The Tor Browser: media/libyuv/source/scale_common.cc@b8a032363ba2 (annotated)

media/libyuv/source/scale_common.cc@b8a032363ba2 (annotated)

media/libyuv/source/scale_common.cc

Thu, 22 Jan 2015 13:21:57 +0100

author: Michael Schloh von Bennewitz <michael@schloh.com>
date: Thu, 22 Jan 2015 13:21:57 +0100
branch: TOR_BUG_9701
changeset 15: b8a032363ba2
permissions: -rw-r--r--

Incorporate requested changes from Mozilla in review:
https://bugzilla.mozilla.org/show_bug.cgi?id=1123480#c6

 /*
  *  Copyright 2013 The LibYuv Project Authors. All rights reserved.
  *
  *  Use of this source code is governed by a BSD-style license
  *  that can be found in the LICENSE file in the root of the source
  *  tree. An additional intellectual property rights grant can be found
  *  in the file PATENTS. All contributing project authors may
  *  be found in the AUTHORS file in the root of the source tree.
  */
 #include "libyuv/scale.h"
 #include <assert.h>
 #include <string.h>
 #include "libyuv/cpu_id.h"
 #include "libyuv/planar_functions.h"  // For CopyARGB
 #include "libyuv/row.h"
 #include "libyuv/scale_row.h"
 #ifdef __cplusplus
 namespace libyuv {
 extern "C" {
 #endif
 static __inline int Abs(int v) {
   return v >= 0 ? v : -v;
 }
 // CPU agnostic row functions
 void ScaleRowDown2_C(const uint8* src_ptr, ptrdiff_t src_stride,
                      uint8* dst, int dst_width) {
   int x;
   for (x = 0; x < dst_width - 1; x += 2) {
     dst[0] = src_ptr[1];
     dst[1] = src_ptr[3];
     dst += 2;
     src_ptr += 4;
   }
   if (dst_width & 1) {
     dst[0] = src_ptr[1];
   }
 }
 void ScaleRowDown2Linear_C(const uint8* src_ptr, ptrdiff_t src_stride,
                            uint8* dst, int dst_width) {
   const uint8* s = src_ptr;
   int x;
   for (x = 0; x < dst_width - 1; x += 2) {
     dst[0] = (s[0] + s[1] + 1) >> 1;
     dst[1] = (s[2] + s[3] + 1) >> 1;
     dst += 2;
     s += 4;
   }
   if (dst_width & 1) {
     dst[0] = (s[0] + s[1] + 1) >> 1;
   }
 }
 void ScaleRowDown2Box_C(const uint8* src_ptr, ptrdiff_t src_stride,
                         uint8* dst, int dst_width) {
   const uint8* s = src_ptr;
   const uint8* t = src_ptr + src_stride;
   int x;
   for (x = 0; x < dst_width - 1; x += 2) {
     dst[0] = (s[0] + s[1] + t[0] + t[1] + 2) >> 2;
     dst[1] = (s[2] + s[3] + t[2] + t[3] + 2) >> 2;
     dst += 2;
     s += 4;
     t += 4;
   }
   if (dst_width & 1) {
     dst[0] = (s[0] + s[1] + t[0] + t[1] + 2) >> 2;
   }
 }
 void ScaleRowDown4_C(const uint8* src_ptr, ptrdiff_t src_stride,
                      uint8* dst, int dst_width) {
   int x;
   for (x = 0; x < dst_width - 1; x += 2) {
     dst[0] = src_ptr[2];
     dst[1] = src_ptr[6];
     dst += 2;
     src_ptr += 8;
   }
   if (dst_width & 1) {
     dst[0] = src_ptr[2];
   }
 }
 void ScaleRowDown4Box_C(const uint8* src_ptr, ptrdiff_t src_stride,
                         uint8* dst, int dst_width) {
   intptr_t stride = src_stride;
   int x;
   for (x = 0; x < dst_width - 1; x += 2) {
     dst[0] = (src_ptr[0] + src_ptr[1] + src_ptr[2] + src_ptr[3] +
              src_ptr[stride + 0] + src_ptr[stride + 1] +
              src_ptr[stride + 2] + src_ptr[stride + 3] +
