voxel-engine/lib/glm/ext/scalar_integer.inl

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#include "../integer.hpp"
namespace glm{
namespace detail
{
template<length_t L, typename T, qualifier Q, bool compute = false>
struct compute_ceilShift
{
GLM_FUNC_QUALIFIER static vec<L, T, Q> call(vec<L, T, Q> const& v, T)
{
return v;
}
};
template<length_t L, typename T, qualifier Q>
struct compute_ceilShift<L, T, Q, true>
{
GLM_FUNC_QUALIFIER static vec<L, T, Q> call(vec<L, T, Q> const& v, T Shift)
{
return v | (v >> Shift);
}
};
template<length_t L, typename T, qualifier Q, bool isSigned = true>
struct compute_ceilPowerOfTwo
{
GLM_FUNC_QUALIFIER static vec<L, T, Q> call(vec<L, T, Q> const& x)
{
GLM_STATIC_ASSERT(!std::numeric_limits<T>::is_iec559, "'ceilPowerOfTwo' only accept integer scalar or vector inputs");
vec<L, T, Q> const Sign(sign(x));
vec<L, T, Q> v(abs(x));
v = v - static_cast<T>(1);
v = v | (v >> static_cast<T>(1));
v = v | (v >> static_cast<T>(2));
v = v | (v >> static_cast<T>(4));
v = compute_ceilShift<L, T, Q, sizeof(T) >= 2>::call(v, 8);
v = compute_ceilShift<L, T, Q, sizeof(T) >= 4>::call(v, 16);
v = compute_ceilShift<L, T, Q, sizeof(T) >= 8>::call(v, 32);
return (v + static_cast<T>(1)) * Sign;
}
};
template<length_t L, typename T, qualifier Q>
struct compute_ceilPowerOfTwo<L, T, Q, false>
{
GLM_FUNC_QUALIFIER static vec<L, T, Q> call(vec<L, T, Q> const& x)
{
GLM_STATIC_ASSERT(!std::numeric_limits<T>::is_iec559, "'ceilPowerOfTwo' only accept integer scalar or vector inputs");
vec<L, T, Q> v(x);
v = v - static_cast<T>(1);
v = v | (v >> static_cast<T>(1));
v = v | (v >> static_cast<T>(2));
v = v | (v >> static_cast<T>(4));
v = compute_ceilShift<L, T, Q, sizeof(T) >= 2>::call(v, 8);
v = compute_ceilShift<L, T, Q, sizeof(T) >= 4>::call(v, 16);
v = compute_ceilShift<L, T, Q, sizeof(T) >= 8>::call(v, 32);
return v + static_cast<T>(1);
}
};
template<bool is_float, bool is_signed>
struct compute_ceilMultiple{};
template<>
struct compute_ceilMultiple<true, true>
{
template<typename genType>
GLM_FUNC_QUALIFIER static genType call(genType Source, genType Multiple)
{
if(Source > genType(0))
return Source + (Multiple - std::fmod(Source, Multiple));
else
return Source + std::fmod(-Source, Multiple);
}
};
template<>
struct compute_ceilMultiple<false, false>
{
template<typename genType>
GLM_FUNC_QUALIFIER static genType call(genType Source, genType Multiple)
{
genType Tmp = Source - genType(1);
return Tmp + (Multiple - (Tmp % Multiple));
}
};
template<>
struct compute_ceilMultiple<false, true>
{
template<typename genType>
GLM_FUNC_QUALIFIER static genType call(genType Source, genType Multiple)
{
assert(Multiple > genType(0));
if(Source > genType(0))
{
genType Tmp = Source - genType(1);
return Tmp + (Multiple - (Tmp % Multiple));
}
else
return Source + (-Source % Multiple);
}
};
template<bool is_float, bool is_signed>
struct compute_floorMultiple{};
template<>
struct compute_floorMultiple<true, true>
{
template<typename genType>
GLM_FUNC_QUALIFIER static genType call(genType Source, genType Multiple)
{
if(Source >= genType(0))
return Source - std::fmod(Source, Multiple);
else
return Source - std::fmod(Source, Multiple) - Multiple;
}
};
template<>
struct compute_floorMultiple<false, false>
{
template<typename genType>
