libwebp: update to 0.5.0

third_party/libwebp/dsp/alpha_processing_sse2.c

Index: third_party/libwebp/dsp/alpha_processing_sse2.c
diff --git a/third_party/libwebp/dsp/alpha_processing_sse2.c b/third_party/libwebp/dsp/alpha_processing_sse2.c
index 3d0a9b57997a4b068bda9bd65b380f680dc23a02..5acb481dcddbb7d71c0008d45f56d3cafbd8bb6d 100644
--- a/third_party/libwebp/dsp/alpha_processing_sse2.c
+++ b/third_party/libwebp/dsp/alpha_processing_sse2.c
@@ -18,6 +18,86 @@
 
 //------------------------------------------------------------------------------
 
+static int DispatchAlpha(const uint8_t* alpha, int alpha_stride,
+                         int width, int height,
+                         uint8_t* dst, int dst_stride) {
+  // alpha_and stores an 'and' operation of all the alpha[] values. The final
+  // value is not 0xff if any of the alpha[] is not equal to 0xff.
+  uint32_t alpha_and = 0xff;
+  int i, j;
+  const __m128i zero = _mm_setzero_si128();
+  const __m128i rgb_mask = _mm_set1_epi32(0xffffff00u);  // to preserve RGB
+  const __m128i all_0xff = _mm_set_epi32(0, 0, ~0u, ~0u);
+  __m128i all_alphas = all_0xff;
+
+  // We must be able to access 3 extra bytes after the last written byte
+  // 'dst[4 * width - 4]', because we don't know if alpha is the first or the
+  // last byte of the quadruplet.
+  const int limit = (width - 1) & ~7;
+
+  for (j = 0; j < height; ++j) {
+    __m128i* out = (__m128i*)dst;
+    for (i = 0; i < limit; i += 8) {
+      // load 8 alpha bytes
+      const __m128i a0 = _mm_loadl_epi64((const __m128i*)&alpha[i]);
+      const __m128i a1 = _mm_unpacklo_epi8(a0, zero);
+      const __m128i a2_lo = _mm_unpacklo_epi16(a1, zero);
+      const __m128i a2_hi = _mm_unpackhi_epi16(a1, zero);
+      // load 8 dst pixels (32 bytes)
+      const __m128i b0_lo = _mm_loadu_si128(out + 0);
+      const __m128i b0_hi = _mm_loadu_si128(out + 1);
+      // mask dst alpha values
+      const __m128i b1_lo = _mm_and_si128(b0_lo, rgb_mask);
+      const __m128i b1_hi = _mm_and_si128(b0_hi, rgb_mask);
+      // combine
+      const __m128i b2_lo = _mm_or_si128(b1_lo, a2_lo);
+      const __m128i b2_hi = _mm_or_si128(b1_hi, a2_hi);
+      // store
+      _mm_storeu_si128(out + 0, b2_lo);
+      _mm_storeu_si128(out + 1, b2_hi);
+      // accumulate eight alpha 'and' in parallel
+      all_alphas = _mm_and_si128(all_alphas, a0);
+      out += 2;
+    }
+    for (; i < width; ++i) {
+      const uint32_t alpha_value = alpha[i];
+      dst[4 * i] = alpha_value;
+      alpha_and &= alpha_value;
+    }
+    alpha += alpha_stride;
+    dst += dst_stride;
+  }
+  // Combine the eight alpha 'and' into a 8-bit mask.
+  alpha_and &= _mm_movemask_epi8(_mm_cmpeq_epi8(all_alphas, all_0xff));
+  return (alpha_and != 0xff);
+}
+
+static void DispatchAlphaToGreen(const uint8_t* alpha, int alpha_stride,
+                                 int width, int height,
+                                 uint32_t* dst, int dst_stride) {
+  int i, j;
+  const __m128i zero = _mm_setzero_si128();
+  const int limit = width & ~15;
+  for (j = 0; j < height; ++j) {
+    for (i = 0; i < limit; i += 16) {   // process 16 alpha bytes
+      const __m128i a0 = _mm_loadu_si128((const __m128i*)&alpha[i]);
+      const __m128i a1 = _mm_unpacklo_epi8(zero, a0);  // note the 'zero' first!
+      const __m128i b1 = _mm_unpackhi_epi8(zero, a0);
+      const __m128i a2_lo = _mm_unpacklo_epi16(a1, zero);
+      const __m128i b2_lo = _mm_unpacklo_epi16(b1, zero);
+      const __m128i a2_hi = _mm_unpackhi_epi16(a1, zero);
+      const __m128i b2_hi = _mm_unpackhi_epi16(b1, zero);
+      _mm_storeu_si128((__m128i*)&dst[i +  0], a2_lo);
+      _mm_storeu_si128((__m128i*)&dst[i +  4], a2_hi);
+      _mm_storeu_si128((__m128i*)&dst[i +  8], b2_lo);
+      _mm_storeu_si128((__m128i*)&dst[i + 12], b2_hi);
+    }
+    for (; i < width; ++i) dst[i] = alpha[i] << 8;
+    alpha += alpha_stride;
+    dst += dst_stride;
+  }
+}
+
 static int ExtractAlpha(const uint8_t* argb, int argb_stride,
                         int width, int height,
                         uint8_t* alpha, int alpha_stride) {
@@ -63,15 +143,156 @@ static int ExtractAlpha(const uint8_t* argb, int argb_stride,
   return (alpha_and == 0xff);
 }
 
