Leaked source code of windows server 2003
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/*++
FHashEx.inl
This file contains the template implementation of the class TFHashEx.
--*/
//---------------------------------------------
template< class Data,
class Key,
class KEYREF /* This is the type used to point or reference items in the cache*/
>
TFHashEx< Data, Key, KEYREF >::TFHashEx( ) :
m_cBuckets( 0 ),
m_cActiveBuckets( 0 ),
m_cNumAlloced( 0 ),
m_cIncrement( 0 ),
m_ppBucket( 0 ),
m_pfnHash( 0 ),
m_pGetKey( 0 ),
m_pMatchKey( 0 ),
m_load( 0 ) {
//
// Very basic constructor
//
}
//---------------------------------------------
template< class Data,
class Key,
class KEYREF
>
BOOL
TFHashEx< Data, Key, KEYREF >::Init(
NEXTPTR pNext,
int cInitial,
int cIncrement,
DWORD (*pfnHash)(KEYREF),
int load,
GETKEY pGetKey,
MATCHKEY pMatchKey
) {
/*++
Routine Description :
Initialize the hash table
Arguments :
pNext - A pointer to Member with class Data where we can hold
our bucket pointers !
cInitial - Initial size of the hash table
cIncrement - Amount to grow the hash table by !
pfnHash - Hash Function -
load - Average bucket length before growing the table !
Return Value :
TRUE if successfull FALSE otherwise
--*/
m_pGetKey = pGetKey ;
m_pMatchKey = pMatchKey ;
//
// Compute nearest power of 2
//
m_pNext = pNext ;
int power = cInitial ;
while( power & (power-1) )
power = power & (power-1) ;
power<<= 1 ;
cInitial = power;
m_load = load ;
m_pfnHash = pfnHash ;
//
// Number of ActiveBuckets is initially half that of the number of buckets.
//
m_cActiveBuckets = power/2 ;
m_cBuckets = power ;
m_cInserts = m_cActiveBuckets * m_load ;
m_cIncrement = m_cActiveBuckets / 4;
m_cNumAlloced = cInitial + 5 * m_cIncrement ;
//
// Allocate bucket pointers and zero initialize
//
m_ppBucket = new Data*[m_cNumAlloced] ;
if( m_ppBucket ) {
ZeroMemory( m_ppBucket, m_cNumAlloced * sizeof( Data*) ) ;
_ASSERT( IsValid( FALSE ) ) ;
return TRUE ;
}
return FALSE ;
}
//------------------------------------------------
template< class Data,
class Key,
class KEYREF
>
BOOL
TFHashEx< Data, Key, KEYREF >::IsValid( BOOL fCheckHash ) {
/*++
Routine Description :
Check that the hash table is valid
Arguments :
fCheckHash - verify that all the buckets contain the correct hash values !
Return Value :
TRUE if successfull FALSE otherwise
--*/
//
// This function checks that all member variables are consistent and correct.
// Do not call this function until AFTER calling the Init() function.
//
if( m_cBuckets <= 0 ||
m_cActiveBuckets <= 0 ||
m_cNumAlloced <= 0 ||
m_cIncrement <= 0 ||
m_load <= 0 )
return FALSE ;
if( m_cActiveBuckets < (m_cBuckets / 2) || m_cActiveBuckets > m_cBuckets )
return FALSE ;
if( m_cActiveBuckets > m_cNumAlloced )
return FALSE ;
if( m_cInserts > (m_load * m_cActiveBuckets) )
return FALSE ;
if( m_ppBucket == 0 )
return FALSE ;
if( fCheckHash ) {
//
// Examine every bucket chain to ensure that elements are in correct slots.
//
for( int i=0; i<m_cNumAlloced; i++ ) {
if( i>=m_cActiveBuckets ) {
if( m_ppBucket[i] != 0 ) {
return FALSE ;
}
} else {
for( Data *p = m_ppBucket[i]; p != 0; p = p->*m_pNext ) {
KEYREF keyref = (p->*m_pGetKey)();
if( ComputeIndex( m_pfnHash( keyref ) ) != unsigned(i) ) {
return FALSE ;
}
}
}
}
}
return TRUE ;
}
//-------------------------------------------------
template< class Data,
class Key,
class KEYREF
>
TFHashEx< Data, Key, KEYREF >::~TFHashEx() {
/*++
Routine Description :
Destroy the hash table !
Arguments :
None
Return Value :
None
--*/
//
// The destructor discards any memory we have allocated.
//
Clear();
}
//-------------------------------------------------
template< class Data,
class Key,
class KEYREF
>
void
TFHashEx< Data, Key, KEYREF >::Clear() {
/*++
Routine Description :
Delete all entries in the table, and reset all member variables !
User must call Init() again before the table is usable !
