gcache.cpp

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// $Id: gcache.cpp 754 2006-04-01 15:29:59Z alex $
//
// GCache.cpp
//
/* @@tag:xara-cn@@ DO NOT MODIFY THIS LINE
================================XARAHEADERSTART===========================
 
               Xara LX, a vector drawing and manipulation program.
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----------------------------------

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=================================XARAHEADEREND============================
 */

#include "camtypes.h"
//#include <afxwin.h>
#include <iostream>
//#include "gcmaths.h"
#include "gcache.h"


CamCache::CamCache( size_t Size, UINT32 Log2MaxEntries )
{
    HashTableSize = 1<<Log2MaxEntries ;
    HashTableMask = HashTableSize-1 ;
    HashTable     = NULL ;
    CacheStart    = NULL ;

    HashTable   = new ( CacheBlock* [HashTableSize] ) ;
    CacheStart  = (CacheBlock*) new BYTE[Size+2*FreeCacheBlockSize] ;

    if (!HashTable || !CacheStart)
    {
        if (HashTable)
        {
            delete [] HashTable  ; HashTable  = NULL ;
        }
        if (CacheStart)
        {
            delete [] CacheStart ; CacheStart = NULL ;
        }
        return ;
    }
    for ( size_t i=0 ; i<HashTableSize ; i++ )
        HashTable[i] = NULL ;
    CacheBlock *FreeBlock ;
    FreeBlock   = (CacheBlock*) ((BYTE*)CacheStart+FreeCacheBlockSize) ;
    CacheEnd    = (CacheBlock*) ((BYTE*)CacheStart+Size-FreeCacheBlockSize) ;
    CacheStart->Prev        = CacheStart ;
                              CacheEnd->Next        = CacheEnd ;
    CacheStart->Next        = CacheEnd->Prev        =
    CacheStart->NextFree    = CacheEnd->PrevFree    = FreeBlock ;
    CacheStart->PrevFree    = CacheEnd->NextFree    = NULL ;
    CacheStart->State       = CacheEnd->State       = 0 ;
    FreeBlock->Prev         = FreeBlock->PrevFree   = CacheStart ;
    FreeBlock->Next         = FreeBlock->NextFree   = CacheEnd ;
    FreeBlock->State        = FREE ;
    LeastUsed = MostUsed = NULL ;
}

//
// Verify should be used after creation of a CamCache object to ensure that it was created OK.
//
BOOL CamCache::Verify()
{
    return HashTable && CacheStart ;
}


CamCache::~CamCache()
{
    delete [] HashTable  ; HashTable  = NULL ;
    delete [] CacheStart ; CacheStart = NULL ;
}


BOOL CamCache::FindPath( UINT32 Handle, INT32* &Points, BYTE* &Types, UINT32 &Length )
{
    INT32 *Object = (INT32*) FindEntry( Handle ) ;
    if ( Object )
    {
        Length = *Object ;
        Points = ++Object ;
        Types = (BYTE*) (Object+2*Length) ;
    }
    return Object!=NULL ;
}

void CamCache::AddPath( UINT32 Handle, INT32* Points, BYTE* Types, UINT32 Length )
{
    INT32 *DPtr = (INT32*) AddEntry( Handle,Length*9+4 ) ;
    *DPtr++ = Length ;
    INT32 *SPtr = Points ;
    size_t i;
    for ( i=0 ; i<2*Length ; i++ )
        *DPtr++ = *SPtr++ ;
    SPtr = (INT32*) Types ;
    Length = (Length+3)>>2 ;                    /* Word length */
    for ( i=0 ; i<Length ; i++ )
        *DPtr++ = *SPtr++ ;
}


