text: #include <gtest/gtest.h>
  #include "cpu.h"
  #include "cpu_core.h"
  #include "util.h"
  #include "macros.h"
  #include "IWelsVP.h"
  #include "downsample.h"
  
  using namespace WelsVP;
  
  void DyadicBilinearDownsampler_ref (uint8_t* pDst, const int32_t kiDstStride,
                                      uint8_t* pSrc, const int32_t kiSrcStride,
                                      const int32_t kiSrcWidth, const int32_t kiSrcHeight) {
    uint8_t* pDstLine = pDst;
    uint8_t* pSrcLine = pSrc;
    const int32_t kiSrcStridex2 = kiSrcStride << 1;
    const int32_t kiDstWidth    = kiSrcWidth  >> 1;
    const int32_t kiDstHeight   = kiSrcHeight >> 1;
  
    for (int32_t j = 0; j < kiDstHeight; j ++) {
      for (int32_t i = 0; i < kiDstWidth; i ++) {
        const int32_t kiSrcX = i << 1;
        const int32_t kiTempRow1 = (pSrcLine[kiSrcX] + pSrcLine[kiSrcX + 1] + 1) >> 1;
        const int32_t kiTempRow2 = (pSrcLine[kiSrcX + kiSrcStride] + pSrcLine[kiSrcX + kiSrcStride + 1] + 1) >> 1;
  
        pDstLine[i] = (uint8_t) ((kiTempRow1 + kiTempRow2 + 1) >> 1);
      }
      pDstLine += kiDstStride;
      pSrcLine += kiSrcStridex2;
    }
  }
  
  void GeneralBilinearFastDownsampler_ref (uint8_t* pDst, const int32_t kiDstStride, const int32_t kiDstWidth,
      const int32_t kiDstHeight,
      uint8_t* pSrc, const int32_t kiSrcStride, const int32_t kiSrcWidth, const int32_t kiSrcHeight) {
    const uint32_t kuiScaleBitWidth = 16, kuiScaleBitHeight = 15;
    const uint32_t kuiScaleWidth = (1 << kuiScaleBitWidth), kuiScaleHeight = (1 << kuiScaleBitHeight);
    int32_t fScalex = WELS_ROUND ((float)kiSrcWidth / (float)kiDstWidth * kuiScaleWidth);
    int32_t fScaley = WELS_ROUND ((float)kiSrcHeight / (float)kiDstHeight * kuiScaleHeight);
    uint32_t x;
    int32_t iYInverse, iXInverse;
  
    uint8_t* pByDst = pDst;
    uint8_t* pByLineDst = pDst;
  
    iYInverse = 1 << (kuiScaleBitHeight - 1);
    for (int32_t i = 0; i < kiDstHeight - 1; i++) {
      int32_t iYy = iYInverse >> kuiScaleBitHeight;
      int32_t fv = iYInverse & (kuiScaleHeight - 1);
  
      uint8_t* pBySrc = pSrc + iYy * kiSrcStride;
  
      pByDst = pByLineDst;
      iXInverse = 1 << (kuiScaleBitWidth - 1);
      for (int32_t j = 0; j < kiDstWidth - 1; j++) {
        int32_t iXx = iXInverse >> kuiScaleBitWidth;
        int32_t iFu = iXInverse & (kuiScaleWidth - 1);
  
        uint8_t* pByCurrent = pBySrc + iXx;
        uint8_t a, b, c, d;
  
        a = *pByCurrent;
        b = * (pByCurrent + 1);
        c = * (pByCurrent + kiSrcStride);
        d = * (pByCurrent + kiSrcStride + 1);
  
