500 lines
18 KiB
C++
500 lines
18 KiB
C++
/****************************************************************************
|
|
* SPHash.h
|
|
* This is modified from sr/include/hash_n.h to minimize dependencies on
|
|
* application specific headers.
|
|
*
|
|
* Owner: bohsu
|
|
* Copyright ©2000 Microsoft Corporation All Rights Reserved.
|
|
*****************************************************************************/
|
|
#pragma once
|
|
|
|
#ifndef WIN32_LEAN_AND_MEAN
|
|
#define WIN32_LEAN_AND_MEAN // Exclude rarely-used stuff from Windows headers
|
|
#endif
|
|
|
|
//--- Includes --------------------------------------------------------------
|
|
#include <windows.h>
|
|
#include <math.h>
|
|
#include <crtdbg.h>
|
|
#ifdef _DEBUG
|
|
#include <stdio.h>
|
|
#endif _DEBUG
|
|
|
|
//--- Forward and External Declarations -------------------------------------
|
|
|
|
//--- TypeDef and Enumeration Declarations ----------------------------------
|
|
|
|
//--- Constants -------------------------------------------------------------
|
|
|
|
//--- Class, Struct and Union Definitions -----------------------------------
|
|
|
|
/***********************************************************************
|
|
* CSPHash Class
|
|
* This is a templated hash table class. Note that the base CSPHash class
|
|
* does not allocate or free the Keys and Values. To define a hash class
|
|
* that manages its Keys and Values, derive a subclass an overload Add()
|
|
* and ...
|
|
*****************************************************************bohsu*/
|
|
template<class KEY, class VALUE>
|
|
class CSPHash
|
|
{
|
|
public:
|
|
// Constructor
|
|
CSPHash(
|
|
VALUE ValueNIL = NULL, // Value representing NIL
|
|
UINT32 uInitialSize = 0); // Initial hash table size
|
|
|
|
// Destructor
|
|
virtual ~CSPHash();
|
|
|
|
// Returns number of (Key, Value) entries used in the hash table.
|
|
inline UINT32 GetNumEntries(void) const { return m_uNumEntriesUsed; }
|
|
|
|
// Returns the next entry starting at the given index. Set puIndex = 0 for the first entry.
|
|
VALUE GetNextEntry(
|
|
UINT32 *puIndex, // Index to start looking for the next entry
|
|
KEY *pKey = NULL) const; // [out] Key of the next entry found
|
|
|
|
// Resets the content hash table.
|
|
virtual void Reset(void);
|
|
|
|
// Adds a (Key, Value) entry to the hash table.
|
|
HRESULT Add(
|
|
KEY Key, // Key to add
|
|
VALUE Val); // Value associated with the Key
|
|
|
|
// Lookup a Value based on the Key. If not found, ValueNIL is returned.
|
|
VALUE Lookup(
|
|
KEY Key) const; // Key to lookup
|
|
|
|
#ifdef _DEBUG
|
|
// Dumps the hash table statistics to file handle.
|
|
void DumpStat(
|
|
FILE *hFile = NULL, // Output file handle. NULL -> DebugWindow
|
|
const char *strHeader = NULL) const; // Trace header
|
|
#endif _DEBUG
|
|
|
|
protected:
|
|
// Data structure containing (Key, Value) pair
|
|
struct ENTRY
|
|
{
|
|
KEY Key;
|
|
VALUE Value;
|
|
};
|
|
|
|
// Find the index corresponding to the given Key.
|
|
int FindIndex(
|
|
KEY Key) const; // Key to search for
|
|
|
|
static UINT32 NextPrime(UINT32 Val);
|
|
|
|
protected:
|
|
//---------------------------------------------------------------
|
|
//--- The following functions can be overloaded by subclasses ---
|
|
//---------------------------------------------------------------
|
|
// If Destroy*() is overloaded, you MUST overload the destructor with:
|
|
// virtual ~CSPDerivedHash() { Reset(); }
|
|
// Calling Reset() in the base class destructor has no effect because
|
|
// the derived subclass will have been destroyed already by the time it
|
|
// gets to the base class destructor. Thus, the correct DestroyKey() and
|
|
// DestroyValue() will never be called.
|
|
|
|
// Hash function mapping the Key to a UINT32 index.
