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Home » U++ Library support » U++ Core » ConvertInt > templatable Convert<T>
ConvertInt > templatable Convert<T> [message #22708] Fri, 07 August 2009 16:17 Go to next message
kohait00 is currently offline  kohait00
Messages: 939
Registered: July 2009
Location: Germany
Experienced Contributor
hi there

I came along to need a Min Max EditValue control, but specificable as template, so to speak.

instead of

EditInt edit, or EditDouble edit


i needed 

MyValueEdit<T> edit;


In code speaking, it should be like

template<class T>
class MyEditMinMax : public EditMinMax<T, Convert<T>>
{};


instead of

typedef EditMinMax<T, ConvertInt> EditInt


so i needed kind of a Convert<T>
to make this possible.

looking at the code, i found out that the Convert Datatype is used as Base some base levels deeper, but ther then as typesafe.

it would be great to have the Convert<T> implementation. i know it would take much recoding, and the api would change, also the speed penalty for stuff like

if(typeid(T)) == typeid(int))
invoke some int specific convert function


is there any intelligent way to do that?

known issues to that:
1. Convert uses a typesafe parametrized standard constructor in ConvertInt (cause of some constants maybe) and the like. this might need to be split, a standard constructor invoking an init function or so..

2. the converters call each another scan founction and implement their own format functions, this might need to form differently.

any comments?

Just keep in mind, what is needed is just a EditMinMax<T> or so, instead of EditMinMax<T, ConvertInt>
the class looks for a fitting converter itself, invoking its functions.

meanwhile, i try to solve it by now, with havnig stuff like that:
there, maybe you'll see and understand better the problem

/// an own Edit Control with min max, using Converters in a different way

template <class DataType/*, class Cv*/>
class MyEditValue : public EditField /*, public Cv*/{

protected:
	//as long as we do not have a Convert<T> need to mirror that
	Convert * pcv;

public:
	MyEditValue& operator=(const DataType& t)  { SetData(t); return *this; }
	operator DataType() const                { return GetData(); }

	MyEditValue()                              
	{
		pcv = NULL;
		if( 	(typeid(DataType) == typeid(int))
			 || (typeid(DataType) == typeid(unsigned int))
			 || (typeid(DataType) == typeid(short))
			 || (typeid(DataType) == typeid(unsigned short))
			 || (typeid(DataType) == typeid(char))
			 || (typeid(DataType) == typeid(unsigned char))
			)
		{
			pcv = new ConvertInt();
		}
		else if( (typeid(DataType) == typeid(double))
			 || (typeid(DataType) == typeid(float))
			)
		{
			pcv = new ConvertDouble();
		}
		else if( (typeid(DataType) == typeid(long))
			 || (typeid(DataType) == typeid(unsigned long))
			)
		{
			pcv = new ConvertInt64();
		}
		else
		{
			D6("MyEditValue","unknown type : " << typeid(DataType).name());
			D6("MyEditValue","not covertible: " << s);
			return;
		}
		
		if(pcv != NULL)
			SetConvert(*pcv); //instead *this
	}

	virtual ~MyEditValue()
	{
		if(pcv != NULL)
			delete pcv;
		pcv = NULL;	
	}
	
	DataType GetMax() 
	{
		if (!pcv) return (DataType)0;

		if( 	(typeid(DataType) == typeid(int))
			 || (typeid(DataType) == typeid(unsigned int))
			 || (typeid(DataType) == typeid(short))
			 || (typeid(DataType) == typeid(unsigned short))
			 || (typeid(DataType) == typeid(char))
			 || (typeid(DataType) == typeid(unsigned char))
			)
		{
			return ((ConvertInt*)pcv)->GetMax();
		}
		else if( (typeid(DataType) == typeid(double))
			 || (typeid(DataType) == typeid(float))
			)
		{
			return ((ConvertDouble*)pcv)->GetMax();
		}
		else if( (typeid(DataType) == typeid(long))
			 || (typeid(DataType) == typeid(unsigned long))
			)
		{
			return ((ConvertInt64*)pcv)->GetMax();
		}
		else
		{
			D6("MyEditMinMax","unknown type : " << typeid(DataType).name());
			D6("MyEditMinMax","not covertible: " << s);
			return (DataType)0;
		}
	}
	