PORTNOTE("other","not used - removed because AddString looks dodgy")
#ifndef EXCLUDE_FROM_XARALX

char* CamCache::FindString( UINT32 Handle )
{
    return (char*) FindEntry( Handle ) ;
}

void CamCache::AddString( UINT32 Handle, char* String )
{
    size_t StringLength = cc_strlenBytes(String)+1 ;    /* Byte length */
    INT32 *SPtr = (INT32*) String ;
    INT32 *DPtr = (INT32*) AddEntry( Handle,StringLength ) ;
    StringLength = (StringLength+3)>>2 ;        /* Word length */
    for ( size_t i=0 ; i<StringLength ; i++ )
        *DPtr++ = *SPtr++ ;
}
#endif


// converted from asm function in gcmaths
UINT32 Hash(UINT32 val)
{
    val ^= (val <<  7) | (val >> 25);
    val ^= (val << 11) | (val >> 21);
    val ^= (val << 19) | (val >> 13);
    val ^= (val << 16) | (val >> 16);
    return val;
}

void* CamCache::FindEntry( UINT32 Handle )
{
    UINT32 HashIndex = Hash( Handle ) & HashTableMask ;
    CacheBlock *Ptr = HashTable[HashIndex] ;
    while ( Ptr )
        if ( Ptr->Handle == Handle )
        {
            if ( Ptr != MostUsed )
            {
                /* Make this the most recently used object */
                if ( Ptr==LeastUsed )
                    LeastUsed = Ptr->NextUsed ;
                else
                    Ptr->PrevUsed->NextUsed = Ptr->NextUsed ;
                Ptr->NextUsed->PrevUsed = Ptr->PrevUsed ;
                Ptr->NextUsed = NULL ;
                Ptr->PrevUsed = MostUsed ;
                MostUsed->NextUsed = Ptr ;
                MostUsed = Ptr ;
            }
            return Ptr->Object ;
        }
        else
            Ptr = Ptr->Link ;

    return NULL ;
}


void* CamCache::AddEntry( UINT32 Handle, size_t ObjectSize )
{
    UINT32 HashIndex = Hash( Handle ) & HashTableMask ;
    CacheBlock *Ptr = HashTable[HashIndex] ;
    while ( Ptr )
        if ( Ptr->Handle == Handle )
            return Ptr->Object ;                    /* Entry already exists */
        else
            Ptr = Ptr->Link ;
    CacheBlock *FreeBlock = CacheStart->NextFree ;
    size_t ObjectBlockSize = (ObjectSize+UsedCacheBlockSize+3) & ~3 ;
    while ( ObjectBlockSize > BlockSize(FreeBlock) )
        if ( !(FreeBlock=FreeBlock->NextFree) )
        {
            /* Remove least recently used object from hash table */
            UINT32 HashIndex = Hash( LeastUsed->Handle ) & HashTableMask ;
            CacheBlock *Ptr = HashTable[HashIndex] ;
            if ( Ptr == LeastUsed )
                HashTable[HashIndex] = LeastUsed->Link ;
            else
            {
                while ( Ptr->Link != LeastUsed )
                    Ptr = Ptr->Link ;
                Ptr->Link = LeastUsed->Link ;
            }               
            /* Merge least recently used object with adjacent free blocks and try again */
            FreeBlock = LeastUsed ;
            LeastUsed = LeastUsed->NextUsed ;
            LeastUsed->PrevUsed = NULL ;
            FreeBlock->State = FREE ;
            CacheStart->NextFree->PrevFree = FreeBlock ;
            FreeBlock->NextFree = CacheStart->NextFree ;
            FreeBlock->PrevFree = CacheStart ;
            CacheStart->NextFree = FreeBlock ;
            CacheBlock *NextBlock = FreeBlock->Next ;
            CacheBlock *PrevBlock = FreeBlock->Prev ;
            if ( NextBlock->State == FREE )
            {
                NextBlock->PrevFree->NextFree = NextBlock->NextFree ;
                NextBlock->NextFree->PrevFree = NextBlock->PrevFree ;
                FreeBlock->Next = NextBlock->Next ;
                NextBlock->Next->Prev = FreeBlock ;
            }
            if ( PrevBlock->State == FREE )
            {
                FreeBlock->PrevFree->NextFree = FreeBlock->NextFree ;
                FreeBlock->NextFree->PrevFree = FreeBlock->PrevFree ;
                PrevBlock->Next = FreeBlock->Next ;
                FreeBlock->Next->Prev = PrevBlock ;
                FreeBlock = PrevBlock ;
            }
        }
    /* Add object */
    if ( ObjectBlockSize+FreeCacheBlockSize > BlockSize(FreeBlock) )
    {
        FreeBlock->PrevFree->NextFree = FreeBlock->NextFree ;
        FreeBlock->NextFree->PrevFree = FreeBlock->PrevFree ;
    }
    else
    {
        CacheBlock *NewBlock = (CacheBlock*) ((BYTE*)FreeBlock+ObjectBlockSize) ;
        NewBlock->Prev      = FreeBlock ;
        NewBlock->Next      = FreeBlock->Next ;
        NewBlock->State     = FREE ;
        NewBlock->NextFree  = FreeBlock->NextFree ;
        NewBlock->PrevFree  = FreeBlock->PrevFree ;
        NewBlock->NextFree->PrevFree = NewBlock->PrevFree->NextFree = NewBlock ;
        FreeBlock->Next     = NewBlock->Next->Prev = NewBlock ;
    }
    FreeBlock->Link     = HashTable[HashIndex] ;
    FreeBlock->PrevUsed = MostUsed ;
    FreeBlock->NextUsed = NULL ;
    FreeBlock->Handle   = Handle ;
    HashTable[HashIndex] = FreeBlock ;
    if ( MostUsed )
        MostUsed->NextUsed = FreeBlock ;
    MostUsed = FreeBlock ;
    if ( !LeastUsed )
        LeastUsed = FreeBlock ;
    return FreeBlock->Object ;
}


