Skip to content

HTTPS clone URL

Subversion checkout URL

You can clone with HTTPS or Subversion.

Download ZIP
branch: master
Fetching contributors…

Cannot retrieve contributors at this time

295 lines (248 sloc) 7.762 kb
/****************************************************************************
* This file is part of PPMd project *
* Written and distributed to public domain by Dmitry Shkarin 1997, *
* 1999-2000 *
* Contents: memory allocation routines *
****************************************************************************/
SubAllocator::SubAllocator()
{
Clean();
}
void SubAllocator::Clean()
{
SubAllocatorSize=0;
}
inline void SubAllocator::InsertNode(void* p,int indx)
{
((RAR_NODE*) p)->next=FreeList[indx].next;
FreeList[indx].next=(RAR_NODE*) p;
}
inline void* SubAllocator::RemoveNode(int indx)
{
RAR_NODE* RetVal=FreeList[indx].next;
FreeList[indx].next=RetVal->next;
return RetVal;
}
inline uint SubAllocator::U2B(int NU)
{
// We calculate the size of units in bytes based on real UNIT_SIZE.
// In original implementation it was 8*NU+4*NU.
return UNIT_SIZE*NU;
}
// Calculate RAR_MEM_BLK+Items address. Real RAR_MEM_BLK size must be
// equal to UNIT_SIZE, so we cannot just add Items to RAR_MEM_BLK address.
inline RAR_MEM_BLK* SubAllocator::MBPtr(RAR_MEM_BLK *BasePtr,int Items)
{
return((RAR_MEM_BLK*)( ((byte *)(BasePtr))+U2B(Items) ));
}
inline void SubAllocator::SplitBlock(void* pv,int OldIndx,int NewIndx)
{
int i, UDiff=Indx2Units[OldIndx]-Indx2Units[NewIndx];
byte* p=((byte*) pv)+U2B(Indx2Units[NewIndx]);
if (Indx2Units[i=Units2Indx[UDiff-1]] != UDiff)
{
InsertNode(p,--i);
p += U2B(i=Indx2Units[i]);
UDiff -= i;
}
InsertNode(p,Units2Indx[UDiff-1]);
}
void SubAllocator::StopSubAllocator()
{
if ( SubAllocatorSize )
{
SubAllocatorSize=0;
free(HeapStart);
}
}
bool SubAllocator::StartSubAllocator(int SASize)
{
uint t=SASize << 20;
if (SubAllocatorSize == t)
return TRUE;
StopSubAllocator();
// Original algorithm expects FIXED_UNIT_SIZE, but actual structure size
// can be larger. So let's recalculate the allocated size and add two more
// units: one as reserve for HeapEnd overflow checks and another
// to provide the space to correctly align UnitsStart.
uint AllocSize=t/FIXED_UNIT_SIZE*UNIT_SIZE+2*UNIT_SIZE;
if ((HeapStart=(byte *)malloc(AllocSize)) == NULL)
{
ErrHandler.MemoryError();
return FALSE;
}
// HeapEnd did not present in original algorithm. We added it to control
// invalid memory access attempts when processing corrupt archived data.
HeapEnd=HeapStart+AllocSize-UNIT_SIZE;
SubAllocatorSize=t;
return TRUE;
}
void SubAllocator::InitSubAllocator()
{
int i, k;
memset(FreeList,0,sizeof(FreeList));
pText=HeapStart;
// Original algorithm operates with 12 byte FIXED_UNIT_SIZE, but actual
// size of RAR_MEM_BLK and PPM_CONTEXT structures can exceed this value
// because of alignment and larger pointer fields size.
// So we define UNIT_SIZE for this larger size and adjust memory
// pointers accordingly.
// Size2 is (HiUnit-LoUnit) memory area size to allocate as originally
// supposed by compression algorithm. It is 7/8 of total allocated size.
uint Size2=FIXED_UNIT_SIZE*(SubAllocatorSize/8/FIXED_UNIT_SIZE*7);
// RealSize2 is the real adjusted size of (HiUnit-LoUnit) memory taking
// into account that our UNIT_SIZE can be larger than FIXED_UNIT_SIZE.
uint RealSize2=Size2/FIXED_UNIT_SIZE*UNIT_SIZE;
// Size1 is the size of memory area from HeapStart to FakeUnitsStart
// as originally supposed by compression algorithm. This area can contain
// different data types, both single symbols and structures.
uint Size1=SubAllocatorSize-Size2;
// Real size of this area. We correct it according to UNIT_SIZE vs