|
|
virtual UINT32 HashKey(KEY Key) const { return (UINT32)Key; }
|
|
|
|
// Compare if two Keys are equal.
|
|
virtual bool AreKeysEqual(KEY Key1, KEY Key2) const { return Key1 == Key2; }
|
|
|
|
// Hash function used to determine the skip count.
|
|
virtual UINT32 HashKey2(KEY Key) const { return 1; }
|
|
|
|
// Overload if a deep copy of the Key needs to be made in Add().
|
|
virtual KEY CopyKey(KEY Key) const { return Key; }
|
|
|
|
// Overload if a deep copy of the Key needs to be made in Add().
|
|
virtual VALUE CopyValue(VALUE Value) const { return Value; }
|
|
|
|
// Overload if the Key needs to be destroyed.
|
|
virtual void DestroyKey(KEY Key) const { }
|
|
|
|
// Overload if the Value needs to be destroyed.
|
|
virtual void DestroyValue(VALUE Value) const { }
|
|
|
|
//------------------------
|
|
//--- Member Variables ---
|
|
//------------------------
|
|
protected:
|
|
ENTRY *m_aTable; // Hash table containing (Key, Value) pairs
|
|
VALUE m_ValueNIL; // Value representing NIL
|
|
UINT32 m_uNumEntries; // Current size of hash table
|
|
UINT32 m_uNumEntriesInit; // Initial size of hash table
|
|
UINT32 m_uNumEntriesUsed; // Current number of entries used in hash table
|
|
|
|
#ifdef _DEBUG
|
|
UINT32 m_uAccess; // Number of times a Key is looked up
|
|
UINT32 m_uSearch; // Number of times a entry in the table is searched
|
|
UINT32 m_uRegrow; // Number of times the hash table regrew
|
|
#endif _DEBUG
|
|
};
|
|
|
|
|
|
/***********************************************************************
|
|
* CSPStringHashW Class
|
|
* CSPStringHashW is a hash of UNICODE strings to VALUEs. The UNICODE string
|
|
* is treated as a constant. It is neither copied during Add() nor deleted
|
|
* during destructor. Likewise, VALUE is treated as a simple data type and
|
|
* is neither copied nor destroyed. If the application wants the class to
|
|
* manage its own copy of the string key or VALUE, derive a subclass and
|
|
* overload Copy*() and/or Destroy().
|
|
*****************************************************************bohsu*/
|
|
template<class VALUE> class CSPStringHashW : public CSPHash<const WCHAR *, VALUE>
|
|
{
|
|
protected:
|
|
UINT32 StringHashW(const WCHAR *wcsKey, UINT32 uPrime) const
|
|
{
|
|
UINT32 uHashIndex = 0;
|
|
for(const WCHAR *pwch = wcsKey; *pwch != NULL; pwch++)
|
|
uHashIndex = uHashIndex * uPrime + *pwch;
|
|
return uHashIndex;
|
|
}
|
|
|
|
//--- Overloaded functions ---
|
|
protected:
|
|
virtual UINT32 HashKey(const WCHAR* wcsKey) const { return StringHashW(wcsKey, 65599); }
|
|
virtual UINT32 HashKey2(const WCHAR* wcsKey) const { return StringHashW(wcsKey, 257); }
|
|
virtual bool AreKeysEqual(const WCHAR* wcsKey1, const WCHAR* wcsKey2) const
|
|
{
|
|
return wcscmp(wcsKey1, wcsKey2) == 0;
|
|
}
|
|
};
|
|
|
|
/***********************************************************************
|
|
* CSPGUIDHash Class
|
|
* CSPGUIDHash is a hash of GUIDs to VALUEs. The GUID pointer is treated
|
|
* as a constant. It is neither copied during Add() nor deleted
|
|
* during destructor. Likewise, VALUE is treated as a simple data type and
|
|
* is neither copied nor destroyed. If the application wants the class to
|
|
* manage its own copy of the GUID key or VALUE, derive a subclass and
|
|
* overload Copy*() and/or Destroy().
