MORMOT的数据序列

MORMOT的数据序列

mormot服务器回复客户端通过Ctxt.OutContent属性。

此属性的类型是：SockString。   // property OutContent: SockString read fOutContent write fOutContent ;

继续跟代码，发现SockString是RawByteString类型。

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type {$ifdef UNICODE}   /// define the fastest Unicode string type of the compiler   SynUnicode = UnicodeString;   /// define a raw 8-bit storage string type, used for data buffer management   SockString = type RawByteString; {$else}   /// define the fastest 16-bit Unicode string type of the compiler   SynUnicode = WideString;   {$ifdef HASCODEPAGE} // FPC may expect a CP, e.g. to compare two string constants   SockString = type RawByteString;   {$else}   /// define a 8-bit raw storage string type, used for data buffer management   SockString = type AnsiString;   {$endif} {$endif}

　继续跟代码，发现RawByteString是AnsiString类型。从下面的代码可以看出，

RawByteString是跨平台的，针对不同的平台有不同的编译开关。这也是为什么要封装一个RawByteString类型。

{$IFDEF NEXTGEN}
  UTF8String = type _AnsiString(65001);
  RawByteString = type _AnsiString($ffff);
  {$NODEFINE UTF8String}
  {$NODEFINE RawByteString}
{$ELSEIF Defined(LINUX64) or Defined(OSX64)}
  UTF8String = type AnsiString(65001);
  RawByteString = type AnsiString($ffff);
  {$NODEFINE UTF8String}
  {$NODEFINE RawByteString}
{$ELSE}
  UTF8String = type AnsiString(65001);
  RawByteString = type AnsiString($ffff);
{$ENDIF}

mormot在SynCommons.pas单元定义了一些RawByteString和其它数据类型相互转换的公共函数，一起来看看。

stream和RawByteString相互转换函数：

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function StreamToRawByteString(aStream: TStream): RawByteString; var current, size: Int64; begin   result := '';   if aStream=nil then     exit;   current := aStream.Position;   if (current=0) and aStream.InheritsFrom(TRawByteStringStream) then begin     result := TRawByteStringStream(aStream).DataString; // fast COW     exit;   end;   size := aStream.Size-current;   if (size=0) or (size>maxInt) then     exit;   SetLength(result,size);   aStream.Read(pointer(result)^,size);   aStream.Position := current; end;

　　

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function RawByteStringToStream(const aString: RawByteString): TStream; begin   result := TRawByteStringStream.Create(aString); end;

　　bytes和RawByteString相互转换函数：

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procedure BytesToRawByteString(const bytes: TBytes; out buf: RawByteString); begin   SetString(buf,PAnsiChar(pointer(bytes)),Length(bytes)); end;

　　

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procedure RawByteStringToBytes(const buf: RawByteString; out bytes: TBytes); var L: Integer; begin   L := Length(buf);   if L<>0 then begin     SetLength(bytes,L);     MoveFast(pointer(buf)^,pointer(bytes)^,L);   end; end;

　　RawByteString和Variant相互转换函数：

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procedure RawByteStringToVariant(const Data: RawByteString; var Value: variant); begin   with TVarData(Value) do begin     {$ifndef FPC}if VType and VTYPE_STATIC<>0 then{$endif}       VarClear(Value);     if Data='' then       VType := varNull else begin       VType := varString;       VAny := nil; // avoid GPF below when assigning a string variable to VAny       RawByteString(VAny) := Data;     end;   end; end;

　　

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procedure VariantToRawByteString(const Value: variant; var Dest: RawByteString); begin   case TVarData(Value).VType of   varEmpty, varNull:     Dest := '';   varString:     Dest := RawByteString(TVarData(Value).VAny);   else // not from RawByteStringToVariant() -> conversion to string     Dest := {$ifdef UNICODE}RawByteString{$else}string{$endif}(Value);   end; end;

　　stream,ansistring,variant基本上代表了常用的数据格式。