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Ogre::RadixSort< TContainer, TContainerValueType, TCompValueType > Class Template Reference

Class for performing a radix sort (fast comparison-less sort based on byte value) on various standard STL containers. More...

#include <OgreRadixSort.h>

List of all members.

Public Types

typedef TContainer::iterator ContainerIter

Public Member Functions

 RadixSort ()
 ~RadixSort ()
template<class TFunction> void sort (TContainer &container, TFunction func)
 Main sort function.


Protected Member Functions

void sortPass (int byteIndex)
template<typename T> void finalPass (int byteIndex, T val)
void finalPass (int byteIndex, int val)
void finalPass (int byteIndex, float val)
unsigned char getByte (int byteIndex, TCompValueType val)

Protected Attributes

int mCounters [4][256]
 Alpha-pass counters of values (histogram) 4 of them so we can radix sort a maximum of a 32bit value.

int mOffsets [256]
 Beta-pass offsets.

int mSortSize
 Sort area size.

int mNumPasses
 Number of passes for this type.

std::vector< SortEntry > mSortArea1
 Temp sort storage.

std::vector< SortEntry > mSortArea2
std::vector< SortEntry > * mSrc
std::vector< SortEntry > * mDest
TContainer mTmpContainer

Detailed Description

template<class TContainer, class TContainerValueType, typename TCompValueType>
class Ogre::RadixSort< TContainer, TContainerValueType, TCompValueType >

Class for performing a radix sort (fast comparison-less sort based on byte value) on various standard STL containers.

Remarks:
A radix sort is a very fast sort algorithm. It doesn't use comparisons and thus is able to break the theoretical minimum O(N*logN) complexity. Radix sort is complexity O(k*N), where k is a constant. Note that radix sorting is not in-place, it requires additional storage, so it trades memory for speed. The overhead of copying means that it is only faster for fairly large datasets, so you are advised to only use it for collections of at least a few hundred items.
This is a template class to allow it to deal with a variety of containers, and a variety of value types to sort on. In addition to providing the container and value type on construction, you also need to supply a functor object which will retrieve the value to compare on for each item in the list. For example, if you had an std::vector of by-value instances of an object of class 'Bibble', and you wanted to sort on Bibble::getDoobrie(), you'd have to firstly create a functor like this: 
        struct BibbleSortFunctor
        {
            float operator()(const Bibble& val) const
            {
                return val.getDoobrie();
            }
        }
Then, you need to declare a RadixSort class which names the container type, the value type in the container, and the type of the value you want to sort by. You can then call the sort function. E.g. 
        RadixSort<BibbleList, Bibble, float> radixSorter;
        BibbleSortFunctor functor;

        radixSorter.sort(myBibbleList, functor);
You should try to reuse RadixSort instances, since repeated allocation of the internal storage is then avoided.
Note:
Radix sorting is often associated with just unsigned integer values. Our implementation can handle both unsigned and signed integers, as well as floats (which are often not supported by other radix sorters). doubles are not supported; you will need to implement your functor object to convert to float if you wish to use this sort routine.

Definition at line 79 of file OgreRadixSort.h.

Member Typedef Documentation

template<class TContainer, class TContainerValueType, typename TCompValueType>
typedef TContainer::iterator Ogre::RadixSort< TContainer, TContainerValueType, TCompValueType >::ContainerIter
 

Definition at line 82 of file OgreRadixSort.h.

Referenced by Ogre::RadixSort< TContainer, TContainerValueType, TCompValueType >::SortEntry::SortEntry().

Constructor & Destructor Documentation

template<class TContainer, class TContainerValueType, typename TCompValueType>
Ogre::RadixSort< TContainer, TContainerValueType, TCompValueType >::RadixSort (   ) 
 

Definition at line 227 of file OgreRadixSort.h.

template<class TContainer, class TContainerValueType, typename TCompValueType>
Ogre::RadixSort< TContainer, TContainerValueType, TCompValueType >::~RadixSort (   ) 
 

Definition at line 228 of file OgreRadixSort.h.

Member Function Documentation

template<class TContainer, class TContainerValueType, typename TCompValueType>
void Ogre::RadixSort< TContainer, TContainerValueType, TCompValueType >::finalPass (  int  byteIndex,
float  val
)  [protected]
 

Definition at line 170 of file OgreRadixSort.h.

template<class TContainer, class TContainerValueType, typename TCompValueType>
void Ogre::RadixSort< TContainer, TContainerValueType, TCompValueType >::finalPass (  int  byteIndex,
int  val
)  [protected]
 

Definition at line 137 of file OgreRadixSort.h.

template<class TContainer, class TContainerValueType, typename TCompValueType>
template<typename T>
void Ogre::RadixSort< TContainer, TContainerValueType, TCompValueType >::finalPass (  int  byteIndex,
T  val
)  [protected]
 

Definition at line 130 of file OgreRadixSort.h.