	DataType GetMin() 
	{
		if (!pcv) return (DataType)0;

		if( 	(typeid(DataType) == typeid(int))
			 || (typeid(DataType) == typeid(unsigned int))
			 || (typeid(DataType) == typeid(short))
			 || (typeid(DataType) == typeid(unsigned short))
			 || (typeid(DataType) == typeid(char))
			 || (typeid(DataType) == typeid(unsigned char))
			)
		{
			return ((ConvertInt*)pcv)->GetMin();
		}
		else if( (typeid(DataType) == typeid(double))
			 || (typeid(DataType) == typeid(float))
			)
		{
			return ((ConvertDouble*)pcv)->GetMin();
		}
		else if( (typeid(DataType) == typeid(long))
			 || (typeid(DataType) == typeid(unsigned long))
			)
		{
			return ((ConvertInt64*)pcv)->GetMin();
		}
		else
		{
			D6("MyEditMinMax","unknown type : " << typeid(DataType).name());
			D6("MyEditMinMax","not covertible: " << s);
			return (DataType)0;
		}
	}

};

template <class DataType/*, class Cv*/>
class MyEditMinMax : public MyEditValue<DataType/*, Cv*/> {
public:
	MyEditMinMax& operator=(const DataType& t)          { SetData(t); return *this; }

	MyEditMinMax() {}
	MyEditMinMax(DataType min, DataType max)            
	{
		//for the converts a *typesafe* call is needed.
		//as long as we dont have Converter<T>::MinMax(), we need to mirror that
		//Cv::MinMax(min, max);
		
		if( 	(typeid(DataType) == typeid(int))
			 || (typeid(DataType) == typeid(unsigned int))
			 || (typeid(DataType) == typeid(short))
			 || (typeid(DataType) == typeid(unsigned short))
			 || (typeid(DataType) == typeid(char))
			 || (typeid(DataType) == typeid(unsigned char))
			)
		{
			((ConvertInt*)MyEditValue<DataType>::pcv)->MinMax(min, max);
		}
		else if( (typeid(DataType) == typeid(double))
			 || (typeid(DataType) == typeid(float))
			)
		{
			((ConvertDouble*)MyEditValue<DataType>::pcv)->MinMax(min, max);
		}
		else if( (typeid(DataType) == typeid(long))
			 || (typeid(DataType) == typeid(unsigned long))
			)
		{
			((ConvertInt64*)MyEditValue<DataType>::pcv)->MinMax(min, max);
		}
		else
		{
			D6("MyEditMinMax","unknown type : " << typeid(DataType).name());
			D6("MyEditMinMax","not covertible: " << s);
		}

	}

	MyEditMinMax& Min(DataType min)                     
	{
		//Cv::Min(min); return *this; 
		if( 	(typeid(DataType) == typeid(int))
			 || (typeid(DataType) == typeid(unsigned int))
			 || (typeid(DataType) == typeid(short))
			 || (typeid(DataType) == typeid(unsigned short))
			 || (typeid(DataType) == typeid(char))
			 || (typeid(DataType) == typeid(unsigned char))
			)
		{
			((ConvertInt*)MyEditValue<DataType>::pcv)->Min(min);
		}
		else if( (typeid(DataType) == typeid(double))
			 || (typeid(DataType) == typeid(float))
			)
		{
			((ConvertDouble*)MyEditValue<DataType>::pcv)->Min(min);
		}
		else if( (typeid(DataType) == typeid(long))
			 || (typeid(DataType) == typeid(unsigned long))
			)
		{
			((ConvertInt64*)MyEditValue<DataType>::pcv)->Min(min);
		}
		else
		{
			D6("MyEditMinMax","unknown type : " << typeid(DataType).name());
			D6("MyEditMinMax","not covertible: " << s);
		}
		return *this;
	}
	