              src_ptr[stride * 2 + 0] + src_ptr[stride * 2 + 1] +
              src_ptr[stride * 2 + 2] + src_ptr[stride * 2 + 3] +
              src_ptr[stride * 3 + 0] + src_ptr[stride * 3 + 1] +
              src_ptr[stride * 3 + 2] + src_ptr[stride * 3 + 3] +
 ) >> 4;
     dst[1] = (src_ptr[4] + src_ptr[5] + src_ptr[6] + src_ptr[7] +
              src_ptr[stride + 4] + src_ptr[stride + 5] +
              src_ptr[stride + 6] + src_ptr[stride + 7] +
              src_ptr[stride * 2 + 4] + src_ptr[stride * 2 + 5] +
              src_ptr[stride * 2 + 6] + src_ptr[stride * 2 + 7] +
              src_ptr[stride * 3 + 4] + src_ptr[stride * 3 + 5] +
              src_ptr[stride * 3 + 6] + src_ptr[stride * 3 + 7] +
 ) >> 4;
     dst += 2;
     src_ptr += 8;
   }
   if (dst_width & 1) {
     dst[0] = (src_ptr[0] + src_ptr[1] + src_ptr[2] + src_ptr[3] +
              src_ptr[stride + 0] + src_ptr[stride + 1] +
              src_ptr[stride + 2] + src_ptr[stride + 3] +
              src_ptr[stride * 2 + 0] + src_ptr[stride * 2 + 1] +
              src_ptr[stride * 2 + 2] + src_ptr[stride * 2 + 3] +
              src_ptr[stride * 3 + 0] + src_ptr[stride * 3 + 1] +
              src_ptr[stride * 3 + 2] + src_ptr[stride * 3 + 3] +
 ) >> 4;
   }
 }
 void ScaleRowDown34_C(const uint8* src_ptr, ptrdiff_t src_stride,
                       uint8* dst, int dst_width) {
   int x;
   assert((dst_width % 3 == 0) && (dst_width > 0));
   for (x = 0; x < dst_width; x += 3) {
     dst[0] = src_ptr[0];
     dst[1] = src_ptr[1];
     dst[2] = src_ptr[3];
     dst += 3;
     src_ptr += 4;
   }
 }
 // Filter rows 0 and 1 together, 3 : 1
 void ScaleRowDown34_0_Box_C(const uint8* src_ptr, ptrdiff_t src_stride,
                             uint8* d, int dst_width) {
   const uint8* s = src_ptr;
   const uint8* t = src_ptr + src_stride;
   int x;
   assert((dst_width % 3 == 0) && (dst_width > 0));
   for (x = 0; x < dst_width; x += 3) {
     uint8 a0 = (s[0] * 3 + s[1] * 1 + 2) >> 2;
     uint8 a1 = (s[1] * 1 + s[2] * 1 + 1) >> 1;
     uint8 a2 = (s[2] * 1 + s[3] * 3 + 2) >> 2;
     uint8 b0 = (t[0] * 3 + t[1] * 1 + 2) >> 2;
     uint8 b1 = (t[1] * 1 + t[2] * 1 + 1) >> 1;
     uint8 b2 = (t[2] * 1 + t[3] * 3 + 2) >> 2;
     d[0] = (a0 * 3 + b0 + 2) >> 2;
     d[1] = (a1 * 3 + b1 + 2) >> 2;
     d[2] = (a2 * 3 + b2 + 2) >> 2;
     d += 3;
     s += 4;
     t += 4;
   }
 }
 // Filter rows 1 and 2 together, 1 : 1
 void ScaleRowDown34_1_Box_C(const uint8* src_ptr, ptrdiff_t src_stride,
                             uint8* d, int dst_width) {
   const uint8* s = src_ptr;
   const uint8* t = src_ptr + src_stride;
   int x;
   assert((dst_width % 3 == 0) && (dst_width > 0));
   for (x = 0; x < dst_width; x += 3) {
     uint8 a0 = (s[0] * 3 + s[1] * 1 + 2) >> 2;
     uint8 a1 = (s[1] * 1 + s[2] * 1 + 1) >> 1;
     uint8 a2 = (s[2] * 1 + s[3] * 3 + 2) >> 2;
     uint8 b0 = (t[0] * 3 + t[1] * 1 + 2) >> 2;
     uint8 b1 = (t[1] * 1 + t[2] * 1 + 1) >> 1;
     uint8 b2 = (t[2] * 1 + t[3] * 3 + 2) >> 2;
     d[0] = (a0 + b0 + 1) >> 1;
     d[1] = (a1 + b1 + 1) >> 1;
     d[2] = (a2 + b2 + 1) >> 1;
     d += 3;
     s += 4;
     t += 4;
   }
 }
 // Scales a single row of pixels using point sampling.
