContext::alloc(gd));
+          append(ModuleContext::alloc(gd.get()));
         }
       }
     }
@@ -7584,10 +7573,7 @@ class ModuleTreeContext::Private
       m_moduleTree.reset(NestingContext::alloc(0,0));
       ClassDefSet visitedClasses;
       // Add modules
-      if (Doxygen::groupSDict)
-      {
-        m_moduleTree->addModules(*Doxygen::groupSDict,visitedClasses);
-      }
+      m_moduleTree->addModules(*Doxygen::groupLinkedMap,visitedClasses);
 
       //%% ModuleList tree:
       static bool init=FALSE;
diff --git a/src/context.h b/src/context.h
index 885b811..4baa164 100644
--- a/src/context.h
+++ b/src/context.h
@@ -26,29 +26,33 @@
 #include "membergroup.h"
 
 class Definition;
+
 class PageDef;
 class PageLinkedMap;
 class PageLinkedRefMap;
+
 class GroupDef;
+class GroupLinkedMap;
+class GroupList;
+
 class NamespaceDef;
 class NamespaceLinkedMap;
 class NamespaceLinkedRefMap;
-class FileDef;
-class FileList;
+
 class FileNameLinkedMap;
 class ClassLinkedMap;
+class MemberNameInfoLinkedMap;
+
+class FileDef;
+class FileList;
 class DirSDict;
 class DirDef;
-class GroupSDict;
-class GroupDef;
-class GroupList;
 struct IncludeInfo;
 class MemberList;
 class MemberSDict;
 class MemberDef;
 struct Argument;
 class ArgumentList;
-class MemberNameInfoLinkedMap;
 class MemberInfo;
 class DotNode;
 class DotGfxHierarchyTable;
@@ -552,7 +556,7 @@ class NestingContext : public RefCountedContext, public TemplateListIntf
     void addFiles(const FileList &,ClassDefSet &visitedClasses);
     void addPages(const PageLinkedMap &pages,bool rootOnly,ClassDefSet &visitedClasses);
     void addPages(const PageLinkedRefMap &pages,bool rootOnly,ClassDefSet &visitedClasses);
-    void addModules(const GroupSDict &modules,ClassDefSet &visitedClasses);
+    void addModules(const GroupLinkedMap &modules,ClassDefSet &visitedClasses);
     void addModules(const GroupList &modules,ClassDefSet &visitedClasses);
     void addClassHierarchy(const ClassLinkedMap &clLinkedMap,ClassDefSet &visitedClasses);
     void addDerivedClasses(const BaseClassList &bcl,bool hideSuper,ClassDefSet &visitedClasses);
@@ -759,7 +763,7 @@ class ModuleListContext : public RefCountedContext, public TemplateListIntf
     virtual int addRef()  { return RefCountedContext::addRef(); }
     virtual int release() { return RefCountedContext::release(); }
 
-    void addModules(const GroupSDict &);
+    void addModules(const GroupLinkedMap &);
     void addModules(const GroupList &);
 
   private:
diff --git a/src/definition.cpp b/src/definition.cpp
index b719388..fa3d521 100644
--- a/src/definition.cpp
+++ b/src/definition.cpp
@@ -68,7 +68,7 @@ class DefinitionImpl::IMPL
     std::unordered_map<std::string,const MemberDef *> sourceRefByDict;
     std::unordered_map<std::string,const MemberDef *> sourceRefsDict;
     RefItemVector xrefListItems;
-    GroupList *partOfGroups = 0;
+    GroupList partOfGroups;
 
     DocInfo   *details = 0;    // not exported
     DocInfo   *inbodyDocs = 0; // not exported
@@ -107,7 +107,6 @@ class DefinitionImpl::IMPL
 
 DefinitionImpl::IMPL::~IMPL()
 {
-  delete partOfGroups;
   delete brief;
   delete details;
   delete body;
@@ -146,7 +145,6 @@ void DefinitionImpl::IMPL::init(const char *df, const char *n)
   sourceRefByDict.clear();
   sourceRefsDict.clear();
   outerScope      = Doxygen::globalScope;
-  partOfGroups    = 0;
   hidden          = FALSE;
   isArtificial    = FALSE;
   lang            = SrcLangExt_Unknown;
@@ -263,20 +261,10 @@ DefinitionImpl::DefinitionImpl(const DefinitionImpl &d)
 {
   m_impl = new DefinitionImpl::IMPL;
   *m_impl = *d.m_impl;
-  m_impl->partOfGroups = 0;
   m_impl->brief = 0;
   m_impl->details = 0;
   m_impl->body = 0;
   m_impl->inbodyDocs = 0;
-  if (d.m_impl->partOfGroups)
-  {
-    GroupListIterator it(*d.m_impl->partOfGroups);
-    GroupDef *gd;
-    for (it.toFirst();(gd=it.current());++it)
-    {
-      makePartOfGroup(gd);
-    }
-  }
   if (d.m_impl->brief)
   {
     m_impl->brief = new BriefInfo(*d.m_impl->brief);
@@ -1506,10 +1494,9 @@ QCString DefinitionImpl::localName() const
   return m_impl->localName;
 }
 
-void DefinitionImpl::makePartOfGroup(GroupDef *gd)
+void DefinitionImpl::makePartOfGroup(const GroupDef *gd)
 {
-  if (m_impl->partOfGroups==0) m_impl->partOfGroups = new GroupList;
-  m_impl->partOfGroups->append(gd);
+  m_impl->partOfGroups.push_back(gd);
 }
 
 void DefinitionImpl::setRefItems(const RefItemVector &sli)
@@ -2000,24 +1987,18 @@ FileDef *DefinitionImpl::getBodyDef() const
   return m_impl->body ? m_impl->body->fileDef : 0;
 }
 
-GroupList *DefinitionImpl::partOfGroups() const
+const GroupList &DefinitionImpl::partOfGroups() const
 {
   return m_impl->partOfGroups;
 }
 
 bool DefinitionImpl::isLinkableViaGroup() const
 {
-  GroupList *gl = partOfGroups();
-  if (gl)
+  for (const auto &gd : partOfGroups())
   {
-    GroupListIterator gli(*gl);
-    GroupDef *gd;
-    for (gli.toFirst();(gd=gli.current());++gli)
-    {
-      if (gd->isLinkable()) return TRUE;
-    }
+    if (gd->isLinkable()) return true;
   }
-  return FALSE;
+  return false;
 }
 
 Definition *DefinitionImpl::getOuterScope() const
diff --git a/src/definition.h b/src/definition.h
index 204e6f6..eb4c42a 100644
--- a/src/definition.h
+++ b/src/definition.h
@@ -261,7 +261,7 @@ class Definition
     /** Returns the programming language this definition was written in. */
     virtual SrcLangExt getLanguage() const = 0;
 
-    virtual GroupList *partOfGroups() const = 0;
+    virtual const GroupList &partOfGroups() const = 0;
     virtual bool isLinkableViaGroup() const = 0;
 
     virtual const RefItemVector &xrefListItems() const = 0;
@@ -361,7 +361,7 @@ class DefinitionMutable
     // --- actions ----
     //-----------------------------------------------------------------------------------
 
-    virtual void makePartOfGroup(GroupDef *gd) = 0;
+    virtual void makePartOfGroup(const GroupDef *gd) = 0;
 