        x  = (((uint32_t) (kuiScaleWidth - 1 - iFu)) * (kuiScaleHeight - 1 - fv) >> kuiScaleBitWidth) * a;
        x += (((uint32_t) (iFu)) * (kuiScaleHeight - 1 - fv) >> kuiScaleBitWidth) * b;
        x += (((uint32_t) (kuiScaleWidth - 1 - iFu)) * (fv) >> kuiScaleBitWidth) * c;
        x += (((uint32_t) (iFu)) * (fv) >> kuiScaleBitWidth) * d;
        x >>= (kuiScaleBitHeight - 1);
        x += 1;
        x >>= 1;
        //x = (((__int64)(SCALE_BIG - 1 - iFu))*(SCALE_BIG - 1 - fv)*a + ((__int64)iFu)*(SCALE_BIG - 1 -fv)*b + ((__int64)(SCALE_BIG - 1 -iFu))*fv*c +
        // ((__int64)iFu)*fv*d + (1 << (2*SCALE_BIT_BIG-1)) ) >> (2*SCALE_BIT_BIG);
        x = WELS_CLAMP (x, 0, 255);
        *pByDst++ = (uint8_t)x;
  
        iXInverse += fScalex;
      }
      *pByDst = * (pBySrc + (iXInverse >> kuiScaleBitWidth));
      pByLineDst += kiDstStride;
      iYInverse += fScaley;
    }
  
    // last row special
    {
      int32_t iYy = iYInverse >> kuiScaleBitHeight;
      uint8_t* pBySrc = pSrc + iYy * kiSrcStride;
  
      pByDst = pByLineDst;
      iXInverse = 1 << (kuiScaleBitWidth - 1);
      for (int32_t j = 0; j < kiDstWidth; j++) {
        int32_t iXx = iXInverse >> kuiScaleBitWidth;
        *pByDst++ = * (pBySrc + iXx);
  
        iXInverse += fScalex;
      }
    }
  }
  
  void GeneralBilinearAccurateDownsampler_ref (uint8_t* pDst, const int32_t kiDstStride, const int32_t kiDstWidth,
      const int32_t kiDstHeight,
      uint8_t* pSrc, const int32_t kiSrcStride, const int32_t kiSrcWidth, const int32_t kiSrcHeight) {
    const int32_t kiScaleBit = 15;
    const int32_t kiScale = (1 << kiScaleBit);
    int32_t iScalex = WELS_ROUND ((float)kiSrcWidth / (float)kiDstWidth * kiScale);
    int32_t iScaley = WELS_ROUND ((float)kiSrcHeight / (float)kiDstHeight * kiScale);
    int64_t x;
    int32_t iYInverse, iXInverse;
  
    uint8_t* pByDst = pDst;
    uint8_t* pByLineDst = pDst;
  
    iYInverse = 1 << (kiScaleBit - 1);
    for (int32_t i = 0; i < kiDstHeight - 1; i++) {
      int32_t iYy = iYInverse >> kiScaleBit;
      int32_t iFv = iYInverse & (kiScale - 1);
  
      uint8_t* pBySrc = pSrc + iYy * kiSrcStride;
  
      pByDst = pByLineDst;
      iXInverse = 1 << (kiScaleBit - 1);
      for (int32_t j = 0; j < kiDstWidth - 1; j++) {
        int32_t iXx = iXInverse >> kiScaleBit;
        int32_t iFu = iXInverse & (kiScale - 1);
  
        uint8_t* pByCurrent = pBySrc + iXx;
        uint8_t a, b, c, d;
  
        a = *pByCurrent;
        b = * (pByCurrent + 1);
        c = * (pByCurrent + kiSrcStride);
        d = * (pByCurrent + kiSrcStride + 1);
  
        x = (((int64_t) (kiScale - 1 - iFu)) * (kiScale - 1 - iFv) * a + ((int64_t)iFu) * (kiScale - 1 - iFv) * b + ((int64_t) (
               kiScale - 1 - iFu)) * iFv * c +
             ((int64_t)iFu) * iFv * d + (int64_t) (1 << (2 * kiScaleBit - 1))) >> (2 * kiScaleBit);
        x = WELS_CLAMP (x, 0, 255);
        *pByDst++ = (uint8_t)x;
  
        iXInverse += iScalex;
      }
      *pByDst = * (pBySrc + (iXInverse >> kiScaleBit));
      pByLineDst += kiDstStride;
      iYInverse += iScaley;
    }
  
