This repository has been archived on 2024-06-13. You can view files and clone it, but cannot push or open issues or pull requests.
2020-08-04 13:13:01 -04:00

653 lines
23 KiB
C++

//========= Copyright Valve Corporation, All rights reserved. ============//
//
// Purpose:
//
// $NoKeywords: $
//=============================================================================
#ifndef THASH_H
#define THASH_H
#ifdef _WIN32
#pragma once
#endif
#include <typeinfo>
//#define DBGFLAG_THASH // Perform extra sanity checks on the
//THash
// THash
// This is a heavyweight, templatized version of DHash.
// It differs from DHash in the following ways:
// - It's templetized, and automatically constructs and destructs its records as
// appropriate
// - It provides a scheduling service, which can be used to touch every record
// in the table
// at a specified interval. The scheduler is low-overhead, and
//provides a very smooth distribution of touches across frames.
// Template arguments:
// Data: the class to be stored in the hash table
// I: the type of the primary key (uint32 by default)
template <class Data, typename I = uint32>
class CTHash {
private:
// RecHdr
// We insert one of these at the beginning of every record. It's used for
// keeping the records in a linked list.
typedef struct RecHdr_t {
RecHdr_t *m_pRecHdrNext; // Next item in our linked list
RecHdr_t *m_pRecHdrPrev; // Previous item in our linked list
I m_unKey; // Key of this item
int m_iBucket; // The bucket we're in
int m_nRunRatio; // We want to run 1 cycle out of every m_nRunRatio
// cycles (not at all if 0).
#ifdef DBGFLAG_THASH
uint
m_iCycleLast; // Last cycle we were visited (whether or not we ran)
#endif
} RecHdr_t;
// Bucket
// Each hash bucket is represented by a Bucket structure, which points to
// the first record with the bucket's hash.
typedef struct Bucket_t {
RecHdr_t *m_pRecHdrFirst; // First record in our list
} Bucket_t;
public:
// Constructors & destructors
CTHash(int cFramesPerCycle);
~CTHash();
// Initializer
void Init(int cRecordInit, int cBuckets);
// Insert a record into the table
Data *PvRecordInsert(I unKey);
// Insert a record into the table and set the allocated object's pointer as
// the hash key
Data *PvRecordInsertAutoKey();
// Changes the key for a previously inserted item
void ChangeKey(Data *pvRecord, I unOldKey, I unNewKey);
// Remove a record
void Remove(I unKey);
// Remove a record
void Remove(Data *pvRecord);
// Remove all records
void RemoveAll();
// Find a record
Data *PvRecordFind(I unKey) const;
// How many records do we have
int Count() const { return m_cRecordInUse; }
// Iterate through our members
Data *PvRecordFirst() const;
Data *PvRecordNext(Data *pvRecordCur) const;
// We provide a scheduling service. Call StartFrameSchedule when you want
// to start running records in a given frame, and repeatedly call
// PvRecordRun until it returns NULL (or you run our of time).