Arguments :
None.
Return Value :
None
--*/
//
// Discards any memory we have allocated - after this, you must
// call Init() again!
//
if( m_ppBucket ) {
_ASSERT( IsValid( TRUE ) ) ;
for( int i=0; i<m_cNumAlloced; i++ ) {
Data *p, *pNext ;
for( p = m_ppBucket[i], pNext = p ? p->*m_pNext : 0;
p!=0; p=pNext, pNext= p ? p->*m_pNext : 0 ) {
delete p ;
}
}
delete[] m_ppBucket;
}
m_cBuckets = 0;
m_cActiveBuckets = 0;
m_cNumAlloced = 0;
m_cIncrement = 0;
m_ppBucket = 0;
m_pfnHash = 0;
m_load = 0;
}
//-------------------------------------------------
template< class Data,
class Key,
class KEYREF
>
void
TFHashEx< Data, Key, KEYREF >::Empty() {
/*++
Routine Description :
Remove all entries in the table, and reset all member variables !
User must call Init() again before the table is usable !
This is just like Clear() but it does do a "delete".
Arguments :
None.
Return Value :
None
--*/
//
// Discards any memory we have allocated - after this, you must
// call Init() again!
//
if( m_ppBucket ) {
_ASSERT( IsValid( TRUE ) ) ;
delete[] m_ppBucket;
}
m_cBuckets = 0;
m_cActiveBuckets = 0;
m_cNumAlloced = 0;
m_cIncrement = 0;
m_ppBucket = 0;
m_pfnHash = 0;
m_load = 0;
}
//-------------------------------------------------
template< class Data,
class Key,
class KEYREF
>
DWORD
TFHashEx< Data, Key, KEYREF >::ComputeIndex( DWORD dw ) {
/*++
Routine Description :
Compute which bucket an element should be in
This function tells us where we should store elements. To do this we mod with
m_cBuckets. Since we only have m_cActiveBuckets in reality, we check the result
of the mod and subtract m_cBuckets over 2 if necessary.
Arguments :
dw - the hash value of the entry we are adding to the table
Return Value :
Index to the bucket to use !
--*/
DWORD dwTemp = dw % m_cBuckets ;
return (dwTemp >= (unsigned)m_cActiveBuckets) ? dwTemp - (m_cBuckets/2) : dwTemp ;
}
template< class Data,
class Key,
class KEYREF
>
BOOL
TFHashEx< Data, Key, KEYREF >::Insert( Data& d ) {
/*++
Routine Description :
Insert a Data element into the hash table
Arguments :
d - reference to the item to be inserted into the table
Return Value :
TRUE if successfull - FALSE otherwise !
--*/
_ASSERT( d.*m_pNext == 0 ) ;
_ASSERT( IsValid( FALSE ) ) ;
if( InsertData( d ) )
return TRUE ;
return FALSE ;
}
template< class Data,
class Key,
class KEYREF
>
BOOL
TFHashEx< Data, Key, KEYREF >::Insert( Data* pd ) {
/*++
Routine Description :
Insert a Data element into the hash table
Arguments :
pd - pointer to the item to be inserted into the table
Return Value :
TRUE if successfull - FALSE otherwise !
--*/
_ASSERT( pd->*m_pNext == 0 ) ;
_ASSERT( IsValid( FALSE ) ) ;
KEYREF keyref = (pd->*m_pGetKey)() ;
if( InsertDataHash( m_pfnHash( keyref ), pd ) )
return TRUE ;
return FALSE ;
}
//-------------------------------------------------
template< class Data,
class Key,
class KEYREF
>
Data*
TFHashEx< Data, Key, KEYREF >::InsertDataHash(
DWORD dwHash,
Data& d
) {
/*++
Routine Description :
Insert an element into the hash table.
We will use member's of Data to hold the bucket chain.
Arguments :
dw - the hash value of the entry we are adding to the table
d - The item we are adding to the table !
Return Value :
Pointer to the Data Item in its final resting place !
--*/
_ASSERT( IsValid( FALSE ) ) ;
_ASSERT( d.*m_pNext == 0 ) ;
//
// First check whether it is time to grow the hash table.
//
if( --m_cInserts == 0 ) {
//
// Check whether we need to reallocate the array of Bucket pointers.
//
if( m_cIncrement + m_cActiveBuckets > m_cNumAlloced ) {
Data** pTemp = new Data*[m_cNumAlloced + 10 * m_cIncrement ] ;
if( pTemp == 0 ) {
//
// bugbug ... need to handles this error better !?
//
return 0 ;
} else {
ZeroMemory( pTemp, (m_cNumAlloced + 10 *m_cIncrement)* sizeof( Data*) ) ;
CopyMemory( pTemp, m_ppBucket, m_cNumAlloced * sizeof( Data* ) ) ;
delete[] m_ppBucket;
m_cNumAlloced += 10 * m_cIncrement ;
m_ppBucket = pTemp ;
}
}
//
// Okay grow the array by m_cIncrement.