     /*! Add the list of anchors that mark the sections that are found in the
      * documentation.
diff --git a/src/definitionimpl.h b/src/definitionimpl.h
index e455dc4..541e346 100644
--- a/src/definitionimpl.h
+++ b/src/definitionimpl.h
@@ -68,7 +68,7 @@ class DefinitionImpl
     int getEndBodyLine() const;
     FileDef *getBodyDef() const;
     SrcLangExt getLanguage() const;
-    GroupList *partOfGroups() const;
+    const GroupList &partOfGroups() const;
     bool isLinkableViaGroup() const;
     const RefItemVector &xrefListItems() const;
     const Definition *findInnerCompound(const char *name) const;
@@ -105,7 +105,7 @@ class DefinitionImpl
     void writeInlineCode(OutputList &ol,const char *scopeName) const;
     void writeSourceRefs(OutputList &ol,const char *scopeName) const;
     void writeSourceReffedBy(OutputList &ol,const char *scopeName) const;
-    void makePartOfGroup(GroupDef *gd);
+    void makePartOfGroup(const GroupDef *gd);
     void writeNavigationPath(OutputList &ol) const;
     QCString navigationPathAsString() const;
     void writeQuickMemberLinks(OutputList &,const MemberDef *) const;
@@ -187,7 +187,7 @@ class DefinitionMixin : public Base
     virtual int getEndBodyLine() const { return m_impl.getEndBodyLine(); }
     virtual FileDef *getBodyDef() const { return m_impl.getBodyDef(); }
     virtual SrcLangExt getLanguage() const { return m_impl.getLanguage(); }
-    virtual GroupList *partOfGroups() const { return m_impl.partOfGroups(); }
+    virtual const GroupList &partOfGroups() const { return m_impl.partOfGroups(); }
     virtual bool isLinkableViaGroup() const { return m_impl.isLinkableViaGroup(); }
     virtual const RefItemVector &xrefListItems() const { return m_impl.xrefListItems(); }
     virtual const Definition *findInnerCompound(const char *name) const { return m_impl.findInnerCompound(name); }
@@ -249,7 +249,7 @@ class DefinitionMixin : public Base
     { m_impl.writeSourceRefs(ol,scopeName); }
     virtual void writeSourceReffedBy(OutputList &ol,const char *scopeName) const
     { m_impl.writeSourceReffedBy(ol,scopeName); }
-    virtual void makePartOfGroup(GroupDef *gd)
+    virtual void makePartOfGroup(const GroupDef *gd)
     { m_impl.makePartOfGroup(gd); }
     virtual void writeNavigationPath(OutputList &ol) const
     { m_impl.writeNavigationPath(ol); }
@@ -393,7 +393,7 @@ class DefinitionAliasMixin : public Base
     { return m_alias->getBodyDef(); }
     virtual SrcLangExt getLanguage() const
     { return m_alias->getLanguage(); }
-    virtual GroupList *partOfGroups() const
+    virtual const GroupList &partOfGroups() const
     { return m_alias->partOfGroups(); }
     virtual bool isLinkableViaGroup() const
     { return m_alias->isLinkableViaGroup(); }
diff --git a/src/docbookgen.cpp b/src/docbookgen.cpp
index f0749be..f810d7b 100644
--- a/src/docbookgen.cpp
+++ b/src/docbookgen.cpp
@@ -484,18 +484,7 @@ DB_GEN_C2("IndexSections " << is)
     case isModuleDocumentation:
       {
         t << "</title>" << endl;
-        GroupSDict::Iterator gli(*Doxygen::groupSDict);
-        GroupDef *gd;
-        bool found=FALSE;
-        for (gli.toFirst();(gd=gli.current()) && !found;++gli)
-        {
-          if (!gd->isReference())
-          {
-            t << "    <xi:include href=\"" << gd->getOutputFileBase() << ".xml\" xmlns:xi=\"http://www.w3.org/2001/XInclude\"/>" << endl;
-            found=TRUE;
-          }
-        }
-        for (;(gd=gli.current());++gli)
+        for (const auto &gd : *Doxygen::groupLinkedMap)
         {
           if (!gd->isReference())
           {
diff --git a/src/docparser.cpp b/src/docparser.cpp
index 61326b4..33faf54 100644
--- a/src/docparser.cpp
+++ b/src/docparser.cpp
@@ -685,7 +685,7 @@ static bool findDocsForMemberOrCompound(const char *commandName,
   const FileDef      *fd=0;
   const GroupDef     *gd=0;
   const PageDef      *pd=0;
-  gd = Doxygen::groupSDict->find(cmdArg);
+  gd = Doxygen::groupLinkedMap->find(cmdArg);
   if (gd) // group
   {
     *pDoc=gd->documentation();
diff --git a/src/dotgroupcollaboration.cpp b/src/dotgroupcollaboration.cpp
index 33ac397..1b632ce 100644
--- a/src/dotgroupcollaboration.cpp
+++ b/src/dotgroupcollaboration.cpp
@@ -60,46 +60,35 @@ void DotGroupCollaboration::buildGraph(const GroupDef* gd)
   // hierarchy.
 
   // Write parents
-  const GroupList *groups = gd->partOfGroups();
-  if ( groups )
+  for (const auto &d : gd->partOfGroups())
   {
-    GroupListIterator gli(*groups);
-    const GroupDef *d;
-    for (gli.toFirst();(d=gli.current());++gli)
-    {
-      DotNode* nnode = m_usedNodes->find(d->name());
-      if ( !nnode )
-      { // add node
-        tmp_url = d->getReference()+"$"+d->getOutputFileBase();
-        QCString tooltip = d->briefDescriptionAsTooltip();
-        nnode = new DotNode(getNextNodeNumber(), d->groupTitle(), tooltip, tmp_url );
-        nnode->markAsVisible();
-        m_usedNodes->insert(d->name(), nnode );
-      }
-      tmp_url = "";
-      addEdge( nnode, m_rootNode, DotGroupCollaboration::thierarchy, tmp_url, tmp_url );
+    DotNode* nnode = m_usedNodes->find(d->name());
+    if ( !nnode )
+    { // add node
+      tmp_url = d->getReference()+"$"+d->getOutputFileBase();
+      QCString tooltip = d->briefDescriptionAsTooltip();
+      nnode = new DotNode(getNextNodeNumber(), d->groupTitle(), tooltip, tmp_url );
+      nnode->markAsVisible();
+      m_usedNodes->insert(d->name(), nnode );
     }
+    tmp_url = "";
+    addEdge( nnode, m_rootNode, DotGroupCollaboration::thierarchy, tmp_url, tmp_url );
   }
 
   // Add subgroups
-  if ( gd->getSubGroups() && gd->getSubGroups()->count() )
+  for (const auto &def : gd->getSubGroups())
   {
-    QListIterator<GroupDef> defli(*gd->getSubGroups());
-    const GroupDef *def;
-    for (;(def=defli.current());++defli)
-    {
-      DotNode* nnode = m_usedNodes->find(def->name());
-      if ( !nnode )
-      { // add node
-        tmp_url = def->getReference()+"$"+def->getOutputFileBase();
-        QCString tooltip = def->briefDescriptionAsTooltip();
-        nnode = new DotNode(getNextNodeNumber(), def->groupTitle(), tooltip, tmp_url );
-        nnode->markAsVisible();
-        m_usedNodes->insert(def->name(), nnode );
-      }
-      tmp_url = "";
-      addEdge( m_rootNode, nnode, DotGroupCollaboration::thierarchy, tmp_url, tmp_url );
+    DotNode* nnode = m_usedNodes->find(def->name());
+    if ( !nnode )
+    { // add node
+      tmp_url = def->getReference()+"$"+def->getOutputFileBase();
+      QCString tooltip = def->briefDescriptionAsTooltip();
+      nnode = new DotNode(getNextNodeNumber(), def->groupTitle(), tooltip, tmp_url );
+      nnode->markAsVisible();
+      m_usedNodes->insert(def->name(), nnode );
     }
+    tmp_url = "";
+    addEdge( m_rootNode, nnode, DotGroupCollaboration::thierarchy, tmp_url, tmp_url );
   }
 
