variant的序列和还原

variant的序列和还原

variant是delphi的万能数据类型，所以先要判断它存储的是哪种类型的数据。

不同类型的数据，要不同地处理。

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procedure TMsgPack.SetAsVariant(const Value: Variant); var   I: Integer;   AType: TVarType;   procedure VarAsBytes;   var     L: Integer;     p: PByte;   begin     FDataType := mptBinary;     L := VarArrayHighBound(Value, 1) + 1;     SetLength(FValue, L);     p := VarArrayLock(Value);     Move(p^, FValue[0], L);     VarArrayUnlock(Value);   end; begin   if VarIsArray(Value) then   begin     AType := VarType(Value);     if (AType and varTypeMask) = varByte then       VarAsBytes     else     begin       checkObjectDataType(mptArray);       ClearAndFreeAllChildren;       for I := VarArrayLowBound(Value, VarArrayDimCount(Value))         to VarArrayHighBound(Value, VarArrayDimCount(Value)) do         Add.AsVariant := Value[I];     end;   end   else   begin     case VarType(Value) of       varSmallInt, varInteger, varByte, varShortInt, varWord,         varLongWord, varInt64:         AsInteger := Value;       varSingle, varDouble, varCurrency:         AsFloat := Value;       varDate:         AsDateTime := Value;       varOleStr, varString{$IFDEF UNICODE}, varUString{$ENDIF}:         AsString := Value;       varBoolean:         AsBoolean := Value;       varNull,varEmpty,varUnknown:         begin           FDataType:=mptNull;           SetLength(FValue, 0);         end;       {$IF RtlVersion>=26}       varUInt64:         AsInteger := Value;       {$IFEND}     else       // null       ;//raise Exception.Create(SVariantConvertNotSupport);     end;   end; end;

　　

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function TMsgPack.GetAsVariant: Variant; var   I: Integer;   procedure BytesAsVariant;   var     L: Integer;     p:PByte;   begin     L := Length(FValue);     Result := VarArrayCreate([0, L - 1], varByte);     p:=VarArrayLock(Result);     Move(FValue[0],p^,L);     VarArrayUnlock(Result);   end;   begin   case FDataType of     mptNull:       Result := null;     mptString:       Result := AsString;     mptInteger:       Result := AsInteger;     mptFloat:       Result := AsFloat;     mptSingle:       Result := AsSingle;     mptDateTime:       Result := AsDateTime;     mptBoolean:       Result := AsBoolean;     mptArray, mptMap:       begin         Result := VarArrayCreate([0, Count - 1], varVariant);         for I := 0 to Count - 1 do           Result[I] := TMsgPack(FChildren[I]).AsVariant;       end;     mptBinary:       BytesAsVariant;   else     raise Exception.Create(SVariantConvertNotSupport);   end; end;