SkNx_shuffle

src/core/SkNx.h

 /*
  * 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 SkNx_DEFINED
 #define SkNx_DEFINED
 
@@ skipping 248 matching lines @@
     static double Sqrt(double val) { return     ::sqrt (       val); }
 
     I pun() const {
         union { T f; I i; } pun = { fVal };
         return pun.i;
     }
 
     T fVal;
 };
 
+// This default implementation can be specialized by ../opts/SkNx_foo.h
+// if there's a better platform-specific shuffle strategy.
+template <typename SkNx, int... Ix>
+inline SkNx SkNx_shuffle_impl(const SkNx& src) { return SkNx( src.template kth<Ix>()... ); }
+
+// This generic shuffle can be called on either SkNi or SkNf with either 1 or N indices:
+//     Sk4f(1,2,3,4) f;

[reed1, 2015/09/01 15:45:03]

do you mean Sk4f f(1,2,3,4); ?

Actually, I think it may be ever clearer to use letters, so as to clearly
distinguish between indices and values

e.g.

Sk4f f(a, b, c, d);

[mtklein_C, 2015/09/01 16:00:03]

Yep, done.

+//     SkNx_shuffle<0>(f);        // ~~~> Sk4f(1,1,1,1)
+//     SkNx_shuffle<2,1,0,3>(f);  // ~~~> Sk4f(3,2,1,4)
+template <int... Ix, typename SkNx>
+inline SkNx SkNx_shuffle(const SkNx& src) { return SkNx_shuffle_impl<SkNx, Ix...>(src); }
+
 }  // namespace
 
+
+
+
 // Include platform specific specializations if available.
 #ifndef SKNX_NO_SIMD
     #if SK_CPU_SSE_LEVEL >= SK_CPU_SSE_LEVEL_SSE2
         #include "../opts/SkNx_sse.h"
     #elif defined(SK_ARM_HAS_NEON)
         #include "../opts/SkNx_neon.h"
     #endif
 #endif
 
 #undef REQUIRE
 
 typedef SkNf<2,    float> Sk2f;
 typedef SkNf<2,   double> Sk2d;
 typedef SkNf<2, SkScalar> Sk2s;
 
 typedef SkNf<4,    float> Sk4f;
 typedef SkNf<4,   double> Sk4d;
 typedef SkNf<4, SkScalar> Sk4s;
 
 typedef SkNi<4,  uint16_t> Sk4h;
 typedef SkNi<8,  uint16_t> Sk8h;
 typedef SkNi<16, uint16_t> Sk16h;
 
 typedef SkNi<16, uint8_t> Sk16b;
 
 typedef SkNi<4,  int32_t> Sk4i;
 typedef SkNi<4, uint32_t> Sk4u;
 
 #endif//SkNx_DEFINED