   //=======================
@@ -204,12 +193,8 @@ void DotGroupCollaboration::addCollaborationMember(
   const Definition* def, QCString& url, EdgeType eType )
 {
   // Create group nodes
-  if ( !def->partOfGroups() )
-    return;
-  GroupListIterator gli(*def->partOfGroups());
-  GroupDef *d;
   QCString tmp_str;
-  for (;(d=gli.current());++gli)
+  for (const auto &d : def->partOfGroups())
   {
     DotNode* nnode = m_usedNodes->find(d->name());
     if ( nnode != m_rootNode )
diff --git a/src/doxygen.cpp b/src/doxygen.cpp
index b438cfa..3a4c5a3 100644
--- a/src/doxygen.cpp
+++ b/src/doxygen.cpp
@@ -123,7 +123,7 @@ NamespaceLinkedMap   *Doxygen::namespaceLinkedMap = 0;
 MemberNameLinkedMap  *Doxygen::memberNameLinkedMap = 0;
 MemberNameLinkedMap  *Doxygen::functionNameLinkedMap = 0;
 FileNameLinkedMap    *Doxygen::inputNameLinkedMap = 0;
-GroupSDict           *Doxygen::groupSDict = 0;
+GroupLinkedMap       *Doxygen::groupLinkedMap = 0;
 PageLinkedMap        *Doxygen::pageLinkedMap = 0;
 PageLinkedMap        *Doxygen::exampleLinkedMap = 0;
 StringDict            Doxygen::aliasDict(257);          // aliases
@@ -334,7 +334,7 @@ static void addRelatedPage(Entry *root)
   GroupDef *gd=0;
   for (const Grouping &g : root->groups)
   {
-    if (!g.groupname.isEmpty() && (gd=Doxygen::groupSDict->find(g.groupname))) break;
+    if (!g.groupname.isEmpty() && (gd=Doxygen::groupLinkedMap->find(g.groupname))) break;
   }
   //printf("---> addRelatedPage() %s gd=%p\n",root->name.data(),gd);
   QCString doc;
@@ -375,7 +375,7 @@ static void buildGroupListFiltered(const Entry *root,bool additional, bool inclu
     if ((root->groupDocType==Entry::GROUPDOC_NORMAL && !additional) ||
         (root->groupDocType!=Entry::GROUPDOC_NORMAL &&  additional))
     {
-      GroupDef *gd = Doxygen::groupSDict->find(root->name);
+      GroupDef *gd = Doxygen::groupLinkedMap->find(root->name);
       //printf("Processing group '%s':'%s' add=%d ext=%d gd=%p\n",
       //    root->type.data(),root->name.data(),additional,includeExternal,gd);
 
@@ -402,19 +402,22 @@ static void buildGroupListFiltered(const Entry *root,bool additional, bool inclu
       {
         if (root->tagInfo())
         {
-          gd = createGroupDef(root->fileName,root->startLine,root->name,root->type,root->tagInfo()->fileName);
+          gd = Doxygen::groupLinkedMap->add(root->name,
+               std::unique_ptr<GroupDef>(
+                  createGroupDef(root->fileName,root->startLine,root->name,root->type,root->tagInfo()->fileName)));
           gd->setReference(root->tagInfo()->tagName);
         }
         else
         {
-          gd = createGroupDef(root->fileName,root->startLine,root->name,root->type);
+          gd = Doxygen::groupLinkedMap->add(root->name,
+               std::unique_ptr<GroupDef>(
+                  createGroupDef(root->fileName,root->startLine,root->name,root->type)));
         }
         gd->setBriefDescription(root->brief,root->briefFile,root->briefLine);
         // allow empty docs for group
         gd->setDocumentation(!root->doc.isEmpty() ? root->doc : QCString(" "),root->docFile,root->docLine,FALSE);
         gd->setInbodyDocumentation( root->inbodyDocs, root->inbodyFile, root->inbodyLine );
         gd->addSectionsToDefinition(root->anchors);
-        Doxygen::groupSDict->append(root->name,gd);
         gd->setRefItems(root->sli);
         gd->setLanguage(root->lang);
       }
@@ -444,7 +447,7 @@ static void findGroupScope(const Entry *root)
       root->parent() && !root->parent()->name.isEmpty())
   {
     GroupDef *gd;
-    if ((gd=Doxygen::groupSDict->find(root->name)))
+    if ((gd=Doxygen::groupLinkedMap->find(root->name)))
     {
       QCString scope = root->parent()->name;
       if (root->parent()->section==Entry::PACKAGEDOC_SEC)
@@ -471,7 +474,7 @@ static void organizeSubGroupsFiltered(const Entry *root,bool additional)
         (root->groupDocType!=Entry::GROUPDOC_NORMAL && additional))
     {
       GroupDef *gd;
-      if ((gd=Doxygen::groupSDict->find(root->name)))
+      if ((gd=Doxygen::groupLinkedMap->find(root->name)))
       {
         //printf("adding %s to group %s\n",root->name.data(),gd->name().data());
         addGroupToGroups(root,gd);
@@ -526,7 +529,7 @@ static void buildFileList(const Entry *root)
       for (const Grouping &g : root->groups)
       {
         GroupDef *gd=0;
-        if (!g.groupname.isEmpty() && (gd=Doxygen::groupSDict->find(g.groupname)))
+        if (!g.groupname.isEmpty() && (gd=Doxygen::groupLinkedMap->find(g.groupname)))
         {
           gd->addFile(fd);
           fd->makePartOfGroup(gd);
@@ -1301,19 +1304,19 @@ void distributeClassGroupRelations()
   {
     //printf("Checking %s\n",cd->name().data());
     // distribute the group to nested classes as well
-    if (visitedClasses.find(cd.get())==visitedClasses.end() && cd->partOfGroups()!=0)
+    if (visitedClasses.find(cd.get())==visitedClasses.end() && !cd->partOfGroups().empty())
     {
       //printf("  Candidate for merging\n");
-      GroupDef *gd = cd->partOfGroups()->at(0);
+      const GroupDef *gd = cd->partOfGroups().front();
       for (const auto &ncd : cd->getClasses())
       {
         ClassDefMutable *ncdm = toClassDefMutable(ncd);
-        if (ncdm && ncdm->partOfGroups()==0)
+        if (ncdm && ncdm->partOfGroups().empty())
         {
           //printf("  Adding %s to group '%s'\n",ncd->name().data(),
           //    gd->groupTitle());
           ncdm->makePartOfGroup(gd);
-          gd->addClass(ncdm);
+          const_cast<GroupDef*>(gd)->addClass(ncdm);
         }
       }
       visitedClasses.insert(cd.get()); // only visit every class once
@@ -1362,16 +1365,10 @@ static ClassDefMutable *createTagLessInstance(const ClassDef *rootCd,const Class
       cd->setFileDef(fd);
       fd->insertClass(cd);
     }
-    GroupList *groups = rootCd->partOfGroups();
-    if ( groups!=0 )
+    for (const auto &gd : rootCd->partOfGroups())
     {
-      GroupListIterator gli(*groups);
-      GroupDef *gd;
-      for (gli.toFirst();(gd=gli.current());++gli)
-      {
-        cd->makePartOfGroup(gd);
-        gd->addClass(cd);
-      }
+      cd->makePartOfGroup(gd);
+      const_cast<GroupDef*>(gd)->addClass(cd);
     }
 
     MemberList *ml = templ->getMemberList(MemberListType_pubAttribs);
@@ -1813,7 +1810,7 @@ static void findUsingDirectives(const Entry *root)
           for (const Grouping &g : root->groups)
           {
             GroupDef *gd=0;
-            if (!g.groupname.isEmpty() && (gd=Doxygen::groupSDict->find(g.groupname)))
+            if (!g.groupname.isEmpty() && (gd=Doxygen::groupLinkedMap->find(g.groupname)))
               gd->addNamespace(nd);
           }
 
@@ -3504,7 +3501,7 @@ static void buildFunctionList(const Entry *root)
                 GroupDef *gd=0;
                 if (!root->groups.empty() && !root->groups.front().groupname.isEmpty())
                 {
-                  gd = Doxygen::groupSDict->find(root->groups.front().groupname);
+                  gd = Doxygen::groupLinkedMap->find(root->groups.front().groupname);
                 }
                 //printf("match!\n");
                 //printf("mnd=%p rnd=%p nsName=%s rnsName=%s\n",mnd,rnd,nsName.data(),rnsName.data());
@@ -4904,9 +4901,7 @@ static void computeMemberReferences()
       ndm->computeAnchors();
     }
   }
-  GroupSDict::Iterator gli(*Doxygen::groupSDict);
-  GroupDef *gd;
-  for (gli.toFirst();(gd=gli.current());++gli)
+  for (const auto &gd : *Doxygen::groupLinkedMap)
   {
     gd->computeAnchors();
   }
@@ -4942,9 +4937,7 @@ static void addListReferences()
     }
   }
 
