source-engine/external/vpc/tier1/utlsymbol.cpp
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2020-04-22 12:56:21 -04:00

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//========= Copyright <20> 1996-2005, Valve Corporation, All rights reserved. ============//
//
// Purpose: Defines a symbol table
//
// $Header: $
// $NoKeywords: $
//=============================================================================//
#pragma warning (disable:4514)
#include "utlsymbol.h"
#include "tier0/threadtools.h"
#include "stringpool.h"
#include "generichash.h"
#include "tier0/vprof.h"
#include <stddef.h>
// memdbgon must be the last include file in a .cpp file!!!
#include "tier0/memdbgon.h"
#define INVALID_STRING_INDEX CStringPoolIndex( 0xFFFF, 0xFFFF )
#define MIN_STRING_POOL_SIZE 2048
//-----------------------------------------------------------------------------
// globals
//-----------------------------------------------------------------------------
CUtlSymbolTableMT* CUtlSymbol::s_pSymbolTable = 0;
bool CUtlSymbol::s_bAllowStaticSymbolTable = true;
//-----------------------------------------------------------------------------
// symbol methods
//-----------------------------------------------------------------------------
void CUtlSymbol::Initialize()
{
// If this assert fails, then the module that this call is in has chosen to disallow
// use of the static symbol table. Usually, it's to prevent confusion because it's easy
// to accidentally use the global symbol table when you really want to use a specific one.
Assert( s_bAllowStaticSymbolTable );
// necessary to allow us to create global symbols
static bool symbolsInitialized = false;
if (!symbolsInitialized)
{
s_pSymbolTable = new CUtlSymbolTableMT;
symbolsInitialized = true;
}
}
void CUtlSymbol::LockTableForRead()
{
Initialize();
s_pSymbolTable->LockForRead();
}
void CUtlSymbol::UnlockTableForRead()
{
s_pSymbolTable->UnlockForRead();
}
//-----------------------------------------------------------------------------
// Purpose: Singleton to delete table on exit from module
//-----------------------------------------------------------------------------
class CCleanupUtlSymbolTable
{
public:
~CCleanupUtlSymbolTable()
{
delete CUtlSymbol::s_pSymbolTable;
CUtlSymbol::s_pSymbolTable = NULL;
}
};
static CCleanupUtlSymbolTable g_CleanupSymbolTable;
CUtlSymbolTableMT* CUtlSymbol::CurrTable()
{
Initialize();
return s_pSymbolTable;
}
//-----------------------------------------------------------------------------
// string->symbol->string
//-----------------------------------------------------------------------------
CUtlSymbol::CUtlSymbol( const char* pStr )
{
m_Id = CurrTable()->AddString( pStr );
}
const char* CUtlSymbol::String( ) const
{
return CurrTable()->String(m_Id);
}
const char* CUtlSymbol::StringNoLock( ) const
{
return CurrTable()->StringNoLock(m_Id);
}
void CUtlSymbol::DisableStaticSymbolTable()
{
s_bAllowStaticSymbolTable = false;
}
//-----------------------------------------------------------------------------
// checks if the symbol matches a string
//-----------------------------------------------------------------------------
bool CUtlSymbol::operator==( const char* pStr ) const
{
if (m_Id == UTL_INVAL_SYMBOL)
return false;
return strcmp( String(), pStr ) == 0;
}
//-----------------------------------------------------------------------------
// symbol table stuff
//-----------------------------------------------------------------------------
inline const char* CUtlSymbolTable::DecoratedStringFromIndex( const CStringPoolIndex &index ) const
{
Assert( index.m_iPool < m_StringPools.Count() );
Assert( index.m_iOffset < m_StringPools[index.m_iPool]->m_TotalLen );
// step over the hash decorating the beginning of the string
return (&m_StringPools[index.m_iPool]->m_Data[index.m_iOffset]);
}
inline const char* CUtlSymbolTable::StringFromIndex( const CStringPoolIndex &index ) const
{
// step over the hash decorating the beginning of the string
return DecoratedStringFromIndex(index)+sizeof(hashDecoration_t);
}
// The first two bytes of each string in the pool are actually the hash for that string.