    // last row special
    {
      int32_t iYy = iYInverse >> kiScaleBit;
      uint8_t* pBySrc = pSrc + iYy * kiSrcStride;
  
      pByDst = pByLineDst;
      iXInverse = 1 << (kiScaleBit - 1);
      for (int32_t j = 0; j < kiDstWidth; j++) {
        int32_t iXx = iXInverse >> kiScaleBit;
        *pByDst++ = * (pBySrc + iXx);
  
        iXInverse += iScalex;
      }
    }
  }
  
  #define GENERATE_DyadicBilinearDownsampler_UT(func, ASM, CPUFLAGS) \
  TEST (DownSampleTest, func) { \
    if (ASM) {\
      int32_t iCpuCores = 0; \
      uint32_t m_uiCpuFeatureFlag = WelsCPUFeatureDetect (&iCpuCores); \
      if (0 == (m_uiCpuFeatureFlag & CPUFLAGS)) \
      return; \
    } \
    ENFORCE_STACK_ALIGN_1D (uint8_t, dst_c, 50000, 16); \
    ENFORCE_STACK_ALIGN_1D (uint8_t, src_c, 50000, 16); \
    int dst_stride_c; \
    int src_stride_c; \
    int src_width_c; \
    int src_height_c; \
    ENFORCE_STACK_ALIGN_1D (uint8_t, dst_a, 50000, 16); \
    ENFORCE_STACK_ALIGN_1D (uint8_t, src_a, 50000, 16); \
    int dst_stride_a; \
    int src_stride_a; \
    int src_width_a; \
    int src_height_a; \
    dst_stride_c = dst_stride_a = 560; \
    src_stride_c = src_stride_a = 560; \
    src_width_c = src_width_a = 512; \
    src_height_c = src_height_a = 80; \
    for (int j = 0; j < 50000; j++) { \
      dst_c[j] = dst_a[j] = rand() % 256; \
      src_c[j] = src_a[j] = rand() % 256; \
    } \
    DyadicBilinearDownsampler_ref (dst_c, dst_stride_c, src_c, src_stride_c, src_width_c, src_height_c); \
    func (dst_a, dst_stride_a, src_a, src_stride_a, src_width_a, src_height_a); \
    for (int j = 0; j < (src_height_c >> 1); j++) { \
      for (int m = 0; m < (src_width_c >> 1); m++) { \
        ASSERT_EQ (dst_c[m + j * dst_stride_c], dst_a[m + j * dst_stride_a]); \
      } \
    } \
  }
  
  #define GENERATE_GeneralBilinearDownsampler_UT(func, ref, ASM, CPUFLAGS) \
  TEST (DownSampleTest, func) { \
    if (ASM) {\
      int32_t iCpuCores = 0; \
      uint32_t m_uiCpuFeatureFlag = WelsCPUFeatureDetect (&iCpuCores); \
      if (0 == (m_uiCpuFeatureFlag & CPUFLAGS)) \
      return; \
    } \
    ENFORCE_STACK_ALIGN_1D (uint8_t, dst_c, 70000, 16); \
    ENFORCE_STACK_ALIGN_1D (uint8_t, src_c, 70000, 16); \
    int dst_stride_c; \
    int dst_width_c; \
    int dst_height_c; \
    int src_stride_c; \
    int src_width_c; \
    int src_height_c; \
    ENFORCE_STACK_ALIGN_1D (uint8_t, dst_a, 70000, 16); \
    ENFORCE_STACK_ALIGN_1D (uint8_t, src_a, 70000, 16); \
    int dst_stride_a; \
    int dst_width_a; \
    int dst_height_a; \
    int src_stride_a; \
    int src_width_a; \
    int src_height_a; \
    dst_stride_c = dst_stride_a = 320; \
    src_stride_c = src_stride_a = 320; \
    src_width_c = src_width_a = 320; \
    src_height_c = src_height_a = 180; \
    dst_width_c = dst_width_a = 300; \
    dst_height_c = dst_height_a = 160; \
    for (int j = 0; j < 70000; j++) { \
      dst_c[j] = dst_a[j] = rand() % 256; \
      src_c[j] = src_a[j] = rand() % 256; \
    } \
    ref (dst_c, dst_stride_c, dst_width_c, dst_height_c, src_c, src_stride_c, src_width_c, src_height_c); \
    func (dst_a, dst_stride_a, dst_width_a, dst_height_a, src_a, src_stride_a, src_width_a, src_height_a); \
    for (int j = 0; j < dst_height_c; j++) { \
      for (int m = 0; m < dst_width_c ; m++) { \
        ASSERT_EQ (dst_c[m + j * dst_stride_c], dst_a[m + j * dst_stride_a]); \
      } \
    } \
  }
  