 void ScaleCols_C(uint8* dst_ptr, const uint8* src_ptr,
                  int dst_width, int x, int dx) {
   int j;
   for (j = 0; j < dst_width - 1; j += 2) {
     dst_ptr[0] = src_ptr[x >> 16];
     x += dx;
     dst_ptr[1] = src_ptr[x >> 16];
     x += dx;
     dst_ptr += 2;
   }
   if (dst_width & 1) {
     dst_ptr[0] = src_ptr[x >> 16];
   }
 }
 // Scales a single row of pixels up by 2x using point sampling.
 void ScaleColsUp2_C(uint8* dst_ptr, const uint8* src_ptr,
                     int dst_width, int x, int dx) {
   int j;
   for (j = 0; j < dst_width - 1; j += 2) {
     dst_ptr[1] = dst_ptr[0] = src_ptr[0];
     src_ptr += 1;
     dst_ptr += 2;
   }
   if (dst_width & 1) {
     dst_ptr[0] = src_ptr[0];
   }
 }
 // (1-f)a + fb can be replaced with a + f(b-a)
 #define BLENDER(a, b, f) (uint8)((int)(a) + \
     ((int)(f) * ((int)(b) - (int)(a)) >> 16))
 void ScaleFilterCols_C(uint8* dst_ptr, const uint8* src_ptr,
                        int dst_width, int x, int dx) {
   int j;
   for (j = 0; j < dst_width - 1; j += 2) {
     int xi = x >> 16;
     int a = src_ptr[xi];
     int b = src_ptr[xi + 1];
     dst_ptr[0] = BLENDER(a, b, x & 0xffff);
     x += dx;
     xi = x >> 16;
     a = src_ptr[xi];
     b = src_ptr[xi + 1];
     dst_ptr[1] = BLENDER(a, b, x & 0xffff);
     x += dx;
     dst_ptr += 2;
   }
   if (dst_width & 1) {
     int xi = x >> 16;
     int a = src_ptr[xi];
     int b = src_ptr[xi + 1];
     dst_ptr[0] = BLENDER(a, b, x & 0xffff);
   }
 }
 void ScaleFilterCols64_C(uint8* dst_ptr, const uint8* src_ptr,
                          int dst_width, int x32, int dx) {
   int64 x = (int64)(x32);
   int j;
   for (j = 0; j < dst_width - 1; j += 2) {
     int64 xi = x >> 16;
     int a = src_ptr[xi];
     int b = src_ptr[xi + 1];
     dst_ptr[0] = BLENDER(a, b, x & 0xffff);
     x += dx;
     xi = x >> 16;
     a = src_ptr[xi];
     b = src_ptr[xi + 1];
     dst_ptr[1] = BLENDER(a, b, x & 0xffff);
     x += dx;
     dst_ptr += 2;
   }
   if (dst_width & 1) {
     int64 xi = x >> 16;
     int a = src_ptr[xi];
     int b = src_ptr[xi + 1];
     dst_ptr[0] = BLENDER(a, b, x & 0xffff);
   }
 }
 #undef BLENDER
 void ScaleRowDown38_C(const uint8* src_ptr, ptrdiff_t src_stride,
                       uint8* dst, int dst_width) {
   int x;
   assert(dst_width % 3 == 0);
   for (x = 0; x < dst_width; x += 3) {
     dst[0] = src_ptr[0];
     dst[1] = src_ptr[3];