#ifdef _DEBUG

ostream& operator << ( ostream& os, CamCache& Cache )
{
    for ( size_t i=0 ; i<Cache.HashTableSize ; i++ )
    {
        os << Cache.HashTable[i] << " " ;
        if ( (i & 7) == 7 )
            os << endl ;
    }
    os << "Start : " << Cache.CacheStart
                     << ", " << Cache.CacheStart->Prev     << "," << Cache.CacheStart->Next
                     << ", " << Cache.CacheStart->PrevFree << "," << Cache.CacheStart->NextFree << endl ;
    CacheBlock *Ptr = Cache.CacheStart->Next ;
    while ( Ptr != Cache.CacheEnd )
    {
        if ( Ptr->State == FREE )
            cout << "FREE  : " << Ptr << ", " << Ptr->Prev     << "," << Ptr->Next
                                      << ", " << Ptr->PrevFree << "," << Ptr->NextFree
                                      << " (" << hex
                                      << Cache.BlockSize(Ptr)-FreeCacheBlockSize
                                      << dec << ")" << endl ;
        else
            cout << "USED  : " << Ptr << ", " << Ptr->Prev     << "," << Ptr->Next
                                      << ", " << Ptr->PrevUsed << "," << Ptr->NextUsed
                                      << ", " << Ptr->Link     << "," << Ptr->Handle
                                      << ", " << (char*) Ptr->Object << " (" << hex
#ifndef EXCLUDE_FROM_XARALX
                                      << Cache.BlockSize(Ptr)-UsedCacheBlockSize-cc_strlenBytes((char*)Ptr->Object)-1
#endif
                                      << dec << ")" << endl ;
        Ptr = Ptr->Next ;
    }
    os << "End   : " << Cache.CacheEnd
                     << ", " << Cache.CacheEnd->Prev     << "," << Cache.CacheEnd->Next
                     << ", " << Cache.CacheEnd->PrevFree << "," << Cache.CacheEnd->NextFree << endl ;
    os << "LeastUsed : " << Cache.LeastUsed << endl ;
    os << " MostUsed : " << Cache. MostUsed << endl ;
    return os ;
}

#endif

---