Arrays Manual

Table of Contents

• About
• PointerArray
• SortedArray
• Utility
• Further Reading

About

The MAXON API provides various array templates. These array types should be used instead of simple C-arrays to store data.

• maxon::BaseArray: Generic array template with should be used in most cases. For a detailed description see BaseArray Manual.
• maxon::PointerArray: An array to store C++ pointers.
• maxon::SortedArray: An array that will automatically sort its elements.
• maxon::BlockArray: An array that consists of blocks of fixed size.

PointerArray

A maxon::PointerArray is optimized to store C++ pointers and owns the pointed objects.

Note

In general it is recommended to manage the lifetime of an object using references, see References.

  // This example shows how to use a PointerArray to manage objects.
 
  // create PointerArray
  maxon::PointerArray<ExampleClass> objects;
 
  // create new objects and insert them into the PointerArray.
  for (maxon::Int i = 0; i < count; ++i)
  {
    // create new object
    ExampleClass* const obj = NewObj(ExampleClass, i) iferr_return;
    // UniqueRef holds temporary ownership
    maxon::UniqueRef<ExampleClass> storage(obj);
    // array takes ownership
    objects.AppendPtr(obj) iferr_return;
    // release ownership after the PointerArray successfully took the ownership
    storage.Disconnect();
  }
 
  // check objects
  const maxon::Int numberOfObjects = objects.GetCount();
  DiagnosticOutput("The array stores @ pointers.", numberOfObjects);
 
  // reset the array; this will delete all elements owned by the array
  objects.Reset();

SortedArray

A sorted array automatically sorts the stored elements on first read access.

• maxon::SortedArray: Generic template for a sorted array class. One must implement "LessThan" and "IsEqual".
• maxon::DefaultSortedArray: Array template for classes providing a "<" and "==" operator.

  // This example uses a SortedArray to store instances of an example class.
 
  // definition of the custom SortedArray based array class
  class ExampleClassSortedArray : public maxon::SortedArray<ExampleClassSortedArray, maxon::BaseArray<ExampleClass>>
  {
public:
    static maxon::Bool LessThan(const ExampleClass& a, const ExampleClass& b)
    {
      return a.GetValue() < b.GetValue();
    }
    static maxon::Bool IsEqual(const ExampleClass& a, const ExampleClass& b)
    {
      return a.GetValue() == b.GetValue();
    }
  };
 
  // create sorted array and insert new objects
  ExampleClassSortedArray sortedArray;
  sortedArray.Append(ExampleClass(100)) iferr_return;
  sortedArray.Append(ExampleClass(10)) iferr_return;
 
  // get first object; the array will get sorted
  ExampleClass* const object = sortedArray.GetFirst();
  if (object)
  {
    DiagnosticOutput("First Element Value: @", object->GetValue());
  }

Utility

These generic array types are used to define functions that can be used with various array types:

• maxon::ArrayInterface: Generic array interface representing all standard array types of the MAXON API.
• maxon::WritableArrayInterface: Like ArrayInterface but allows write into the given array.

// This example function uses WritableArrayInterface to present
// a flexible interface that can be used with various array types.
 
static void PrintIntArrayInfo(maxon::WritableArrayInterface<maxon::Int>& array)
{
  // get the size of the array
  const maxon::Int size = array.GetCount();
  DiagnosticOutput("Array Size: @", size);
 
  // print the value of the array's first element
  if (size > 0)
  {
    maxon::Int element = array[0];
    DiagnosticOutput("First Element: @", element);
  }
}

Further Reading

• Data Containers & Collections
• MAXON API Containers & Data Collections
• BaseArray Manual
• References