	MyEditMinMax& Max(DataType max)                     
	{
		//Cv::Max(max); return *this; 
		if( 	(typeid(DataType) == typeid(int))
			 || (typeid(DataType) == typeid(unsigned int))
			 || (typeid(DataType) == typeid(short))
			 || (typeid(DataType) == typeid(unsigned short))
			 || (typeid(DataType) == typeid(char))
			 || (typeid(DataType) == typeid(unsigned char))
			)
		{
			((ConvertInt*)MyEditValue<DataType>::pcv)->Max(max);
		}
		else if( (typeid(DataType) == typeid(double))
			 || (typeid(DataType) == typeid(float))
			)
		{
			((ConvertDouble*)MyEditValue<DataType>::pcv)->Max(max);
		}
		else if( (typeid(DataType) == typeid(long))
			 || (typeid(DataType) == typeid(unsigned long))
			)
		{
			((ConvertInt64*)MyEditValue<DataType>::pcv)->Max(max);
		}
		else
		{
			D6("MyEditMinMax","unknown type : " << typeid(DataType).name());
			D6("MyEditMinMax","not covertible: " << s);
		}
		return *this;
	}
	
	MyEditMinMax& NotNull(bool nn = true)               
	{
		//Cv::NotNull(nn); return *this; 
		if( 	(typeid(DataType) == typeid(int))
			 || (typeid(DataType) == typeid(unsigned int))
			 || (typeid(DataType) == typeid(short))
			 || (typeid(DataType) == typeid(unsigned short))
			 || (typeid(DataType) == typeid(char))
			 || (typeid(DataType) == typeid(unsigned char))
			)
		{
			((ConvertInt*)MyEditValue<DataType>::pcv)->NotNull(nn);
		}
		else if( (typeid(DataType) == typeid(double))
			 || (typeid(DataType) == typeid(float))
			)
		{
			((ConvertDouble*)MyEditValue<DataType>::pcv)->NotNull(nn);
		}
		else if( (typeid(DataType) == typeid(long))
			 || (typeid(DataType) == typeid(unsigned long))
			)
		{
			((ConvertInt64*)MyEditValue<DataType>::pcv)->NotNull(nn);
		}
		else
		{
			D6("MyEditMinMax","unknown type : " << typeid(DataType).name());
			D6("MyEditMinMax","not covertible: " << s);
			return;
		}
	}
};


///



[Updated on: Fri, 07 August 2009 16:59]

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Re: ConvertInt > templatable Convert<T> [message #22709 is a reply to message #22708] Fri, 07 August 2009 18:03 Go to previous messageGo to next message
mrjt is currently offline  mrjt
Messages: 705
Registered: March 2007
Location: London
Contributor
I'm not really sure what problem you're trying to solve with this, though I think I see what you're trying to do.

I think there are simpler ways of achieving it though, for instance:
template <class DataType>
class ConvertT : public Convert
{
private:
	DataType minval;
	DataType maxval;
	bool notnull;
	
public:
	ConvertT() : minval(Null), maxval(Null), notnull(false) {}

	virtual Value Scan(const Value& text) const {
		if (IsNotNull() && IsNull(text)) return NotNullError();
		Value v;
		if( 	(typeid(DataType) == typeid(int))
			 || (typeid(DataType) == typeid(unsigned int))
			 || (typeid(DataType) == typeid(short))
			 || (typeid(DataType) == typeid(unsigned short))
			 || (typeid(DataType) == typeid(char))
			 || (typeid(DataType) == typeid(unsigned char))
			)
		{
			v = StdConvertInt().Scan(text);
		}
		else if( (typeid(DataType) == typeid(double))
			 || (typeid(DataType) == typeid(float))
			)
		{
			v = StdConvertDouble().Scan(text);
		}
		else if( (typeid(DataType) == typeid(uint64))
			 || (typeid(DataType) == typeid(int64))
			)
		{
			v = ConvertInt64().Scan(text); // No StdConvert64
		}
		else 
			v = StdConvert().Scan(text);
			
