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cdev-1.7.2n/include/cdevStrHash.h
2022-12-13 12:44:04 +01:00

139 lines
4.7 KiB
C++

//-----------------------------------------------------------------------------
// Copyright (c) 1994,1995 Southeastern Universities Research Association,
// Continuous Electron Beam Accelerator Facility
//
// This software was developed under a United States Government license
// described in the NOTICE file included as part of this distribution.
//
// CEBAF Data Acquisition Group, 12000 Jefferson Ave., Newport News, VA 23606
// Email: coda@cebaf.gov Tel: (804) 249-7101 Fax: (804) 249-7363
//-----------------------------------------------------------------------------
//
// Description:
// cdevStrHash: cdev hash table keyed by a variable length string
// Open Hash with buckets implemented by single linked lists
//
// Note: void *s are stored inside the table. This class
// will not manage these pointers. Callers have to
// manage these pointers
//
// Note: this is unsafe C++ practice. Use at your own risk
//
// Reason: It is so difficult to use a template class inside
// a shared library. (Cfront based C++ compiler cannot
// instantiate a template class during compilation time
//
// Author: Jie Chen
// CEBAF Data Acquisition Group
//
// Revision History:
// cdevStrHash.h,v
// Revision 1.3 1996/08/26 21:12:38 akers
// Added getData method to iterator
//
// Revision 1.2 1995/07/05 18:38:30 chen
// add simple str hash function
//
// Revision 1.1 1995/06/30 15:08:42 chen
// string hash table
//
//
#ifndef _CDEV_STR_HASH_H
#define _CDEV_STR_HASH_H
#include <cdevSlist.h>
//======================================================================
// One simple string hash function
// This hash function is used in cdevDevice and caChannel.
// It returns integer value between 0 to MAX_INTEGER_VALUE
// and this value will be moded with the size of the hash
// table.
// It may be changed to a different hash function in
// release 1.1
//======================================================================
extern CDEVAPI unsigned int cdevStrHashFunc (char *str);
typedef char* cdevKeyItem;
typedef void* cdevHashItem;
//======================================================================
// class cdevStrHash
// collection of buckets indexed by hashed values
//======================================================================
class cdevStrHashIterator;
class CDEV_CLASS_SPEC cdevStrHash
{
public:
// constructor
// construct a table with entry max and hash function *f
// hash function return any integer from 0 to MAX_INT_VALUE
cdevStrHash (unsigned int max, unsigned int (*f)(cdevKeyItem));
// destructor
virtual ~cdevStrHash (void);
// operations
// is the table empty: return 1: yes. return 0: no
virtual int isEmpty();
// clear the elements of the set
virtual void deleteAllValues();
// add an element to the collection
virtual void add (cdevKeyItem key, cdevHashItem ele);
// test to see whether this hash table includes one particular element
virtual int find (cdevKeyItem key, cdevHashItem ele) const;
// remove an element. return 0: ele is not inside table. return 1: success
virtual int remove (cdevKeyItem key, cdevHashItem ele);
// return a reference to a particular bucket according to the key
cdevSlist& bucketRef (cdevKeyItem key);
protected:
friend class cdevStrHashIterator;
// the actual table itself is a vector of buckets
const unsigned int tablesize;
cdevSlist* buckets;
// convert key into unsigned integer value in range
unsigned int hash(const cdevKeyItem& key) const;
private:
unsigned int (*hashCode_)(cdevKeyItem);
};
//======================================================================
// class cdevStrHashIterator
// iterator protocol for hash tables
//======================================================================
class CDEV_CLASS_SPEC cdevStrHashIterator
{
public:
// constructor and destructor
cdevStrHashIterator (cdevStrHash& v);
~cdevStrHashIterator (void);
// iterator protocol
int init (void);
cdevHashItem operator ()(void);
cdevHashItem getData (void);
int operator ! (void);
int operator ++(void);
void operator = (cdevHashItem value);
protected:
cdevStrHash& base;
unsigned int currentIndex;
// Single iterator within a bucket
cdevSlistIterator* itr;
// getNextIterator used to set internal iterator pointer
// return 1: got it. return 0: no more iterator
int getNextIterator (void);
};
#endif