     dst[2] = src_ptr[6];
     dst += 3;
     src_ptr += 8;
   }
 }
 // 8x3 -> 3x1
 void ScaleRowDown38_3_Box_C(const uint8* src_ptr,
                             ptrdiff_t src_stride,
                             uint8* dst_ptr, int dst_width) {
   intptr_t stride = src_stride;
   int i;
   assert((dst_width % 3 == 0) && (dst_width > 0));
   for (i = 0; i < dst_width; i += 3) {
     dst_ptr[0] = (src_ptr[0] + src_ptr[1] + src_ptr[2] +
         src_ptr[stride + 0] + src_ptr[stride + 1] +
         src_ptr[stride + 2] + src_ptr[stride * 2 + 0] +
         src_ptr[stride * 2 + 1] + src_ptr[stride * 2 + 2]) *
         (65536 / 9) >> 16;
     dst_ptr[1] = (src_ptr[3] + src_ptr[4] + src_ptr[5] +
         src_ptr[stride + 3] + src_ptr[stride + 4] +
         src_ptr[stride + 5] + src_ptr[stride * 2 + 3] +
         src_ptr[stride * 2 + 4] + src_ptr[stride * 2 + 5]) *
         (65536 / 9) >> 16;
     dst_ptr[2] = (src_ptr[6] + src_ptr[7] +
         src_ptr[stride + 6] + src_ptr[stride + 7] +
         src_ptr[stride * 2 + 6] + src_ptr[stride * 2 + 7]) *
         (65536 / 6) >> 16;
     src_ptr += 8;
     dst_ptr += 3;
   }
 }
 // 8x2 -> 3x1
 void ScaleRowDown38_2_Box_C(const uint8* src_ptr, ptrdiff_t src_stride,
                             uint8* dst_ptr, int dst_width) {
   intptr_t stride = src_stride;
   int i;
   assert((dst_width % 3 == 0) && (dst_width > 0));
   for (i = 0; i < dst_width; i += 3) {
     dst_ptr[0] = (src_ptr[0] + src_ptr[1] + src_ptr[2] +
         src_ptr[stride + 0] + src_ptr[stride + 1] +
         src_ptr[stride + 2]) * (65536 / 6) >> 16;
     dst_ptr[1] = (src_ptr[3] + src_ptr[4] + src_ptr[5] +
         src_ptr[stride + 3] + src_ptr[stride + 4] +
         src_ptr[stride + 5]) * (65536 / 6) >> 16;
     dst_ptr[2] = (src_ptr[6] + src_ptr[7] +
         src_ptr[stride + 6] + src_ptr[stride + 7]) *
         (65536 / 4) >> 16;
     src_ptr += 8;
     dst_ptr += 3;
   }
 }
 void ScaleAddRows_C(const uint8* src_ptr, ptrdiff_t src_stride,
                     uint16* dst_ptr, int src_width, int src_height) {
   int x;
   assert(src_width > 0);
   assert(src_height > 0);
   for (x = 0; x < src_width; ++x) {
     const uint8* s = src_ptr + x;
     unsigned int sum = 0u;
     int y;
     for (y = 0; y < src_height; ++y) {
       sum += s[0];
       s += src_stride;
     }
     // TODO(fbarchard): Consider limitting height to 256 to avoid overflow.
