Team Fortress 2 Source Code as on 22/4/2020
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//========= Copyright Valve Corporation, All rights reserved. ============//
//
// Purpose:
//
// $NoKeywords: $
//
// Thread-safe hash class
//===========================================================================//
#ifndef UTLTSHASH_H
#define UTLTSHASH_H
#ifdef _WIN32
#pragma once
#endif
#include <limits.h>
#include "tier0/threadtools.h"
#include "tier1/mempool.h"
#include "generichash.h"
//=============================================================================
//
// Threadsafe Hash
//
// Number of buckets must be a power of 2.
// Key must be intp sized (32-bits on x32, 64-bits on x64)
// Designed for a usage pattern where the data is semi-static, and there
// is a well-defined point where we are guaranteed no queries are occurring.
//
// Insertions are added into a thread-safe list, and when Commit() is called,
// the insertions are moved into a lock-free list
//
// Elements are never individually removed; clears must occur at a time
// where we and guaranteed no queries are occurring
//
typedef intp UtlTSHashHandle_t;
template < class T >
abstract_class ITSHashConstructor
{
public:
virtual void Construct( T* pElement ) = 0;
};
template < class T >
class CDefaultTSHashConstructor : public ITSHashConstructor< T >
{
public:
virtual void Construct( T* pElement )
{
::Construct( pElement );
}
};
template < int BUCKET_COUNT, class KEYTYPE = intp >
class CUtlTSHashGenericHash
{
public:
static int Hash( const KEYTYPE &key, int nBucketMask )
{
int nHash = HashIntConventional( (intp)key );
if ( BUCKET_COUNT <= USHRT_MAX )
{
nHash ^= ( nHash >> 16 );
}
if ( BUCKET_COUNT <= UCHAR_MAX )
{
nHash ^= ( nHash >> 8 );
}
return ( nHash & nBucketMask );
}
static bool Compare( const KEYTYPE &lhs, const KEYTYPE &rhs )
{
return lhs == rhs;
}
};
template < int BUCKET_COUNT, class KEYTYPE >
class CUtlTSHashUseKeyHashMethod
{
public:
static int Hash( const KEYTYPE &key, int nBucketMask )
{
uint32 nHash = key.HashValue();
return ( nHash & nBucketMask );
}
static bool Compare( const KEYTYPE &lhs, const KEYTYPE &rhs )
{
return lhs == rhs;
}
};
template< class T, int BUCKET_COUNT, class KEYTYPE = intp, class HashFuncs = CUtlTSHashGenericHash< BUCKET_COUNT, KEYTYPE >, int nAlignment = 0 >
class CUtlTSHash
{
public:
// Constructor/Deconstructor.
CUtlTSHash( int nAllocationCount );
~CUtlTSHash();
// Invalid handle.
static UtlTSHashHandle_t InvalidHandle( void ) { return ( UtlTSHashHandle_t )0; }
// Retrieval. Super fast, is thread-safe
UtlTSHashHandle_t Find( KEYTYPE uiKey );
// Insertion ( find or add ).
UtlTSHashHandle_t Insert( KEYTYPE uiKey, const T &data, bool *pDidInsert = NULL );
UtlTSHashHandle_t Insert( KEYTYPE uiKey, ITSHashConstructor<T> *pConstructor, bool *pDidInsert = NULL );
// This insertion method assumes the element is not in the hash table, skips
UtlTSHashHandle_t FastInsert( KEYTYPE uiKey, const T &data );
UtlTSHashHandle_t FastInsert( KEYTYPE uiKey, ITSHashConstructor<T> *pConstructor );
// Commit recent insertions, making finding them faster.