|
|
*****************************************************************bohsu*/
|
|
template<class VALUE> class CSPGUIDHash : public CSPHash<const GUID *, VALUE>
|
|
{
|
|
//--- Overloaded functions ---
|
|
protected:
|
|
virtual UINT32 HashKey(const GUID *pguidKey) const { return pguidKey->Data1; }
|
|
virtual UINT32 HashKey2(const GUID *pguidKey) const { return pguidKey->Data2; }
|
|
virtual bool AreKeysEqual(const GUID *pguidKey1, const GUID *pguidKey2) const
|
|
{
|
|
// It is annoying that operator== for GUIDs return int (BOOL) instead of bool.
|
|
return (*pguidKey1 == *pguidKey2) != 0;
|
|
}
|
|
};
|
|
|
|
//--- Function Declarations -------------------------------------------------
|
|
|
|
//--- Inline Function Definitions -------------------------------------------
|
|
|
|
/**********************************************************************
|
|
* CSPHash::CSPHash *
|
|
*------------------*
|
|
* Description:
|
|
* Constructor.
|
|
****************************************************************bohsu*/
|
|
template<class KEY, class VALUE>
|
|
CSPHash<KEY, VALUE>::CSPHash(
|
|
VALUE ValueNIL, // Value representing NIL
|
|
UINT32 uInitialSize) // Initial hash table size
|
|
{
|
|
m_ValueNIL = ValueNIL;
|
|
m_aTable = 0;
|
|
m_uNumEntries = 0;
|
|
m_uNumEntriesInit = uInitialSize; // Estimated final number of entries to be stored.
|
|
m_uNumEntriesUsed = 0;
|
|
|
|
#ifdef _DEBUG
|
|
m_uAccess = 0;
|
|
m_uSearch = 0;
|
|
m_uRegrow = 0;
|
|
#endif _DEBUG
|
|
}
|
|
|
|
/**********************************************************************
|
|
* CSPHash::~CSPHash *
|
|
*-------------------*
|
|
* Description:
|
|
* Destructor. This does not free KEY and VALUE.
|
|
* If Destroy*() is overloaded, call Reset() in the subclass destructor.
|
|
****************************************************************bohsu*/
|
|
template<class KEY, class VALUE>
|
|
CSPHash<KEY, VALUE>::~CSPHash()
|
|
{
|
|
delete [] m_aTable;
|
|
}
|
|
|
|
/**********************************************************************
|
|
* CSPHash::GetNextEntry *
|
|
*-----------------------*
|
|
* Description:
|
|
* Returns the next entry starting at the given index. Set puIndex = 0 for the first entry.
|
|
****************************************************************bohsu*/
|
|
template<class KEY, class VALUE>
|
|
VALUE CSPHash<KEY, VALUE>::GetNextEntry(
|
|
UINT32 *puIndex, // Index to start looking for the next entry
|
|
KEY *pKey) const // [out] Key of the next entry found
|
|
{
|
|
while (*puIndex < m_uNumEntries)
|
|
{
|
|
if (m_aTable[*puIndex].Value != m_ValueNIL)
|
|
{
|
|
if(pKey) *pKey = m_aTable[*puIndex].Key;
|
|
return m_aTable[(*puIndex)++].Value;
|
|
}
|
|
++*puIndex;
|
|
}
|
|
return m_ValueNIL;
|
|
}
|
|
|
|
/**********************************************************************
|
|
* CSPHash::Reset *
|
|
*----------------*
|
|
* Description:
|
|
* Resets the content hash table.
|
|
****************************************************************bohsu*/
|
|
template<class KEY, class VALUE>
|
|
void CSPHash<KEY, VALUE>::Reset()
|
|
{
|
|
for (UINT32 i=0; i < m_uNumEntries; i++)
|
|
{
|
|
if(m_aTable[i].Value != m_ValueNIL)
|
|
{
|
|
DestroyKey(m_aTable[i].Key);
|
|
DestroyValue(m_aTable[i].Value);
|
|
m_aTable[i].Value = m_ValueNIL;
|
|
}
|
|
}
|
|
|
|
m_uNumEntriesUsed = 0;
|
|
#ifdef _DEBUG
|
|
m_uAccess = m_uSearch = m_uRegrow = 0;
|
|
#endif _DEBUG
|
|
}
|
|
|
|
/**********************************************************************
|
|
* CSPHash::Add *
|
|
*--------------*
|
|
* Description:
|
|
* Adds a (Key, Value) entry to the hash table.
