小风吹耳朵 發表於 2020-12-9 13:53:00

delphi内存映射（跨平台）

<p>delphi内存映射（跨平台）</p>
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<pre class="brush:csharp;gutter:true;">/// &lt;author&gt;cxg 2020-12-9&lt;/author&gt;

unit yn.map;

interface

uses
SysUtils,
{$IFDEF posix}
Posix.SysMman
{$ENDIF}
{$IFDEF mswindows}
Windows
{$ENDIF}
;

type
PShareMem = ^TShareMem;

TShareMem = record
    size: Cardinal;
    data: Pointer;
end;

type
TWriteRead = procedure (data: pointer) of object;

TMemMap = class
private
    FShareMemName: string;
    FFileHandle: THandle;
    p: PShareMem;
    FWrite: TWriteRead;
    FRead: TWriteRead;
public
    constructor Create(const ShareMemName: string; data: Pointer; const dataLen: Cardinal); overload;
    destructor Destroy; override;
public
    function createFileMap: Boolean;
    function map: Boolean;
    function unMap: Boolean;
    function openFileMap: Boolean;
    function closeFileMap: Boolean;
public
    procedure write;
    procedure read;
public
    property OnWrite: TWriteRead read FWrite write FWrite;
    property OnRead: TWriteRead read FRead write FRead;
end;

implementation

{ TMemMap }

function TMemMap.closeFileMap: Boolean;
begin
{$IFDEF mswindows}
Result := CloseHandle(FFileHandle);
{$ENDIF}
end;

constructor TMemMap.Create(const ShareMemName: string; data: Pointer; const dataLen: Cardinal);
begin
FFileHandle := 0;
FShareMemName := ShareMemName;
New(p);
p^.data := data;
p^.size := dataLen;
end;

function TMemMap.createFileMap: Boolean;
begin
{$IFDEF mswindows}
FFileHandle := CreateFileMapping($FFFFFFFF, nil, PAGE_READWRITE, 0, p^.size, PChar(FShareMemName));
Result := FFileHandle &lt;&gt; 0;
{$ENDIF}
end;

destructor TMemMap.Destroy;
begin
self.closeFileMap;
Dispose(p^.data);
Dispose(p);
inherited;
end;

function TMemMap.map: Boolean;
begin
{$IFDEF mswindows}
p^.data := MapViewOfFile(FFileHandle, FILE_MAP_ALL_ACCESS, 0, 0, p^.size);
Result := p &lt;&gt; nil;
{$ELSE}
mmap(p^.data, p^.size, PROT_READ or PROT_WRITE, MAP_SHARED, 0, 0);
{$ENDIF}
end;

function TMemMap.openFileMap: Boolean;
begin
{$IFDEF mswindows}
FFileHandle := OpenFileMapping(FILE_MAP_ALL_ACCESS, false, PChar(FShareMemName));
Result := FFileHandle &lt;&gt; 0;
{$ENDIF}
end;

procedure TMemMap.read;
begin
openFileMap;
self.map;
if Assigned(FRead) then
    FRead(p^.data);
Self.unMap;
end;

function TMemMap.unMap: Boolean;
begin
{$IFDEF mswindows}
Result := UnmapViewOfFile(p^.data);
{$ELSE}
munmap(p^.data, p^.size);
{$ENDIF}
end;

procedure TMemMap.write;
begin
if FFileHandle = 0 then
    self.createFileMap;
map;
if Assigned(FWrite) then
    FWrite(p^.data);
Self.unMap;
end;

end.
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    <p>本文来自博客园，作者：{咏南中间件}，转载请注明原文链接：https://www.cnblogs.com/hnxxcxg/p/14108131.html</p><br><br>
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