// Only call when you're certain no threads are accessing the hash table
void Commit( );
// Removal. Only call when you're certain no threads are accessing the hash table
void FindAndRemove( KEYTYPE uiKey );
void Remove( UtlTSHashHandle_t hHash ) { FindAndRemove( GetID( hHash ) ); }
void RemoveAll( void );
void Purge( void );
// Returns the number of elements in the hash table
int Count() const;
// Returns elements in the table
int GetElements( int nFirstElement, int nCount, UtlTSHashHandle_t *pHandles ) const;
// Element access
T &Element( UtlTSHashHandle_t hHash );
T const &Element( UtlTSHashHandle_t hHash ) const;
T &operator[]( UtlTSHashHandle_t hHash );
T const &operator[]( UtlTSHashHandle_t hHash ) const;
KEYTYPE GetID( UtlTSHashHandle_t hHash ) const;
// Convert element * to hashHandle
UtlTSHashHandle_t ElementPtrToHandle( T* pElement ) const;
private:
// Templatized for memory tracking purposes
template < typename Data_t >
struct HashFixedDataInternal_t
{
KEYTYPE m_uiKey;
HashFixedDataInternal_t< Data_t >* m_pNext;
Data_t m_Data;
};
typedef HashFixedDataInternal_t<T> HashFixedData_t;
enum
{
BUCKET_MASK = BUCKET_COUNT - 1
};
struct HashBucket_t
{
HashFixedData_t *m_pFirst;
HashFixedData_t *m_pFirstUncommitted;
CThreadSpinRWLock m_AddLock;
};
UtlTSHashHandle_t Find( KEYTYPE uiKey, HashFixedData_t *pFirstElement, HashFixedData_t *pLastElement );
UtlTSHashHandle_t InsertUncommitted( KEYTYPE uiKey, HashBucket_t &bucket );
CMemoryPoolMT m_EntryMemory;
HashBucket_t m_aBuckets[BUCKET_COUNT];
bool m_bNeedsCommit;
#ifdef _DEBUG
CInterlockedInt m_ContentionCheck;
#endif
};
//-----------------------------------------------------------------------------
// Purpose: Constructor
//-----------------------------------------------------------------------------
template<class T, int BUCKET_COUNT, class KEYTYPE, class HashFuncs, int nAlignment>
CUtlTSHash<T,BUCKET_COUNT,KEYTYPE,HashFuncs,nAlignment>::CUtlTSHash( int nAllocationCount ) :
m_EntryMemory( sizeof( HashFixedData_t ), nAllocationCount, CUtlMemoryPool::GROW_SLOW, MEM_ALLOC_CLASSNAME( HashFixedData_t ), nAlignment )
{
#ifdef _DEBUG
m_ContentionCheck = 0;
#endif
m_bNeedsCommit = false;
for ( int i = 0; i < BUCKET_COUNT; i++ )
{
HashBucket_t &bucket = m_aBuckets[ i ];
bucket.m_pFirst = NULL;
bucket.m_pFirstUncommitted = NULL;
}
}
//-----------------------------------------------------------------------------
// Purpose: Deconstructor
//-----------------------------------------------------------------------------
template<class T, int BUCKET_COUNT, class KEYTYPE, class HashFuncs, int nAlignment>
CUtlTSHash<T,BUCKET_COUNT,KEYTYPE,HashFuncs,nAlignment>::~CUtlTSHash()
{
#ifdef _DEBUG
if ( m_ContentionCheck != 0 )
{
DebuggerBreak();
}
#endif
Purge();
}
//-----------------------------------------------------------------------------
// Purpose: Destroy dynamically allocated hash data.