//
m_cActiveBuckets += m_cIncrement ;
if( m_cActiveBuckets > m_cBuckets )
m_cBuckets *= 2 ;
m_cInserts = m_cIncrement * m_load ;
//
// Now do some rehashing of elements.
//
for( int i = -m_cIncrement; i < 0; i++ ) {
int iCurrent = (m_cActiveBuckets + i) - (m_cBuckets / 2) ;
Data** ppNext = &m_ppBucket[ iCurrent ] ;
Data* p = *ppNext ;
while( p ) {
KEYREF keyref = (p->*m_pGetKey)();
int index = ComputeIndex( m_pfnHash( keyref ) ) ;
Data* pNext = p->*m_pNext ;
if( index != iCurrent) {
*ppNext = pNext ;
p->*m_pNext = m_ppBucket[index] ;
m_ppBucket[index] = p ;
} else {
ppNext = &(p->*m_pNext) ;
}
p = pNext ;
}
}
_ASSERT( IsValid( TRUE ) ) ;
}
//
// Finally, insert into the Hash Table.
//
//DWORD index = ComputeIndex( m_pfnHash( d.GetKey() ) ) ;
KEYREF keyref = (d.*m_pGetKey)();
_ASSERT( dwHash == m_pfnHash( keyref ) ) ;
DWORD index = ComputeIndex( dwHash ) ;
_ASSERT( index < unsigned(m_cActiveBuckets) ) ;
d.*m_pNext = m_ppBucket[index] ;
m_ppBucket[index] = &d ;
_ASSERT( IsValid( FALSE ) ) ;
return &d ;
}
//-------------------------------------------------
template< class Data,
class Key,
class KEYREF
>
Data*
TFHashEx< Data, Key, KEYREF >::InsertDataHash(
DWORD dwHash,
Data* pd
) {
/*++
Routine Description :
Insert an element into the hash table.
We will use member's of Data to hold the bucket chain.
Arguments :
dw - the hash value of the entry we are adding to the table
pd - Pointer to the item we are adding to the table !
Return Value :
Pointer to the Data Item in its final resting place !
--*/
_ASSERT( IsValid( FALSE ) ) ;
_ASSERT( pd->*m_pNext == 0 ) ;
//
// First check whether it is time to grow the hash table.
//
if( --m_cInserts == 0 ) {
//
// Check whether we need to reallocate the array of Bucket pointers.
//
if( m_cIncrement + m_cActiveBuckets > m_cNumAlloced ) {
Data** pTemp = new Data*[m_cNumAlloced + 10 * m_cIncrement ] ;
if( pTemp == 0 ) {
//
// bugbug ... need to handles this error better !?
//
return 0 ;
} else {
ZeroMemory( pTemp, (m_cNumAlloced + 10 *m_cIncrement)* sizeof( Data*) ) ;
CopyMemory( pTemp, m_ppBucket, m_cNumAlloced * sizeof( Data* ) ) ;
delete[] m_ppBucket;
m_cNumAlloced += 10 * m_cIncrement ;
m_ppBucket = pTemp ;
}
}
//
// Okay grow the array by m_cIncrement.
//
m_cActiveBuckets += m_cIncrement ;
if( m_cActiveBuckets > m_cBuckets )
m_cBuckets *= 2 ;
m_cInserts = m_cIncrement * m_load ;
//
// Now do some rehashing of elements.
//
for( int i = -m_cIncrement; i < 0; i++ ) {
int iCurrent = (m_cActiveBuckets + i) - (m_cBuckets / 2) ;
Data** ppNext = &m_ppBucket[ iCurrent ] ;
Data* p = *ppNext ;
while( p ) {
KEYREF keyref = (p->*m_pGetKey)();
int index = ComputeIndex( m_pfnHash( keyref ) ) ;
Data* pNext = p->*m_pNext ;
if( index != iCurrent) {
*ppNext = pNext ;
p->*m_pNext = m_ppBucket[index] ;
m_ppBucket[index] = p ;
} else {
ppNext = &(p->*m_pNext) ;
}
p = pNext ;
}
}
_ASSERT( IsValid( TRUE ) ) ;
}
//
// Finally, insert into the Hash Table.