-  GroupSDict::Iterator gli(*Doxygen::groupSDict);
-  GroupDef *gd;
-  for (gli.toFirst();(gd=gli.current());++gli)
+  for (const auto &gd : *Doxygen::groupLinkedMap)
   {
     gd->addListReferences();
   }
@@ -8038,9 +8031,7 @@ static void sortMemberLists()
   }
 
   // sort group member lists
-  GroupSDict::Iterator gli(*Doxygen::groupSDict);
-  GroupDef *gd;
-  for (gli.toFirst();(gd=gli.current());++gli)
+  for (const auto &gd : *Doxygen::groupLinkedMap)
   {
     gd->sortMemberLists();
   }
@@ -8111,9 +8102,7 @@ static void countMembers()
     }
   }
 
-  GroupSDict::Iterator gli(*Doxygen::groupSDict);
-  GroupDef *gd;
-  for (gli.toFirst();(gd=gli.current());++gli)
+  for (const auto &gd : *Doxygen::groupLinkedMap)
   {
     gd->countMembers();
   }
@@ -8248,9 +8237,7 @@ static void addMembersToMemberGroup()
     }
   }
   // for each group
-  GroupSDict::Iterator gli(*Doxygen::groupSDict);
-  GroupDef *gd;
-  for (gli.toFirst();(gd=gli.current());++gli)
+  for (const auto &gd : *Doxygen::groupLinkedMap)
   {
     gd->addMembersToMemberGroup();
   }
@@ -8287,9 +8274,7 @@ static void distributeMemberGroupDocumentation()
     }
   }
   // for each group
-  GroupSDict::Iterator gli(*Doxygen::groupSDict);
-  GroupDef *gd;
-  for (gli.toFirst();(gd=gli.current());++gli)
+  for (const auto &gd : *Doxygen::groupLinkedMap)
   {
     gd->distributeMemberGroupDocumentation();
   }
@@ -8326,9 +8311,7 @@ static void findSectionsInDocumentation()
     }
   }
   // for each group
-  GroupSDict::Iterator gli(*Doxygen::groupSDict);
-  GroupDef *gd;
-  for (gli.toFirst();(gd=gli.current());++gli)
+  for (const auto &gd : *Doxygen::groupLinkedMap)
   {
     gd->findSectionsInDocumentation();
   }
@@ -8966,9 +8949,7 @@ static void generateExampleDocs()
 
 static void generateGroupDocs()
 {
-  GroupSDict::Iterator gli(*Doxygen::groupSDict);
-  GroupDef *gd;
-  for (gli.toFirst();(gd=gli.current());++gli)
+  for (const auto &gd : *Doxygen::groupLinkedMap)
   {
     if (!gd->isReference())
     {
@@ -10170,8 +10151,7 @@ void initDoxygen()
 #endif
   Doxygen::memberNameLinkedMap = new MemberNameLinkedMap;
   Doxygen::functionNameLinkedMap = new MemberNameLinkedMap;
-  Doxygen::groupSDict = new GroupSDict(17);
-  Doxygen::groupSDict->setAutoDelete(TRUE);
+  Doxygen::groupLinkedMap = new GroupLinkedMap;
   Doxygen::namespaceLinkedMap = new NamespaceLinkedMap;
   Doxygen::classLinkedMap = new ClassLinkedMap;
   Doxygen::hiddenClassLinkedMap = new ClassLinkedMap;
@@ -10231,7 +10211,7 @@ void cleanUpDoxygen()
 
   delete Doxygen::memberNameLinkedMap;
   delete Doxygen::functionNameLinkedMap;
-  delete Doxygen::groupSDict;
+  delete Doxygen::groupLinkedMap;
   delete Doxygen::namespaceLinkedMap;
   delete Doxygen::directories;
 
@@ -10793,9 +10773,7 @@ static void writeTagFile()
     }
   }
   // for each group
-  GroupSDict::Iterator gli(*Doxygen::groupSDict);
-  GroupDef *gd;
-  for (gli.toFirst();(gd=gli.current());++gli)
+  for (const auto &gd : *Doxygen::groupLinkedMap)
   {
     if (gd->isLinkableInProject()) gd->writeTagFile(tagFile);
   }
@@ -11642,10 +11620,12 @@ void parseInput()
 
   if (Config_getBool(SORT_GROUP_NAMES))
   {
-    Doxygen::groupSDict->sort();
-    GroupSDict::Iterator gli(*Doxygen::groupSDict);
-    GroupDef *gd;
-    for (gli.toFirst();(gd=gli.current());++gli)
+    std::sort(Doxygen::groupLinkedMap->begin(),
+              Doxygen::groupLinkedMap->end(),
+              [](const auto &g1,const auto &g2)
+              { return qstrcmp(g1->groupTitle(),g2->groupTitle())<0; });
+
+    for (const auto &gd : *Doxygen::groupLinkedMap)
     {
       gd->sortSubGroups();
     }
diff --git a/src/doxygen.h b/src/doxygen.h
index 7fd5180..dc1b7bb 100644
--- a/src/doxygen.h
+++ b/src/doxygen.h
@@ -45,7 +45,7 @@ class BufStr;
 class CiteDict;
 class MemberDef;
 class GroupDef;
-class GroupSDict;
+class GroupLinkedMap;
 class FileDef;
 class ClassDef;
 class ClassLinkedMap;
@@ -113,7 +113,7 @@ class Doxygen
     static MemberNameLinkedMap      *memberNameLinkedMap;
     static MemberNameLinkedMap      *functionNameLinkedMap;
     static StringUnorderedMap        namespaceAliasMap;
-    static GroupSDict               *groupSDict;
+    static GroupLinkedMap           *groupLinkedMap;
     static NamespaceLinkedMap       *namespaceLinkedMap;
     static StringDict                tagDestinationDict;
     static StringDict                aliasDict;
diff --git a/src/filedef.cpp b/src/filedef.cpp
index 49fb4d9..3fd542f 100644
--- a/src/filedef.cpp
+++ b/src/filedef.cpp
@@ -1758,20 +1758,18 @@ static void addDirsAsGroups(Directory *root,GroupDef *parent,int level)
   GroupDef *gd=0;
   if (root->kind()==DirEntry::Dir)
   {
-    gd = createGroupDef("[generated]",
+    gd = Doxygen::groupLinkedMap->add(root->path(),
+           std::unique_ptr<GroupDef>(
+              createGroupDef("[generated]",
                       1,
                       root->path(), // name
                       root->name()  // title
-                     );
+                     )));
     if (parent)
     {
       parent->addGroup(gd);
       gd->makePartOfGroup(parent);
     }
-    else
-    {
-      Doxygen::groupSDict->append(root->path(),gd);
-    }
   }
   QListIterator<DirEntry> dli(root->children());
   DirEntry *de;
diff --git a/src/groupdef.cpp b/src/groupdef.cpp
index df9b6eb..2d6663f 100644
--- a/src/groupdef.cpp
+++ b/src/groupdef.cpp
@@ -103,7 +103,7 @@ class GroupDefImpl : public DefinitionMixin<GroupDef>
     virtual FileList *      getFiles() const        { return m_fileList; }
     virtual const ClassLinkedRefMap &getClasses() const         { return m_classes; }
     virtual const NamespaceLinkedRefMap &getNamespaces() const  { return m_namespaces; }
-    virtual GroupList *     getSubGroups() const       { return m_groupList; }
+    virtual const GroupList &getSubGroups() const               { return m_groups; }
     virtual const PageLinkedRefMap &getPages() const            { return m_pages; }
     virtual const DirList & getDirs() const                     { return m_dirList; }
     virtual const PageLinkedRefMap &getExamples() const         { return m_examples; }
@@ -142,7 +142,7 @@ class GroupDefImpl : public DefinitionMixin<GroupDef>
     FileList *           m_fileList;            // list of files in the group
     ClassLinkedRefMap    m_classes;             // list of classes in the group
     NamespaceLinkedRefMap m_namespaces;         // list of namespaces in the group
-    GroupList *          m_groupList;           // list of sub groups.
+    GroupList            m_groups;              // list of sub groups.
     PageLinkedRefMap     m_pages;               // list of pages in the group
     PageLinkedRefMap     m_examples;            // list of examples in the group
     DirList              m_dirList;             // list of directories in the group
@@ -168,7 +168,6 @@ GroupDefImpl::GroupDefImpl(const char *df,int dl,const char *na,const char *t,
                    const char *refFileName) : DefinitionMixin(df,dl,1,na)
 {
   m_fileList = new FileList;
-  m_groupList = new GroupList;
   if (refFileName)
   {
     m_fileName=stripExtension(refFileName);
@@ -189,7 +188,6 @@ GroupDefImpl::GroupDefImpl(const char *df,int dl,const char *na,const char *t,
 GroupDefImpl::~GroupDefImpl()
 {
   delete m_fileList;
-  delete m_groupList;
   delete m_allMemberList;
 }
 