//-----------------------------------------------------------------------------
template<class T, int BUCKET_COUNT, class KEYTYPE, class HashFuncs, int nAlignment>
inline void CUtlTSHash<T,BUCKET_COUNT,KEYTYPE,HashFuncs,nAlignment>::Purge( void )
{
RemoveAll();
}
//-----------------------------------------------------------------------------
// Returns the number of elements in the hash table
//-----------------------------------------------------------------------------
template<class T, int BUCKET_COUNT, class KEYTYPE, class HashFuncs, int nAlignment>
inline int CUtlTSHash<T,BUCKET_COUNT,KEYTYPE,HashFuncs,nAlignment>::Count() const
{
return m_EntryMemory.Count();
}
//-----------------------------------------------------------------------------
// Returns elements in the table
//-----------------------------------------------------------------------------
template<class T, int BUCKET_COUNT, class KEYTYPE, class HashFuncs, int nAlignment>
int CUtlTSHash<T,BUCKET_COUNT,KEYTYPE,HashFuncs,nAlignment>::GetElements( int nFirstElement, int nCount, UtlTSHashHandle_t *pHandles ) const
{
int nIndex = 0;
for ( int i = 0; i < BUCKET_COUNT; i++ )
{
const HashBucket_t &bucket = m_aBuckets[ i ];
bucket.m_AddLock.LockForRead( );
for ( HashFixedData_t *pElement = bucket.m_pFirstUncommitted; pElement; pElement = pElement->m_pNext )
{
if ( --nFirstElement >= 0 )
continue;
pHandles[ nIndex++ ] = (UtlTSHashHandle_t)pElement;
if ( nIndex >= nCount )
{
bucket.m_AddLock.UnlockRead( );
return nIndex;
}
}
bucket.m_AddLock.UnlockRead( );
}
return nIndex;
}
//-----------------------------------------------------------------------------
// Purpose: Insert data into the hash table given its key (KEYTYPE),
// without a check to see if the element already exists within the tree.
//-----------------------------------------------------------------------------
template<class T, int BUCKET_COUNT, class KEYTYPE, class HashFuncs, int nAlignment>
inline UtlTSHashHandle_t CUtlTSHash<T,BUCKET_COUNT,KEYTYPE,HashFuncs,nAlignment>::InsertUncommitted( KEYTYPE uiKey, HashBucket_t &bucket )
{
m_bNeedsCommit = true;
HashFixedData_t *pNewElement = static_cast< HashFixedData_t * >( m_EntryMemory.Alloc() );
pNewElement->m_pNext = bucket.m_pFirstUncommitted;
bucket.m_pFirstUncommitted = pNewElement;
pNewElement->m_uiKey = uiKey;
return (UtlTSHashHandle_t)pNewElement;
}
//-----------------------------------------------------------------------------
// Purpose: Insert data into the hash table given its key, with
// a check to see if the element already exists within the tree.
//-----------------------------------------------------------------------------
template<class T, int BUCKET_COUNT, class KEYTYPE, class HashFuncs, int nAlignment>
inline UtlTSHashHandle_t CUtlTSHash<T,BUCKET_COUNT,KEYTYPE,HashFuncs,nAlignment>::Insert( KEYTYPE uiKey, const T &data, bool *pDidInsert )
{
#ifdef _DEBUG
if ( m_ContentionCheck != 0 )
{
DebuggerBreak();
}
#endif
if ( pDidInsert )
{
*pDidInsert = false;
}
int iBucket = HashFuncs::Hash( uiKey, BUCKET_MASK );
HashBucket_t &bucket = m_aBuckets[ iBucket ];
// First try lock-free
UtlTSHashHandle_t h = Find( uiKey );