void SetRunRatio(Data *pvRecord, int nRunRatio);
void SetMicroSecPerCycle(int cMicroSecPerCycle, int cMicroSecPerFrame) {
m_cFramesPerCycle = cMicroSecPerCycle / cMicroSecPerFrame;
}
void StartFrameSchedule(bool bNewFrame);
Data *PvRecordRun();
bool BCompletedPass();
#ifdef DBGFLAG_VALIDATE
virtual void Validate(CValidator &validator, const char *pchName);
#endif // DBGFLAG_VALIDATE
private:
// Insert a record into the table
Data *PvRecordInsertInternal(RecHdr_t *pRecHdr, I unKey);
// Get the record associated with a THashHdr
Data *PvRecordFromPRecHdr(RecHdr_t *pRecHdr) const {
return (Data *)(((uint8 *)pRecHdr + sizeof(RecHdr_t)));
}
// Get the RecHdr preceding a PvRecord
RecHdr_t *PRecHdrFromPvRecord(Data *pvRecord) const {
return (((RecHdr_t *)pvRecord) - 1);
}
// Get the hash bucket corresponding to a key
int IBucket(I unKey) const;
void InsertIntoHash(RecHdr_t *pRecHdr, I unKey);
void RemoveFromHash(Data *pvRecord);
int m_cBucket; // # of hash buckets we have
Bucket_t *m_pBucket; // Big array of hash buckets
CUtlMemoryPool *m_pMemoryPoolRecord; // All our data records
int m_cRecordInUse; // # of records in use
RecHdr_t m_RecHdrHead; // Head of our linked list
RecHdr_t m_RecHdrTail; // Tail of our linked list
int m_cFramesPerCycle; // Run each of our records once every
// m_cFramesPerCycle frames
RecHdr_t *m_pRecHdrRunNext; // Next record to run (be careful-- this is
// more complicated than it sounds)
int m_iBucketRunMax; // Stop running when we get to this bucket
uint m_iCycleCur; // Current cycle (ie, how many times we've made a
// complete scheduler pass)
uint m_iCycleLast; // Our previous cycle
uint m_iFrameCur; // Our current frame (incremented once each
// StartFrameSchedule)
uint m_iCycleLastReported; // Last cycle checked by BCompletedPass()
};
//-----------------------------------------------------------------------------
// Purpose: Constructor
// Input: cMicroSecRunInterval - How often we want the scheduler to
// run each of our records
//-----------------------------------------------------------------------------
template <class Data, class I>
CTHash<Data, I>::CTHash(int cFramesPerCycle) {
m_cBucket = 0;
m_pBucket = NULL;
m_pMemoryPoolRecord = NULL;
m_cRecordInUse = 0;
m_cFramesPerCycle = cFramesPerCycle;
m_pRecHdrRunNext = &m_RecHdrTail; // This will make us start at the
// beginning on our first frame
m_iBucketRunMax = 0;
m_iCycleCur = 0;
m_iCycleLast = 0;
m_iFrameCur = 0;
m_iCycleLastReported = 0;
m_RecHdrHead.m_pRecHdrPrev = NULL;
m_RecHdrHead.m_pRecHdrNext = &m_RecHdrTail;
m_RecHdrHead.m_iBucket = -1;
m_RecHdrTail.m_pRecHdrPrev = &m_RecHdrHead;
m_RecHdrTail.m_pRecHdrNext = NULL;
}
//-----------------------------------------------------------------------------
// Purpose: Destructor
//-----------------------------------------------------------------------------
template <class Data, class I>
CTHash<Data, I>::~CTHash() {
RemoveAll();
if (NULL != m_pBucket) FreePv(m_pBucket);
m_pBucket = NULL;
if (NULL != m_pMemoryPoolRecord) delete (m_pMemoryPoolRecord);
m_pMemoryPoolRecord = NULL;
}
//-----------------------------------------------------------------------------
// Purpose: Initializer. Allocate our various arrays, and set up the free
// list.
// Input: cRecordInit - Initial # of data records we can contain
// cBucket - # of hash buckets we should
//use
//-----------------------------------------------------------------------------
template <class Data, class I>
void CTHash<Data, I>::Init(int cRecordInit, int cBucket) {
Assert(
cRecordInit >
0); // need to init with non-zero value or memory pool will never grow
// Copy our parameters
m_cBucket = cBucket;
// Alloc our arrays
m_pBucket = (Bucket_t *)PvAlloc(sizeof(Bucket_t) * m_cBucket);
m_pMemoryPoolRecord =
new CUtlMemoryPool(sizeof(Data) + sizeof(RecHdr_t), cRecordInit,
CUtlMemoryPool::GROW_SLOW);
// Init the hash buckets
for (int iBucket = 0; iBucket < m_cBucket; iBucket++)
m_pBucket[iBucket].m_pRecHdrFirst = NULL;
// Make the tail have an illegally large bucket
m_RecHdrTail.m_iBucket = m_cBucket + 1;
}
//-----------------------------------------------------------------------------