@@ -548,16 +546,11 @@ bool GroupDefImpl::findGroup(const GroupDef *def) const
   {
     return TRUE;
   }
-  else if (m_groupList)
+  for (const auto &gd : m_groups)
   {
-    GroupListIterator it(*m_groupList);
-    GroupDef *gd;
-    for (;(gd=it.current());++it)
+    if (gd->findGroup(def))
     {
-      if (gd->findGroup(def))
-      {
-        return TRUE;
-      }
+      return TRUE;
     }
   }
   return FALSE;
@@ -569,13 +562,12 @@ void GroupDefImpl::addGroup(const GroupDef *def)
   //if (Config_getBool(SORT_MEMBER_DOCS))
   //  groupList->inSort(def);
   //else
-  m_groupList->append(def);
+  m_groups.push_back(def);
 }
 
 bool GroupDefImpl::isASubGroup() const
 {
-  GroupList *groups = partOfGroups();
-  return groups!=0 && groups->count()!=0;
+  return !partOfGroups().empty();
 }
 
 void GroupDefImpl::countMembers()
@@ -599,7 +591,7 @@ size_t GroupDefImpl::numDocMembers() const
   return m_fileList->count()+
          m_classes.size()+
          m_namespaces.size()+
-         m_groupList->count()+
+         m_groups.size()+
          m_allMemberList->count()+
          m_pages.size()+
          m_examples.size();
@@ -679,7 +671,7 @@ void GroupDefImpl::writeTagFile(FTextStream &tagFile)
         break;
       case LayoutDocEntry::GroupDirs:
         {
-          for(const auto &dd : m_dirList)
+          for (const auto &dd : m_dirList)
           {
             if (dd->isLinkableInProject())
             {
@@ -690,16 +682,11 @@ void GroupDefImpl::writeTagFile(FTextStream &tagFile)
         break;
       case LayoutDocEntry::GroupNestedGroups:
         {
-          if (m_groupList)
+          for (const auto &gd : m_groups)
           {
-            QListIterator<GroupDef> it(*m_groupList);
-            GroupDef *gd;
-            for (;(gd=it.current());++it)
+            if (gd->isVisible())
             {
-              if (gd->isVisible())
-              {
-                tagFile << "    <subgroup>" << convertToXML(gd->name()) << "</subgroup>" << endl;
-              }
+              tagFile << "    <subgroup>" << convertToXML(gd->name()) << "</subgroup>" << endl;
             }
           }
         }
@@ -892,14 +879,9 @@ void GroupDefImpl::writeNestedGroups(OutputList &ol,const QCString &title)
 {
   // write list of groups
   int count=0;
-  if (m_groupList->count()>0)
+  for (const auto &gd : m_groups)
   {
-    QListIterator<GroupDef> it(*m_groupList);
-    GroupDef *gd;
-    for (;(gd=it.current());++it)
-    {
-      if (gd->isVisible()) count++;
-    }
+    if (gd->isVisible()) count++;
   }
   if (count>0)
   {
@@ -907,13 +889,7 @@ void GroupDefImpl::writeNestedGroups(OutputList &ol,const QCString &title)
     ol.parseText(title);
     ol.endMemberHeader();
     ol.startMemberList();
-    if (Config_getBool(SORT_GROUP_NAMES))
-    {
-      m_groupList->sort();
-    }
-    QListIterator<GroupDef> it(*m_groupList);
-    GroupDef *gd;
-    for (;(gd=it.current());++it)
+    for (const auto &gd : m_groups)
     {
       if (gd->isVisible())
       {
@@ -1070,7 +1046,7 @@ void GroupDefImpl::writeSummaryLinks(OutputList &ol) const
     if ((lde->kind()==LayoutDocEntry::GroupClasses && m_classes.declVisible()) ||
         (lde->kind()==LayoutDocEntry::GroupNamespaces && m_namespaces.declVisible()) ||
         (lde->kind()==LayoutDocEntry::GroupFiles && m_fileList->count()>0) ||
-        (lde->kind()==LayoutDocEntry::GroupNestedGroups && m_groupList->count()>0) ||
+        (lde->kind()==LayoutDocEntry::GroupNestedGroups && !m_groups.empty()>0) ||
         (lde->kind()==LayoutDocEntry::GroupDirs && !m_dirList.empty())
        )
     {
@@ -1335,7 +1311,6 @@ void GroupDefImpl::writeQuickMemberLinks(OutputList &ol,const MemberDef *current
       }
     }
   }
-
   ol.writeString("        </table>\n");
   ol.writeString("      </div>\n");
 }
@@ -1348,11 +1323,11 @@ void addClassToGroups(const Entry *root,ClassDef *cd)
 {
   for (const Grouping &g : root->groups)
   {
-    GroupDef *gd=0;
-    if (!g.groupname.isEmpty() && (gd=Doxygen::groupSDict->find(g.groupname)))
+    GroupDef *gd = Doxygen::groupLinkedMap->find(g.groupname);
+    if (gd && gd->addClass(cd))
     {
       ClassDefMutable *cdm = toClassDefMutable(cd);
-      if (cdm && gd->addClass(cdm))
+      if (cdm)
       {
         cdm->makePartOfGroup(gd);
       }
@@ -1366,17 +1341,14 @@ void addNamespaceToGroups(const Entry *root,NamespaceDef *nd)
   //printf("root->groups.size()=%d\n",root->groups.size());
   for (const Grouping &g : root->groups)
   {
-    GroupDef *gd=0;
+    GroupDef *gd = Doxygen::groupLinkedMap->find(g.groupname);
     //printf("group '%s'\n",s->data());
-    if (!g.groupname.isEmpty() && (gd=Doxygen::groupSDict->find(g.groupname)))
+    if (gd && gd->addNamespace(nd))
     {
-      if (gd->addNamespace(nd))
+      NamespaceDefMutable *ndm = toNamespaceDefMutable(nd);
+      if (ndm)
       {
-        NamespaceDefMutable *ndm = toNamespaceDefMutable(nd);
-        if (ndm)
-        {
-          ndm->makePartOfGroup(gd);
-        }
+        ndm->makePartOfGroup(gd);
       }
       //printf("Namespace %s: in group %s\n",nd->name().data(),s->data());
     }
@@ -1388,9 +1360,9 @@ void addDirToGroups(const Entry *root,DirDef *dd)
   //printf("*** root->groups.size()=%d\n",root->groups.size());
   for (const Grouping &g : root->groups)
   {
-    GroupDef *gd=0;
+    GroupDef *gd = Doxygen::groupLinkedMap->find(g.groupname);
     //printf("group '%s'\n",g->groupname.data());
-    if (!g.groupname.isEmpty() && (gd=Doxygen::groupSDict->find(g.groupname)))
+    if (gd)
     {
       gd->addDir(dd);
       dd->makePartOfGroup(gd);
@@ -1404,8 +1376,8 @@ void addGroupToGroups(const Entry *root,GroupDef *subGroup)
   //printf("addGroupToGroups for %s groups=%d\n",root->name.data(),root->groups.size());
   for (const Grouping &g : root->groups)
   {
-    GroupDef *gd=0;
-    if (!g.groupname.isEmpty() && (gd=Doxygen::groupSDict->find(g.groupname)))
+    GroupDef *gd = Doxygen::groupLinkedMap->find(g.groupname);
+    if (gd)
     {
       if (gd==subGroup)
       {
@@ -1439,7 +1411,7 @@ void addMemberToGroups(const Entry *root,MemberDef *md)
   {
     GroupDef *gd=0;
     if (!g.groupname.isEmpty() &&
-        (gd=Doxygen::groupSDict->find(g.groupname)) &&
+        (gd=Doxygen::groupLinkedMap->find(g.groupname)) &&
         g.pri >= pri)
     {
       if (fgd && gd!=fgd && g.pri==pri)
@@ -1538,8 +1510,8 @@ void addExampleToGroups(const Entry *root,PageDef *eg)
 {
   for (const Grouping &g : root->groups)
   {
-    GroupDef *gd=0;
-    if (!g.groupname.isEmpty() && (gd=Doxygen::groupSDict->find(g.groupname)))
+    GroupDef *gd = Doxygen::groupLinkedMap->find(g.groupname);
+    if (gd)
     {
       gd->addExample(eg);
       eg->makePartOfGroup(gd);
@@ -1749,7 +1721,10 @@ void GroupDefImpl::removeMemberFromList(MemberListType lt,MemberDef *md)
 
