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+ optimizations in SysTinyReAllocMem for the case when growing the heap block

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and there is enough free space after the block

git-svn-id: trunk@28723 -
This commit is contained in:
nickysn 2014-09-29 09:48:45 +00:00
parent b70c5efa65
commit 1e0a69fa7f
1 changed files with 70 additions and 7 deletions
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77
rtl/inc/tinyheap.inc
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@ -260,6 +260,9 @@
function SysTinyReAllocMem(var p: pointer; size: ptruint):pointer;
var
oldsize, OldAllocSize, NewAllocSize: ptruint;
after_block, before_block: PTinyHeapBlock;
after_block_size: PtrUInt;
new_after_block: PTinyHeapBlock;
begin
{$ifdef DEBUG_TINY_HEAP}
Write('SysTinyReAllocMem(', HexStr(p), ',', size, ')=');
@ -299,15 +302,75 @@
end
else
begin
result := AllocMem(size);
if result <> nil then
{ we're increasing the memory block size. First, find if there are free memory blocks immediately
before and after our memory block. }
after_block := FreeList;
before_block := nil;
while (after_block<>HeapPtr) and (TTinyHeapPointerArithmeticType(after_block) < TTinyHeapPointerArithmeticType(p)) do
begin
if oldsize > size then
oldsize := size;
move(pbyte(p)^, pbyte(result)^, oldsize);
before_block := after_block;
after_block := after_block^.Next;
end;
{ is after_block immediately after our block? }
if after_block=Pointer(TTinyHeapPointerArithmeticType(p)+(OldAllocSize-PtrUInt(SizeOf(TTinyHeapMemBlockSize)))) then
begin
if after_block = HeapPtr then
after_block_size := PtrUInt(TTinyHeapPointerArithmeticType(HeapEnd)-TTinyHeapPointerArithmeticType(HeapPtr))
else
after_block_size := DecodeTinyHeapFreeBlockSize(after_block^.size);
end
else
after_block_size := 0;
{ is there enough room after the block? }
if (OldAllocSize+after_block_size)>=NewAllocSize then
begin
if after_block = HeapPtr then
begin
HeapPtr:=Pointer(TTinyHeapPointerArithmeticType(HeapPtr)+(NewAllocSize-OldAllocSize));
if assigned(before_block) then
before_block^.Next := HeapPtr
else
FreeList := HeapPtr;
end
else
begin
if (NewAllocSize-OldAllocSize)=after_block_size then
begin
if assigned(before_block) then
before_block^.Next := after_block^.Next
else
FreeList := after_block^.Next;
end
else
begin
new_after_block := PTinyHeapBlock(TTinyHeapPointerArithmeticType(after_block)+(NewAllocSize-OldAllocSize));
new_after_block^.Next:=after_block^.Next;
new_after_block^.Size:=EncodeTinyHeapFreeBlockSize(after_block_size-(NewAllocSize-OldAllocSize));
if assigned(before_block) then
before_block^.Next := new_after_block
else
FreeList := new_after_block;
end;
end;
PTinyHeapMemBlockSize(p)[-1] := size;
FillChar((TTinyHeapPointerArithmeticType(p)+oldsize)^, size-oldsize, 0);
end
else
begin
{ is before_block immediately before our block? }
//if assigned(before_block) and (Pointer(TTinyHeapPointerArithmeticType(before_block)+DecodeTinyHeapFreeBlockSize(before_block^.Size))=Pointer(TTinyHeapPointerArithmeticType(p)-SizeOf(TTinyHeapMemBlockSize))) then
// ;
result := AllocMem(size);
if result <> nil then
begin
if oldsize > size then
oldsize := size;
move(pbyte(p)^, pbyte(result)^, oldsize);
end;
SysTinyFreeMem(p);
p := result;
end;
SysTinyFreeMem(p);
p := result;
end;
end;
{$ifdef DEBUG_TINY_HEAP}