if ( h != InvalidHandle() )
return h;
// Now, try again, but only look in uncommitted elements
bucket.m_AddLock.LockForWrite( );
h = Find( uiKey, bucket.m_pFirstUncommitted, bucket.m_pFirst );
if ( h == InvalidHandle() )
{
h = InsertUncommitted( uiKey, bucket );
CopyConstruct( &Element(h), data );
if ( pDidInsert )
{
*pDidInsert = true;
}
}
bucket.m_AddLock.UnlockWrite( );
return h;
}
template<class T, int BUCKET_COUNT, class KEYTYPE, class HashFuncs, int nAlignment>
inline UtlTSHashHandle_t CUtlTSHash<T,BUCKET_COUNT,KEYTYPE,HashFuncs,nAlignment>::Insert( KEYTYPE uiKey, ITSHashConstructor<T> *pConstructor, bool *pDidInsert )
{
#ifdef _DEBUG
if ( m_ContentionCheck != 0 )
{
DebuggerBreak();
}
#endif
if ( pDidInsert )
{
*pDidInsert = false;
}
// First try lock-free
UtlTSHashHandle_t h = Find( uiKey );
if ( h != InvalidHandle() )
return h;
// Now, try again, but only look in uncommitted elements
int iBucket = HashFuncs::Hash( uiKey, BUCKET_MASK );
HashBucket_t &bucket = m_aBuckets[ iBucket ];
bucket.m_AddLock.LockForWrite( );
h = Find( uiKey, bucket.m_pFirstUncommitted, bucket.m_pFirst );
if ( h == InvalidHandle() )
{
// Useful if non-trivial work needs to happen to make data; don't want to
// do it and then have to undo it if it turns out we don't need to add it
h = InsertUncommitted( uiKey, bucket );
pConstructor->Construct( &Element(h) );
if ( pDidInsert )
{
*pDidInsert = true;
}
}
bucket.m_AddLock.UnlockWrite( );
return h;
}
//-----------------------------------------------------------------------------
// Purpose: Insert data into the hash table given its key
// without a check to see if the element already exists within the tree.
//-----------------------------------------------------------------------------
template<class T, int BUCKET_COUNT, class KEYTYPE, class HashFuncs, int nAlignment>
inline UtlTSHashHandle_t CUtlTSHash<T,BUCKET_COUNT,KEYTYPE,HashFuncs,nAlignment>::FastInsert( KEYTYPE uiKey, const T &data )
{
#ifdef _DEBUG
if ( m_ContentionCheck != 0 )
{
DebuggerBreak();
}
#endif
int iBucket = HashFuncs::Hash( uiKey, BUCKET_MASK );
HashBucket_t &bucket = m_aBuckets[ iBucket ];
bucket.m_AddLock.LockForWrite( );
UtlTSHashHandle_t h = InsertUncommitted( uiKey, bucket );
CopyConstruct( &Element(h), data );
bucket.m_AddLock.UnlockWrite( );
return h;
}
template<class T, int BUCKET_COUNT, class KEYTYPE, class HashFuncs, int nAlignment>
inline UtlTSHashHandle_t CUtlTSHash<T,BUCKET_COUNT,KEYTYPE,HashFuncs,nAlignment>::FastInsert( KEYTYPE uiKey, ITSHashConstructor<T> *pConstructor )
{
#ifdef _DEBUG
if ( m_ContentionCheck != 0 )
{
DebuggerBreak();
}
#endif
int iBucket = HashFuncs::Hash( uiKey, BUCKET_MASK );
HashBucket_t &bucket = m_aBuckets[ iBucket ];
bucket.m_AddLock.LockForWrite( );
UtlTSHashHandle_t h = InsertUncommitted( uiKey, bucket );
pConstructor->Construct( &Element(h) );
bucket.m_AddLock.UnlockWrite( );
return h;
}
//-----------------------------------------------------------------------------
// Purpose: Commits all uncommitted insertions
//-----------------------------------------------------------------------------
template<class T, int BUCKET_COUNT, class KEYTYPE, class HashFuncs, int nAlignment>