|
|
****************************************************************bohsu*/
|
|
template<class KEY, class VALUE>
|
|
HRESULT CSPHash<KEY, VALUE>::Add(
|
|
KEY Key, // Key to add
|
|
VALUE Val) // Value associated with the Key
|
|
{
|
|
int ientry;
|
|
|
|
// Implementation uses Val==m_ValueNIL to detect empty entries.
|
|
_ASSERTE(Val != m_ValueNIL);
|
|
|
|
// Grow if allowed and we're more than half full.
|
|
// (Also handles initial alloc)
|
|
if (m_uNumEntriesUsed * 2 >= m_uNumEntries)
|
|
{
|
|
/* half-full, too crowded ==> regrow */
|
|
ENTRY * oldtable = m_aTable;
|
|
UINT32 oldentry = m_uNumEntries;
|
|
UINT32 prime = NextPrime(max(m_uNumEntriesUsed * 3 + 17, m_uNumEntriesInit));
|
|
|
|
#ifdef _DEBUG
|
|
m_uRegrow++;
|
|
#endif _DEBUG
|
|
|
|
// Alloc new table.
|
|
m_aTable = new ENTRY[prime];
|
|
if (m_aTable == NULL)
|
|
{
|
|
m_aTable = oldtable;
|
|
return E_OUTOFMEMORY;
|
|
}
|
|
|
|
for (UINT32 i=0; i < prime; i++)
|
|
{
|
|
m_aTable[i].Value = m_ValueNIL;
|
|
}
|
|
|
|
m_uNumEntries = prime;
|
|
|
|
for (i = 0; i < oldentry; i++)
|
|
{
|
|
if (oldtable[i].Value != m_ValueNIL)
|
|
{
|
|
ientry = FindIndex(oldtable[i].Key);
|
|
_ASSERTE(ientry >= 0 && m_aTable[ientry].Value == m_ValueNIL);
|
|
m_aTable[ientry] = oldtable[i];
|
|
}
|
|
}
|
|
delete [] oldtable;
|
|
}
|
|
|
|
// Find out where this element should end up.
|
|
ientry = FindIndex(Key);
|
|
if (ientry < 0)
|
|
return E_FAIL; // Too full
|
|
|
|
if (m_aTable[ientry].Value == m_ValueNIL)
|
|
{
|
|
// Not already there. Add it.
|
|
m_aTable[ientry].Key = CopyKey(Key);
|
|
m_aTable[ientry].Value = CopyValue(Val);
|
|
|
|
m_uNumEntriesUsed++;
|
|
}
|
|
else
|
|
{
|
|
return S_FALSE; // It was already there.
|
|
}
|
|
|
|
return S_OK;
|
|
}
|
|
|
|
/**********************************************************************
|
|
* CSPHash::Lookup *
|
|
*-----------------*
|
|
* Description:
|
|
* Lookup a Value based on the Key. If not found, ValueNIL is returned.
|
|
****************************************************************bohsu*/
|
|
template<class KEY, class VALUE>
|
|
VALUE CSPHash<KEY, VALUE>::Lookup(
|
|
KEY Key) const // Key to lookup
|
|
{
|
|
int ientry = FindIndex(Key);
|
|
if (ientry < 0)
|
|
return m_ValueNIL;
|
|
|
|
return m_aTable[ientry].Value;
|
|
}
|
|
|
|
#ifdef _DEBUG
|
|
/**********************************************************************
|
|
* CSPHash::DumpStat *
|
|
*-------------------*
|
|
* Description:
|
|
* Dumps the hash table statistics to file handle.
|
|
****************************************************************bohsu*/
|
|
template<class KEY, class VALUE>
|
|
void CSPHash<KEY, VALUE>::DumpStat(
|
|
FILE *hFile, // Output file handle.
