unit FastShareMem;
(*
* Shared Memory Allocator for Delphi DLL's
* Version: 2.10
*
* Features:
* No runtime dll required.
* No performance degradation.
* Faster than ShareMem/Borlndmm.dll.
*
* Usage:
* Windows:
* Must be the FIRST unit listed in the project file's USES section
* for both dll and exe projects. If you install a memory manager for
* leak detection, it should be listed immediately AFTER this unit.
* Linux:
* Not needed. May be commented out using conditional directives:
* uses {$IFDEF WIN32} FastShareMem, {$ENDIF}
*
* Author: Emil M. Santos
* You may use and modify this software as you wish, but this section
* must be kept intact. Please see Readme.txt for copyright and disclaimer.
*
* Send bugs/comments to [email]fastsharemem@codexterity.com[/email]
* On the web: [url]http://www.codexterity.com[/url]
* To be notified of new versions by email, subscribe to the site alerter facility.
Revision History:
2003 Dec 03: Version 2.10. Added GetAllocMemCount and GetAllocMemSize functions.
From a contribution by Andrey Nikolayevich Aban'shin (andrey@ecobank.san.ru).
2003 Dec 03: Version 2.00 released. Complete rewrite; now uses a window class
to exchange data between modules. Safer, and *much* simpler.
The code is also much shorter.
2003 Aug 27: Removed reference to SysUtils. This was causing subtle bugs.
Update by Alex Blach (entwicklung@zmi.de)
2003 May 7: Fixed "Combining signed and unsigned types" warning. Replaced
integers with longword where appropriate.
Thanks to Nagy Krisztián (chris@manage.co.hu)
2002 Oct 9: Separated MEM_DECOMMIT and MEM_RELEASE calls. Thanks to Maurice Fletcher and Alexandr Kozin.
2002 Sep 9: Thanks to Ai Ming (aiming@ynxx.com) for these changes:
Modified to work with Windows NT/2000/XP.
Added reference-counting mechanism.
2002 Aug 14: Rewrote address-computation code to better match windows 98
allocation. VirtualAlloc may round down requested address *twice*.
Replaced ASSERTs with (lower-level) Win32 MessageBox calls.
(Thanks to Darryl Strickland (DStrickland@carolina.rr.com))
*)
(*
Note to contributors:
If you're going to edit this code, keep in mind the following things:
* We shouldn't dynamically allocate Delphi 'objects' here, like strings,
obejcts etc. All memory should come from the Windows API, or be statically
allocated.
* We shouln't raise exceptions here, since an exception is a Delphi object,
and thus consumes heap memory.
* For the above reasons, we cannot use most VCL facilities here.
*)
interface
var
GetAllocMemCount:
function: integer;
GetAllocMemSize:
function: integer;
implementation
uses Windows;
const
ClassName = '
_com.codexterity.fastsharemem.dataclass';
type
TFastSharememPack =
record
MemMgr: TMemoryManagerEx;
_GetAllocMemSize:
function: integer;
_GetAllocMemCount:
function: integer;
end;
function _GetAllocMemCount: integer;
begin
Result := System.AllocMemCount;
end;
function _GetAllocMemSize: integer;
begin
Result := System.AllocMemSize;
end;
var
MemPack: TFastSharememPack;
OldMemMgr: TMemoryManagerEx;
wc: TWndClass;
isHost: boolean;
initialization
if (
not GetClassInfo(HInstance, ClassName, wc))
then
begin
GetMemoryManager(MemPack.MemMgr);
MemPack._GetAllocMemCount := @_GetAllocMemCount;
MemPack._GetAllocMemSize := @_GetAllocMemSize;
GetAllocMemCount := @_GetAllocMemCount;
GetAllocMemSize := @_GetAllocMemSize;
FillChar(wc, sizeof(wc), 0);
wc.lpszClassName := ClassName;
wc.style := CS_GLOBALCLASS;
wc.HInstance := HInstance;
wc.lpfnWndProc := @MemPack;
if RegisterClass(wc) = 0
then
begin
MessageBox(0,
'
Shared Memory Allocator setup failed: Cannot register class.',
'
FastShareMem', 0);
Halt;
end;
isHost := true;
end
else
begin
GetMemoryManager(OldMemMgr);
// optional
SetMemoryManager(TFastSharememPack(wc.lpfnWndProc^).MemMgr);
GetAllocMemCount := TFastSharememPack(wc.lpfnWndProc^)._GetAllocMemCount;
GetAllocMemSize := TFastSharememPack(wc.lpfnWndProc^)._GetAllocMemSize;
isHost := false;
end;
finalization
if isHost
then
UnregisterClass(ClassName, HInstance)
else
SetMemoryManager(OldMemMgr);
// optional
end.