Revert "Revert "Revert "Fix issue with derived classes, but only fix …

…it for PHP 5.4 and up. Closes #211"""

This reverts commit c512e02.

zend/classimpl.cpp

@@ -38,46 +38,18 @@ ClassImpl::~ClassImpl()
  */
 static ClassImpl *self(zend_class_entry *entry)
 {
-#if PHP_VERSION_ID >= 50400
-
-    /**
-     *  somebody could have extended this class from PHP userland, in which
-     *  case trying to dereference the doc_comment would result in a disaster
-     *  because it does not point to a class implemented by PHP-CPP at all!
-     *
-     *  if this happens we need to keep going until we find the object that
-     *  was implemented by us. For this we are going to make the assumption
-     *  that we are the only ones misusing the doc_comment the way we do.
-     *
-     *  Usually the doc_comment is not set (it equals the nullptr) and if it
-     *  is set, the accompanying doc_comment_len should be non-zero to
-     *  indicate the number of characters in it.
-     */
-    while (entry->parent && entry->info.user.doc_comment == nullptr && entry->info.user.doc_comment_len == 0)
-    {
-        // we did not create this class entry, but luckily we have a parent
-        entry = entry->parent;
-    }
+    // we need the base class (in user space the class may have been overridden,
+    // but we are not interested in these user space classes)
+    while (entry->parent) entry = entry->parent;
 
+#if PHP_VERSION_ID >= 50400
     // retrieve the comment (it has a pointer hidden in it to the ClassBase object)
     const char *comment = entry->info.user.doc_comment;
 
     // the first byte of the comment is an empty string (null character), but
     // the next bytes contain a pointer to the ClassBase class
     return *((ClassImpl **)(comment + 1));
 #else
-
-    /**
-     *  This is likely not correct: If the class was extended using PHP-CPP
-     *  itself, we should retrieve the ClassImpl directly, however there is
-     *  no sane way to check this here, unlike in PHP 5.4.
-     *
-     *  We therefore always go to the very base, of which we are sure that
-     *  we are the implementers. This way - at least - we don't cause any
-     *  segfaults.
-     */
-    while (entry->parent) entry = entry->parent;
-
     // on php 5.3 we store the pointer to impl after the name in the entry
     ClassImpl** impl = (ClassImpl**)(entry->name + 1 + entry->name_length);
 
@@ -504,7 +476,7 @@ int ClassImpl::cast(zval *val, zval *retval, int type TSRMLS_DC)
 
         // @todo do we turn into endless conversion if the __toString object returns 'this' ??
         // (and if it does: who cares? If the extension programmer is stupid, why do we have to suffer?)
-
+        
         // is the original parameter overwritten?
         if (val == retval) zval_dtor(val);