|
|
const char *strHeader) const // Trace header
|
|
{
|
|
if(hFile == NULL)
|
|
{
|
|
char buf[100];
|
|
|
|
sprintf(buf, "(%s) hash statistics:\n", strHeader ? strHeader : "");
|
|
OutputDebugString(buf);
|
|
sprintf(buf, "load=%d/%d = %.3g, regrow = %d\n", m_uNumEntriesUsed, m_uNumEntries,
|
|
(m_uNumEntries == 0) ? 0 : (float)m_uNumEntriesUsed/(float)m_uNumEntries, m_uRegrow);
|
|
OutputDebugString(buf);
|
|
sprintf(buf, "access %d/%d = %g\n\n", m_uSearch, m_uAccess,
|
|
(m_uAccess == 0) ? 0 :
|
|
(float) m_uSearch / (float) m_uAccess);
|
|
OutputDebugString(buf);
|
|
}
|
|
else
|
|
{
|
|
fprintf(hFile, "(%s) hash statistics:\n", strHeader ? strHeader : "");
|
|
fprintf(hFile, "load=%d/%d = %.3g, regrow = %d\n", m_uNumEntriesUsed, m_uNumEntries,
|
|
(m_uNumEntries == 0) ? 0 : (float)m_uNumEntriesUsed/(float)m_uNumEntries, m_uRegrow);
|
|
fprintf(hFile, "access %d/%d = %g\n\n", m_uSearch, m_uAccess,
|
|
(m_uAccess == 0) ? 0 :
|
|
(float) m_uSearch / (float) m_uAccess);
|
|
}
|
|
}
|
|
#endif _DEBUG
|
|
|
|
/**********************************************************************
|
|
* CSPHash::FindIndex *
|
|
*--------------------*
|
|
* Description:
|
|
* Find the index corresponding to the given Key.
|
|
****************************************************************bohsu*/
|
|
template<class KEY, class VALUE>
|
|
int CSPHash<KEY, VALUE>::FindIndex(
|
|
KEY Key) const
|
|
{
|
|
#ifdef _DEBUG
|
|
// Hack: Violate const declaration for statistics member variables
|
|
const_cast<CSPHash *>(this)->m_uAccess++;
|
|
#endif _DEBUG
|
|
|
|
if (m_uNumEntries == 0)
|
|
return -1;
|
|
|
|
UINT32 start = HashKey(Key) % m_uNumEntries;
|
|
UINT32 index = start;
|
|
|
|
UINT32 skip = 0;
|
|
|
|
do
|
|
{
|
|
#ifdef _DEBUG
|
|
// Hack: Violate const declaration for statistics member variables
|
|
const_cast<CSPHash *>(this)->m_uSearch++;
|
|
#endif _DEBUG
|
|
|
|
// Not in table; return index where it should be placed.
|
|
if (m_aTable[index].Value == m_ValueNIL)
|
|
return index;
|
|
|
|
if (AreKeysEqual(m_aTable[index].Key, Key))
|
|
return index;
|
|
|
|
if (skip == 0)
|
|
{
|
|
skip = HashKey2(Key);
|
|
|
|
// Limit skip amount to non-zero and less than hash table size.
|
|
// Since m_uNumEntries is prime, they are relatively prime and so we're guaranteed
|
|
// to visit every bucket.
|
|
if (m_uNumEntries > 1)
|
|
skip = skip % (m_uNumEntries - 1) + 1;
|
|
}
|
|
|
|
index += skip;
|
|
if (index >= m_uNumEntries)
|
|
index -= m_uNumEntries;
|
|
} while (index != start);
|
|
|
|
_ASSERTE(m_uNumEntriesUsed == m_uNumEntries);
|
|
return -1; /* all full and not found */
|
|
}
|
|
|
|
/**********************************************************************
|
|
* CSPHash::NextPrime *
|
|
*--------------------*
|
|
* Description:
|
|
* Return a prime number greater than or equal to Val.
|
|
* If overflow occurs, return 0.
|
|
*
|
|
* To Do: This function can be optimized significantly.
|
|
****************************************************************bohsu*/
|
|
template<class KEY, class VALUE>
|
|
UINT32 CSPHash<KEY, VALUE>::NextPrime(UINT32 Val)
|
|
{
|
|
UINT32 maxFactor;
|
|
UINT32 i;
|
|
|
|
if (Val < 2) return 2; // the smallest prime number
|
|
while(Val < 0xFFFFFFFF)
|
|
{
|
|
maxFactor = (UINT32) sqrt ((double) Val); // Is Val a prime number?
|
|
|
|
for (i = 2; i <= maxFactor; i++) // Is i a factor of Val?
|
|
if (Val % i == 0) break;
|
|
|
|
if (i > maxFactor) return (Val);
|
|
Val++;
|
|
};
|
|
return 0;
|
|
}
|
|
|