     dst_ptr[x] = sum < 65535u ? sum : 65535u;
   }
 }
 void ScaleARGBRowDown2_C(const uint8* src_argb,
                          ptrdiff_t src_stride,
                          uint8* dst_argb, int dst_width) {
   const uint32* src = (const uint32*)(src_argb);
   uint32* dst = (uint32*)(dst_argb);
   int x;
   for (x = 0; x < dst_width - 1; x += 2) {
     dst[0] = src[1];
     dst[1] = src[3];
     src += 4;
     dst += 2;
   }
   if (dst_width & 1) {
     dst[0] = src[1];
   }
 }
 void ScaleARGBRowDown2Linear_C(const uint8* src_argb,
                                ptrdiff_t src_stride,
                                uint8* dst_argb, int dst_width) {
   int x;
   for (x = 0; x < dst_width; ++x) {
     dst_argb[0] = (src_argb[0] + src_argb[4] + 1) >> 1;
     dst_argb[1] = (src_argb[1] + src_argb[5] + 1) >> 1;
     dst_argb[2] = (src_argb[2] + src_argb[6] + 1) >> 1;
     dst_argb[3] = (src_argb[3] + src_argb[7] + 1) >> 1;
     src_argb += 8;
     dst_argb += 4;
   }
 }
 void ScaleARGBRowDown2Box_C(const uint8* src_argb, ptrdiff_t src_stride,
                             uint8* dst_argb, int dst_width) {
   int x;
   for (x = 0; x < dst_width; ++x) {
     dst_argb[0] = (src_argb[0] + src_argb[4] +
                   src_argb[src_stride] + src_argb[src_stride + 4] + 2) >> 2;
     dst_argb[1] = (src_argb[1] + src_argb[5] +
                   src_argb[src_stride + 1] + src_argb[src_stride + 5] + 2) >> 2;
     dst_argb[2] = (src_argb[2] + src_argb[6] +
                   src_argb[src_stride + 2] + src_argb[src_stride + 6] + 2) >> 2;
     dst_argb[3] = (src_argb[3] + src_argb[7] +
                   src_argb[src_stride + 3] + src_argb[src_stride + 7] + 2) >> 2;
     src_argb += 8;
     dst_argb += 4;
   }
 }
 void ScaleARGBRowDownEven_C(const uint8* src_argb, ptrdiff_t src_stride,
                             int src_stepx,
                             uint8* dst_argb, int dst_width) {
   const uint32* src = (const uint32*)(src_argb);
   uint32* dst = (uint32*)(dst_argb);
   int x;
   for (x = 0; x < dst_width - 1; x += 2) {
     dst[0] = src[0];
     dst[1] = src[src_stepx];
     src += src_stepx * 2;
     dst += 2;
   }
   if (dst_width & 1) {
     dst[0] = src[0];
   }
 }
 void ScaleARGBRowDownEvenBox_C(const uint8* src_argb,
                                ptrdiff_t src_stride,
                                int src_stepx,
                                uint8* dst_argb, int dst_width) {
   int x;
   for (x = 0; x < dst_width; ++x) {
     dst_argb[0] = (src_argb[0] + src_argb[4] +
                   src_argb[src_stride] + src_argb[src_stride + 4] + 2) >> 2;
     dst_argb[1] = (src_argb[1] + src_argb[5] +
                   src_argb[src_stride + 1] + src_argb[src_stride + 5] + 2) >> 2;
     dst_argb[2] = (src_argb[2] + src_argb[6] +
                   src_argb[src_stride + 2] + src_argb[src_stride + 6] + 2) >> 2;
     dst_argb[3] = (src_argb[3] + src_argb[7] +
                   src_argb[src_stride + 3] + src_argb[src_stride + 7] + 2) >> 2;
     src_argb += src_stepx * 4;
     dst_argb += 4;
   }
 }
 // Scales a single row of pixels using point sampling.
 void ScaleARGBCols_C(uint8* dst_argb, const uint8* src_argb,
                      int dst_width, int x, int dx) {
   const uint32* src = (const uint32*)(src_argb);
   uint32* dst = (uint32*)(dst_argb);
   int j;
   for (j = 0; j < dst_width - 1; j += 2) {
     dst[0] = src[x >> 16];
     x += dx;
     dst[1] = src[x >> 16];
     x += dx;
     dst += 2;
   }
   if (dst_width & 1) {
     dst[0] = src[x >> 16];
   }
 }
 void ScaleARGBCols64_C(uint8* dst_argb, const uint8* src_argb,
                        int dst_width, int x32, int dx) {
   int64 x = (int64)(x32);
   const uint32* src = (const uint32*)(src_argb);
   uint32* dst = (uint32*)(dst_argb);
   int j;
   for (j = 0; j < dst_width - 1; j += 2) {
     dst[0] = src[x >> 16];
     x += dx;
     dst[1] = src[x >> 16];
     x += dx;
     dst += 2;
   }
   if (dst_width & 1) {
     dst[0] = src[x >> 16];
   }
 }
 // Scales a single row of pixels up by 2x using point sampling.