// Purpose: Inserts a new record into the table
// Input: unKey - Primary key of the new record
// Output: Pointer to the new record
//-----------------------------------------------------------------------------
template <class Data, class I>
Data *CTHash<Data, I>::PvRecordInsert(I unKey) {
Assert(PvRecordFind(unKey) ==
NULL); // keys are unique; no record with this key may exist
// Find a free record
RecHdr_t *pRecHdr = (RecHdr_t *)m_pMemoryPoolRecord->Alloc();
return PvRecordInsertInternal(pRecHdr, unKey);
}
//-----------------------------------------------------------------------------
// Purpose: Inserts a new record into the table and sets its key to the pointer
// value of the record
// Output: Pointer to the new record
//-----------------------------------------------------------------------------
template <class Data, class I>
Data *CTHash<Data, I>::PvRecordInsertAutoKey() {
// Find a free record
RecHdr_t *pRecHdr = (RecHdr_t *)m_pMemoryPoolRecord->Alloc();
return PvRecordInsertInternal(pRecHdr, (I)PvRecordFromPRecHdr(pRecHdr));
}
//-----------------------------------------------------------------------------
// Purpose: Inserts an allocated record into the hash table with specified key
// and calls the constructor of the allocated object
// Input: pRecHdr - record to insert
// unKey - hash key to use for record
// Output: Pointer to the new record
//-----------------------------------------------------------------------------
template <class Data, class I>
Data *CTHash<Data, I>::PvRecordInsertInternal(RecHdr_t *pRecHdr, I unKey) {
InsertIntoHash(pRecHdr, unKey);
// assert that we don't have too many items per bucket
static bool s_bPerfWarning = false;
if (!s_bPerfWarning && Count() >= (5 * m_cBucket)) {
s_bPerfWarning = true;
AssertMsg(false,
"Performance warning: too many items, not enough buckets");
Msg("not enough buckets in thash class %s (%d records, %d buckets)\n",
#ifdef _WIN32
typeid(*this).raw_name(),
#else
typeid(*this).name(),
#endif
Count(), m_cBucket);
}
// Construct ourselves
Data *pData = PvRecordFromPRecHdr(pRecHdr);
Construct<Data>(pData);
return pData;
}
//-----------------------------------------------------------------------------
// Purpose: Changes key on previously inserted item
// Input: pvRecord - record to change key for
// unOldKey - old key (not strictly needed, but
//helpful consistency check) unNewKey - new key to use
//-----------------------------------------------------------------------------
template <class Data, class I>
void CTHash<Data, I>::ChangeKey(Data *pvRecord, I unOldKey, I unNewKey) {
Data *pvRecordFound = PvRecordFind(unOldKey);
Assert(pvRecordFound == pvRecord);
if (pvRecordFound == pvRecord) {
RemoveFromHash(pvRecord);
InsertIntoHash(PRecHdrFromPvRecord(pvRecord), unNewKey);
}
}
//-----------------------------------------------------------------------------
// Purpose: Removes the entry with a specified key from the table
// Input: unKey - Key of the entry to remove
//-----------------------------------------------------------------------------
template <class Data, class I>
void CTHash<Data, I>::Remove(I unKey) {
Data *pvRemove = (Data *)PvRecordFind(unKey);
Assert(pvRemove);
if (!pvRemove) return;
Remove(pvRemove);
}
//-----------------------------------------------------------------------------
// Purpose: Removes the specified entry from the table
// Input: pvRemove - Pointer to the entry to remove
//-----------------------------------------------------------------------------
template <class Data, class I>
void CTHash<Data, I>::Remove(Data *pvRemove) {
// Destruct the record we're removing
Destruct<Data>(pvRemove);
RemoveFromHash(pvRemove);
m_pMemoryPoolRecord->Free(PRecHdrFromPvRecord(pvRemove));
}
//-----------------------------------------------------------------------------
// Purpose: Removes all entries from the table
//-----------------------------------------------------------------------------
template <class Data, class I>
void CTHash<Data, I>::RemoveAll() {
Data *pvRecord = PvRecordFirst();
while (pvRecord) {
Data *pvRecordNext = PvRecordNext(pvRecord);