Referenced by Ogre::RadixSort< RenderablePassList, RenderablePass, uint32 >::sort().

template<class TContainer, class TContainerValueType, typename TCompValueType>
unsigned char Ogre::RadixSort< TContainer, TContainerValueType, TCompValueType >::getByte (  int  byteIndex,
TCompValueType  val
)  [protected]
 

Definition at line 216 of file OgreRadixSort.h.

Referenced by Ogre::RadixSort< RenderablePassList, RenderablePass, uint32 >::finalPass(), Ogre::RadixSort< RenderablePassList, RenderablePass, uint32 >::sort(), and Ogre::RadixSort< RenderablePassList, RenderablePass, uint32 >::sortPass().

template<class TContainer, class TContainerValueType, typename TCompValueType>
template<class TFunction>
void Ogre::RadixSort< TContainer, TContainerValueType, TCompValueType >::sort (  TContainer &  container,
TFunction  func
) 
 

Main sort function.

Parameters:
container A container of the type you declared when declaring
func A functor which returns the value for comparison when given a container value

Definition at line 236 of file OgreRadixSort.h.

template<class TContainer, class TContainerValueType, typename TCompValueType>
void Ogre::RadixSort< TContainer, TContainerValueType, TCompValueType >::sortPass (  int  byteIndex  )  [protected]
 

Definition at line 111 of file OgreRadixSort.h.

Referenced by Ogre::RadixSort< RenderablePassList, RenderablePass, uint32 >::finalPass(), and Ogre::RadixSort< RenderablePassList, RenderablePass, uint32 >::sort().

Member Data Documentation

template<class TContainer, class TContainerValueType, typename TCompValueType>
int Ogre::RadixSort< TContainer, TContainerValueType, TCompValueType >::mCounters[4][256] [protected]
 

Alpha-pass counters of values (histogram) 4 of them so we can radix sort a maximum of a 32bit value.

Definition at line 86 of file OgreRadixSort.h.

template<class TContainer, class TContainerValueType, typename TCompValueType>
std::vector<SortEntry>* Ogre::RadixSort< TContainer, TContainerValueType, TCompValueType >::mDest [protected]
 

Definition at line 107 of file OgreRadixSort.h.

template<class TContainer, class TContainerValueType, typename TCompValueType>
int Ogre::RadixSort< TContainer, TContainerValueType, TCompValueType >::mNumPasses [protected]
 

Number of passes for this type.

Definition at line 92 of file OgreRadixSort.h.

template<class TContainer, class TContainerValueType, typename TCompValueType>
int Ogre::RadixSort< TContainer, TContainerValueType, TCompValueType >::mOffsets[256] [protected]
 

Beta-pass offsets.

Definition at line 88 of file OgreRadixSort.h.

template<class TContainer, class TContainerValueType, typename TCompValueType>
std::vector<SortEntry> Ogre::RadixSort< TContainer, TContainerValueType, TCompValueType >::mSortArea1 [protected]
 

Temp sort storage.

Definition at line 104 of file OgreRadixSort.h.

template<class TContainer, class TContainerValueType, typename TCompValueType>
std::vector<SortEntry> Ogre::RadixSort< TContainer, TContainerValueType, TCompValueType >::mSortArea2 [protected]
 

Definition at line 105 of file OgreRadixSort.h.

template<class TContainer, class TContainerValueType, typename TCompValueType>
int Ogre::RadixSort< TContainer, TContainerValueType, TCompValueType >::mSortSize [protected]
 

Sort area size.

Definition at line 90 of file OgreRadixSort.h.

template<class TContainer, class TContainerValueType, typename TCompValueType>
std::vector<SortEntry>* Ogre::RadixSort< TContainer, TContainerValueType, TCompValueType >::mSrc [protected]
 

Definition at line 106 of file OgreRadixSort.h.

template<class TContainer, class TContainerValueType, typename TCompValueType>
TContainer Ogre::RadixSort< TContainer, TContainerValueType, TCompValueType >::mTmpContainer [protected]
 

Definition at line 108 of file OgreRadixSort.h.

The documentation for this class was generated from the following file:

Copyright © 2000-2005 by The OGRE Team
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Last modified Sun Mar 12 14:41:54 2006