glm/glm/gtx/integer.inl

///////////////////////////////////////////////////////////////////////////////////////////////////
// OpenGL Mathematics Copyright (c) 2005 - 2011 G-Truc Creation (www.g-truc.net)
///////////////////////////////////////////////////////////////////////////////////////////////////
// Created : 2005-12-24
// Updated : 2006-12-06
// Licence : This source is under MIT License
// File    : glm/gtx/integer.inl
///////////////////////////////////////////////////////////////////////////////////////////////////

namespace glm{

// pow
GLM_FUNC_QUALIFIER int pow(int x, int y)
{
	if(y == 0)
		return 1;
    int result = x;
    for(int i = 1; i < y; ++i)
        result *= x;
    return result;
}

// sqrt: From Christopher J. Musial, An integer square root, Graphics Gems, 1990, page 387
GLM_FUNC_QUALIFIER int sqrt(int x)
{
    if(x <= 1) return x;

    int NextTrial = x >> 1;
    int CurrentAnswer;

    do
    {
        CurrentAnswer = NextTrial;
        NextTrial = (NextTrial + x / NextTrial) >> 1;
    } while(NextTrial < CurrentAnswer);

    return CurrentAnswer;
}

// mod
GLM_FUNC_QUALIFIER int mod(int x, int y)
{
	return x - y * (x / y);
}

// factorial (!12 max, integer only)
template <typename genType>
GLM_FUNC_QUALIFIER genType factorial(genType const & x)
{
	genType Temp = x;
    genType Result;
    for(Result = 1; Temp > 1; --Temp)
        Result *= Temp;
    return Result;
}

template <typename valType>
GLM_FUNC_QUALIFIER detail::tvec2<valType> factorial(
	detail::tvec2<valType> const & x)
{
    return detail::tvec2<valType>(
        factorial(x.x),
        factorial(x.y));
}

template <typename valType>
GLM_FUNC_QUALIFIER detail::tvec3<valType> factorial(
	detail::tvec3<valType> const & x)
{
    return detail::tvec3<valType>(
        factorial(x.x),
        factorial(x.y),
        factorial(x.z));
}

template <typename valType>
GLM_FUNC_QUALIFIER detail::tvec4<valType> factorial(
	detail::tvec4<valType> const & x)
{
    return detail::tvec4<valType>(
        factorial(x.x),
        factorial(x.y),
        factorial(x.z),
        factorial(x.w));
}

}//namespace glm