296 lines
7.7 KiB
C++
296 lines
7.7 KiB
C++
/****************************************************************************
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* This file is part of PPMd project *
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* Written and distributed to public domain by Dmitry Shkarin 1997, *
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* 1999-2000 *
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* Contents: memory allocation routines *
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****************************************************************************/
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static const uint UNIT_SIZE=Max(sizeof(RARPPM_CONTEXT),sizeof(RARPPM_MEM_BLK));
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static const uint FIXED_UNIT_SIZE=12;
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SubAllocator::SubAllocator()
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{
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Clean();
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}
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void SubAllocator::Clean()
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{
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SubAllocatorSize=0;
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}
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inline void SubAllocator::InsertNode(void* p,int indx)
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{
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((RAR_NODE*) p)->next=FreeList[indx].next;
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FreeList[indx].next=(RAR_NODE*) p;
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}
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inline void* SubAllocator::RemoveNode(int indx)
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{
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RAR_NODE* RetVal=FreeList[indx].next;
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FreeList[indx].next=RetVal->next;
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return RetVal;
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}
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inline uint SubAllocator::U2B(int NU)
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{
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// We calculate the size of units in bytes based on real UNIT_SIZE.
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// In original implementation it was 8*NU+4*NU.
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return UNIT_SIZE*NU;
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}
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// Calculate RARPPM_MEM_BLK+Items address. Real RARPPM_MEM_BLK size must be
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// equal to UNIT_SIZE, so we cannot just add Items to RARPPM_MEM_BLK address.
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inline RARPPM_MEM_BLK* SubAllocator::MBPtr(RARPPM_MEM_BLK *BasePtr,int Items)
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{
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return((RARPPM_MEM_BLK*)( ((byte *)(BasePtr))+U2B(Items) ));
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}
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inline void SubAllocator::SplitBlock(void* pv,int OldIndx,int NewIndx)
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{
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int i, UDiff=Indx2Units[OldIndx]-Indx2Units[NewIndx];
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byte* p=((byte*) pv)+U2B(Indx2Units[NewIndx]);
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if (Indx2Units[i=Units2Indx[UDiff-1]] != UDiff)
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{
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InsertNode(p,--i);
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p += U2B(i=Indx2Units[i]);
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UDiff -= i;
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}
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InsertNode(p,Units2Indx[UDiff-1]);
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}
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void SubAllocator::StopSubAllocator()
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{
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if ( SubAllocatorSize )
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{
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SubAllocatorSize=0;
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free(HeapStart);
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}
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}
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bool SubAllocator::StartSubAllocator(int SASize)
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{
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uint t=SASize << 20;
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if (SubAllocatorSize == t)
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return true;
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StopSubAllocator();
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// Original algorithm expects FIXED_UNIT_SIZE, but actual structure size
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// can be larger. So let's recalculate the allocated size and add two more
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// units: one as reserve for HeapEnd overflow checks and another
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// to provide the space to correctly align UnitsStart.
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uint AllocSize=t/FIXED_UNIT_SIZE*UNIT_SIZE+2*UNIT_SIZE;
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if ((HeapStart=(byte *)malloc(AllocSize)) == NULL)
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{
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ErrHandler.MemoryError();
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return false;
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}
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// HeapEnd did not present in original algorithm. We added it to control
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// invalid memory access attempts when processing corrupt archived data.
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HeapEnd=HeapStart+AllocSize-UNIT_SIZE;
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SubAllocatorSize=t;
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return true;
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}
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void SubAllocator::InitSubAllocator()
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{
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int i, k;
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memset(FreeList,0,sizeof(FreeList));
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pText=HeapStart;
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// Original algorithm operates with 12 byte FIXED_UNIT_SIZE, but actual
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// size of RARPPM_MEM_BLK and RARPPM_CONTEXT structures can exceed this value
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// because of alignment and larger pointer fields size.
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// So we define UNIT_SIZE for this larger size and adjust memory
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// pointers accordingly.
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// Size2 is (HiUnit-LoUnit) memory area size to allocate as originally
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// supposed by compression algorithm. It is 7/8 of total allocated size.
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uint Size2=FIXED_UNIT_SIZE*(SubAllocatorSize/8/FIXED_UNIT_SIZE*7);
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// RealSize2 is the real adjusted size of (HiUnit-LoUnit) memory taking
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// into account that our UNIT_SIZE can be larger than FIXED_UNIT_SIZE.
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uint RealSize2=Size2/FIXED_UNIT_SIZE*UNIT_SIZE;
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// Size1 is the size of memory area from HeapStart to FakeUnitsStart
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// as originally supposed by compression algorithm. This area can contain
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// different data types, both single symbols and structures.
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uint Size1=SubAllocatorSize-Size2;
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// Real size of this area. We correct it according to UNIT_SIZE vs
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// FIXED_UNIT_SIZE difference. Also we add one more UNIT_SIZE
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// to compensate a possible reminder from Size1/FIXED_UNIT_SIZE,
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// which would be lost otherwise. We add UNIT_SIZE instead of
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// this Size1%FIXED_UNIT_SIZE reminder, because it allows to align
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// UnitsStart easily and adding more than reminder is ok for algorithm.
