src/core/Sk4px.h - skia - Git at Google

 /*
  * Copyright 2015 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */

 #ifndef Sk4px_DEFINED
 #define Sk4px_DEFINED

 #include "include/core/SkColor.h"
 #include "include/private/SkColorData.h"
 #include "include/private/SkVx.h"

 // 1, 2 or 4 SkPMColors, generally vectorized.
 class Sk4px {
 public:
     Sk4px(const skvx::byte16& v) : fV(v) {}

     static Sk4px DupPMColor(SkPMColor c) {
         skvx::uint4 splat(c);

         Sk4px v;
         memcpy((void*)&v, &splat, 16);
         return v;
     }

     // RGBA rgba XYZW xyzw -> AAAA aaaa WWWW wwww
     Sk4px alphas() const {
         static_assert(SK_A32_SHIFT == 24, "This method assumes little-endian.");
         return Sk4px(skvx::shuffle<3,3,3,3, 7,7,7,7, 11,11,11,11, 15,15,15,15>(fV));
     }
     Sk4px inv() const { return Sk4px(skvx::byte16(255) - fV); }

     // When loading or storing fewer than 4 SkPMColors, we use the low lanes.
     static Sk4px Load4(const SkPMColor px[4]) {
         Sk4px v;
         memcpy((void*)&v, px, 16);
         return v;
     }
     static Sk4px Load2(const SkPMColor px[2]) {
         Sk4px v;
         memcpy((void*)&v, px, 8);
         return v;
     }
     static Sk4px Load1(const SkPMColor px[1]) {
         Sk4px v;
         memcpy((void*)&v, px, 4);
         return v;
     }

     // Ditto for Alphas... Load2Alphas fills the low two lanes of Sk4px.
     // AaXx -> AAAA aaaa XXXX xxxx
     static Sk4px Load4Alphas(const SkAlpha alphas[4]) {
         skvx::byte4 a = skvx::byte4::Load(alphas);
         return Sk4px(skvx::shuffle<0,0,0,0, 1,1,1,1, 2,2,2,2, 3,3,3,3>(a));
     }
     // Aa   -> AAAA aaaa ???? ????
     static Sk4px Load2Alphas(const SkAlpha alphas[2]) {
         skvx::byte2 a = skvx::byte2::Load(alphas);
         return Sk4px(join(skvx::shuffle<0,0,0,0, 1,1,1,1>(a), skvx::byte8()));
     }

     void store4(SkPMColor px[4]) const { memcpy(px, this, 16); }
     void store2(SkPMColor px[2]) const { memcpy(px, this,  8); }
     void store1(SkPMColor px[1]) const { memcpy(px, this,  4); }

     // 1, 2, or 4 SkPMColors with 16-bit components.
     // This is most useful as the result of a multiply, e.g. from mulWiden().
     class Wide {
     public:
         Wide(const skvx::Vec<16, uint16_t>& v) : fV(v) {}

         // Rounds, i.e. (x+127) / 255.
         Sk4px div255() const { return Sk4px(skvx::div255(fV)); }

         Wide operator * (const Wide& o) const { return Wide(fV * o.fV); }
         Wide operator + (const Wide& o) const { return Wide(fV + o.fV); }
         Wide operator - (const Wide& o) const { return Wide(fV - o.fV); }
         Wide operator >> (int bits) const { return Wide(fV >> bits); }
         Wide operator << (int bits) const { return Wide(fV << bits); }

     private:
         skvx::Vec<16, uint16_t> fV;
     };

     // Widen 8-bit values to low 8-bits of 16-bit lanes.
     Wide widen() const { return Wide(skvx::cast<uint16_t>(fV)); }
     // 8-bit x 8-bit -> 16-bit components.
     Wide mulWiden(const skvx::byte16& o) const { return Wide(mull(fV, o)); }

     // The only 8-bit multiply we use is 8-bit x 8-bit -> 16-bit.  Might as well make it pithy.
     Wide operator * (const Sk4px& o) const { return this->mulWiden(o.fV); }