// Thus we compare hashes rather than entire strings for a significant perf benefit.
// However since there is a high rate of hash collision we must still compare strings
// if the hashes match.
bool CUtlSymbolTable::CLess::operator()( const CStringPoolIndex &i1, const CStringPoolIndex &i2 ) const
{
// Need to do pointer math because CUtlSymbolTable is used in CUtlVectors, and hence
// can be arbitrarily moved in memory on a realloc. Yes, this is portable. In reality,
// right now at least, because m_LessFunc is the first member of CUtlRBTree, and m_Lookup
// is the first member of CUtlSymbolTabke, this == pTable
CUtlSymbolTable *pTable = (CUtlSymbolTable *)( (byte *)this - offsetof(CUtlSymbolTable::CTree, m_LessFunc) ) - offsetof(CUtlSymbolTable, m_Lookup );
#if 1 // using the hashes
const char *str1, *str2;
hashDecoration_t hash1, hash2;
if (i1 == INVALID_STRING_INDEX)
{
str1 = pTable->m_pUserSearchString;
hash1 = pTable->m_nUserSearchStringHash;
}
else
{
str1 = pTable->DecoratedStringFromIndex( i1 );
hashDecoration_t storedHash = *reinterpret_cast<const hashDecoration_t *>(str1);
str1 += sizeof(hashDecoration_t);
AssertMsg2( storedHash == ( !pTable->m_bInsensitive ? HashString(str1) : HashStringCaseless(str1) ),
"The stored hash (%d) for symbol %s is not correct.", storedHash, str1 );
hash1 = storedHash;
}
if (i2 == INVALID_STRING_INDEX)
{
str2 = pTable->m_pUserSearchString;
hash2 = pTable->m_nUserSearchStringHash;
}
else
{
str2 = pTable->DecoratedStringFromIndex( i2 );
hashDecoration_t storedHash = *reinterpret_cast<const hashDecoration_t *>(str2);
str2 += sizeof(hashDecoration_t);
AssertMsg2( storedHash == ( !pTable->m_bInsensitive ? HashString(str2) : HashStringCaseless(str2) ),
"The stored hash (%d) for symbol '%s' is not correct.", storedHash, str2 );
hash2 = storedHash;
}
// compare the hashes
if ( hash1 == hash2 )
{
if ( !str1 && str2 )
return false;
if ( !str2 && str1 )
return true;
if ( !str1 && !str2 )
return false;
// if the hashes match compare the strings
if ( !pTable->m_bInsensitive )
return strcmp( str1, str2 ) < 0;
else
return V_stricmp( str1, str2 ) < 0;
}
else
{
return hash1 < hash2;
}
#else // not using the hashes, just comparing strings
const char* str1 = (i1 == INVALID_STRING_INDEX) ? pTable->m_pUserSearchString :
pTable->StringFromIndex( i1 );
const char* str2 = (i2 == INVALID_STRING_INDEX) ? pTable->m_pUserSearchString :
pTable->StringFromIndex( i2 );
if ( !str1 && str2 )
return false;
if ( !str2 && str1 )
return true;
if ( !str1 && !str2 )
return false;
if ( !pTable->m_bInsensitive )
return strcmp( str1, str2 ) < 0;
else
return strcmpi( str1, str2 ) < 0;
#endif
}
//-----------------------------------------------------------------------------
// constructor, destructor
//-----------------------------------------------------------------------------
CUtlSymbolTable::CUtlSymbolTable( int growSize, int initSize, bool caseInsensitive ) :
m_Lookup( growSize, initSize ), m_bInsensitive( caseInsensitive ), m_StringPools( 8 )
{
}
CUtlSymbolTable::~CUtlSymbolTable()
{
// Release the stringpool string data
RemoveAll();
}
CUtlSymbol CUtlSymbolTable::Find( const char* pString ) const
{
VPROF( "CUtlSymbol::Find" );
if (!pString)
return CUtlSymbol();
// Store a special context used to help with insertion