 void GroupDefImpl::sortSubGroups()
 {
-  m_groupList->sort();
+  std::sort(m_groups.begin(),
+            m_groups.end(),
+            [](const auto &g1,const auto &g2)
+            { return qstrcmp(g1->groupTitle(),g2->groupTitle())<0; });
 }
 
 bool GroupDefImpl::isLinkableInProject() const
diff --git a/src/groupdef.h b/src/groupdef.h
index 98a40f1..2ab8231 100644
--- a/src/groupdef.h
+++ b/src/groupdef.h
@@ -25,6 +25,7 @@
 #include "dirdef.h"
 #include "layout.h"
 #include "membergroup.h"
+#include "linkedmap.h"
 
 class MemberList;
 class FileList;
@@ -98,7 +99,7 @@ class GroupDef : public DefinitionMutable, public Definition
     virtual FileList *      getFiles() const = 0;
     virtual const ClassLinkedRefMap &getClasses() const = 0;
     virtual const NamespaceLinkedRefMap &getNamespaces() const = 0;
-    virtual GroupList *     getSubGroups() const = 0;
+    virtual const GroupList &getSubGroups() const = 0;
     virtual const PageLinkedRefMap &getPages() const = 0;
     virtual const DirList & getDirs() const = 0;
     virtual const PageLinkedRefMap &getExamples() const = 0;
@@ -117,36 +118,12 @@ const GroupDef      *toGroupDef(const Definition *d);
 
 // ------------------
 
-
-/** A sorted dictionary of GroupDef objects. */
-class GroupSDict : public SDict<GroupDef>
+class GroupLinkedMap : public LinkedMap<GroupDef>
 {
-  public:
-    GroupSDict(uint size) : SDict<GroupDef>(size) {}
-    virtual ~GroupSDict() {}
-  private:
-    int compareValues(const GroupDef *item1,const GroupDef *item2) const
-    {
-      return qstrcmp(item1->groupTitle(),item2->groupTitle());
-    }
 };
 
-/** A list of GroupDef objects. */
-class GroupList : public QList<GroupDef>
+class GroupList : public std::vector<const GroupDef *>
 {
-  public:
-    int compareValues(const GroupDef *item1,const GroupDef *item2) const
-    {
-      return qstrcmp(item1->groupTitle(),item2->groupTitle());
-    }
-};
-
-/** An iterator for GroupDef objects in a GroupList. */
-class GroupListIterator : public QListIterator<GroupDef>
-{
-  public:
-    GroupListIterator(const GroupList &l) : QListIterator<GroupDef>(l) {}
-    virtual ~GroupListIterator() {}
 };
 
 void addClassToGroups    (const Entry *root,ClassDef *cd);
diff --git a/src/index.cpp b/src/index.cpp
index 3d3448d..f8ee056 100644
--- a/src/index.cpp
+++ b/src/index.cpp
@@ -398,7 +398,7 @@ void addMembersToIndex(T *def,LayoutDocManager::LayoutPart part,
       {
         for (const auto &cd : def->getClasses())
         {
-          if (cd->isLinkable() && (cd->partOfGroups()==0 || def->definitionType()==Definition::TypeGroup))
+          if (cd->isLinkable() && (cd->partOfGroups().empty() || def->definitionType()==Definition::TypeGroup))
           {
             static bool inlineSimpleStructs = Config_getBool(INLINE_SIMPLE_STRUCTS);
             bool isNestedClass = def->definitionType()==Definition::TypeClass;
@@ -1569,7 +1569,7 @@ static void writeClassTree(const ListType &cl,FTVHelp *ftv,bool addToIndex,bool
           addMembersToIndex(cd,LayoutDocManager::Class,
                             cd->displayName(FALSE),
                             cd->anchor(),
-                            addToIndex && cd->partOfGroups()==0 && !cd->isSimple());
+                            addToIndex && cd->partOfGroups().empty() && !cd->isSimple());
         }
         if (count>0)
         {
@@ -3654,9 +3654,7 @@ static void writePageIndex(OutputList &ol)
 static int countGroups()
 {
   int count=0;
-  GroupSDict::Iterator gli(*Doxygen::groupSDict);
-  GroupDef *gd;
-  for (gli.toFirst();(gd=gli.current());++gli)
+  for (const auto &gd : *Doxygen::groupLinkedMap)
   {
     if (!gd->isReference())
     {
@@ -3738,7 +3736,7 @@ void writeGraphInfo(OutputList &ol)
 /*!
  * write groups as hierarchical trees
  */
-static void writeGroupTreeNode(OutputList &ol, GroupDef *gd, int level, FTVHelp* ftv, bool addToIndex)
+static void writeGroupTreeNode(OutputList &ol, const GroupDef *gd, int level, FTVHelp* ftv, bool addToIndex)
 {
   //bool fortranOpt = Config_getBool(OPTIMIZE_FOR_FORTRAN);
   //bool vhdlOpt    = Config_getBool(OPTIMIZE_OUTPUT_VHDL);
@@ -3760,8 +3758,8 @@ static void writeGroupTreeNode(OutputList &ol, GroupDef *gd, int level, FTVHelp*
   {
     //printf("gd->name()=%s #members=%d\n",gd->name().data(),gd->countMembers());
     // write group info
-    bool hasSubGroups = gd->getSubGroups()->count()>0;
-    bool hasSubPages = !gd->getPages().empty();
+    bool hasSubGroups = !gd->getSubGroups().empty();
+    bool hasSubPages  = !gd->getPages().empty();
     size_t numSubItems = 0;
     if (1 /*Config_getBool(TOC_EXPAND)*/)
     {
@@ -3859,7 +3857,7 @@ static void writeGroupTreeNode(OutputList &ol, GroupDef *gd, int level, FTVHelp*
         {
           //bool nestedClassInSameGroup =
           //    cd->getOuterScope() && cd->getOuterScope()->definitionType()==Definition::TypeClass &&
-          //    cd->getOuterScope()->partOfGroups()!=0 && cd->getOuterScope()->partOfGroups()->contains(gd);
+          //    cd->getOuterScope()->partOfGroups().empty() && cd->getOuterScope()->partOfGroups()->contains(gd);
           //printf("===== GroupClasses: %s visible=%d nestedClassInSameGroup=%d\n",cd->name().data(),cd->isVisible(),nestedClassInSameGroup);
           if (cd->isVisible() /*&& !nestedClassInSameGroup*/)
           {
@@ -3949,12 +3947,10 @@ static void writeGroupTreeNode(OutputList &ol, GroupDef *gd, int level, FTVHelp*
       }
       else if (lde->kind()==LayoutDocEntry::GroupNestedGroups)
       {
-        if (gd->getSubGroups()->count()>0)
+        if (!gd->getSubGroups().empty())
         {
           startIndexHierarchy(ol,level+1);
-          QListIterator<GroupDef> gli(*gd->getSubGroups());
-          GroupDef *subgd = 0;
-          for (gli.toFirst();(subgd=gli.current());++gli)
+          for (const auto &subgd : gd->getSubGroups())
           {
             writeGroupTreeNode(ol,subgd,level+1,ftv,addToIndex);
           }
@@ -3985,11 +3981,9 @@ static void writeGroupHierarchy(OutputList &ol, FTVHelp* ftv,bool addToIndex)
     ol.disable(OutputGenerator::Html);
   }
   startIndexHierarchy(ol,0);
-  GroupSDict::Iterator gli(*Doxygen::groupSDict);
-  GroupDef *gd;
-  for (gli.toFirst();(gd=gli.current());++gli)
+  for (const auto &gd : *Doxygen::groupLinkedMap)
   {
-    writeGroupTreeNode(ol,gd,0,ftv,addToIndex);
+    writeGroupTreeNode(ol,gd.get(),0,ftv,addToIndex);
   }
   endIndexHierarchy(ol,0);
   if (ftv)
diff --git a/src/latexgen.cpp b/src/latexgen.cpp
index 7db49d9..485b513 100644
--- a/src/latexgen.cpp
+++ b/src/latexgen.cpp
@@ -998,9 +998,7 @@ void LatexGenerator::startIndexSection(IndexSections is)
       break;
     case isModuleDocumentation:
       {
-        GroupSDict::Iterator gli(*Doxygen::groupSDict);
-        GroupDef *gd;
-        for (gli.toFirst();(gd=gli.current());++gli)
+        for (const auto &gd : *Doxygen::groupLinkedMap)
         {
           if (!gd->isReference())
           {
@@ -1144,24 +1142,17 @@ void LatexGenerator::endIndexSection(IndexSections is)
       break;
     case isModuleDocumentation:
       {
-        GroupSDict::Iterator gli(*Doxygen::groupSDict);
-        GroupDef *gd;
         bool found=FALSE;
-        for (gli.toFirst();(gd=gli.current()) && !found;++gli)
+        for (const auto &gd : *Doxygen::groupLinkedMap)
         {
           if (!gd->isReference())
           {
-            t << "}\n\\input{" << gd->getOutputFileBase() << "}\n";
-            found=TRUE;
-          }
-        }
-        for (;(gd=gli.current());++gli)
-        {
-          if (!gd->isReference())
-          {
-            //if (compactLatex) t << "\\input"; else t << "\\include";
-            t << "\\include";
-            t << "{" << gd->getOutputFileBase() << "}\n";
+            if (!found)
+            {
+              t << "}\n";
+              found=TRUE;
+            }
+            t << "\\input{" << gd->getOutputFileBase() << "}\n";
           }
         }
       }
diff --git a/src/pagedef.cpp b/src/pagedef.cpp
index 63c0803..d3cf823 100644
--- a/src/pagedef.cpp
+++ b/src/pagedef.cpp
@@ -45,7 +45,7 @@ class PageDefImpl : public DefinitionMixin<PageDef>
     virtual QCString anchor() const { return QCString(); }
     virtual void findSectionsInDocumentation();
     virtual QCString title() const { return m_title; }
-    virtual GroupDef *  getGroupDef() const;
+    virtual const GroupDef * getGroupDef() const;
     virtual const PageLinkedRefMap &getSubPages() const { return m_subPages; }
     virtual void addInnerCompound(const Definition *d);
     virtual bool visibleInIndex() const;
@@ -101,10 +101,9 @@ void PageDefImpl::findSectionsInDocumentation()
   docFindSections(documentation(),this,docFile());
 }
 