inline void CUtlTSHash<T,BUCKET_COUNT,KEYTYPE,HashFuncs,nAlignment>::Commit( )
{
// FIXME: Is this legal? Want this to be lock-free
if ( !m_bNeedsCommit )
return;
// This must occur when no queries are occurring
#ifdef _DEBUG
m_ContentionCheck++;
#endif
for ( int i = 0; i < BUCKET_COUNT; i++ )
{
HashBucket_t &bucket = m_aBuckets[ i ];
bucket.m_AddLock.LockForRead( );
bucket.m_pFirst = bucket.m_pFirstUncommitted;
bucket.m_AddLock.UnlockRead( );
}
m_bNeedsCommit = false;
#ifdef _DEBUG
m_ContentionCheck--;
#endif
}
//-----------------------------------------------------------------------------
// Purpose: Remove a single element from the hash
//-----------------------------------------------------------------------------
template<class T, int BUCKET_COUNT, class KEYTYPE, class HashFuncs, int nAlignment>
inline void CUtlTSHash<T,BUCKET_COUNT,KEYTYPE,HashFuncs,nAlignment>::FindAndRemove( KEYTYPE uiKey )
{
if ( m_EntryMemory.Count() == 0 )
return;
// This must occur when no queries are occurring
#ifdef _DEBUG
m_ContentionCheck++;
#endif
int iBucket = HashFuncs::Hash( uiKey, BUCKET_MASK );
HashBucket_t &bucket = m_aBuckets[ iBucket ];
bucket.m_AddLock.LockForWrite( );
HashFixedData_t *pPrev = NULL;
for ( HashFixedData_t *pElement = bucket.m_pFirstUncommitted; pElement; pPrev = pElement, pElement = pElement->m_pNext )
{
if ( !HashFuncs::Compare( pElement->m_uiKey, uiKey ) )
continue;
if ( pPrev )
{
pPrev->m_pNext = pElement->m_pNext;
}
else
{
bucket.m_pFirstUncommitted = pElement->m_pNext;
}
if ( bucket.m_pFirst == pElement )
{
bucket.m_pFirst = bucket.m_pFirst->m_pNext;
}
Destruct( &pElement->m_Data );
#ifdef _DEBUG
memset( pElement, 0xDD, sizeof(HashFixedData_t) );
#endif
m_EntryMemory.Free( pElement );
break;
}
bucket.m_AddLock.UnlockWrite( );
#ifdef _DEBUG
m_ContentionCheck--;
#endif
}
//-----------------------------------------------------------------------------
// Purpose: Remove all elements from the hash
//-----------------------------------------------------------------------------
template<class T, int BUCKET_COUNT, class KEYTYPE, class HashFuncs, int nAlignment>
inline void CUtlTSHash<T,BUCKET_COUNT,KEYTYPE,HashFuncs,nAlignment>::RemoveAll( void )
{
m_bNeedsCommit = false;
if ( m_EntryMemory.Count() == 0 )
return;
// This must occur when no queries are occurring
#ifdef _DEBUG
m_ContentionCheck++;
#endif
for ( int i = 0; i < BUCKET_COUNT; i++ )
{
HashBucket_t &bucket = m_aBuckets[ i ];
bucket.m_AddLock.LockForWrite( );
for ( HashFixedData_t *pElement = bucket.m_pFirstUncommitted; pElement; pElement = pElement->m_pNext )
{
Destruct( &pElement->m_Data );
}
bucket.m_pFirst = NULL;
bucket.m_pFirstUncommitted = NULL;
bucket.m_AddLock.UnlockWrite( );
}
m_EntryMemory.Clear();
#ifdef _DEBUG
m_ContentionCheck--;
#endif
}
//-----------------------------------------------------------------------------
// Finds an element, but only in the committed elements
//-----------------------------------------------------------------------------
template<class T, int BUCKET_COUNT, class KEYTYPE, class HashFuncs, int nAlignment>