Remove(pvRecord);
pvRecord = pvRecordNext;
}
}
//-----------------------------------------------------------------------------
// Purpose: Finds the entry with a specified key
// Input: unKey - Key to find
//-----------------------------------------------------------------------------
template <class Data, class I>
Data *CTHash<Data, I>::PvRecordFind(I unKey) const {
// Find our hash bucket
int iBucket = IBucket(unKey);
// Walk the bucket's list looking for an exact match
for (RecHdr_t *pRecHdr = m_pBucket[iBucket].m_pRecHdrFirst;
NULL != pRecHdr && pRecHdr->m_iBucket == iBucket;
pRecHdr = pRecHdr->m_pRecHdrNext) {
if (unKey == pRecHdr->m_unKey) return PvRecordFromPRecHdr(pRecHdr);
}
// Didn't find a match
return NULL;
}
//-----------------------------------------------------------------------------
// Purpose: Finds our first record
// Output: Pointer to our first record
//-----------------------------------------------------------------------------
template <class Data, class I>
Data *CTHash<Data, I>::PvRecordFirst() const {
if (&m_RecHdrTail != m_RecHdrHead.m_pRecHdrNext)
return PvRecordFromPRecHdr(m_RecHdrHead.m_pRecHdrNext);
else
return NULL;
}
//-----------------------------------------------------------------------------
// Purpose: Iterates to the record after a given record
// Input: Pointer to a current record
// Output: Pointer to the next record
//-----------------------------------------------------------------------------
template <class Data, class I>
Data *CTHash<Data, I>::PvRecordNext(Data *pvRecordCur) const {
RecHdr_t *pRecHdr = PRecHdrFromPvRecord(pvRecordCur);
if (&m_RecHdrTail == pRecHdr->m_pRecHdrNext) return NULL;
return PvRecordFromPRecHdr(pRecHdr->m_pRecHdrNext);
}
//-----------------------------------------------------------------------------
// Purpose: Sets the run ratio of a particular record in the hash table.
// The record will be run 1 cycle out of every nRunRatio
//cycles.
// Input: pvRecord - The record we're setting
// nRunRatio - The run ratio for this record
//-----------------------------------------------------------------------------
template <class Data, class I>
void CTHash<Data, I>::SetRunRatio(Data *pvRecord, int nRunRatio) {
PRecHdrFromPvRecord(pvRecord)->m_nRunRatio = nRunRatio;
}
//-----------------------------------------------------------------------------
// Purpose: Prepares us to run all records that are due to be run this frame.
// Records are run at a particular time dependent on their hash
//bucket, regardless of when they were last run.
// Input: bNewFrame - True if this is a new frame. If false, we've
// run
// off the end of the list and are
//checking whether we need to keep going at the beginning.
//-----------------------------------------------------------------------------
template <class Data, class I>
void CTHash<Data, I>::StartFrameSchedule(bool bNewFrame) {
// Calculate our current frame and cycle cycle
if (bNewFrame) {
m_iCycleLast = m_iCycleCur;
m_iFrameCur++;
m_iCycleCur = m_iFrameCur / m_cFramesPerCycle;
}
// Calculate the last bucket to run
int iFrameInCycle = m_iFrameCur % m_cFramesPerCycle;
m_iBucketRunMax = (int)(((int64)(iFrameInCycle + 1) * (int64)m_cBucket) /
(int64)m_cFramesPerCycle);
AssertFatal(m_iBucketRunMax >= 0 && m_iBucketRunMax <= m_cBucket);
// Are we starting a new cycle?
if (m_iCycleCur > m_iCycleLast) {
#ifdef DBGFLAG_THASH
Assert(m_iCycleCur == m_iCycleLast + 1);
#endif
// Did we finish the last cycle?
if (&m_RecHdrTail == m_pRecHdrRunNext) {
m_pRecHdrRunNext = m_RecHdrHead.m_pRecHdrNext;
}
// No-- finish it up before moving on
else {
m_iBucketRunMax = m_cBucket + 1;
}
}
}
//-----------------------------------------------------------------------------
// Purpose: Returns the next record to run, if any
// Output: Pointer to the next record that needs to run (NULL if we're
// done)
//-----------------------------------------------------------------------------
template <class Data, class I>
Data *CTHash<Data, I>::PvRecordRun() {
// Loop until we find a record to run, or until we pass m_iBucketRunMax
for (;;) {
// Are we past our stopping point?
