library dll_mql5;
{ Important note about DLL memory management: ShareMem must be the
first unit in your library's USES clause AND your project's (select
Project-View Source) USES clause if your DLL exports any procedures or
functions that pass strings as parameters or function results. This
applies to all strings passed to and from your DLL--even those that
are nested in records and classes. ShareMem is the interface unit to
the BORLNDMM.DLL shared memory manager, which must be deployed along
with your DLL. To avoid using BORLNDMM.DLL, pass string information
using PChar or ShortString parameters. }
uses
Math,
Windows, // it needed for the MessageBox function
Dialogs, // it needed for the ShowMessage function from the Dialogs unit
SysUtils, // the UnixDateDelta constant from there
DateUtils, // the IncSecon and DateTimeToUnix functions are used
Graphics,
ap in 'src\ap.pas',
ablasf in 'src\ablasf.pas',
ablas in 'src\ablas.pas',
blas in 'src\blas.pas',
bdsvd in 'src\bdsvd.pas',
svd in 'src\svd.pas',
creflections in 'src\creflections.pas',
descriptivestatistics in 'src\descriptivestatistics.pas',
gammafunc in 'src\gammafunc.pas',
hblas in 'src\hblas.pas',
igammaf in 'src\igammaf.pas',
linreg in 'src\linreg.pas',
normaldistr in 'src\normaldistr.pas',
ortfac in 'src\ortfac.pas',
reflections in 'src\reflections.pas',
rotations in 'src\rotations.pas',
sblas in 'src\sblas.pas';
{$R *.res}
//----------------------------------------------------------+
//
//----------------------------------------------------------+
type
DoubleArray = array[0..2047, 0..1] of double;
StructData = packed record
i: Integer;
d: Double;
b: Boolean;
dt:Int64;
end;
var Buffer: PWideChar;
StrGlobal: WideString;
const BUFFER_SIZE = 255;
//------------------------------------------------------+
// to prevent errors, use the stdcall (or cdecl) for the exported functions
//------------------------------------------------------+
procedure MsgBox(); stdcall;
begin
{1} MessageBox(0,'Hello World!','terminal', MB_OK);
{2} ShowMessage('Hello World!'); // alternative to the MessageBox function
end;
//----------------------------------------------------------+
//
//----------------------------------------------------------+
Function MQL5_Time_To_TDateTime(dt: Int64): TDateTime;
begin
Result:= IncSecond(UnixDateDelta, dt);
end;
//----------------------------------------------------------+
//
//----------------------------------------------------------+
Function TDateTime_To_MQL5_Time(dt: TDateTime):Int64;
begin
Result:= DateTimeToUnix(dt);
end;
//----------------------------------------------------------+
//
//----------------------------------------------------------+
function SetParam(var i: Integer; d: Double; const b: Boolean;
var dt: Int64): PWideChar; stdcall;
begin
if (b) then d:=0; // the value of the variable d is not changed in the calling program
i:= 10; // assign a new value for i
dt:= TDateTime_To_MQL5_Time(Now()); // assign the current time for dt
Result:= 'The values of variables i and dt are changed';
end;
//----------------------------------------------------------+
//
//----------------------------------------------------------+
function SetStruct(var data: StructData): PWideChar; stdcall;
begin
if (data.b) then data.d:=0;
data.i:= 10; // assign a new value for i
data.dt:= TDateTime_To_MQL5_Time(Now()); // assign the current time for dt
Result:= 'The values of variables i, d and dt are changed';
end;
//----------------------------------------------------------+
//
//----------------------------------------------------------+
function SetArray(var arr: IntegerArray; const len: Cardinal): PWideChar; stdcall;
var i:Integer;
begin
Result:='Fibonacci numbers:';
if (len < 3) then exit;
arr[0]:= 0;
arr[1]:= 1;
for i := 2 to len-1 do
arr[i]:= arr[i-1] + arr[i-2];
end;
//----------------------------------------------------------+
//
//----------------------------------------------------------+
function SetOptional(var a:Integer; b:Integer=0):PWideChar; stdcall;
begin
if (b=0) then Result:='Call with default parameters'
else Result:='Call without default parameters';
end;
//----------------------------------------------------------+
//
//----------------------------------------------------------+
procedure SetString(const str:PWideChar) stdcall;
begin
StrCat(str,'Current time:');
strCat(str, PWideChar(TimeToStr(Now)));
end;
//----------------------------------------------------------+
//
//----------------------------------------------------------+
function GetStringBuffer():PWideChar; stdcall;
var StrLocal: WideString;
begin
// working through the dynamically allocated memory buffer
StrPCopy(Buffer, WideFormat('Current date and time: %s', [DateTimeToStr(Now)]));
// working through the global varialble of WideString type
StrGlobal:=WideFormat('Current time: %s', [TimeToStr(Time)]);
// working through the local varialble of WideString type
StrLocal:= WideFormat('Current date: %s', [DateToStr(Date)]);
{A} Result := Buffer;
{B} Result := PWideChar(StrGlobal);
// it's equal to the following
Result := @StrGlobal[1];
{Ñ} Result := 'Return of the line stored in the code section';
// memory pointer, that can be released when exit from the function
{D} Result := @StrLocal[1];
end;
//----------------------------------------------------------+
//
//----------------------------------------------------------+
function CalcLRChannel(var rates: DoubleArray; const len: Integer;
var A, B, max: Double):Integer; stdcall;
var arr: TReal2DArray;
info: Integer;
value: Double;
begin
SetLength(arr,len,2);
// copying data to two-dimensional array
for info:= 0 to len - 1 do
begin
arr[info,0]:= rates[info,0];
arr[info,1]:= rates[info,1];
end;
// calculation of linear regression coefficients
LRLine(arr, len, info, A, B);
// find the maximal deviation from the approximation line found
// and determine the channel width
max:= rates[0,1] - A;
for info := 1 to len - 1 do
begin
value:= Abs(rates[info,1]- (A + B*info));
if (value > max) then max := value;
end;
Result:=0;
end;
//----------------------------------------------------------+
//
//----------------------------------------------------------+
exports
CalcLRChannel,
GetStringBuffer,
SetString,
SetOptional,
SetArray,
SetStruct,
SetParam,
{A} MsgBox,
{B} MsgBox name 'MessageBox';// rename of the exported function
//----------------------------------------------------------+
//
//----------------------------------------------------------+
procedure DLLEntryPoint(dwReason: DWord); // events handler
begin
case dwReason of
DLL_PROCESS_ATTACH: // DLL attached to the process;
// allocate memory
Buffer:=AllocMem(BUFFER_SIZE);
DLL_PROCESS_DETACH: // DLL detached from the process;
// release memory
FreeMem(Buffer);
end;
end;
//----------------------------------------------------------+
//
//----------------------------------------------------------+
begin
DllProc := @DLLEntryPoint; //Assign event handler
DLLEntryPoint(DLL_PROCESS_ATTACH);
end.