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  #include <qimage.h>
  #include <private/qimage_p.h>
  #include <private/qsimd_p.h>
  
  #ifdef QT_HAVE_SSSE3
  
  QT_BEGIN_NAMESPACE
  
  // Convert a scanline of RGB888 (src) to RGB32 (dst)
  // src must be at least len * 3 bytes
  // dst must be at least len * 4 bytes
  Q_GUI_EXPORT void QT_FASTCALL qt_convert_rgb888_to_rgb32_ssse3(quint32 *dst, const uchar *src, int len)
  {
      quint32 *const end = dst + len;
  
      // Prologue, align dst to 16 bytes. The alignment is done on dst because it has 4 store()
      // for each 3 load() of src.
      const int offsetToAlignOn16Bytes = (4 - ((reinterpret_cast<quintptr>(dst) >> 2) & 0x3)) & 0x3;
      const int prologLength = qMin(len, offsetToAlignOn16Bytes);
  
      for (int i = 0; i < prologLength; ++i) {
          *dst++ = qRgb(src[0], src[1], src[2]);
          src += 3;
      }
  
      // Mask the 4 first colors of the RGB888 vector
      const __m128i shuffleMask = _mm_set_epi8(0xff, 9, 10, 11, 0xff, 6, 7, 8, 0xff, 3, 4, 5, 0xff, 0, 1, 2);
  
      // Mask the 4 last colors of a RGB888 vector with an offset of 1 (so the last 3 bytes are RGB)
      const __m128i shuffleMaskEnd = _mm_set_epi8(0xff, 13, 14, 15, 0xff, 10, 11, 12, 0xff, 7, 8, 9, 0xff, 4, 5, 6);
  
      // Mask to have alpha = 0xff
      const __m128i alphaMask = _mm_set1_epi32(0xff000000);
  
      __m128i *inVectorPtr = (__m128i *)src;
      __m128i *dstVectorPtr = (__m128i *)dst;
  
      const int simdRoundCount = (len - prologLength) / 16; // one iteration in the loop converts 16 pixels
      for (int i = 0; i < simdRoundCount; ++i) {
          /*
           RGB888 has 5 pixels per vector, + 1 byte from the next pixel. The idea here is
           to load vectors of RGB888 and use palignr to select a vector out of two vectors.
  
           After 3 loads of RGB888 and 3 stores of RGB32, we have 4 pixels left in the last
           vector of RGB888, we can mask it directly to get a last store or RGB32. After that,
           the first next byte is a R, and we can loop for the next 16 pixels.
  
           The conversion itself is done with a byte permutation (pshufb).
           */
          __m128i firstSrcVector = _mm_lddqu_si128(inVectorPtr);
          __m128i outputVector = _mm_shuffle_epi8(firstSrcVector, shuffleMask);
          _mm_store_si128(dstVectorPtr, _mm_or_si128(outputVector, alphaMask));
          ++inVectorPtr;
          ++dstVectorPtr;
  
          // There are 4 unused bytes left in srcVector, we need to load the next 16 bytes
          // and load the next input with palignr
          __m128i secondSrcVector = _mm_lddqu_si128(inVectorPtr);
          __m128i srcVector = _mm_alignr_epi8(secondSrcVector, firstSrcVector, 12);
          outputVector = _mm_shuffle_epi8(srcVector, shuffleMask);
          _mm_store_si128(dstVectorPtr, _mm_or_si128(outputVector, alphaMask));
          ++inVectorPtr;
          ++dstVectorPtr;
          firstSrcVector = secondSrcVector;
  
          // We now have 8 unused bytes left in firstSrcVector
          secondSrcVector = _mm_lddqu_si128(inVectorPtr);
          srcVector = _mm_alignr_epi8(secondSrcVector, firstSrcVector, 8);
          outputVector = _mm_shuffle_epi8(srcVector, shuffleMask);
          _mm_store_si128(dstVectorPtr, _mm_or_si128(outputVector, alphaMask));
          ++inVectorPtr;
          ++dstVectorPtr;
  
          // There are now 12 unused bytes in firstSrcVector.
          // We can mask them directly, almost there.
          outputVector = _mm_shuffle_epi8(secondSrcVector, shuffleMaskEnd);
          _mm_store_si128(dstVectorPtr, _mm_or_si128(outputVector, alphaMask));
          ++dstVectorPtr;
      }
      src = (uchar *)inVectorPtr;
      dst = (quint32 *)dstVectorPtr;
  
      while (dst != end) {
          *dst++ = qRgb(src[0], src[1], src[2]);
          src += 3;
      }
  }
  
  void convert_RGB888_to_RGB32_ssse3(QImageData *dest, const QImageData *src, Qt::ImageConversionFlags)
  {
      Q_ASSERT(src->format == QImage::Format_RGB888);
      Q_ASSERT(dest->format == QImage::Format_RGB32 || dest->format == QImage::Format_ARGB32 || dest->format == QImage::Format_ARGB32_Premultiplied);
      Q_ASSERT(src->width == dest->width);
      Q_ASSERT(src->height == dest->height);
  
      const uchar *src_data = (uchar *) src->data;
      quint32 *dest_data = (quint32 *) dest->data;
  
      for (int i = 0; i < src->height; ++i) {
          qt_convert_rgb888_to_rgb32_ssse3(dest_data, src_data, src->width);
          src_data += src->bytes_per_line;
          dest_data = (quint32 *)((uchar*)dest_data + dest->bytes_per_line);
      }
  }
  
  QT_END_NAMESPACE
  
  #endif // QT_HAVE_SSSE3
  