m_pUserSearchString = pString;
m_nUserSearchStringHash = m_bInsensitive ? HashStringCaseless(pString) : HashString(pString) ;
// Passing this special invalid symbol makes the comparison function
// use the string passed in the context
UtlSymId_t idx = m_Lookup.Find( INVALID_STRING_INDEX );
#ifdef _DEBUG
m_pUserSearchString = NULL;
m_nUserSearchStringHash = 0;
#endif
return CUtlSymbol( idx );
}
int CUtlSymbolTable::FindPoolWithSpace( int len ) const
{
for ( int i=0; i < m_StringPools.Count(); i++ )
{
StringPool_t *pPool = m_StringPools[i];
if ( (pPool->m_TotalLen - pPool->m_SpaceUsed) >= len )
{
return i;
}
}
return -1;
}
//-----------------------------------------------------------------------------
// Finds and/or creates a symbol based on the string
//-----------------------------------------------------------------------------
CUtlSymbol CUtlSymbolTable::AddString( const char* pString )
{
VPROF("CUtlSymbol::AddString");
if (!pString)
return CUtlSymbol( UTL_INVAL_SYMBOL );
CUtlSymbol id = Find( pString );
if (id.IsValid())
return id;
int lenString = strlen(pString) + 1; // length of just the string
int lenDecorated = lenString + sizeof(hashDecoration_t); // and with its hash decoration
// make sure that all strings are aligned on 2-byte boundaries so the hashes will read correctly
COMPILE_TIME_ASSERT(sizeof(hashDecoration_t) == 2);
lenDecorated = (lenDecorated + 1) & (~0x01); // round up to nearest multiple of 2
// Find a pool with space for this string, or allocate a new one.
int iPool = FindPoolWithSpace( lenDecorated );
if ( iPool == -1 )
{
// Add a new pool.
int newPoolSize = MAX( lenDecorated + sizeof( StringPool_t ), MIN_STRING_POOL_SIZE );
StringPool_t *pPool = (StringPool_t*)malloc( newPoolSize );
pPool->m_TotalLen = newPoolSize - sizeof( StringPool_t );
pPool->m_SpaceUsed = 0;
iPool = m_StringPools.AddToTail( pPool );
}
// Compute a hash
hashDecoration_t hash = m_bInsensitive ? HashStringCaseless(pString) : HashString(pString) ;
// Copy the string in.
StringPool_t *pPool = m_StringPools[iPool];
Assert( pPool->m_SpaceUsed < 0xFFFF ); // This should never happen, because if we had a string > 64k, it
// would have been given its entire own pool.
unsigned short iStringOffset = pPool->m_SpaceUsed;
const char *startingAddr = &pPool->m_Data[pPool->m_SpaceUsed];
// store the hash at the head of the string
*((hashDecoration_t *)(startingAddr)) = hash;
// and then the string's data
memcpy( (void *)(startingAddr + sizeof(hashDecoration_t)), pString, lenString );
pPool->m_SpaceUsed += lenDecorated;
// insert the string into the vector.
CStringPoolIndex index;
index.m_iPool = iPool;
index.m_iOffset = iStringOffset;
MEM_ALLOC_CREDIT();
UtlSymId_t idx = m_Lookup.Insert( index );
return CUtlSymbol( idx );
}
//-----------------------------------------------------------------------------
// Look up the string associated with a particular symbol
//-----------------------------------------------------------------------------
const char* CUtlSymbolTable::String( CUtlSymbol id ) const
{
if (!id.IsValid())
return "";
Assert( m_Lookup.IsValidIndex((UtlSymId_t)id) );
return StringFromIndex( m_Lookup[id] );
}
//-----------------------------------------------------------------------------
// Remove all symbols in the table.