     Sk4px operator + (const Sk4px& o) const { return Sk4px(fV + o.fV); }
     Sk4px operator - (const Sk4px& o) const { return Sk4px(fV - o.fV); }
     Sk4px operator < (const Sk4px& o) const { return Sk4px(fV < o.fV); }
     Sk4px operator & (const Sk4px& o) const { return Sk4px(fV & o.fV); }
     Sk4px thenElse(const Sk4px& t, const Sk4px& e) const {
         return Sk4px(if_then_else(fV, t.fV, e.fV));
     }

     // Generally faster than (*this * o).div255().
     // May be incorrect by +-1, but is always exactly correct when *this or o is 0 or 255.
     Sk4px approxMulDiv255(const Sk4px& o) const {
         return Sk4px(approx_scale(fV, o.fV));
     }

     Sk4px saturatedAdd(const Sk4px& o) const {
         return Sk4px(saturated_add(fV, o.fV));
     }

     // A generic driver that maps fn over a src array into a dst array.
     // fn should take an Sk4px (4 src pixels) and return an Sk4px (4 dst pixels).
     template <typename Fn>
     [[maybe_unused]] static void MapSrc(int n, SkPMColor* dst, const SkPMColor* src, const Fn& fn) {
         SkASSERT(dst);
         SkASSERT(src);
         // This looks a bit odd, but it helps loop-invariant hoisting across different calls to fn.
         // Basically, we need to make sure we keep things inside a single loop.
         while (n > 0) {
             if (n >= 8) {
                 Sk4px dst0 = fn(Load4(src+0)),
                       dst4 = fn(Load4(src+4));
                 dst0.store4(dst+0);
                 dst4.store4(dst+4);
                 dst += 8; src += 8; n -= 8;
                 continue;  // Keep our stride at 8 pixels as long as possible.
             }
             SkASSERT(n <= 7);
             if (n >= 4) {
                 fn(Load4(src)).store4(dst);
                 dst += 4; src += 4; n -= 4;
             }
             if (n >= 2) {
                 fn(Load2(src)).store2(dst);
                 dst += 2; src += 2; n -= 2;
             }
             if (n >= 1) {
                 fn(Load1(src)).store1(dst);
             }
             break;
         }
     }

     // As above, but with dst4' = fn(dst4, src4).
     template <typename Fn>
     [[maybe_unused]] static void MapDstSrc(int n, SkPMColor* dst, const SkPMColor* src,
                                            const Fn& fn) {
         SkASSERT(dst);
         SkASSERT(src);
         while (n > 0) {
             if (n >= 8) {
                 Sk4px dst0 = fn(Load4(dst+0), Load4(src+0)),
                       dst4 = fn(Load4(dst+4), Load4(src+4));
                 dst0.store4(dst+0);
                 dst4.store4(dst+4);
                 dst += 8; src += 8; n -= 8;
                 continue;  // Keep our stride at 8 pixels as long as possible.
             }
             SkASSERT(n <= 7);
             if (n >= 4) {
                 fn(Load4(dst), Load4(src)).store4(dst);
                 dst += 4; src += 4; n -= 4;
             }
             if (n >= 2) {
                 fn(Load2(dst), Load2(src)).store2(dst);
                 dst += 2; src += 2; n -= 2;
             }
             if (n >= 1) {
                 fn(Load1(dst), Load1(src)).store1(dst);
             }
             break;
         }
     }

     // As above, but with dst4' = fn(dst4, alpha4).
     template <typename Fn>
     [[maybe_unused]] static void MapDstAlpha(int n, SkPMColor* dst, const SkAlpha* a,
                                              const Fn& fn) {
         SkASSERT(dst);
         SkASSERT(a);
         while (n > 0) {
             if (n >= 8) {
                 Sk4px dst0 = fn(Load4(dst+0), Load4Alphas(a+0)),
                       dst4 = fn(Load4(dst+4), Load4Alphas(a+4));
                 dst0.store4(dst+0);
                 dst4.store4(dst+4);
                 dst += 8; a += 8; n -= 8;
                 continue;  // Keep our stride at 8 pixels as long as possible.
             }
             SkASSERT(n <= 7);
             if (n >= 4) {
                 fn(Load4(dst), Load4Alphas(a)).store4(dst);
                 dst += 4; a += 4; n -= 4;
             }
             if (n >= 2) {
                 fn(Load2(dst), Load2Alphas(a)).store2(dst);
                 dst += 2; a += 2; n -= 2;
             }
             if (n >= 1) {
                 fn(Load1(dst), skvx::byte16(*a)).store1(dst);
             }
             break;
         }
     }