if (m_pRecHdrRunNext->m_iBucket >= m_iBucketRunMax) {
// If this cycle ran to the very end, see if we need to start over
if (m_iBucketRunMax > m_cBucket) {
StartFrameSchedule(false);
continue;
}
return NULL;
}
#ifdef DBGFLAG_THASH
Assert(m_pRecHdrRunNext->m_iBucket >= m_iBucketRunFirst);
if (0 != m_pRecHdrRunNext->m_iCycleLast) {
if (m_pRecHdrRunNext->m_iCycleLast == m_iCycleCur) {
DMsg(SPEW_CONSOLE, 1,
"Double cycle: hdr = 0x%x, last frame = %d, curFrame = "
"%d, first = %d, last = %d, bucket = %d\n",
m_pRecHdrRunNext, m_pRecHdrRunNext->m_iFrameLast, m_iFrame,
m_iBucketRunFirst, m_iBucketRunMax,
m_pRecHdrRunNext->m_iBucket);
} else if (m_pRecHdrRunNext->m_iCycleLast != m_iCycleCur - 1) {
DMsg(SPEW_CONSOLE, 1,
"Skipped cycle: hdr = 0x%x, cycleLast = %u, cycleCur = %u "
"(missed %u cycles)\n",
m_pRecHdrRunNext, m_pRecHdrRunNext->m_iCycleLast,
m_iCycleCur, m_iCycleCur - m_pRecHdrRunNext->m_iCycleLast);
Assert(false);
}
}
m_pRecHdrRunNext->m_iCycleLast = m_iCycleCur;
m_pRecHdrRunNext->m_iFrameLast = m_iFrame;
#endif
// Set up the record to run next time
RecHdr_t *pRecHdrCur = m_pRecHdrRunNext;
m_pRecHdrRunNext = m_pRecHdrRunNext->m_pRecHdrNext;
// Does this record need to run?
if (0 == pRecHdrCur->m_nRunRatio) continue;
if (0 == m_iCycleCur % pRecHdrCur->m_nRunRatio)
return PvRecordFromPRecHdr(pRecHdrCur);
}
}
//-----------------------------------------------------------------------------
// Purpose: Return true if we've completed a scheduler pass since last called
//-----------------------------------------------------------------------------
template <class Data, class I>
bool CTHash<Data, I>::BCompletedPass() {
if (m_iCycleCur != m_iCycleLastReported) {
m_iCycleLastReported = m_iCycleCur;
return true;
}
return false;
}
extern const unsigned char
g_CTHashRandomValues[256]; // definition lives in globals.cpp
//-----------------------------------------------------------------------------
// Purpose: Returns the index of the hash bucket corresponding to a particular
// key Input: unKey - Key to find Output: Index of the hash bucket
// corresponding to unKey
//-----------------------------------------------------------------------------
template <class Data, class I>
int CTHash<Data, I>::IBucket(I unKey) const {
AssertFatal(m_cBucket > 0);
// This is a pearsons hash variant that returns a maximum of 32 bits
size_t size = sizeof(I);
const uint8 *k = (const uint8 *)&unKey;
uint32 byte_one = 0, byte_two = 0, byte_three = 0, byte_four = 0, n;
while (size) {
--size;
n = *k++;
byte_one = g_CTHashRandomValues[byte_one ^ n];
if (size) {
--size;
n = *k++;
byte_two = g_CTHashRandomValues[byte_two ^ n];
} else
break;
if (size) {
--size;
n = *k++;
byte_three = g_CTHashRandomValues[byte_three ^ n];
} else
break;
if (size) {
--size;
n = *k++;
byte_four = g_CTHashRandomValues[byte_four ^ n];
} else
break;
}
uint32 idx =
(byte_four << 24) | (byte_three << 16) | (byte_two << 8) | byte_one;
idx = idx % m_cBucket;
return ((int)idx);
}
#ifdef DBGFLAG_VALIDATE
//-----------------------------------------------------------------------------
// Purpose: Run a global validation pass on all of our data structures and
// memory
// allocations.