//-----------------------------------------------------------------------------
void CUtlSymbolTable::RemoveAll()
{
m_Lookup.Purge();
for ( int i=0; i < m_StringPools.Count(); i++ )
free( m_StringPools[i] );
m_StringPools.RemoveAll();
}
//-----------------------------------------------------------------------------
// Purpose:
// Input : *pFileName -
// Output : FileNameHandle_t
//-----------------------------------------------------------------------------
FileNameHandle_t CUtlFilenameSymbolTable::FindOrAddFileName( const char *pFileName )
{
if ( !pFileName )
{
return NULL;
}
// find first
FileNameHandle_t hFileName = FindFileName( pFileName );
if ( hFileName )
{
return hFileName;
}
// Fix slashes+dotslashes and make lower case first..
char fn[ MAX_PATH ];
V_strncpy( fn, pFileName, sizeof( fn ) );
V_RemoveDotSlashes( fn );
// Split the filename into constituent parts
char basepath[ MAX_PATH ];
V_ExtractFilePath( fn, basepath, sizeof( basepath ) );
char filename[ MAX_PATH ];
V_strncpy( filename, fn + V_strlen( basepath ), sizeof( filename ) );
// not found, lock and look again
FileNameHandleInternal_t handle;
m_lock.LockForWrite();
handle.path = m_StringPool.FindStringHandle( basepath );
handle.file = m_StringPool.FindStringHandle( filename );
if ( handle.path && handle.file )
{
// found
m_lock.UnlockWrite();
return *( FileNameHandle_t * )( &handle );
}
// safely add it
handle.path = m_StringPool.ReferenceStringHandle( basepath );
handle.file = m_StringPool.ReferenceStringHandle( filename );
m_lock.UnlockWrite();
return *( FileNameHandle_t * )( &handle );
}
FileNameHandle_t CUtlFilenameSymbolTable::FindFileName( const char *pFileName )
{
if ( !pFileName )
{
return NULL;
}
// Fix slashes+dotslashes and make lower case first..
char fn[ MAX_PATH ];
V_strncpy( fn, pFileName, sizeof( fn ) );
V_RemoveDotSlashes( fn );
// Split the filename into constituent parts
char basepath[ MAX_PATH ];
V_ExtractFilePath( fn, basepath, sizeof( basepath ) );
char filename[ MAX_PATH ];
V_strncpy( filename, fn + V_strlen( basepath ), sizeof( filename ) );
FileNameHandleInternal_t handle;
m_lock.LockForRead();
handle.path = m_StringPool.FindStringHandle(basepath);
handle.file = m_StringPool.FindStringHandle(filename);
m_lock.UnlockRead();
if ( ( handle.path == 0 ) || ( handle.file == 0 ) )
return NULL;
return *( FileNameHandle_t * )( &handle );
}
//-----------------------------------------------------------------------------
// Purpose:
// Input : handle -
// Output : const char
//-----------------------------------------------------------------------------
bool CUtlFilenameSymbolTable::String( const FileNameHandle_t& handle, char *buf, int buflen )
{
buf[ 0 ] = 0;
FileNameHandleInternal_t *internal = ( FileNameHandleInternal_t * )&handle;
if ( !internal )
{
return false;
}
m_lock.LockForRead();
const char *path = m_StringPool.HandleToString(internal->path);
const char *fn = m_StringPool.HandleToString(internal->file);
m_lock.UnlockRead();
if ( !path || !fn )
{
return false;
}
V_strncpy( buf, path, buflen );
V_strncat( buf, fn, buflen, COPY_ALL_CHARACTERS );
return true;
}
void CUtlFilenameSymbolTable::RemoveAll()
{
m_StringPool.FreeAll();
}
void CUtlFilenameSymbolTable::SpewStrings()
{
m_lock.LockForRead();
m_StringPool.SpewStrings();
m_lock.UnlockRead();
}
bool CUtlFilenameSymbolTable::SaveToBuffer( CUtlBuffer &buffer )
{
m_lock.LockForRead();
bool bResult = m_StringPool.SaveToBuffer( buffer );
m_lock.UnlockRead();
return bResult;
}
bool CUtlFilenameSymbolTable::RestoreFromBuffer( CUtlBuffer &buffer )
{
m_lock.LockForWrite();
bool bResult = m_StringPool.RestoreFromBuffer( buffer );
m_lock.UnlockWrite();
return bResult;
}