     // As above, but with dst4' = fn(dst4, src4, alpha4).
     template <typename Fn>
     [[maybe_unused]] static void MapDstSrcAlpha(int n, SkPMColor* dst, const SkPMColor* src,
                                                 const SkAlpha* a, const Fn& fn) {
         SkASSERT(dst);
         SkASSERT(src);
         SkASSERT(a);
         while (n > 0) {
             if (n >= 8) {
                 Sk4px dst0 = fn(Load4(dst+0), Load4(src+0), Load4Alphas(a+0)),
                       dst4 = fn(Load4(dst+4), Load4(src+4), Load4Alphas(a+4));
                 dst0.store4(dst+0);
                 dst4.store4(dst+4);
                 dst += 8; src += 8; a += 8; n -= 8;
                 continue;  // Keep our stride at 8 pixels as long as possible.
             }
             SkASSERT(n <= 7);
             if (n >= 4) {
                 fn(Load4(dst), Load4(src), Load4Alphas(a)).store4(dst);
                 dst += 4; src += 4; a += 4; n -= 4;
             }
             if (n >= 2) {
                 fn(Load2(dst), Load2(src), Load2Alphas(a)).store2(dst);
                 dst += 2; src += 2; a += 2; n -= 2;
             }
             if (n >= 1) {
                 fn(Load1(dst), Load1(src), skvx::byte16(*a)).store1(dst);
             }
             break;
         }
     }

 private:
     Sk4px() = default;

     skvx::byte16 fV;
 };

 static_assert(sizeof(Sk4px) == sizeof(skvx::byte16));
 static_assert(alignof(Sk4px) == alignof(skvx::byte16));

 #endif // Sk4px_DEFINED
	/*
	* Copyright 2015 Google Inc.
	*
	* Use of this source code is governed by a BSD-style license that can be
	* found in the LICENSE file.
	*/

	#ifndef Sk4px_DEFINED
	#define Sk4px_DEFINED

	#include "include/core/SkColor.h"
	#include "include/private/SkColorData.h"
	#include "include/private/SkVx.h"

	// 1, 2 or 4 SkPMColors, generally vectorized.
	class Sk4px {
	public:
	Sk4px(const skvx::byte16& v) : fV(v) {}

	static Sk4px DupPMColor(SkPMColor c) {
	skvx::uint4 splat(c);

	Sk4px v;
	memcpy((void*)&v, &splat, 16);
	return v;
	}

	// RGBA rgba XYZW xyzw -> AAAA aaaa WWWW wwww
	Sk4px alphas() const {
	static_assert(SK_A32_SHIFT == 24, "This method assumes little-endian.");
	return Sk4px(skvx::shuffle<3,3,3,3, 7,7,7,7, 11,11,11,11, 15,15,15,15>(fV));
	}
	Sk4px inv() const { return Sk4px(skvx::byte16(255) - fV); }

	// When loading or storing fewer than 4 SkPMColors, we use the low lanes.
	static Sk4px Load4(const SkPMColor px[4]) {
	Sk4px v;
	memcpy((void*)&v, px, 16);
	return v;
	}
	static Sk4px Load2(const SkPMColor px[2]) {
	Sk4px v;
	memcpy((void*)&v, px, 8);
	return v;
	}
	static Sk4px Load1(const SkPMColor px[1]) {
	Sk4px v;
	memcpy((void*)&v, px, 4);
	return v;
	}