-GroupDef *PageDefImpl::getGroupDef() const
+const GroupDef *PageDefImpl::getGroupDef() const
 {
-  GroupList *groups = partOfGroups();
-  return groups!=0 ? groups->getFirst() : 0;
+  return !partOfGroups().empty() ? partOfGroups().front() : 0;
 }
 
 QCString PageDefImpl::getOutputFileBase() const
diff --git a/src/pagedef.h b/src/pagedef.h
index d651fa6..c0a7bf0 100644
--- a/src/pagedef.h
+++ b/src/pagedef.h
@@ -42,7 +42,7 @@ class PageDef : public DefinitionMutable, public Definition
     virtual QCString anchor() const = 0;
     virtual void findSectionsInDocumentation() = 0;
     virtual QCString title() const = 0;
-    virtual GroupDef *  getGroupDef() const = 0;
+    virtual const GroupDef *getGroupDef() const = 0;
     virtual const PageLinkedRefMap &getSubPages() const = 0;
     virtual void addInnerCompound(const Definition *) = 0;
     virtual bool visibleInIndex() const = 0;
diff --git a/src/perlmodgen.cpp b/src/perlmodgen.cpp
index da9121f..854b3df 100644
--- a/src/perlmodgen.cpp
+++ b/src/perlmodgen.cpp
@@ -2131,13 +2131,10 @@ void PerlModGenerator::generatePerlModForGroup(const GroupDef *gd)
     m_output.closeList();
   }
 
-  GroupList *gl = gd->getSubGroups();
-  if (gl)
+  if (!gd->getSubGroups().empty())
   {
     m_output.openList("groups");
-    GroupListIterator gli(*gl);
-    const GroupDef *sgd;
-    for (gli.toFirst();(sgd=gli.current());++gli)
+    for (const auto &sgd : gd->getSubGroups())
       m_output.openHash()
 	.addFieldQuotedString("title", sgd->groupTitle())
 	.closeHash();
@@ -2210,11 +2207,9 @@ bool PerlModGenerator::generatePerlModOutput()
   m_output.closeList();
 
   m_output.openList("groups");
-  GroupSDict::Iterator gli(*Doxygen::groupSDict);
-  const GroupDef *gd;
-  for (;(gd=gli.current());++gli)
+  for (const auto &gd : *Doxygen::groupLinkedMap)
   {
-    generatePerlModForGroup(gd);
+    generatePerlModForGroup(gd.get());
   }
   m_output.closeList();
 
diff --git a/src/rtfgen.cpp b/src/rtfgen.cpp
index d1c2eaf..a7cb1e3 100644
--- a/src/rtfgen.cpp
+++ b/src/rtfgen.cpp
@@ -471,9 +471,7 @@ void RTFGenerator::startIndexSection(IndexSections is)
     case isModuleDocumentation:
       {
         //Module Documentation
-        GroupSDict::Iterator gli(*Doxygen::groupSDict);
-        GroupDef *gd;
-        for (gli.toFirst();(gd=gli.current());++gli)
+        for (const auto &gd : *Doxygen::groupLinkedMap)
         {
           if (!gd->isReference())
           {
@@ -741,10 +739,8 @@ void RTFGenerator::endIndexSection(IndexSections is)
       break;
     case isModuleDocumentation:
       {
-        GroupSDict::Iterator gli(*Doxygen::groupSDict);
-        GroupDef *gd;
         t << "{\\tc \\v " << theTranslator->trModuleDocumentation() << "}"<< endl;
-        for (gli.toFirst();(gd=gli.current());++gli)
+        for (const auto &gd : *Doxygen::groupLinkedMap)
         {
           if (!gd->isReference())
           {
diff --git a/src/searchindex.cpp b/src/searchindex.cpp
index 7cb3afa..89f1681 100644
--- a/src/searchindex.cpp
+++ b/src/searchindex.cpp
@@ -837,9 +837,7 @@ void createJavaScriptSearchIndex()
   }
 