-#endif   // WEBP_USE_SSE2
+//------------------------------------------------------------------------------
+// Non-dither premultiplied modes
+
+#define MULTIPLIER(a)   ((a) * 0x8081)
+#define PREMULTIPLY(x, m) (((x) * (m)) >> 23)
+
+// We can't use a 'const int' for the SHUFFLE value, because it has to be an
+// immediate in the _mm_shufflexx_epi16() instruction. We really a macro here.
+#define APPLY_ALPHA(RGBX, SHUFFLE, MASK, MULT) do {             \
+  const __m128i argb0 = _mm_loadl_epi64((__m128i*)&(RGBX));     \
+  const __m128i argb1 = _mm_unpacklo_epi8(argb0, zero);         \
+  const __m128i alpha0 = _mm_and_si128(argb1, MASK);            \
+  const __m128i alpha1 = _mm_shufflelo_epi16(alpha0, SHUFFLE);  \
+  const __m128i alpha2 = _mm_shufflehi_epi16(alpha1, SHUFFLE);  \
+  /* alpha2 = [0 a0 a0 a0][0 a1 a1 a1] */                       \
+  const __m128i scale0 = _mm_mullo_epi16(alpha2, MULT);         \
+  const __m128i scale1 = _mm_mulhi_epu16(alpha2, MULT);         \
+  const __m128i argb2 = _mm_mulhi_epu16(argb1, scale0);         \
+  const __m128i argb3 = _mm_mullo_epi16(argb1, scale1);         \
+  const __m128i argb4 = _mm_adds_epu16(argb2, argb3);           \
+  const __m128i argb5 = _mm_srli_epi16(argb4, 7);               \
+  const __m128i argb6 = _mm_or_si128(argb5, alpha0);            \
+  const __m128i argb7 = _mm_packus_epi16(argb6, zero);          \
+  _mm_storel_epi64((__m128i*)&(RGBX), argb7);                   \
+} while (0)
+
+static void ApplyAlphaMultiply(uint8_t* rgba, int alpha_first,
+                               int w, int h, int stride) {
+  const __m128i zero = _mm_setzero_si128();
+  const int kSpan = 2;
+  const int w2 = w & ~(kSpan - 1);
+  while (h-- > 0) {
+    uint32_t* const rgbx = (uint32_t*)rgba;
+    int i;
+    if (!alpha_first) {
+      const __m128i kMask = _mm_set_epi16(0xff, 0, 0, 0, 0xff, 0, 0, 0);
+      const __m128i kMult =
+          _mm_set_epi16(0, 0x8081, 0x8081, 0x8081, 0, 0x8081, 0x8081, 0x8081);
+      for (i = 0; i < w2; i += kSpan) {
+        APPLY_ALPHA(rgbx[i], _MM_SHUFFLE(0, 3, 3, 3), kMask, kMult);
+      }
+    } else {
+      const __m128i kMask = _mm_set_epi16(0, 0, 0, 0xff, 0, 0, 0, 0xff);
+      const __m128i kMult =
+          _mm_set_epi16(0x8081, 0x8081, 0x8081, 0, 0x8081, 0x8081, 0x8081, 0);
+      for (i = 0; i < w2; i += kSpan) {
+        APPLY_ALPHA(rgbx[i], _MM_SHUFFLE(0, 0, 0, 3), kMask, kMult);
+      }
+    }
+    // Finish with left-overs.
+    for (; i < w; ++i) {
+      uint8_t* const rgb = rgba + (alpha_first ? 1 : 0);
+      const uint8_t* const alpha = rgba + (alpha_first ? 0 : 3);
+      const uint32_t a = alpha[4 * i];
+      if (a != 0xff) {
+        const uint32_t mult = MULTIPLIER(a);
+        rgb[4 * i + 0] = PREMULTIPLY(rgb[4 * i + 0], mult);