 void ScaleARGBColsUp2_C(uint8* dst_argb, const uint8* src_argb,
                         int dst_width, int x, int dx) {
   const uint32* src = (const uint32*)(src_argb);
   uint32* dst = (uint32*)(dst_argb);
   int j;
   for (j = 0; j < dst_width - 1; j += 2) {
     dst[1] = dst[0] = src[0];
     src += 1;
     dst += 2;
   }
   if (dst_width & 1) {
     dst[0] = src[0];
   }
 }
 // Mimics SSSE3 blender
 #define BLENDER1(a, b, f) ((a) * (0x7f ^ f) + (b) * f) >> 7
 #define BLENDERC(a, b, f, s) (uint32)( \
     BLENDER1(((a) >> s) & 255, ((b) >> s) & 255, f) << s)
 #define BLENDER(a, b, f) \
     BLENDERC(a, b, f, 24) | BLENDERC(a, b, f, 16) | \
     BLENDERC(a, b, f, 8) | BLENDERC(a, b, f, 0)
 void ScaleARGBFilterCols_C(uint8* dst_argb, const uint8* src_argb,
                            int dst_width, int x, int dx) {
   const uint32* src = (const uint32*)(src_argb);
   uint32* dst = (uint32*)(dst_argb);
   int j;
   for (j = 0; j < dst_width - 1; j += 2) {
     int xi = x >> 16;
     int xf = (x >> 9) & 0x7f;
     uint32 a = src[xi];
     uint32 b = src[xi + 1];
     dst[0] = BLENDER(a, b, xf);
     x += dx;
     xi = x >> 16;
     xf = (x >> 9) & 0x7f;
     a = src[xi];
     b = src[xi + 1];
     dst[1] = BLENDER(a, b, xf);
     x += dx;
     dst += 2;
   }
   if (dst_width & 1) {
     int xi = x >> 16;
     int xf = (x >> 9) & 0x7f;
     uint32 a = src[xi];
     uint32 b = src[xi + 1];
     dst[0] = BLENDER(a, b, xf);
   }
 }
 void ScaleARGBFilterCols64_C(uint8* dst_argb, const uint8* src_argb,
                              int dst_width, int x32, int dx) {
   int64 x = (int64)(x32);
   const uint32* src = (const uint32*)(src_argb);
   uint32* dst = (uint32*)(dst_argb);
   int j;
   for (j = 0; j < dst_width - 1; j += 2) {
     int64 xi = x >> 16;
     int xf = (x >> 9) & 0x7f;
     uint32 a = src[xi];
     uint32 b = src[xi + 1];
     dst[0] = BLENDER(a, b, xf);
     x += dx;
     xi = x >> 16;
     xf = (x >> 9) & 0x7f;
     a = src[xi];
     b = src[xi + 1];
     dst[1] = BLENDER(a, b, xf);
     x += dx;
     dst += 2;
   }
   if (dst_width & 1) {
     int64 xi = x >> 16;
     int xf = (x >> 9) & 0x7f;
     uint32 a = src[xi];
     uint32 b = src[xi + 1];
     dst[0] = BLENDER(a, b, xf);
   }
 }
 #undef BLENDER1
 #undef BLENDERC
 #undef BLENDER
 // Scale plane vertically with bilinear interpolation.
 void ScalePlaneVertical(int src_height,
                         int dst_width, int dst_height,
                         int src_stride, int dst_stride,
                         const uint8* src_argb, uint8* dst_argb,
                         int x, int y, int dy,
                         int bpp, enum FilterMode filtering) {
   // TODO(fbarchard): Allow higher bpp.
