HashARC<class K,class T> - Auto resizing hash-table.

Developer Documentation

Centre for Vision, Speech & Signal Processing

Comments:
This is a SMALL object !

Though this inherits from HashT which is a big-object, this function's effectively random use of Resize, means handle to this table may be damages without warning.

For a reference counted version of this class see RCHashARC

HashARC should inherit HashC privately, but because of bugs in g++ this stops the iterator working (the iterator should really be a friend.) I'll fix this hopefully with the next release of gcc.

Parent Classes:

HashC

HashARBaseC

Variables:

UIndex Elements;: friend HashIterT;

Methods:

HashARC(): Default constructor.
HashARC(istream & in): Stream constructor.
HashARC(UIndex nBins): Create table with nBins.
Bin size must be at least 1.
HashARC(const HashARC<K,T> & Oth): Copy table.
HashARC(Tuple2C<K,T> * data): Initalise from simple array.
NB. Array must be terminated by a duplicate of the first key. (i.e. == must return true between them)
HashARC<K,T> Copy() const: Make a copy.
const T * Lookup(const K & Key) const: Find data matching key.
Ptr == NULL, if matching key not found.
T * Lookup(const K & Key): Find data matching key.
Ptr == NULL, if matching key not found.
BooleanT Lookup(const K & key,T & data): Lookup data for key.
Returns true if data is found, copy is place in 'data'.
BooleanT Update(const K & Key,const T & Data): Update member of HashCable, will create new one if it doesn't
exist. Returns: True=Member existed already. False=New one was added.
T & Update(const K & Key): Get value, add default if its not there. Return refrence anyway.
BooleanT Insert(const K & Key,const T & Data): Standard insert function, as Update(K,T).
Returns: True=Member existed already. False=New one was added.
T & Access(const K & key,const T & def = T()): Access key, if it does exists create a new bin with value 'def'
Retuns a refrence to the new entry.
T & operator[](const K & Key): Associative array style of access.
const T & operator[](const K & Key) const: Associative array style of access.
BooleanT Del(const K & Key): Delete member from table.
Returns TRUE if Key was in hash table.
BooleanT DelNoResize(const K & Key): Delete member from table, without resizing.
T Get(const K & Key): Get data element from table, and remove it.
BooleanT IsElm(const K & Key) const: Is key used in the table.
void Empty(void): Remove all items from table.
BooleanT IsEmpty(void) const: Is table empty ?
UIntT Size(void) const: Number of elements in table.
void Move(HashARC<K,T> & oth): Move contents of another table into this one.
leave other empty. The previous contents of this table are removed.
void AddFrom(HashARC<K,T> & oth,BooleanT replace = true): Add contents of another table into this one.
leave other empty. if replace is true the old table
void Add(const HashARC<K,T> & oth): Add contents of another table into this one.
const HashARC<K,T> & operator=(const HashARC<K,T> & oth)
bool operator==(const HashARC<K,T> & oth) const: Is this hash table the same as another ?
bool operator!=(const HashARC<K,T> & oth) const: Is this hash table different from another ?
UIntT Hash() const: Get a hash value for the hash table.
SArray1dC<HashElemLst> & GetTable_Internal() const: Don't use this function, it's a bug work around,
and I'll remove it as soon as gcc is fixed.
T & Add(const K & Key,const T & Data): Add member to table.
!! Doesn't check if member already exists !!
T & Add(const K & Key): Add member created with default constructor.
!! Doesn't check if member already exists !!
void CheckAdd(void): Need to increase size ?
void CheckDel(void): Need to decrease size ?
SArray1dC<HashElemLst> & AccessTable()
const SArray1dC<HashElemLst> & AccessTable() const
istream & operator>>(istream & in,HashARC<K,T> & obj)
BinOStreamC & operator<<(BinOStreamC & out,const HashARC<K,T> & oth)

#include "amma/Hash.hh"

HashC<K,T> Copy() const: Make a copy of the table.
const T * Lookup(const K & Key) const: Find data matching key.
Ptr == NULL, if matching key not found.
T * Lookup(const K & Key): Find data matching key.
Ptr == NULL, if matching key not found.
BooleanT Lookup(const K & Key,T & data): Lookup data for key.
Returns true if data is found, copy is place in 'data'.
BooleanT Update(const K & Key,const T & Data): Update member of HashTable, will create new one if it doesn't
exist. Require's a default constructor & a working assigment operator !! Returns: True=Member existed already. False=New one was added.
T & Update(const K & Key): Get value, add default if its not there. Return refrence anyway.
T & operator[](const K & Key): Associative array style interface.
const T & operator[](const K & Key) const: Associative array style of access.
BooleanT Insert(const K & Key,const T & Data): Default insertion operation, same as Update(K,T);
T & Access(const K & key,const T & def = T()): Access key, if it does exists create a new bin with value 'def'
Retuns a refrence to the new entry.
BooleanT Del(const K & Key): Delete member from table.
T Get(const K & Key): Get data element from table, and remove it.
BooleanT IsElm(const K & Key) const: Is key used in the table ?
void Empty(void): Remove all items from table.
UIntT Size(void) const: Count number of elements in table.
BooleanT IsEmpty(void) const: Is the table empty ?
UIndex Bins(void) const: Number of bins in the HashTable.
void Resize(USize NewSize): Resize HashCable.
WARNING: this empties the old table & creates a new one, so it will leave other handles pointing to an empty hash table.
const HashC<K,T> & operator=(const HashC<K,T> & Oth): Assign from another hash table.
BooleanT IsSameTable(const HashC<K,T> & oth) const
T & Add(const K & Key,const T & Data): Add member to table. !! Doesn't check if member already exists !!
T & Add(const K & Key): Add member created with default constructor. !! Doesn't check if member already exists !!
HashElemT<K,T> * LookupHV(const K & Value,UIndex & HashVal) const
BooleanT Del(HashElemT<K,T> * Elem,UIndex & HashVal)
SArray1dC<HashElemLst> & GetTable_Internal() const: Don't use this function, it's a bug work around, and I'll remove it as soon as gcc is fixed.
ostream & operator<<(ostream & out,const HashC<K,T> & obj)
HashElemT<K,T> * LookupHV(const K & Value,HashBaseC::UIndex & HashVal) const: //////////////////////////////// Lookup data in hash table, constant.
BooleanT Del(HashElemT<K,T> * Elem,HashBaseC::UIndex & HashVal): ///////////////////////////// Add member to table. !! Doesn't check if member already exists !!
void Resize(HashBaseC::USize NewSize)

Programmer:Charles Galambos, Documentation by CxxDoc: Tue Mar 20 10:49:27 2001

HashARC<class K,class T>

Auto resizing hash-table.

include	"amma/HashAR.hh"
User Level:	Default
Library:	Hash1d
Example:	WordFreq.cc
Section:	Containers.Hash Tables
In Scope:	std