XML parser - library for MetaTrader 5

XML parser – library MetaTrader 5

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A library for parsing of XML documents. Pure MQL5, it doesn’t uses any external libraries.

To use the library, just include it:

#include <Xml\XmlBase.mqh>

Example:

#include <Xml\XmlBase.mqh>

CXmlDocument doc;

void OnStart() 
{
  string file = "File.xml";
  string err;
  if (doc.CreateFromText(file,err))
  {
    CXmlElement * xmlItem = doc.FDocumentElement.GetChild(0);
    for (int i=0; i<xmlItem.GetChildCount(); i++) 
    if (xmlItem.GetChild(i).GetName() == "LAYER")
    {
      CXmlElement* layer = xmlItem.GetChild(i);
      for (int j=0; j<layer.GetChildCount(); ++j) 
      {        
        if (layer.GetChild(j).GetName() == "NEURON")
        {
           /* .... */
        }
      }
    }
  }
}

Notes:

  • The library was written when constuctors in MQL5 were without parameters;
  • Only basic functions of Xml standard is supported;
  • Plese inform me about errors, suggestions and bug fixes.

Main components:

CXmlDocument class provides methods for downloading of XML documents from file/string and save to file.

CreateX functions parses XML documents and create hierarchy of DOM model, the working with it can be done using FDocumentElement 

class CXmlDocument 
{
  private:

    void DoElementTrimText(CXmlElement &aXmlItem) ;
  
  public:
    CXmlElement FDocumentElement;

    void CXmlDocument ();
    void ~CXmlDocument ();
    void Clear();
    void CopyTo (CXmlDocument &xmlDoc);
  
    bool  CreateFromText (const string& xml, string& err);
    bool  CreateFromFile (const string filename, string& err);
    bool  SaveToFile (const string filename);

    string GetXml();
};

 

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CXmlElement class is a base interface of any XML document. It provides access to elements, attributes and content

class CXmlElement 
{
  private:
    string         FName;
    CXmlAttribute* FAttributes[];
    CXmlElement   *FElements[];
    string         FText;
    CXmlElement*   FParent;
  public:  
    //--- constructor methods
    void  CXmlElement ();
    void ~CXmlElement ();
    void Init (const string aName, const CXmlElement* aParent=NULL, const string aText="");
    void CopyTo (CXmlElement &aDst);
    virtual void Clear ();
    
    //--- main service methods
    string GetName () const;
    void SetName (const string aName);
    string GetText () const;
    void SetText (const string aText);
    CXmlElement* GetParent () const;
    void SetParent (CXmlElement* aParent);
    
    //--- attribute service methods
    int GetAttributeCount () const;
    int GetAttributeIndex (CXmlAttribute* aAttr) const;
    CXmlAttribute* GetAttribute (const string aName) const;
    CXmlAttribute* GetAttribute (int aPos) const;
    string GetAttributeValue (const string aName) const;
    
    CXmlAttribute* AttributeInsertAt (CXmlAttribute* aAttr, int aPos);
    CXmlAttribute* AttributeAdd (CXmlAttribute* aAttr);
    CXmlAttribute* AttributeInsertAfter (CXmlAttribute* aAfter, CXmlAttribute* aAttr);
    CXmlAttribute* AttributeInsertBefore (CXmlAttribute* aBefore, CXmlAttribute* aAttr);
    CXmlAttribute* AttributeRemove (CXmlAttribute* aAttr);
    CXmlAttribute* AttributeRemove (int aPos);
    void AttributeDelete (CXmlAttribute* aAttr);
    void AttributeDelete (int aPos);
    void AttributeDeleteAll ();
  
    //--- child service methods
    int GetChildCount() const;
    int GetChildIndex (CXmlElement* aElement) const;
    CXmlElement* GetChild (const string aName) const;
    CXmlElement* GetChild (int aPos) const;
    string GetChildText (const string aName) const;

    CXmlElement* ChildInsertAt (CXmlElement* aElement, int aPos);
    CXmlElement* ChildAdd (CXmlElement* aElement);
    CXmlElement* ChildInsertAfter (CXmlElement* aAfter, CXmlElement* aElement);
    CXmlElement* ChildInsertBefore (CXmlElement* aBefore, CXmlElement* aElement);
    CXmlElement* ChildRemove (CXmlElement* aElement);
    CXmlElement* ChildRemove (int aPos);
    void ChildDelete (CXmlElement* aElement);
    void ChildDelete (int aPos);
    void ChildDeleteAll ();
  
    string GetXml(int aLevel);
};

 

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CXmlAttribute is a simple class for working with attributes

class CXmlAttribute 
{
  private:
    string FName;
    string FValue;
 public:
    //--- constructor methods
    void CXmlAttribute ();
    void ~CXmlAttribute ();

    void Init (const string aName, const string aValue);
    virtual void Clear ();
    virtual CXmlAttribute* Clone ();
    
    //--- service methods
    string GetName () const;
    void SetName (const string aName);
    string GetValue () const;
    void SetValue (const string aValue);    
};


XML parser – library MetaTrader 5
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