   int dst_width_bytes = dst_width * bpp;
   void (*InterpolateRow)(uint8* dst_argb, const uint8* src_argb,
       ptrdiff_t src_stride, int dst_width, int source_y_fraction) =
       InterpolateRow_C;
   const int max_y = (src_height > 1) ? ((src_height - 1) << 16) - 1 : 0;
   int j;
   assert(bpp >= 1 && bpp <= 4);
   assert(src_height != 0);
   assert(dst_width > 0);
   assert(dst_height > 0);
   src_argb += (x >> 16) * bpp;
 #if defined(HAS_INTERPOLATEROW_SSE2)
   if (TestCpuFlag(kCpuHasSSE2) && dst_width_bytes >= 16) {
     InterpolateRow = InterpolateRow_Any_SSE2;
     if (IS_ALIGNED(dst_width_bytes, 16)) {
       InterpolateRow = InterpolateRow_Unaligned_SSE2;
       if (IS_ALIGNED(src_argb, 16) && IS_ALIGNED(src_stride, 16) &&
           IS_ALIGNED(dst_argb, 16) && IS_ALIGNED(dst_stride, 16)) {
         InterpolateRow = InterpolateRow_SSE2;
       }
     }
   }
 #endif
 #if defined(HAS_INTERPOLATEROW_SSSE3)
   if (TestCpuFlag(kCpuHasSSSE3) && dst_width_bytes >= 16) {
     InterpolateRow = InterpolateRow_Any_SSSE3;
     if (IS_ALIGNED(dst_width_bytes, 16)) {
       InterpolateRow = InterpolateRow_Unaligned_SSSE3;
       if (IS_ALIGNED(src_argb, 16) && IS_ALIGNED(src_stride, 16) &&
           IS_ALIGNED(dst_argb, 16) && IS_ALIGNED(dst_stride, 16)) {
         InterpolateRow = InterpolateRow_SSSE3;
       }
     }
   }
 #endif
 #if defined(HAS_INTERPOLATEROW_AVX2)
   if (TestCpuFlag(kCpuHasAVX2) && dst_width_bytes >= 32) {
     InterpolateRow = InterpolateRow_Any_AVX2;
     if (IS_ALIGNED(dst_width_bytes, 32)) {
       InterpolateRow = InterpolateRow_AVX2;
     }
   }
 #endif
 #if defined(HAS_INTERPOLATEROW_NEON)
   if (TestCpuFlag(kCpuHasNEON) && dst_width_bytes >= 16) {
     InterpolateRow = InterpolateRow_Any_NEON;
     if (IS_ALIGNED(dst_width_bytes, 16)) {
       InterpolateRow = InterpolateRow_NEON;
     }
   }
 #endif
 #if defined(HAS_INTERPOLATEROWS_MIPS_DSPR2)
   if (TestCpuFlag(kCpuHasMIPS_DSPR2) && dst_width_bytes >= 4 &&
       IS_ALIGNED(src_argb, 4) && IS_ALIGNED(src_stride, 4) &&
       IS_ALIGNED(dst_argb, 4) && IS_ALIGNED(dst_stride, 4)) {
     InterpolateRow = InterpolateRow_Any_MIPS_DSPR2;
     if (IS_ALIGNED(dst_width_bytes, 4)) {
       InterpolateRow = InterpolateRow_MIPS_DSPR2;
     }
   }
 #endif
   for (j = 0; j < dst_height; ++j) {
     int yi;
     int yf;
     if (y > max_y) {
       y = max_y;
     }
     yi = y >> 16;
     yf = filtering ? ((y >> 8) & 255) : 0;
     InterpolateRow(dst_argb, src_argb + yi * src_stride,
                    src_stride, dst_width_bytes, yf);
     dst_argb += dst_stride;
     y += dy;
   }
 }
 // Simplify the filtering based on scale factors.
 enum FilterMode ScaleFilterReduce(int src_width, int src_height,
                                   int dst_width, int dst_height,
                                   enum FilterMode filtering) {
   if (src_width < 0) {
     src_width = -src_width;
   }
   if (src_height < 0) {
     src_height = -src_height;
   }
   if (filtering == kFilterBox) {
     // If scaling both axis to 0.5 or larger, switch from Box to Bilinear.
     if (dst_width * 2 >= src_width && dst_height * 2 >= src_height) {
       filtering = kFilterBilinear;
     }
     // If scaling to larger, switch from Box to Bilinear.
     if (dst_width >= src_width || dst_height >= src_height) {
       filtering = kFilterBilinear;
     }
   }
   if (filtering == kFilterBilinear) {
     if (src_height == 1) {
       filtering = kFilterLinear;
     }
     // TODO(fbarchard): Detect any odd scale factor and reduce to Linear.
