text: /*
   * Copyright 2011 Google Inc.
   *
   * Use of this source code is governed by a BSD-style license that can be
   * found in the LICENSE file.
   */
  
  #include "SkBlitRow.h"
  #include "SkBlitMask.h"
  #include "SkColorData.h"
  #include "SkOpts.h"
  #include "SkUtils.h"
  
  #define UNROLL
  
  static void S32_Opaque_BlitRow32(SkPMColor* SK_RESTRICT dst,
                                   const SkPMColor* SK_RESTRICT src,
                                   int count, U8CPU alpha) {
      SkASSERT(255 == alpha);
      memcpy(dst, src, count * 4);
  }
  
  static void S32_Blend_BlitRow32(SkPMColor* SK_RESTRICT dst,
                                  const SkPMColor* SK_RESTRICT src,
                                  int count, U8CPU alpha) {
      SkASSERT(alpha <= 255);
      if (count > 0) {
          unsigned src_scale = SkAlpha255To256(alpha);
  
  #ifdef UNROLL
          if (count & 1) {
              *dst = SkPMLerp(*src, *dst, src_scale);
              src += 1;
              dst += 1;
              count -= 1;
          }
  
          const SkPMColor* SK_RESTRICT srcEnd = src + count;
          while (src != srcEnd) {
              *dst = SkPMLerp(*src, *dst, src_scale);
              src += 1;
              dst += 1;
              *dst = SkPMLerp(*src, *dst, src_scale);
              src += 1;
              dst += 1;
          }
  #else
          do {
              *dst = SkPMLerp(*src, *dst, src_scale);
              src += 1;
              dst += 1;
          } while (--count > 0);
  #endif
      }
  }
  
  static void S32A_Blend_BlitRow32(SkPMColor* SK_RESTRICT dst,
                                   const SkPMColor* SK_RESTRICT src,
                                   int count, U8CPU alpha) {
      SkASSERT(alpha <= 255);
      if (count > 0) {
  #ifdef UNROLL
          if (count & 1) {
              *dst = SkBlendARGB32(*(src++), *dst, alpha);
              dst += 1;
              count -= 1;
          }
  
          const SkPMColor* SK_RESTRICT srcEnd = src + count;
          while (src != srcEnd) {
              *dst = SkBlendARGB32(*(src++), *dst, alpha);
              dst += 1;
              *dst = SkBlendARGB32(*(src++), *dst, alpha);
              dst += 1;
          }
  #else
          do {
              *dst = SkBlendARGB32(*src, *dst, alpha);
              src += 1;
              dst += 1;
          } while (--count > 0);
  #endif
      }
  }
  
  ///////////////////////////////////////////////////////////////////////////////
  
  static const SkBlitRow::Proc32 gDefault_Procs32[] = {
      S32_Opaque_BlitRow32,
      S32_Blend_BlitRow32,
      nullptr,
      S32A_Blend_BlitRow32
  };
  
  SkBlitRow::Proc32 SkBlitRow::Factory32(unsigned flags) {
      SkASSERT(flags < SK_ARRAY_COUNT(gDefault_Procs32));
      // just so we don't crash
      flags &= kFlags32_Mask;
  
      if (flags == 2) {
          // S32A_Opaque_BlitRow32 has been ported to SkOpts, but not the others yet.
          return SkOpts::blit_row_s32a_opaque;
      }
  
      SkBlitRow::Proc32 proc = PlatformProcs32(flags);
      if (nullptr == proc) {
          proc = gDefault_Procs32[flags];
      }
      SkASSERT(proc);
      return proc;
  }
  
  void SkBlitRow::Color32(SkPMColor dst[], const SkPMColor src[], int count, SkPMColor color) {
      switch (SkGetPackedA32(color)) {
          case   0: memmove(dst, src, count * sizeof(SkPMColor)); return;
          case 255: sk_memset32(dst, color, count);               return;
      }
      return SkOpts::blit_row_color32(dst, src, count, color);
  }
  