		if (!IsNull(v) && !IsNull(minval) && !IsNull(maxval)) {
			DataType m = DataType(v);
			if(m >= minval && m <= maxval) 
				return v;
			return ErrorValue(UPP::Format(t_("Number must be between %s and %s."), Format(minval), Format(maxval)));
		}
		return v;
	}
	virtual Value Format(const Value& q) const {
                // You may want to check the type of q here to ensure it matches DataType
		return StdConvert().Format(q);
	}
	
	ConvertT<DataType>& MinMax(DataType _min, DataType _max) { minval = _min; maxval = _max; return *this; }
	ConvertT<DataType>& Min(DataType _min)                { minval = _min; return *this; }
	ConvertT<DataType>& Max(DataType _max)                { maxval = _max; return *this; }
	ConvertT<DataType>& NotNull(bool b = true)            { notnull = b; return *this; }
	ConvertT<DataType>& NoNotNull()                       { return NotNull(false); }
	DataType         	GetMin() const                    { return minval; }
	DataType         	GetMax() const                    { return maxval; }
	bool        		IsNotNull() const                 { return notnull; }
};

And then use templated edit ctrls like so:
template <class T>
struct EditMinMaxT : public EditMinMax<T, ConvertT<T> >
{ };

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Re: ConvertInt > templatable Convert<T> [message #22825 is a reply to message #22709] Thu, 20 August 2009 10:18 Go to previous messageGo to next message
kohait00 is currently offline  kohait00
Messages: 939
Registered: July 2009
Location: Germany
Experienced Contributor
thanks, i'l accomodate the code, maybe we can include it in Upp also

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icon14.gif  this one worked for me [message #22826 is a reply to message #22825] Thu, 20 August 2009 11:48 Go to previous messageGo to next message
kohait00 is currently offline  kohait00
Messages: 939
Registered: July 2009
Location: Germany
Experienced Contributor
had to change it slightly..code is found at bottom

i havent been able to test it extensivly, but it seems to work quite well..but so far it works for int and float

so incase anyone wants to have a number EditField without specifying Type directly..

so instead of 
EditInt edit;


you can use
EditMinMax<DataType, ConvertT<DataType> > edit;


or event better
template <class DataType>
EditNumber : public EditMinMax<DataType, ConvertT<DataType> > {}

EditNumber<float> edit;
EditNumber<T> edit2;



now here is the code that i could compile.
thanks for help Smile

template <class DataType>
class ConvertT : public Convert
{
private:
	DataType minval;
	DataType maxval;
	bool notnull;
	
public:
	//ConvertT() : minval(Null), maxval(Null), notnull(false) {}
	ConvertT()
	{
		if( 	(typeid(DataType) == typeid(int))
			 || (typeid(DataType) == typeid(short))
			 || (typeid(DataType) == typeid(char))
			 || (typeid(DataType) == typeid(int64))
			)
		{
			minval = (DataType) (1<<(8*sizeof(DataType)-1)); //0x8000...
			maxval = (DataType) (minval - 1);//0x7FFF..
			notnull = true;
		}

		else if( 	(typeid(DataType) == typeid(unsigned int))
			 || (typeid(DataType) == typeid(unsigned short))
			 || (typeid(DataType) == typeid(unsigned char))
			 || (typeid(DataType) == typeid(uint64))
			)
		{
			minval = 0;
			maxval = (DataType) (-1); //FFFF...
			notnull = true;
		}
		
		else
		{
			minval = (DataType)0; //Null;
			maxval = (DataType)0; //Null;
			notnull = false;
		}
		