	// Ditto for Alphas... Load2Alphas fills the low two lanes of Sk4px.
	// AaXx -> AAAA aaaa XXXX xxxx
	static Sk4px Load4Alphas(const SkAlpha alphas[4]) {
	skvx::byte4 a = skvx::byte4::Load(alphas);
	return Sk4px(skvx::shuffle<0,0,0,0, 1,1,1,1, 2,2,2,2, 3,3,3,3>(a));
	}
	// Aa -> AAAA aaaa ???? ????
	static Sk4px Load2Alphas(const SkAlpha alphas[2]) {
	skvx::byte2 a = skvx::byte2::Load(alphas);
	return Sk4px(join(skvx::shuffle<0,0,0,0, 1,1,1,1>(a), skvx::byte8()));
	}

	void store4(SkPMColor px[4]) const { memcpy(px, this, 16); }
	void store2(SkPMColor px[2]) const { memcpy(px, this, 8); }
	void store1(SkPMColor px[1]) const { memcpy(px, this, 4); }

	// 1, 2, or 4 SkPMColors with 16-bit components.
	// This is most useful as the result of a multiply, e.g. from mulWiden().
	class Wide {
	public:
	Wide(const skvx::Vec<16, uint16_t>& v) : fV(v) {}

	// Rounds, i.e. (x+127) / 255.
	Sk4px div255() const { return Sk4px(skvx::div255(fV)); }

	Wide operator * (const Wide& o) const { return Wide(fV * o.fV); }
	Wide operator + (const Wide& o) const { return Wide(fV + o.fV); }
	Wide operator - (const Wide& o) const { return Wide(fV - o.fV); }
	Wide operator >> (int bits) const { return Wide(fV >> bits); }
	Wide operator << (int bits) const { return Wide(fV << bits); }

	private:
	skvx::Vec<16, uint16_t> fV;
	};

	// Widen 8-bit values to low 8-bits of 16-bit lanes.
	Wide widen() const { return Wide(skvx::cast<uint16_t>(fV)); }
	// 8-bit x 8-bit -> 16-bit components.
	Wide mulWiden(const skvx::byte16& o) const { return Wide(mull(fV, o)); }

	// The only 8-bit multiply we use is 8-bit x 8-bit -> 16-bit. Might as well make it pithy.
	Wide operator * (const Sk4px& o) const { return this->mulWiden(o.fV); }

	Sk4px operator + (const Sk4px& o) const { return Sk4px(fV + o.fV); }
	Sk4px operator - (const Sk4px& o) const { return Sk4px(fV - o.fV); }
	Sk4px operator < (const Sk4px& o) const { return Sk4px(fV < o.fV); }
	Sk4px operator & (const Sk4px& o) const { return Sk4px(fV & o.fV); }
	Sk4px thenElse(const Sk4px& t, const Sk4px& e) const {
	return Sk4px(if_then_else(fV, t.fV, e.fV));
	}

	// Generally faster than (this o).div255().
	// May be incorrect by +-1, but is always exactly correct when *this or o is 0 or 255.
	Sk4px approxMulDiv255(const Sk4px& o) const {
	return Sk4px(approx_scale(fV, o.fV));
	}

	Sk4px saturatedAdd(const Sk4px& o) const {
	return Sk4px(saturated_add(fV, o.fV));
	}

	// A generic driver that maps fn over a src array into a dst array.
	// fn should take an Sk4px (4 src pixels) and return an Sk4px (4 dst pixels).
	template <typename Fn>
	[[maybe_unused]] static void MapSrc(int n, SkPMColor* dst, const SkPMColor* src, const Fn& fn) {
	SkASSERT(dst);
	SkASSERT(src);
	// This looks a bit odd, but it helps loop-invariant hoisting across different calls to fn.
	// Basically, we need to make sure we keep things inside a single loop.
	while (n > 0) {
	if (n >= 8) {
	Sk4px dst0 = fn(Load4(src+0)),
	dst4 = fn(Load4(src+4));
	dst0.store4(dst+0);
	dst4.store4(dst+4);
	dst += 8; src += 8; n -= 8;
	continue; // Keep our stride at 8 pixels as long as possible.
	}
	SkASSERT(n <= 7);
	if (n >= 4) {
	fn(Load4(src)).store4(dst);
	dst += 4; src += 4; n -= 4;
	}
	if (n >= 2) {
	fn(Load2(src)).store2(dst);
	dst += 2; src += 2; n -= 2;
	}
	if (n >= 1) {
	fn(Load1(src)).store1(dst);
	}
	break;
	}
	}