// Input: validator - Our global validator object
// pchName - Our name (typically a member var in our
//container)
//-----------------------------------------------------------------------------
template <class Data, class I>
void CTHash<Data, I>::Validate(CValidator &validator, const char *pchName) {
VALIDATE_SCOPE();
validator.ClaimMemory(m_pBucket);
ValidatePtr(m_pMemoryPoolRecord);
#if defined(_DEBUG)
// first verify m_cRecordInUse
Data *pvRecord = PvRecordFirst();
int cItems = 0;
while (pvRecord) {
Data *pvRecordNext = PvRecordNext(pvRecord);
cItems++;
pvRecord = pvRecordNext;
}
Assert(m_cRecordInUse == cItems);
// then ask the mempool to verify this
if (m_pMemoryPoolRecord) m_pMemoryPoolRecord->LeakCheck(cItems);
#endif // _DEBUG
}
#endif // DBGFLAG_VALIDATE
//-----------------------------------------------------------------------------
// Purpose: Inserts a new record into the table
// Input: unKey - Primary key of the new record
// Output: Pointer to the new record
//-----------------------------------------------------------------------------
template <class Data, class I>
void CTHash<Data, I>::InsertIntoHash(RecHdr_t *pRecHdr, I unKey) {
m_cRecordInUse++;
// Init the RecHdr
pRecHdr->m_unKey = unKey;
pRecHdr->m_nRunRatio = 1;
// Find our hash bucket
int iBucket = IBucket(unKey);
pRecHdr->m_iBucket = iBucket;
#ifdef DBGFLAG_THASH
pRecHdr->m_iCycleLast = 0;
#endif
// Find where to insert ourselves in the linked list
RecHdr_t *pRecHdrInsertBefore = &m_RecHdrTail;
// Find the first bucket with anything in it that's at or after our bucket
for (int iBucketT = iBucket; iBucketT < m_cBucket; iBucketT++) {
if (NULL != m_pBucket[iBucketT].m_pRecHdrFirst) {
pRecHdrInsertBefore = m_pBucket[iBucketT].m_pRecHdrFirst;
break;
}
}
// Insert ourselves
pRecHdr->m_pRecHdrNext = pRecHdrInsertBefore;
pRecHdr->m_pRecHdrPrev = pRecHdrInsertBefore->m_pRecHdrPrev;
pRecHdrInsertBefore->m_pRecHdrPrev = pRecHdr;
pRecHdr->m_pRecHdrPrev->m_pRecHdrNext = pRecHdr;
// Our bucket should point to us
m_pBucket[iBucket].m_pRecHdrFirst = pRecHdr;
}
//-----------------------------------------------------------------------------
// Purpose: Removes the specified entry from the table
// Input: pvRemove - Pointer to the entry to remove
//-----------------------------------------------------------------------------
template <class Data, class I>
void CTHash<Data, I>::RemoveFromHash(Data *pvRemove) {
// Find our RecHdr
RecHdr_t *pRecHdr = PRecHdrFromPvRecord(pvRemove);
// If our bucket points to us, point it to the next record (or else NULL)
int iBucket = IBucket(pRecHdr->m_unKey);
if (pRecHdr == m_pBucket[iBucket].m_pRecHdrFirst) {
if (pRecHdr->m_pRecHdrNext->m_iBucket == iBucket)
m_pBucket[iBucket].m_pRecHdrFirst = pRecHdr->m_pRecHdrNext;
else
m_pBucket[iBucket].m_pRecHdrFirst = NULL;
}
// Remove us from the linked list
pRecHdr->m_pRecHdrPrev->m_pRecHdrNext = pRecHdr->m_pRecHdrNext;
pRecHdr->m_pRecHdrNext->m_pRecHdrPrev = pRecHdr->m_pRecHdrPrev;
// Are we the next record to run?
if (pRecHdr == m_pRecHdrRunNext) m_pRecHdrRunNext = pRecHdr->m_pRecHdrNext;
m_cRecordInUse--;
}
#endif // THASH_H