// FIXED_UNIT_SIZE difference. Also we add one more UNIT_SIZE
// to compensate a possible reminder from Size1/FIXED_UNIT_SIZE,
// which would be lost otherwise. We add UNIT_SIZE instead of
// this Size1%FIXED_UNIT_SIZE reminder, because it allows to align
// UnitsStart easily and adding more than reminder is ok for algorithm.
uint RealSize1=Size1/FIXED_UNIT_SIZE*UNIT_SIZE+UNIT_SIZE;
// RealSize1 must be divided by UNIT_SIZE without a reminder, so UnitsStart
// is aligned to UNIT_SIZE. It is important for those architectures,
// where a proper memory alignment is mandatory. Since we produce RealSize1
// multiplying by UNIT_SIZE, this condition is always true. So LoUnit,
// UnitsStart, HeapStart are properly aligned,
LoUnit=UnitsStart=HeapStart+RealSize1;
// When we reach FakeUnitsStart, we restart the model. It is where
// the original algorithm expected to see UnitsStart. Real UnitsStart
// can have a larger value.
FakeUnitsStart=HeapStart+Size1;
HiUnit=LoUnit+RealSize2;
for (i=0,k=1;i < N1 ;i++,k += 1)
Indx2Units[i]=k;
for (k++;i < N1+N2 ;i++,k += 2)
Indx2Units[i]=k;
for (k++;i < N1+N2+N3 ;i++,k += 3)
Indx2Units[i]=k;
for (k++;i < N1+N2+N3+N4;i++,k += 4)
Indx2Units[i]=k;
for (GlueCount=k=i=0;k < 128;k++)
{
i += (Indx2Units[i] < k+1);
Units2Indx[k]=i;
}
}
inline void SubAllocator::GlueFreeBlocks()
{
RAR_MEM_BLK s0, * p, * p1;
int i, k, sz;
if (LoUnit != HiUnit)
*LoUnit=0;
for (i=0, s0.next=s0.prev=&s0;i < N_INDEXES;i++)
while ( FreeList[i].next )
{
p=(RAR_MEM_BLK*)RemoveNode(i);
p->insertAt(&s0);
p->Stamp=0xFFFF;
p->NU=Indx2Units[i];
}
for (p=s0.next;p != &s0;p=p->next)
while ((p1=MBPtr(p,p->NU))->Stamp == 0xFFFF && int(p->NU)+p1->NU < 0x10000)
{
p1->remove();
p->NU += p1->NU;
}
while ((p=s0.next) != &s0)
{
for (p->remove(), sz=p->NU;sz > 128;sz -= 128, p=MBPtr(p,128))
InsertNode(p,N_INDEXES-1);
if (Indx2Units[i=Units2Indx[sz-1]] != sz)
{
k=sz-Indx2Units[--i];
InsertNode(MBPtr(p,sz-k),k-1);
}
InsertNode(p,i);
}
}
void* SubAllocator::AllocUnitsRare(int indx)
{
if ( !GlueCount )
{
GlueCount = 255;
GlueFreeBlocks();
if ( FreeList[indx].next )
return RemoveNode(indx);
}
int i=indx;
do
{
if (++i == N_INDEXES)
{
GlueCount--;
i=U2B(Indx2Units[indx]);
int j=FIXED_UNIT_SIZE*Indx2Units[indx];
if (FakeUnitsStart-pText > j)
{
FakeUnitsStart-=j;
UnitsStart -= i;
return(UnitsStart);
}
return(NULL);
}
} while ( !FreeList[i].next );
void* RetVal=RemoveNode(i);
SplitBlock(RetVal,i,indx);
return RetVal;
}
inline void* SubAllocator::AllocUnits(int NU)
{
int indx=Units2Indx[NU-1];
if ( FreeList[indx].next )
return RemoveNode(indx);
void* RetVal=LoUnit;
LoUnit += U2B(Indx2Units[indx]);
if (LoUnit <= HiUnit)
return RetVal;
LoUnit -= U2B(Indx2Units[indx]);
return AllocUnitsRare(indx);
}
void* SubAllocator::AllocContext()
{
if (HiUnit != LoUnit)
return (HiUnit -= UNIT_SIZE);
if ( FreeList->next )
return RemoveNode(0);
return AllocUnitsRare(0);
}
void* SubAllocator::ExpandUnits(void* OldPtr,int OldNU)
{
int i0=Units2Indx[OldNU-1], i1=Units2Indx[OldNU-1+1];
if (i0 == i1)
return OldPtr;
void* ptr=AllocUnits(OldNU+1);
if ( ptr )
{
memcpy(ptr,OldPtr,U2B(OldNU));
InsertNode(OldPtr,i0);
}
return ptr;
}
void* SubAllocator::ShrinkUnits(void* OldPtr,int OldNU,int NewNU)
{
int i0=Units2Indx[OldNU-1], i1=Units2Indx[NewNU-1];
if (i0 == i1)
return OldPtr;
if ( FreeList[i1].next )
{
void* ptr=RemoveNode(i1);
memcpy(ptr,OldPtr,U2B(NewNU));
InsertNode(OldPtr,i0);
return ptr;
}
else
{
SplitBlock(OldPtr,i0,i1);
return OldPtr;
}
}
void SubAllocator::FreeUnits(void* ptr,int OldNU)
{
InsertNode(ptr,Units2Indx[OldNU-1]);
}
Jump to Line
Something went wrong with that request. Please try again.