From d8a9860e920a473bc6d3a563b2a47d8c41904b74 Mon Sep 17 00:00:00 2001
From: nickysn <nickysn@gmail.com>
Date: Tue, 7 Oct 2014 14:36:23 +0000
Subject: [PATCH] + optimization in tinyheap's reallocmem for the case when
there's not enough space after the block, but it becomes enough when the
space before the block is also reclaimed
git-svn-id: trunk@28786 -
---
rtl/inc/tinyheap.inc | 66 ++++++++++++++++++++++++++++++++++++--------
1 file changed, 55 insertions(+), 11 deletions(-)
diff --git a/rtl/inc/tinyheap.inc b/rtl/inc/tinyheap.inc
index e4c1d6991e..155417b67c 100644
--- a/rtl/inc/tinyheap.inc
+++ b/rtl/inc/tinyheap.inc
@@ -260,8 +260,8 @@
function SysTinyReAllocMem(var p: pointer; size: ptruint):pointer;
var
oldsize, OldAllocSize, NewAllocSize: ptruint;
- after_block, before_block: PTinyHeapBlock;
- after_block_size: PtrUInt;
+ after_block, before_block, before_before_block: PTinyHeapBlock;
+ after_block_size, before_block_size: PtrUInt;
new_after_block: PTinyHeapBlock;
begin
{$ifdef DEBUG_TINY_HEAP}
@@ -306,8 +306,10 @@
before and after our memory block. }
after_block := FreeList;
before_block := nil;
+ before_before_block := nil;
while (after_block<>HeapPtr) and (TTinyHeapPointerArithmeticType(after_block) < TTinyHeapPointerArithmeticType(p)) do
begin
+ before_before_block := before_block;
before_block := after_block;
after_block := after_block^.Next;
end;
@@ -358,18 +360,60 @@
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
- // ;
+ if assigned(before_block) and (Pointer(TTinyHeapPointerArithmeticType(before_block)+DecodeTinyHeapFreeBlockSize(before_block^.Size))=Pointer(TTinyHeapPointerArithmeticType(p)-SizeOf(TTinyHeapMemBlockSize))) then
+ before_block_size := DecodeTinyHeapFreeBlockSize(before_block^.Size)
+ else
+ before_block_size := 0;
- result := AllocMem(size);
- if result <> nil then
+ { if there's enough space, we can slide our current block back and reclaim before_block }
+ if (before_block_size<NewAllocSize) and ((before_block_size+OldAllocSize+after_block_size)>=NewAllocSize) and
+ { todo: implement this also for after_block_size>0 }
+ (after_block_size>0) then
begin
- if oldsize > size then
- oldsize := size;
- move(pbyte(p)^, pbyte(result)^, oldsize);
+ if (before_block_size+OldAllocSize+after_block_size)=NewAllocSize then
+ begin
+ if after_block=HeapPtr then
+ begin
+ HeapPtr := HeapEnd;
+ if assigned(before_before_block) then
+ before_before_block^.Next := HeapPtr
+ else
+ FreeList := HeapPtr;
+ end
+ else
+ if assigned(before_before_block) then
+ before_before_block^.Next := after_block^.Next
+ else
+ FreeList := after_block^.Next;
+ end;
+ Result := Pointer(TTinyHeapPointerArithmeticType(before_block)+SizeOf(TTinyHeapMemBlockSize));
+ Move(p^, Result^, oldsize);
+ PTinyHeapMemBlockSize(before_block)^ := size;
+ if (before_block_size+OldAllocSize+after_block_size)>NewAllocSize then
+ begin
+ new_after_block := PTinyHeapBlock(TTinyHeapPointerArithmeticType(before_block)+NewAllocSize);
+ new_after_block^.Next:=after_block^.Next;
+ new_after_block^.Size:=EncodeTinyHeapFreeBlockSize(before_block_size+after_block_size-(NewAllocSize-OldAllocSize));
+ if assigned(before_before_block) then
+ before_before_block^.Next := new_after_block
+ else
+ FreeList := new_after_block;
+ end;
+ FillChar((TTinyHeapPointerArithmeticType(Result)+oldsize)^, size-oldsize, 0);
+ p := Result;
+ end
+ else
+ begin
+ 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;
end;