   // index groups
-  GroupSDict::Iterator gli(*Doxygen::groupSDict);
-  GroupDef *gd;
-  for (gli.toFirst();(gd=gli.current());++gli)
+  for (const auto &gd : *Doxygen::groupLinkedMap)
   {
     if (gd->isLinkable())
     {
@@ -848,8 +846,8 @@ void createJavaScriptSearchIndex()
       {
         char letter[MAX_UTF8_CHAR_SIZE];
         getUtf8Char(title,letter,CaseModifier::ToLower);
-        g_searchIndexInfo[SEARCH_INDEX_ALL].add(letter,gd);
-        g_searchIndexInfo[SEARCH_INDEX_GROUPS].add(letter,gd);
+        g_searchIndexInfo[SEARCH_INDEX_ALL].add(letter,gd.get());
+        g_searchIndexInfo[SEARCH_INDEX_GROUPS].add(letter,gd.get());
       }
     }
   }
diff --git a/src/sqlite3gen.cpp b/src/sqlite3gen.cpp
index a9b701a..7c7e77b 100644
--- a/src/sqlite3gen.cpp
+++ b/src/sqlite3gen.cpp
@@ -1293,20 +1293,15 @@ static void writeInnerPages(const PageLinkedRefMap &pl, struct Refid outer_refid
   }
 }
 
-static void writeInnerGroups(const GroupList *gl, struct Refid outer_refid)
+static void writeInnerGroups(const GroupList &gl, struct Refid outer_refid)
 {
-  if (gl)
+  for (const auto &sgd : gl)
   {
-    GroupListIterator gli(*gl);
-    const GroupDef *sgd;
-    for (gli.toFirst();(sgd=gli.current());++gli)
-    {
-      struct Refid inner_refid = insertRefid(sgd->getOutputFileBase());
+    struct Refid inner_refid = insertRefid(sgd->getOutputFileBase());
 
-      bindIntParameter(contains_insert,":inner_rowid", inner_refid.rowid);
-      bindIntParameter(contains_insert,":outer_rowid", outer_refid.rowid);
-      step(contains_insert);
-    }
+    bindIntParameter(contains_insert,":inner_rowid", inner_refid.rowid);
+    bindIntParameter(contains_insert,":outer_rowid", outer_refid.rowid);
+    step(contains_insert);
   }
 }
 
@@ -2539,21 +2534,17 @@ void generateSqlite3()
   }
 
   // + groups
-  GroupSDict::Iterator gli(*Doxygen::groupSDict);
-  const GroupDef *gd;
-  for (;(gd=gli.current());++gli)
+  for (const auto &gd : *Doxygen::groupLinkedMap)
   {
     msg("Generating Sqlite3 output for group %s\n",gd->name().data());
-    generateSqlite3ForGroup(gd);
+    generateSqlite3ForGroup(gd.get());
   }
 
   // + page
+  for (const auto &pd : *Doxygen::pageLinkedMap)
   {
-    for (const auto &pd : *Doxygen::pageLinkedMap)
-    {
-      msg("Generating Sqlite3 output for page %s\n",pd->name().data());
-      generateSqlite3ForPage(pd.get(),FALSE);
-    }
+    msg("Generating Sqlite3 output for page %s\n",pd->name().data());
+    generateSqlite3ForPage(pd.get(),FALSE);
   }
 
   // + dirs
@@ -2568,12 +2559,10 @@ void generateSqlite3()
   }
 
   // + examples
+  for (const auto &pd : *Doxygen::exampleLinkedMap)
   {
-    for (const auto &pd : *Doxygen::exampleLinkedMap)
-    {
-      msg("Generating Sqlite3 output for example %s\n",pd->name().data());
-      generateSqlite3ForPage(pd.get(),TRUE);
-    }
+    msg("Generating Sqlite3 output for example %s\n",pd->name().data());
+    generateSqlite3ForPage(pd.get(),TRUE);
   }
 
   // + main page
diff --git a/src/util.cpp b/src/util.cpp
index 0f195c2..b7fedc3 100644
--- a/src/util.cpp
+++ b/src/util.cpp
@@ -3037,7 +3037,7 @@ bool resolveRef(/* in */  const char *scName,
     //    md->name().data(),md,md->anchor().data(),md->isLinkable(),(*resContext)->name().data());
     return TRUE;
   }
-  else if (inSeeBlock && !nameStr.isEmpty() && (gd=Doxygen::groupSDict->find(nameStr)))
+  else if (inSeeBlock && !nameStr.isEmpty() && (gd=Doxygen::groupLinkedMap->find(nameStr)))
   { // group link
     *resContext=gd;
     return TRUE;
@@ -3214,7 +3214,7 @@ bool resolveLink(/* in */ const char *scName,
     *resContext=pd;
     return TRUE;
   }
-  else if ((gd=Doxygen::groupSDict->find(linkRef))) // link to a group
+  else if ((gd=Doxygen::groupLinkedMap->find(linkRef))) // link to a group
   {
     *resContext=gd;
     return TRUE;
@@ -5034,8 +5034,7 @@ void addRefItem(const RefItemVector &sli,
 
 bool recursivelyAddGroupListToTitle(OutputList &ol,const Definition *d,bool root)
 {
-  GroupList *groups = d->partOfGroups();
-  if (groups) // write list of group to which this definition belongs
+  if (!d->partOfGroups().empty()) // write list of group to which this definition belongs
   {
     if (root)
     {
@@ -5043,10 +5042,8 @@ bool recursivelyAddGroupListToTitle(OutputList &ol,const Definition *d,bool root
       ol.disableAllBut(OutputGenerator::Html);
       ol.writeString("<div class=\"ingroups\">");
     }
-    GroupListIterator gli(*groups);
-    GroupDef *gd;
     bool first=true;
-    for (gli.toFirst();(gd=gli.current());++gli)
+    for (const auto &gd : d->partOfGroups())
     {
       if (!first) { ol.writeString(" &#124; "); } else first=false;
       if (recursivelyAddGroupListToTitle(ol, gd, FALSE))
diff --git a/src/xmlgen.cpp b/src/xmlgen.cpp
index c005e03..c6d5bc3 100644
--- a/src/xmlgen.cpp
+++ b/src/xmlgen.cpp
@@ -1193,18 +1193,13 @@ static void writeInnerPages(const PageLinkedRefMap &pl,FTextStream &t)
   }
 }
 
-static void writeInnerGroups(const GroupList *gl,FTextStream &t)
+static void writeInnerGroups(const GroupList &gl,FTextStream &t)
 {
-  if (gl)
+  for (const auto &sgd : gl)
   {
-    GroupListIterator gli(*gl);
-    const GroupDef *sgd;
-    for (gli.toFirst();(sgd=gli.current());++gli)
-    {
-      t << "    <innergroup refid=\"" << sgd->getOutputFileBase()
-        << "\">" << convertToXML(sgd->groupTitle())
-        << "</innergroup>" << endl;
-    }
+    t << "    <innergroup refid=\"" << sgd->getOutputFileBase()
+      << "\">" << convertToXML(sgd->groupTitle())
+      << "</innergroup>" << endl;
   }
 }
 
@@ -1950,19 +1945,15 @@ void generateXML()
       generateXMLForFile(fd.get(),t);
     }
   }
-  GroupSDict::Iterator gli(*Doxygen::groupSDict);
-  const GroupDef *gd;
-  for (;(gd=gli.current());++gli)
+  for (const auto &gd : *Doxygen::groupLinkedMap)
   {
     msg("Generating XML output for group %s\n",gd->name().data());
-    generateXMLForGroup(gd,t);
+    generateXMLForGroup(gd.get(),t);
   }
+  for (const auto &pd : *Doxygen::pageLinkedMap)
   {
-    for (const auto &pd : *Doxygen::pageLinkedMap)
-    {
-      msg("Generating XML output for page %s\n",pd->name().data());
-      generateXMLForPage(pd.get(),t,FALSE);
-    }
+    msg("Generating XML output for page %s\n",pd->name().data());
+    generateXMLForPage(pd.get(),t,FALSE);
   }
   {
     DirDef *dir;
@@ -1973,12 +1964,10 @@ void generateXML()
       generateXMLForDir(dir,t);
     }
   }
+  for (const auto &pd : *Doxygen::exampleLinkedMap)
   {
-    for (const auto &pd : *Doxygen::exampleLinkedMap)
-    {
-      msg("Generating XML output for example %s\n",pd->name().data());
-      generateXMLForPage(pd.get(),t,TRUE);
-    }
+    msg("Generating XML output for example %s\n",pd->name().data());
+    generateXMLForPage(pd.get(),t,TRUE);
   }
   if (Doxygen::mainPage)
   {