Uv c++ and sketchup

[giuseppe500]

hello.
I 'm creating a shetchup importer ,that use a texture atlas .
I'm a beginner and i wouldn't go inside the jungle of wrap/tile of texture atlas custom shaders.
my problem now is to recognize what are wrapped/tiled and what are not for process without atlas the tiled/wrapped textures.
I'm creating this function in c++:

bool CMesh;;IsTiled()
{
        std;;vector<TEXCOORD*>;;iterator itBegin =      m_vTextureCoord.begin();
        std;;vector<TEXCOORD*>;;iterator itEnd =        m_vTextureCoord.end();

        for(;itBegin != itEnd; itBegin++)
                if(abs((*itBegin)->U) >1 || abs((*itBegin)->V) >1)
                return true;
        
        if(m_pMaterial->GetTypeMaterial() == eTextureDouble){
                std;;vector<TEXCOORD*>;;iterator itBegin =      m_vTextureCoordBack.begin();
                std;;vector<TEXCOORD*>;;iterator itEnd =        m_vTextureCoordBack.end();

                for(;itBegin != itEnd; itBegin++)
                        if(abs((*itBegin)->U) >1 || abs((*itBegin)->V) >1)
                        return true;
        }               
        return false;
}

but i see that this is wrong:

abs((*itBegin)->U) >1

i removed the abs():

if( ((*itBegin)->U) >1 || ((*itBegin)->U) <0)
return true;//is tiled/wrapped

the problem is that i have some texture UV of U = -0.4 V = 0.2 and with a simple atlas algorithm it work fine !
why?
the texture UV don't be from 0 to 1 ?

this is the code for read from sketchup api the uv:

        m_pApi->ImportVertexUV(&fu, &fv, &fw, &fub, &fvb, &fqb);
        TEXCOORD *ptUV = new TEXCOORD;
        ptUV->U = fu  ;
        ptUV->V = 1- fv ;//this is added from me without explanations , only 
for ;"so 'works"  BAD!!!!
        
        ptUV->W = fw;
        
        vVectorUV.push_back(ptUV);

//ecc...
//ecc...

how i can recognize uv and wrapped texture?
I heard that sketchup does not normalizes the coordinates uv, is it possible?
how do I normalizing if this is the problem?

thanks.