//
//DWORD index = ComputeIndex( m_pfnHash( d.GetKey() ) ) ;
KEYREF keyref = (pd->*m_pGetKey)();
_ASSERT( dwHash == m_pfnHash( keyref ) ) ;
DWORD index = ComputeIndex( dwHash ) ;
_ASSERT( index < unsigned(m_cActiveBuckets) ) ;
pd->*m_pNext = m_ppBucket[index] ;
m_ppBucket[index] = pd ;
_ASSERT( IsValid( FALSE ) ) ;
return pd ;
}
//-------------------------------------------------
template< class Data,
class Key,
class KEYREF
>
inline Data*
TFHashEx< Data, Key, KEYREF >::InsertData( Data& d ) {
/*++
Routine Description :
Insert an element into the hash table.
We will use member's of Data to hold the bucket chain,
and we will also compute the hash of the key !
Arguments :
d - The item we are adding to the table !
Return Value :
Pointer to the Data Item in its final resting place !
--*/
_ASSERT( IsValid( FALSE ) ) ;
KEYREF keyref = (d.*m_pGetKey)() ;
return InsertDataHash( m_pfnHash( keyref ), d ) ;
}
//-----------------------------------------------
template< class Data,
class Key,
class KEYREF
>
BOOL
TFHashEx< Data, Key, KEYREF >::Search( KEYREF k,
Data &dOut
) {
/*++
Routine Description :
Search for an element in the hashtable.
Arguments :
k - key of the item to find
dOut - A reference that we will set to the
located data item
Return Value :
TRUE if found, FALSE otherwise
--*/
const Data* pData = SearchKey( k ) ;
if( pData ) {
dOut = *pData ;
return TRUE ;
}
return FALSE ;
}
//-----------------------------------------------
template< class Data,
class Key,
class KEYREF
>
Data*
TFHashEx< Data, Key, KEYREF >::SearchKeyHash(
DWORD dwHash,
KEYREF k
) {
/*++
Routine Description :
Search for an element in the Hash Table,
Arguments :
dwHash - the hash value of the entry we are adding to the table
k - reference to the key we are to compare against
Return Value :
Pointer to the Data Item in its final resting place !
--*/
_ASSERT( IsValid( FALSE ) ) ;
_ASSERT( dwHash == (m_pfnHash)(k) ) ;
DWORD index = ComputeIndex( dwHash ) ;
Data* p = m_ppBucket[index] ;
while( p ) {
if( (p->*m_pMatchKey)( k ) )
break ;
p = p->*m_pNext ;
}
return p ;
}
//-----------------------------------------------
template< class Data,
class Key,
class KEYREF
>
inline Data*
TFHashEx< Data, Key, KEYREF >::SearchKey( KEYREF k ) {
/*++
Routine Description :
Search for an element in the Hash Table,
We will compute the hash of the key.
Arguments :
k - reference to the key we are to compare against
Return Value :
Pointer to the Data Item in its final resting place !
--*/
_ASSERT( IsValid( FALSE ) ) ;
return SearchKeyHash( m_pfnHash( k ), k ) ;
}
//-----------------------------------------------
template< class Data,
class Key,
class KEYREF
>
BOOL
TFHashEx< Data, Key, KEYREF >::Delete( KEYREF k ) {
/*++
Routine Description :
Find an element in the hash table, remove it from
the table and then destroy it !
Arguments :
k - reference to the key we are to compare against
Return Value :
TRUE if an item is found and destroyed, FALSE otherwise !
--*/
Data* p = DeleteData( k, 0 ) ;
if( p ) {
delete p ;
return TRUE ;
}
return FALSE ;
}
//-----------------------------------------------
template< class Data,
class Key,
class KEYREF
>
Data*
TFHashEx< Data, Key, KEYREF >::DeleteData( KEYREF k,
Data* pd
) {
//
// Remove an element from the Hash Table. We only need the
// Key to find the element we wish to remove.
//
_ASSERT( IsValid( FALSE ) ) ;
DWORD dwHash = (m_pfnHash)( k ) ;
DWORD index = ComputeIndex( dwHash ) ;
Data** ppNext = &m_ppBucket[index] ;
Data* p = *ppNext ;
while( p ) {
if( (p->*m_pMatchKey)( k ) )
break ;
ppNext = &(p->*m_pNext) ;
p = *ppNext ;
}
if( p ) {
//
// If we were given a pointer to a data block, than the client
// wants us to check to make sure that we are deleting the correct
// instance !!
//
if( !pd || pd == p ) {
*ppNext = p->*m_pNext ;
p->*m_pNext = 0 ;
//
// Finally - since we removed something from the hash table
// increment the number of inserts so that we don't keep splitting
// the table unnecessarily !
//
m_cInserts++ ;
_ASSERT( IsValid( FALSE ) ) ;
} else {
p = 0 ;
}
}
_ASSERT( IsValid( FALSE ) ) ;
return p ;
}
template< class Data,
class Key,
class KEYREF
>
DWORD
TFHashEx< Data, Key, KEYREF >::ComputeHash( KEYREF k ) {
return m_pfnHash( k ) ;
}