	}

	virtual Value Scan(const Value& text) const {
		if (IsNotNull() && IsNull(text)) return NotNullError();
		Value v;
		if( 	(typeid(DataType) == typeid(int))
			 || (typeid(DataType) == typeid(unsigned int))
			 || (typeid(DataType) == typeid(short))
			 || (typeid(DataType) == typeid(unsigned short))
			 || (typeid(DataType) == typeid(char))
			 || (typeid(DataType) == typeid(unsigned char))
			)
		{
			v = StdConvertInt().Scan(text);
		}
		else if( (typeid(DataType) == typeid(double))
			 || (typeid(DataType) == typeid(float))
			)
		{
			v = StdConvertDouble().Scan(text);
		}
		else if( (typeid(DataType) == typeid(uint64))
			 || (typeid(DataType) == typeid(int64))
			)
		{
			v = ConvertInt64().Scan(text); // No StdConvert64
		}
		else 
			v = StdConvert().Scan(text);
			
		if (	!IsNull(v) 
			//&& 	!IsNull(minval) 
			//&& 	!IsNull(maxval)
			&& IsNotNull()
			) 
		{
			DataType m;

			if( 	(typeid(DataType) == typeid(int))
				 || (typeid(DataType) == typeid(unsigned int))
				 || (typeid(DataType) == typeid(short))
				 || (typeid(DataType) == typeid(unsigned short))
				 || (typeid(DataType) == typeid(char))
				 || (typeid(DataType) == typeid(unsigned char))
				)
			{
				m = (DataType)(int)(v);
			}
			else if( (typeid(DataType) == typeid(double))
				 || (typeid(DataType) == typeid(float))
				)
			{
				m = (DataType)(double)(v);
			}
			else if( (typeid(DataType) == typeid(uint64))
				 || (typeid(DataType) == typeid(int64))
				)
			{
				m = (DataType)(int64)(v);
			}
			else
			{
				return ErrorValue(UPP::Format(t_("Number must be a valid type. %s"), Format((DataType)(0)))); //gives compile errors if no second format
			}


			if(m >= minval && m <= maxval) 
				return v;
			return ErrorValue(UPP::Format(t_("Number must be between %s and %s."), Format(minval), Format(maxval)));
		}
		return v;
	}
	virtual Value Format(const Value& q) const 
	{
		// You may want to check the type of q here to ensure it matches DataType
		return StdConvert().Format(q);
	}
	
	ConvertT<DataType>& MinMax(DataType _min, DataType _max) { minval = _min; maxval = _max; return *this; }
	ConvertT<DataType>& Min(DataType _min)                { minval = _min; return *this; }
	ConvertT<DataType>& Max(DataType _max)                { maxval = _max; return *this; }
	ConvertT<DataType>& NotNull(bool b = true)            { notnull = b; return *this; }
	ConvertT<DataType>& NoNotNull()                       { return NotNull(false); }
	DataType         	GetMin() const                    { return minval; }
	DataType         	GetMax() const                    { return maxval; }
	bool        		IsNotNull() const                 { return notnull; }
};

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Re: this one worked for me [message #22828 is a reply to message #22826] Thu, 20 August 2009 16:26 Go to previous message
mrjt is currently offline  mrjt
Messages: 705
Registered: March 2007
Location: London
Contributor
Well, the problem is that you are trying to use types that cannot have a Null defined for them (this is usually the case for smaller variants of a type, float and short for instance). These cannot be directly converted to and from Values.

I actually should have removed all of these types from my version as it won't work compile (as you discovered). Hacking in arbitrary Null values isn't a very good solution IMO.

What I hadn't thought of before was that the task would be much more easily accomplished with something like:
struct ConvertUnsignedChar : public ConvertInt
{
	ConvertUnsignedChar() {	MinMax(0, 255); }	
};

template <class CONVERT, const int CHARS>
struct EditCustom : public EditMinMax<int, CONVERT >
{
	EditCustom() { MaxChars(CHARS); }
};

typedef EditCustom<ConvertUnsignedChar, 3> EditUnsignedChar;
(This would be even simpler if you didn't need the max chars)

Since you're doing all the RTTI typeid stuff internally anyway, why not just do it in a function somewhere to create the correct type of EditField/Convert and avoid all the horrific bodging?

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