string to s32

[ArakisTheKitsune]

It's not much but I am kinda surprised that this function does not exists. I needed it so I wrote one.
Just add this code in irrString.h

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s32 toS32(void)
        {
                s32 result = 0;
 
                stringw buff = this->subString(0, this->findFirstChar(L"."));
                if(buff == "")
                {
                        buff = this->c_str();
                }
 
                for(u32 i = 0; i < buff.size(); ++i)
                {
                        
                        s32 y = 0;
 
                        if( (s32(buff[i]) < 48) || (s32(buff[i]) > 57) )
                        {
                                return 0;
                        }
 
                        if(buff.size() == 1)
                        {
                                return (s32(buff[i]) - 48);
                        }
                        else
                        {
                                y = (s32(buff[i]) - 48);
                                if( i < (buff.size() - 1))
                                {
                                        s32 m = 1;
                                        for(u32 z = 1; z < (buff.size() - i); ++z )
                                        {
 
                                                m *= 10;
                                        }
 
                                        y *= m;
                                }
                        }
 
                        result += y;
                        
                }
 
                return result;
        }

If code find any non number char it will return 0.
If number is float or double, numbers after the decimal point will be trimmed.

[REDDemon]

isn't there a floating point parser in the XML reader?

[CuteAlien]

No, the stuff is in irr::core namespace in the fast_atof.h header. Corresponding function in Irrlicht would be irr::core::strtol10.

[ArakisTheKitsune]

Yes... I was not aware of that.
This is much simpler:

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s32 toS32(void)
        {
                core::stringc c(this->c_str());
                return core::strtol10(c.c_str());
        }

I am kinda embarrassment but hey every day you learn something new.

[CuteAlien]

Don't worry, I think I found those functions also only after using Irrlicht for a long time :-)

[Voxel]

Hi everyone,

I would like to share the following small code snippet with you. You can convert a value of any type into another result type. The only dependency is that output and input oterator have to exist for the types. Oh, and it's STL based...
The syntax corresponds to the cast operators.

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#ifndef __CONVERT_H__
#define __CONVERT_H__
 
#include <sstream>
 
template <class result_type, class value_type>
inline result_type& convert(value_type value, result_type& result)
 {
    std::stringstream stream;
    stream << value;      // insert value to stream
    stream >> result;     // write value to result
    return result;
}
 
template <class result_type, class value_type>
inline result_type convert(value_type value)
 {
    result_type result; // store conversions result here
    return convert<result_type, value_type>(value, result);
}
 
#endif

e.g. converting floating point value into string and vice versa using the second method.

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double fValue = convert<double>("42.0");
std::string sValue = convert<std::string>(fValue);

If you want to avoid the temporary value within the second method you can use the first method directly:

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std::string sValue2;
convert<double, std::string>(fValue, sValue);

or without the explicit template specification at the expense of readability:

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std::string sValue2;
convert(fValue, sValue2);

Maybe someone finds it useful...

Voxel