inline UtlTSHashHandle_t CUtlTSHash<T,BUCKET_COUNT,KEYTYPE,HashFuncs,nAlignment>::Find( KEYTYPE uiKey, HashFixedData_t *pFirstElement, HashFixedData_t *pLastElement )
{
#ifdef _DEBUG
if ( m_ContentionCheck != 0 )
{
DebuggerBreak();
}
#endif
for ( HashFixedData_t *pElement = pFirstElement; pElement != pLastElement; pElement = pElement->m_pNext )
{
if ( HashFuncs::Compare( pElement->m_uiKey, uiKey ) )
return (UtlTSHashHandle_t)pElement;
}
return InvalidHandle();
}
//-----------------------------------------------------------------------------
// Finds an element, but only in the committed elements
//-----------------------------------------------------------------------------
template<class T, int BUCKET_COUNT, class KEYTYPE, class HashFuncs, int nAlignment>
inline UtlTSHashHandle_t CUtlTSHash<T,BUCKET_COUNT,KEYTYPE,HashFuncs,nAlignment>::Find( KEYTYPE uiKey )
{
int iBucket = HashFuncs::Hash( uiKey, BUCKET_MASK );
const HashBucket_t &bucket = m_aBuckets[iBucket];
UtlTSHashHandle_t h = Find( uiKey, bucket.m_pFirst, NULL );
if ( h != InvalidHandle() )
return h;
// Didn't find it in the fast ( committed ) list. Let's try the slow ( uncommitted ) one
bucket.m_AddLock.LockForRead( );
h = Find( uiKey, bucket.m_pFirstUncommitted, bucket.m_pFirst );
bucket.m_AddLock.UnlockRead( );
return h;
}
//-----------------------------------------------------------------------------
// Purpose: Return data given a hash handle.
//-----------------------------------------------------------------------------
template<class T, int BUCKET_COUNT, class KEYTYPE, class HashFuncs, int nAlignment>
inline T &CUtlTSHash<T,BUCKET_COUNT,KEYTYPE,HashFuncs,nAlignment>::Element( UtlTSHashHandle_t hHash )
{
return ((HashFixedData_t *)hHash)->m_Data;
}
template<class T, int BUCKET_COUNT, class KEYTYPE, class HashFuncs, int nAlignment>
inline T const &CUtlTSHash<T,BUCKET_COUNT,KEYTYPE,HashFuncs,nAlignment>::Element( UtlTSHashHandle_t hHash ) const
{
return ((HashFixedData_t *)hHash)->m_Data;
}
template<class T, int BUCKET_COUNT, class KEYTYPE, class HashFuncs, int nAlignment>
inline T &CUtlTSHash<T,BUCKET_COUNT,KEYTYPE,HashFuncs,nAlignment>::operator[]( UtlTSHashHandle_t hHash )
{
return ((HashFixedData_t *)hHash)->m_Data;
}
template<class T, int BUCKET_COUNT, class KEYTYPE, class HashFuncs, int nAlignment>
inline T const &CUtlTSHash<T,BUCKET_COUNT,KEYTYPE,HashFuncs,nAlignment>::operator[]( UtlTSHashHandle_t hHash ) const
{
return ((HashFixedData_t *)hHash)->m_Data;
}
template<class T, int BUCKET_COUNT, class KEYTYPE, class HashFuncs, int nAlignment>
inline KEYTYPE CUtlTSHash<T,BUCKET_COUNT,KEYTYPE,HashFuncs,nAlignment>::GetID( UtlTSHashHandle_t hHash ) const
{
return ((HashFixedData_t *)hHash)->m_uiKey;
}
// Convert element * to hashHandle
template<class T, int BUCKET_COUNT, class KEYTYPE, class HashFuncs, int nAlignment>
inline UtlTSHashHandle_t CUtlTSHash<T,BUCKET_COUNT,KEYTYPE,HashFuncs,nAlignment>::ElementPtrToHandle( T* pElement ) const
{
Assert( pElement );
HashFixedData_t *pFixedData = (HashFixedData_t*)( (uint8*)pElement - offsetof( HashFixedData_t, m_Data ) );
Assert( m_EntryMemory.IsAllocationWithinPool( pFixedData ) );
return (UtlTSHashHandle_t)pFixedData;
}
#endif // UTLTSHASH_H