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uint RealSize1=Size1/FIXED_UNIT_SIZE*UNIT_SIZE+UNIT_SIZE;
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// RealSize1 must be divided by UNIT_SIZE without a reminder, so UnitsStart
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// is aligned to UNIT_SIZE. It is important for those architectures,
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// where a proper memory alignment is mandatory. Since we produce RealSize1
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// multiplying by UNIT_SIZE, this condition is always true. So LoUnit,
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// UnitsStart, HeapStart are properly aligned,
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LoUnit=UnitsStart=HeapStart+RealSize1;
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// When we reach FakeUnitsStart, we restart the model. It is where
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// the original algorithm expected to see UnitsStart. Real UnitsStart
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// can have a larger value.
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FakeUnitsStart=HeapStart+Size1;
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HiUnit=LoUnit+RealSize2;
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for (i=0,k=1;i < N1 ;i++,k += 1)
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Indx2Units[i]=k;
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for (k++;i < N1+N2 ;i++,k += 2)
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Indx2Units[i]=k;
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for (k++;i < N1+N2+N3 ;i++,k += 3)
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Indx2Units[i]=k;
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for (k++;i < N1+N2+N3+N4;i++,k += 4)
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Indx2Units[i]=k;
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for (GlueCount=k=i=0;k < 128;k++)
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{
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i += (Indx2Units[i] < k+1);
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Units2Indx[k]=i;
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}
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}
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inline void SubAllocator::GlueFreeBlocks()
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{
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RARPPM_MEM_BLK s0, * p, * p1;
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int i, k, sz;
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if (LoUnit != HiUnit)
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*LoUnit=0;
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for (i=0, s0.next=s0.prev=&s0;i < N_INDEXES;i++)
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while ( FreeList[i].next )
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{
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p=(RARPPM_MEM_BLK*)RemoveNode(i);
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p->insertAt(&s0);
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p->Stamp=0xFFFF;
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p->NU=Indx2Units[i];
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}
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for (p=s0.next;p != &s0;p=p->next)
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while ((p1=MBPtr(p,p->NU))->Stamp == 0xFFFF && int(p->NU)+p1->NU < 0x10000)
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{
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p1->remove();
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p->NU += p1->NU;
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}
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while ((p=s0.next) != &s0)
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{
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for (p->remove(), sz=p->NU;sz > 128;sz -= 128, p=MBPtr(p,128))
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InsertNode(p,N_INDEXES-1);
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if (Indx2Units[i=Units2Indx[sz-1]] != sz)
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{
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k=sz-Indx2Units[--i];
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InsertNode(MBPtr(p,sz-k),k-1);
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}
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InsertNode(p,i);
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}
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}
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void* SubAllocator::AllocUnitsRare(int indx)
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{
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if ( !GlueCount )
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{
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GlueCount = 255;
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GlueFreeBlocks();
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if ( FreeList[indx].next )
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return RemoveNode(indx);
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}
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int i=indx;
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do
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{
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if (++i == N_INDEXES)
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{
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GlueCount--;
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i=U2B(Indx2Units[indx]);
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int j=FIXED_UNIT_SIZE*Indx2Units[indx];
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if (FakeUnitsStart - pText > j)
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{
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FakeUnitsStart -= j;
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UnitsStart -= i;
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return UnitsStart;
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}
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return NULL;
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}
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} while ( !FreeList[i].next );
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void* RetVal=RemoveNode(i);
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SplitBlock(RetVal,i,indx);
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return RetVal;
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}
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inline void* SubAllocator::AllocUnits(int NU)
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{
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int indx=Units2Indx[NU-1];
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if ( FreeList[indx].next )
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return RemoveNode(indx);
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void* RetVal=LoUnit;
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LoUnit += U2B(Indx2Units[indx]);
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if (LoUnit <= HiUnit)
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return RetVal;
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LoUnit -= U2B(Indx2Units[indx]);
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return AllocUnitsRare(indx);
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}
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void* SubAllocator::AllocContext()
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{
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if (HiUnit != LoUnit)
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return (HiUnit -= UNIT_SIZE);
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if ( FreeList->next )
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return RemoveNode(0);
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return AllocUnitsRare(0);
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}
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void* SubAllocator::ExpandUnits(void* OldPtr,int OldNU)
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{
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int i0=Units2Indx[OldNU-1], i1=Units2Indx[OldNU-1+1];
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if (i0 == i1)
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return OldPtr;
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void* ptr=AllocUnits(OldNU+1);
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if ( ptr )
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{
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memcpy(ptr,OldPtr,U2B(OldNU));
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InsertNode(OldPtr,i0);
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}
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return ptr;
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}
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void* SubAllocator::ShrinkUnits(void* OldPtr,int OldNU,int NewNU)
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{
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int i0=Units2Indx[OldNU-1], i1=Units2Indx[NewNU-1];
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if (i0 == i1)
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return OldPtr;
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if ( FreeList[i1].next )
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{
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void* ptr=RemoveNode(i1);
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memcpy(ptr,OldPtr,U2B(NewNU));
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InsertNode(OldPtr,i0);
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return ptr;
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}
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else
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{
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SplitBlock(OldPtr,i0,i1);
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return OldPtr;
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}
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}
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void SubAllocator::FreeUnits(void* ptr,int OldNU)
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{
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InsertNode(ptr,Units2Indx[OldNU-1]);
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}
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