  
  GENERATE_DyadicBilinearDownsampler_UT (DyadicBilinearDownsampler_c, 0, 0)
  GENERATE_GeneralBilinearDownsampler_UT (GeneralBilinearFastDownsampler_c, GeneralBilinearFastDownsampler_ref, 0, 0)
  GENERATE_GeneralBilinearDownsampler_UT (GeneralBilinearAccurateDownsampler_c, GeneralBilinearAccurateDownsampler_ref, 0,
                                          0)
  
  #if defined(X86_ASM)
  GENERATE_DyadicBilinearDownsampler_UT (DyadicBilinearDownsamplerWidthx32_sse, 1, WELS_CPU_SSE)
  GENERATE_DyadicBilinearDownsampler_UT (DyadicBilinearDownsamplerWidthx16_sse, 1, WELS_CPU_SSE)
  GENERATE_DyadicBilinearDownsampler_UT (DyadicBilinearDownsamplerWidthx8_sse, 1, WELS_CPU_SSE)
  
  GENERATE_DyadicBilinearDownsampler_UT (DyadicBilinearDownsamplerWidthx32_ssse3, 1, WELS_CPU_SSSE3)
  GENERATE_DyadicBilinearDownsampler_UT (DyadicBilinearDownsamplerWidthx16_ssse3, 1, WELS_CPU_SSSE3)
  
  GENERATE_DyadicBilinearDownsampler_UT (DyadicBilinearDownsamplerWidthx32_sse4, 1, WELS_CPU_SSE41)
  GENERATE_DyadicBilinearDownsampler_UT (DyadicBilinearDownsamplerWidthx16_sse4, 1, WELS_CPU_SSE41)
  
  GENERATE_GeneralBilinearDownsampler_UT (GeneralBilinearFastDownsamplerWrap_sse2, GeneralBilinearFastDownsampler_ref, 1,
                                          WELS_CPU_SSE2)
  GENERATE_GeneralBilinearDownsampler_UT (GeneralBilinearAccurateDownsamplerWrap_sse2,
                                          GeneralBilinearAccurateDownsampler_ref, 1, WELS_CPU_SSE2)
  #endif
  
  #if defined(HAVE_NEON)
  GENERATE_DyadicBilinearDownsampler_UT (DyadicBilinearDownsamplerWidthx32_neon, 1, WELS_CPU_NEON)
  GENERATE_DyadicBilinearDownsampler_UT (DyadicBilinearDownsampler_neon, 1, WELS_CPU_NEON)
  
  GENERATE_GeneralBilinearDownsampler_UT (GeneralBilinearAccurateDownsamplerWrap_neon,
                                          GeneralBilinearAccurateDownsampler_ref, 1, WELS_CPU_NEON)
  #endif
  
  #if defined(HAVE_NEON_AARCH64)
  GENERATE_DyadicBilinearDownsampler_UT (DyadicBilinearDownsamplerWidthx32_AArch64_neon, 1, WELS_CPU_NEON)
  GENERATE_DyadicBilinearDownsampler_UT (DyadicBilinearDownsampler_AArch64_neon, 1, WELS_CPU_NEON)
  
  GENERATE_GeneralBilinearDownsampler_UT (GeneralBilinearAccurateDownsamplerWrap_AArch64_neon,
                                          GeneralBilinearAccurateDownsampler_ref, 1, WELS_CPU_NEON)
  #endif
  