libcruft-util/coord/store.hpp

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/*
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* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
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* http://www.apache.org/licenses/LICENSE-2.0
*
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* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*
* Copyright 2015 Danny Robson <danny@nerdcruft.net>
*/
#ifndef __UTIL_COORD_STORE_HPP
#define __UTIL_COORD_STORE_HPP
#include "names.hpp"
#include "../platform.hpp"
#include <cstdlib>
namespace util { namespace coord {
///////////////////////////////////////////////////////////////////////////
// Coordinate storage class.
//
// Types of arity multiples of 4 with payloads of at least 16 bytes
// (T >= uint16_t) are guaranteed to be aligned appropriately for SSE (see
// specialisations below).
template <
size_t S,
typename T,
typename...
>
struct
alignas (
sizeof (T) * S % 16 == 0 && sizeof (T) * S >= 16 ? 16 : alignof (T)
)
store {
T data[S];
};
///////////////////////////////////////////////////////////////////////////
template <typename T>
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struct store<3,T,rgba,hsv> {
union {
T data[3];
struct { T r,g,b; };
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struct { T h,s,v; };
};
};
// Align on 16 bytes if the data is at least 16 bytes long. Prevents tiny
// types like colour4u requiring massive alignments, reduces internal
// fragmentation.
//
// TODO: expand this for other instruction sets. maybe switch on type.
template <typename T>
struct
alignas (
sizeof (T) * 4u >= 16 ? 16 : alignof (T)
)
store<4,T,rgba,hsv> {
union {
T data[4];
struct { T r,g,b,a; };
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struct { T h,s,v; };
};
};
///////////////////////////////////////////////////////////////////////////
template <typename T>
struct store<2,T,xyzw> {
union {
T data[2];
struct { T x,y; };
};
};
template <typename T>
struct store<3,T,xyzw> {
union {
T data[3];
struct { T x,y,z; };
};
};
// Align on 16 bytes if the data is at least 16 bytes long. Prevents tiny
// types like colour4u requiring massive alignments, reduces internal
// fragmentation.
//
// TODO: expand this for other instruction sets. maybe switch on type.
template <typename T>
struct
alignas (
sizeof (T) * 4u >= 16 ? 16 : alignof (T)
)
store<4,T,xyzw> {
union {
T data[4];
struct { T x,y,z,w; };
};
};
///////////////////////////////////////////////////////////////////////////
template <typename T>
struct store<2,T,xyzw,stpq> {
union {
T data[2];
struct { T x,y; };
struct { T s,t; };
};
};
template <typename T>
struct store<3,T,xyzw,stpq> {
union {
T data[3];
struct { T x,y,z; };
struct { T s,t,p; };
};
};
// Align on 16 bytes if the data is at least 16 bytes long. Prevents tiny
// types like colour4u requiring massive alignments, reduces internal
// fragmentation.
//
// TODO: expand this for other instruction sets. maybe switch on type.
template <typename T>
struct
alignas (
sizeof (T) * 4u >= 16 ? 16 : alignof (T)
)
store<4,T,xyzw,stpq> {
union {
T data[4];
struct { T x,y,z,w; };
struct { T s,t,p,q; };
};
};
///////////////////////////////////////////////////////////////////////////
template <typename T>
struct store<2,T,whd> {
union {
T data[2];
struct { T w,h; };
};
};
template <typename T>
struct store<3,T,whd> {
union {
T data[3];
struct { T w,h,d; };
};
};
} }
#endif