GLM_FUNC_QUALIFIER static genType call(genType Source, genType Multiple)
{
if(Source >= genType(0))
return Source - Source % Multiple;
else
{
genType Tmp = Source + genType(1);
return Tmp - Tmp % Multiple - Multiple;
}
}
};
template<>
struct compute_floorMultiple<false, true>
{
template<typename genType>
GLM_FUNC_QUALIFIER static genType call(genType Source, genType Multiple)
{
if(Source >= genType(0))
return Source - Source % Multiple;
else
{
genType Tmp = Source + genType(1);
return Tmp - Tmp % Multiple - Multiple;
}
}
};
}//namespace detail
template<typename genIUType>
GLM_FUNC_QUALIFIER bool isPowerOfTwo(genIUType Value)
{
GLM_STATIC_ASSERT(std::numeric_limits<genIUType>::is_integer, "'isPowerOfTwo' only accept integer inputs");
genIUType const Result = glm::abs(Value);
return !(Result & (Result - 1));
}
template<typename genIUType>
GLM_FUNC_QUALIFIER genIUType nextPowerOfTwo(genIUType value)
{
GLM_STATIC_ASSERT(std::numeric_limits<genIUType>::is_integer, "'nextPowerOfTwo' only accept integer inputs");
return detail::compute_ceilPowerOfTwo<1, genIUType, defaultp, std::numeric_limits<genIUType>::is_signed>::call(vec<1, genIUType, defaultp>(value)).x;
}
template<typename genIUType>
GLM_FUNC_QUALIFIER genIUType prevPowerOfTwo(genIUType value)
{
GLM_STATIC_ASSERT(std::numeric_limits<genIUType>::is_integer, "'prevPowerOfTwo' only accept integer inputs");
return isPowerOfTwo(value) ? value : static_cast<genIUType>(static_cast<genIUType>(1) << static_cast<genIUType>(findMSB(value)));
}
template<typename genIUType>
GLM_FUNC_QUALIFIER bool isMultiple(genIUType Value, genIUType Multiple)
{
GLM_STATIC_ASSERT(std::numeric_limits<genIUType>::is_integer, "'isMultiple' only accept integer inputs");
return isMultiple(vec<1, genIUType>(Value), vec<1, genIUType>(Multiple)).x;
}
template<typename genIUType>
GLM_FUNC_QUALIFIER genIUType nextMultiple(genIUType Source, genIUType Multiple)
{
GLM_STATIC_ASSERT(std::numeric_limits<genIUType>::is_integer, "'nextMultiple' only accept integer inputs");
return detail::compute_ceilMultiple<std::numeric_limits<genIUType>::is_iec559, std::numeric_limits<genIUType>::is_signed>::call(Source, Multiple);
}
template<typename genIUType>
GLM_FUNC_QUALIFIER genIUType prevMultiple(genIUType Source, genIUType Multiple)
{
GLM_STATIC_ASSERT(std::numeric_limits<genIUType>::is_integer, "'prevMultiple' only accept integer inputs");
return detail::compute_floorMultiple<std::numeric_limits<genIUType>::is_iec559, std::numeric_limits<genIUType>::is_signed>::call(Source, Multiple);
}
template<typename genIUType>
GLM_FUNC_QUALIFIER int findNSB(genIUType x, int significantBitCount)
{
GLM_STATIC_ASSERT(std::numeric_limits<genIUType>::is_integer, "'findNSB' only accept integer inputs");
if(bitCount(x) < significantBitCount)
return -1;
genIUType const One = static_cast<genIUType>(1);
int bitPos = 0;
genIUType key = x;
int nBitCount = significantBitCount;
int Step = sizeof(x) * 8 / 2;
while (key > One)
{
genIUType Mask = static_cast<genIUType>((One << Step) - One);
genIUType currentKey = key & Mask;
int currentBitCount = bitCount(currentKey);
if (nBitCount > currentBitCount)
{
nBitCount -= currentBitCount;
bitPos += Step;
key >>= static_cast<genIUType>(Step);
}
else
{
key = key & Mask;
}
Step >>= 1;
}
return static_cast<int>(bitPos);
}
}//namespace glm