Set up some hooks for premul/swizzzle opts.

src/core/SkOpts.cpp

 /*
  * Copyright 2015 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "SkOnce.h"
 #include "SkOpts.h"
 
@@ skipping 31 matching lines @@
             return (uint64_t)(edx) << 32 | eax;
         }
     #endif
 #elif !defined(SK_ARM_HAS_NEON)      && \
        defined(SK_CPU_ARM32)         && \
        defined(SK_BUILD_FOR_ANDROID) && \
       !defined(SK_BUILD_FOR_ANDROID_FRAMEWORK)
     #include <cpu-features.h>
 #endif
 
+namespace sk_default {
+
+// These variable names in these functions just pretend the input is BGRA.
+// They work fine with both RGBA and BGRA.
+
+static void premul_xxxa(uint32_t dst[], const uint32_t src[], int count) {
+    for (int i = 0; i < count; i++) {
+        uint8_t a = src[i] >> 24,
+                r = src[i] >> 16,
+                g = src[i] >>  8,
+                b = src[i] >>  0;
+        r = (r*a+127)/255;

[msarett, 2016/01/07 21:35:06]

Currently, we use this:

static inline U8CPU SkMulDiv255Round(U16CPU a, U16CPU b) {
    SkASSERT(a <= 32767);
    SkASSERT(b <= 32767);
    unsigned prod = a*b + 128;
    return (prod + (prod >> 8)) >> 8;
}

Are these identical or will Gold annoy us if I hook up to these?

+        g = (g*a+127)/255;
+        b = (b*a+127)/255;
+        dst[i] = (uint32_t)a << 24
+               | (uint32_t)r << 16
+               | (uint32_t)g <<  8
+               | (uint32_t)b <<  0;
+    }
+}
+
+static void swaprb_xxxa(uint32_t dst[], const uint32_t src[], int count) {
+    for (int i = 0; i < count; i++) {
+        uint8_t a = src[i] >> 24,
+                r = src[i] >> 16,
+                g = src[i] >>  8,
+                b = src[i] >>  0;
+        dst[i] = (uint32_t)a << 24
+               | (uint32_t)b << 16
+               | (uint32_t)g <<  8
+               | (uint32_t)r <<  0;
+    }
+}
+
+static void premul_swaprb_xxxa(uint32_t dst[], const uint32_t src[], int count) {
+    for (int i = 0; i < count; i++) {
+        uint8_t a = src[i] >> 24,
+                r = src[i] >> 16,
+                g = src[i] >>  8,
+                b = src[i] >>  0;
+        r = (r*a+127)/255;
+        g = (g*a+127)/255;
+        b = (b*a+127)/255;
+        dst[i] = (uint32_t)a << 24
+               | (uint32_t)b << 16
+               | (uint32_t)g <<  8
+               | (uint32_t)r <<  0;
+    }
+}
+
+}  // namespace sk_default
+
 namespace SkOpts {
     // Define default function pointer values here...
     // If our global compile options are set high enough, these defaults might even be
     // CPU-specialized, e.g. a typical x86-64 machine might start with SSE2 defaults.
     // They'll still get a chance to be replaced with even better ones, e.g. using SSE4.1.
     decltype(rsqrt)                     rsqrt = sk_default::rsqrt;
     decltype(memset16)               memset16 = sk_default::memset16;
     decltype(memset32)               memset32 = sk_default::memset32;
     decltype(create_xfermode) create_xfermode = sk_default::create_xfermode;
     decltype(color_cube_filter_span) color_cube_filter_span = sk_default::color_cube_filter_span;
@@ skipping 11 matching lines @@
     decltype(fill_block_dimensions) fill_block_dimensions = sk_default::fill_block_dimensions;
 
     decltype(blit_mask_d32_a8) blit_mask_d32_a8 = sk_default::blit_mask_d32_a8;
 
     decltype(blit_row_color32) blit_row_color32 = sk_default::blit_row_color32;
 
     decltype(matrix_translate)       matrix_translate       = sk_default::matrix_translate;
     decltype(matrix_scale_translate) matrix_scale_translate = sk_default::matrix_scale_translate;
     decltype(matrix_affine)          matrix_affine          = sk_default::matrix_affine;
 
+    decltype(       premul_xxxa)        premul_xxxa = sk_default::       premul_xxxa;
+    decltype(       swaprb_xxxa)        swaprb_xxxa = sk_default::       swaprb_xxxa;
+    decltype(premul_swaprb_xxxa) premul_swaprb_xxxa = sk_default::premul_swaprb_xxxa;
+
     // Each Init_foo() is defined in src/opts/SkOpts_foo.cpp.
     void Init_ssse3();
     void Init_sse41();
     void Init_sse42() {}
     void Init_avx();
     void Init_avx2() {}
     void Init_neon();
 
     static void init() {
         // TODO: Chrome's not linking _sse* opts on iOS simulator builds.  Bug or feature?
@@ skipping 25 matching lines @@
 
     SK_DECLARE_STATIC_ONCE(gInitOnce);
     void Init() { SkOnce(&gInitOnce, init); }
 
 #if SK_ALLOW_STATIC_GLOBAL_INITIALIZERS
     static struct AutoInit {
         AutoInit() { Init(); }
     } gAutoInit;
 #endif
 }