     if (dst_height == src_height || dst_height * 3 == src_height) {
       filtering = kFilterLinear;
     }
     // TODO(fbarchard): Remove 1 pixel wide filter restriction, which is to
     // avoid reading 2 pixels horizontally that causes memory exception.
     if (src_width == 1) {
       filtering = kFilterNone;
     }
   }
   if (filtering == kFilterLinear) {
     if (src_width == 1) {
       filtering = kFilterNone;
     }
     // TODO(fbarchard): Detect any odd scale factor and reduce to None.
     if (dst_width == src_width || dst_width * 3 == src_width) {
       filtering = kFilterNone;
     }
   }
   return filtering;
 }
 // Divide num by div and return as 16.16 fixed point result.
 int FixedDiv_C(int num, int div) {
   return (int)(((int64)(num) << 16) / div);
 }
 // Divide num by div and return as 16.16 fixed point result.
 int FixedDiv1_C(int num, int div) {
   return (int)((((int64)(num) << 16) - 0x00010001) /
                           (div - 1));
 }
 #define CENTERSTART(dx, s) (dx < 0) ? -((-dx >> 1) + s) : ((dx >> 1) + s)
 // Compute slope values for stepping.
 void ScaleSlope(int src_width, int src_height,
                 int dst_width, int dst_height,
                 enum FilterMode filtering,
                 int* x, int* y, int* dx, int* dy) {
   assert(x != NULL);
   assert(y != NULL);
   assert(dx != NULL);
   assert(dy != NULL);
   assert(src_width != 0);
   assert(src_height != 0);
   assert(dst_width > 0);
   assert(dst_height > 0);
   // Check for 1 pixel and avoid FixedDiv overflow.
   if (dst_width == 1 && src_width >= 32768) {
     dst_width = src_width;
   }
   if (dst_height == 1 && src_height >= 32768) {
     dst_height = src_height;
   }
   if (filtering == kFilterBox) {
     // Scale step for point sampling duplicates all pixels equally.
     *dx = FixedDiv(Abs(src_width), dst_width);
     *dy = FixedDiv(src_height, dst_height);
     *x = 0;
     *y = 0;
   } else if (filtering == kFilterBilinear) {
     // Scale step for bilinear sampling renders last pixel once for upsample.
     if (dst_width <= Abs(src_width)) {
       *dx = FixedDiv(Abs(src_width), dst_width);
       *x = CENTERSTART(*dx, -32768);  // Subtract 0.5 (32768) to center filter.
     } else if (dst_width > 1) {
       *dx = FixedDiv1(Abs(src_width), dst_width);
       *x = 0;
     }
     if (dst_height <= src_height) {
       *dy = FixedDiv(src_height,  dst_height);
       *y = CENTERSTART(*dy, -32768);  // Subtract 0.5 (32768) to center filter.
     } else if (dst_height > 1) {
       *dy = FixedDiv1(src_height, dst_height);
       *y = 0;
     }
   } else if (filtering == kFilterLinear) {
     // Scale step for bilinear sampling renders last pixel once for upsample.
     if (dst_width <= Abs(src_width)) {
       *dx = FixedDiv(Abs(src_width), dst_width);
       *x = CENTERSTART(*dx, -32768);  // Subtract 0.5 (32768) to center filter.
     } else if (dst_width > 1) {
       *dx = FixedDiv1(Abs(src_width), dst_width);
       *x = 0;
     }
     *dy = FixedDiv(src_height, dst_height);
     *y = *dy >> 1;
   } else {
     // Scale step for point sampling duplicates all pixels equally.
     *dx = FixedDiv(Abs(src_width), dst_width);
     *dy = FixedDiv(src_height, dst_height);
     *x = CENTERSTART(*dx, 0);
     *y = CENTERSTART(*dy, 0);
   }
   // Negative src_width means horizontally mirror.
   if (src_width < 0) {
     *x += (dst_width - 1) * *dx;
     *dx = -*dx;
     // src_width = -src_width;   // Caller must do this.
   }
 }
 #undef CENTERSTART
 #ifdef __cplusplus
 }  // extern "C"
 }  // namespace libyuv
 #endif

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media/libyuv/source/scale_common.cc@b8a032363ba2 (annotated)

media/libyuv/source/scale_common.cc