	// As above, but with dst4' = fn(dst4, src4).
	template <typename Fn>
	[[maybe_unused]] static void MapDstSrc(int n, SkPMColor* dst, const SkPMColor* src,
	const Fn& fn) {
	SkASSERT(dst);
	SkASSERT(src);
	while (n > 0) {
	if (n >= 8) {
	Sk4px dst0 = fn(Load4(dst+0), Load4(src+0)),
	dst4 = fn(Load4(dst+4), Load4(src+4));
	dst0.store4(dst+0);
	dst4.store4(dst+4);
	dst += 8; src += 8; n -= 8;
	continue; // Keep our stride at 8 pixels as long as possible.
	}
	SkASSERT(n <= 7);
	if (n >= 4) {
	fn(Load4(dst), Load4(src)).store4(dst);
	dst += 4; src += 4; n -= 4;
	}
	if (n >= 2) {
	fn(Load2(dst), Load2(src)).store2(dst);
	dst += 2; src += 2; n -= 2;
	}
	if (n >= 1) {
	fn(Load1(dst), Load1(src)).store1(dst);
	}
	break;
	}
	}

	// As above, but with dst4' = fn(dst4, alpha4).
	template <typename Fn>
	[[maybe_unused]] static void MapDstAlpha(int n, SkPMColor* dst, const SkAlpha* a,
	const Fn& fn) {
	SkASSERT(dst);
	SkASSERT(a);
	while (n > 0) {
	if (n >= 8) {
	Sk4px dst0 = fn(Load4(dst+0), Load4Alphas(a+0)),
	dst4 = fn(Load4(dst+4), Load4Alphas(a+4));
	dst0.store4(dst+0);
	dst4.store4(dst+4);
	dst += 8; a += 8; n -= 8;
	continue; // Keep our stride at 8 pixels as long as possible.
	}
	SkASSERT(n <= 7);
	if (n >= 4) {
	fn(Load4(dst), Load4Alphas(a)).store4(dst);
	dst += 4; a += 4; n -= 4;
	}
	if (n >= 2) {
	fn(Load2(dst), Load2Alphas(a)).store2(dst);
	dst += 2; a += 2; n -= 2;
	}
	if (n >= 1) {
	fn(Load1(dst), skvx::byte16(*a)).store1(dst);
	}
	break;
	}
	}

	// As above, but with dst4' = fn(dst4, src4, alpha4).
	template <typename Fn>
	[[maybe_unused]] static void MapDstSrcAlpha(int n, SkPMColor* dst, const SkPMColor* src,
	const SkAlpha* a, const Fn& fn) {
	SkASSERT(dst);
	SkASSERT(src);
	SkASSERT(a);
	while (n > 0) {
	if (n >= 8) {
	Sk4px dst0 = fn(Load4(dst+0), Load4(src+0), Load4Alphas(a+0)),
	dst4 = fn(Load4(dst+4), Load4(src+4), Load4Alphas(a+4));
	dst0.store4(dst+0);
	dst4.store4(dst+4);
	dst += 8; src += 8; a += 8; n -= 8;
	continue; // Keep our stride at 8 pixels as long as possible.
	}
	SkASSERT(n <= 7);
	if (n >= 4) {
	fn(Load4(dst), Load4(src), Load4Alphas(a)).store4(dst);
	dst += 4; src += 4; a += 4; n -= 4;
	}
	if (n >= 2) {
	fn(Load2(dst), Load2(src), Load2Alphas(a)).store2(dst);
	dst += 2; src += 2; a += 2; n -= 2;
	}
	if (n >= 1) {
	fn(Load1(dst), Load1(src), skvx::byte16(*a)).store1(dst);
	}
	break;
	}
	}

	private:
	Sk4px() = default;

	skvx::byte16 fV;
	};

	static_assert(sizeof(Sk4px) == sizeof(skvx::byte16));
	static_assert(alignof(Sk4px) == alignof(skvx::byte16));

	#endif // Sk4px_DEFINED