Use "..." to implement subelementByPath

genericfileelement.h

@@ -101,8 +101,8 @@ public:
     const ImplementationType* firstChild() const;
     ImplementationType* lastChild();
     const ImplementationType* lastChild() const;
-    ImplementationType* subelementByPath(const std::initializer_list<IdentifierType> &path, Diagnostics &diag);
+    ImplementationType* subelementByPath(Diagnostics &diag, IdentifierType item);
-    ImplementationType* subelementByPath(std::list<IdentifierType> &path, Diagnostics &diag);
+    ImplementationType* subelementByPath(Diagnostics &diag, IdentifierType item, IdentifierType remainingPath...);
     ImplementationType* childById(const IdentifierType &id, Diagnostics &diag);
     ImplementationType* siblingById(const IdentifierType &id, Diagnostics &diag, bool includeThis = false);
     bool isParent() const;
@@ -522,7 +522,7 @@ inline const ImplementationType *GenericFileElement<ImplementationType>::lastChi
 }
 
 /*!
- * \brief Returns the sub element for the specified \a path.
+ * \brief Returns the sub element for the specified path.
  *
  * The current element keeps ownership over the returned element.
  * If no element could be found nullptr is returned.
@@ -531,41 +531,45 @@ inline const ImplementationType *GenericFileElement<ImplementationType>::lastChi
  * \throws Throws std::ios_base::failure when an IO error occurs.
  */
 template <class ImplementationType>
-inline ImplementationType *GenericFileElement<ImplementationType>::subelementByPath(const std::initializer_list<IdentifierType> &path, Diagnostics &diag)
+ImplementationType *GenericFileElement<ImplementationType>::subelementByPath(Diagnostics &diag, IdentifierType item)
 {
-    std::list<GenericFileElement<ImplementationType>::IdentifierType> list(path);
+    // ensure element is parsed
-    return subelementByPath(list, diag);
+    parse(diag);
+    // return the element if it matches the current and last item in the path
+    if(item == id()) {
+        return static_cast<ImplementationType *>(this);
+    }
+    // check whether a sibling matches the item
+    if(nextSibling()) {
+        return nextSibling()->subelementByPath(diag, item);
+    }
+    return nullptr;
 }
 
 /*!
- * \brief Returns the sub element for the specified \a path.
+ * \brief Returns the sub element for the specified path.
  *
  * The current element keeps ownership over the returned element.
  * If no element could be found nullptr is returned.
- * The specified \a path will modified.
  *
  * \throws Throws a parsing exception when a parsing error occurs.
  * \throws Throws std::ios_base::failure when an IO error occurs.
  */
 template <class ImplementationType>
-ImplementationType *GenericFileElement<ImplementationType>::subelementByPath(std::list<IdentifierType> &path, Diagnostics &diag)
+ImplementationType *GenericFileElement<ImplementationType>::subelementByPath(Diagnostics &diag, IdentifierType item, IdentifierType remainingPath...)
 {
-    parse(diag); // ensure element is parsed
+    // ensure element is parsed
-    if(path.size()) {
+    parse(diag);
-        if(path.front() == id()) {
+    // continue with next item in path if the element matches the current item
-            if(path.size() == 1) {
+    if(item == id()) {
-                return static_cast<ImplementationType *>(this);
+        if(!firstChild()) {
-            } else {
+            return nullptr;
-                if(firstChild()) {
-                    path.pop_front();
-                    return firstChild()->subelementByPath(path, diag);
-                }
-            }
-        } else {
-            if(nextSibling()) {
-                return nextSibling()->subelementByPath(path, diag);
-            }
         }
+        return firstChild()->subelementByPath(diag, remainingPath);
+    }
+    // check whether a sibling matches the current item
+    if(nextSibling()) {
+        return nextSibling()->subelementByPath(diag, item, remainingPath);
     }
     return nullptr;
 }

mp4/mp4container.cpp

@@ -50,7 +50,7 @@ ElementPosition Mp4Container::determineTagPosition(Diagnostics &diag) const
 {
     if(m_firstElement) {
         const Mp4Atom *mediaDataAtom = m_firstElement->siblingById(Mp4AtomIds::MediaData, diag);
-        const Mp4Atom *userDataAtom = m_firstElement->subelementByPath({Mp4AtomIds::Movie, Mp4AtomIds::UserData}, diag);
+        const Mp4Atom *userDataAtom = m_firstElement->subelementByPath(diag, Mp4AtomIds::Movie, Mp4AtomIds::UserData);
         if(mediaDataAtom && userDataAtom) {
             return userDataAtom->startOffset() < mediaDataAtom->startOffset() ? ElementPosition::BeforeData : ElementPosition::AfterData;
         }
@@ -89,7 +89,7 @@ void Mp4Container::internalParseHeader(Diagnostics &diag)
 void Mp4Container::internalParseTags(Diagnostics &diag)
 {
     const string context("parsing tags of MP4 container");
-    if(Mp4Atom *udtaAtom = firstElement()->subelementByPath({Mp4AtomIds::Movie, Mp4AtomIds::UserData}, diag)) {
+    if(Mp4Atom *udtaAtom = firstElement()->subelementByPath(diag, Mp4AtomIds::Movie, Mp4AtomIds::UserData)) {
         Mp4Atom *metaAtom = udtaAtom->childById(Mp4AtomIds::Meta, diag);
         bool surplusMetaAtoms = false;
         while(metaAtom) {
@@ -153,7 +153,7 @@ void Mp4Container::internalParseTracks(Diagnostics &diag)
                 diag.emplace_back(DiagLevel::Critical, "mvhd atom is does not exist.", context);
             }
             // get mvex atom which holds default values for fragmented files
-            if(Mp4Atom *mehdAtom = moovAtom->subelementByPath({Mp4AtomIds::MovieExtends, Mp4AtomIds::MovieExtendsHeader}, diag)) {
+            if(Mp4Atom *mehdAtom = moovAtom->subelementByPath(diag, Mp4AtomIds::MovieExtends, Mp4AtomIds::MovieExtendsHeader)) {
                 m_fragmented = true;
                 if(mehdAtom->dataSize() > 0) {
                     stream().seekg(static_cast<iostream::off_type>(mehdAtom->dataOffset()));