MML Data Bridge Required Files

Below are the required files to use the MML Data Bridge

• Purchase the bridge here: https://www.mql5.com/en/market/product/152143?source=Site+Market+Product+Page#
• User Set Up Manual: https://www.mql5.com/en/blogs/post/766374
• Common Issues and Resolves: https://www.mql5.com/en/blogs/post/766376
• MML Data Bridge Code Structure and MQL5 Programing Challenges: https://www.mql5.com/en/blogs/post/766520

#ifndef dataStructs
#define dataStructs

//input a defined length for char array
#define CHAR_FIELD_WIDTH 128 //leave name as is, used as char field width for the bridge

//Define your data structures below

//Example 1
struct DIRECTION {
    datetime time;
    int signal;
};

//Example 2
struct BTC_DATA {
    datetime time;
    double actual_price;
    double predicted_price;
    double price_residual;
    double price_error_pct;
    double actual_return;
    double predicted_return;
    double return_residual;
    double direction_correct;
    char dataset_name[CHAR_FIELD_WIDTH];
};

#endif 

MMLUtility.mqh

#property strict
#include <dataStructs.mqh>


// Make sure this matches the .ex5 name in MQL5/Libraries
#import "MMLDataBridge.ex5"
  // These exactly match your exported functions:
  void initializeBridge_internal(string eaName);  
  void shutdownBridge_internal();  // 
 bool getRecordBytes_internal(const string csvFileName, uchar &out[]); // exported above
  string CStrFromCharArray(const char &arr[], int max_len = CHAR_FIELD_WIDTH);
#import



// ---- Public API #1b: initializeBridge(eaName) ----
void initializeBridge(string eaName){
 initializeBridge_internal(eaName);
}

// ---- Public API #2: shutDownBridge() ----
void shutDownBridge() { 
  shutdownBridge_internal();
}

// ---- Public API #3: CharArrayToStr() ----
string CharArrayToStr(const char &arr[]) { 
  return CStrFromCharArray(arr); }

// ---- Public API #4: returnData<T>() ----
// Pull raw bytes from the bridge and map them into a POD struct T.
// Templated wrapper that preserves your original returnData signature
template<typename T>
bool returnData(const string csvFileName, T &out) {
   // Ask bridge for the raw bytes (bridge will size 'bytes' correctly)
   uchar bytes[];
   if (!getRecordBytes_internal(csvFileName, bytes))
      return false;

   const int need = sizeof(out);
   const int have = ArraySize(bytes);

   if (have != need) {
      if (have > need) {
         PrintFormat("MML Data Bridge: Struct size mismatch for '%s'", csvFileName);
         Print("   Your struct is missing %d field(s) or has incorrect field types.");
         PrintFormat("   Solution: Add missing field(s) to your struct or check field data types");
         // Size mismatch means the struct doesn't match the data - fail to prevent reading corrupted data
         return false;
      } else {
         PrintFormat("MML Data Bridge: Struct size mismatch for '%s'", csvFileName);
         PrintFormat("   This means your struct has %d extra field(s) or incorrect field types");
         PrintFormat("   Solution: Remove extra field(s) from your struct or check field data types");
         // If BIN has fewer bytes than struct, we can't fill it -> fail.
         return false;
      }
   }

   // Correct order: struct first, bytes second
   return CharArrayToStruct(out, bytes, 0);
}