+        rgb[4 * i + 1] = PREMULTIPLY(rgb[4 * i + 1], mult);
+        rgb[4 * i + 2] = PREMULTIPLY(rgb[4 * i + 2], mult);
+      }
+    }
+    rgba += stride;
+  }
+}
+#undef MULTIPLIER
+#undef PREMULTIPLY
+
+// -----------------------------------------------------------------------------
+// Apply alpha value to rows
+
+// We use: kINV255 = (1 << 24) / 255 = 0x010101
+// So: a * kINV255 = (a << 16) | [(a << 8) | a]
+// -> _mm_mulhi_epu16() takes care of the (a<<16) part,
+// and _mm_mullo_epu16(a * 0x0101,...) takes care of the "(a << 8) | a" one.
+
+static void MultARGBRow(uint32_t* const ptr, int width, int inverse) {
+  int x = 0;
+  if (!inverse) {
+    const int kSpan = 2;
+    const __m128i zero = _mm_setzero_si128();
+    const __m128i kRound =
+        _mm_set_epi16(0, 1 << 7, 1 << 7, 1 << 7, 0, 1 << 7, 1 << 7, 1 << 7);
+    const __m128i kMult =
+        _mm_set_epi16(0, 0x0101, 0x0101, 0x0101, 0, 0x0101, 0x0101, 0x0101);
+    const __m128i kOne64 = _mm_set_epi16(1u << 8, 0, 0, 0, 1u << 8, 0, 0, 0);
+    const int w2 = width & ~(kSpan - 1);
+    for (x = 0; x < w2; x += kSpan) {
+      const __m128i argb0 = _mm_loadl_epi64((__m128i*)&ptr[x]);
+      const __m128i argb1 = _mm_unpacklo_epi8(argb0, zero);
+      const __m128i tmp0 = _mm_shufflelo_epi16(argb1, _MM_SHUFFLE(3, 3, 3, 3));
+      const __m128i tmp1 = _mm_shufflehi_epi16(tmp0, _MM_SHUFFLE(3, 3, 3, 3));
+      const __m128i tmp2 = _mm_srli_epi64(tmp1, 16);
+      const __m128i scale0 = _mm_mullo_epi16(tmp1, kMult);
+      const __m128i scale1 = _mm_or_si128(tmp2, kOne64);
+      const __m128i argb2 = _mm_mulhi_epu16(argb1, scale0);
+      const __m128i argb3 = _mm_mullo_epi16(argb1, scale1);
+      const __m128i argb4 = _mm_adds_epu16(argb2, argb3);
+      const __m128i argb5 = _mm_adds_epu16(argb4, kRound);
+      const __m128i argb6 = _mm_srli_epi16(argb5, 8);
+      const __m128i argb7 = _mm_packus_epi16(argb6, zero);
+      _mm_storel_epi64((__m128i*)&ptr[x], argb7);
+    }
+  }
+  width -= x;
+  if (width > 0) WebPMultARGBRowC(ptr + x, width, inverse);
+}
+
+static void MultRow(uint8_t* const ptr, const uint8_t* const alpha,
+                    int width, int inverse) {
+  int x = 0;
+  if (!inverse) {
+    const int kSpan = 8;
+    const __m128i zero = _mm_setzero_si128();
+    const __m128i kRound = _mm_set1_epi16(1 << 7);
+    const int w2 = width & ~(kSpan - 1);
+    for (x = 0; x < w2; x += kSpan) {
+      const __m128i v0 = _mm_loadl_epi64((__m128i*)&ptr[x]);
+      const __m128i v1 = _mm_unpacklo_epi8(v0, zero);
+      const __m128i alpha0 = _mm_loadl_epi64((const __m128i*)&alpha[x]);
+      const __m128i alpha1 = _mm_unpacklo_epi8(alpha0, zero);
+      const __m128i alpha2 = _mm_unpacklo_epi8(alpha0, alpha0);
+      const __m128i v2 = _mm_mulhi_epu16(v1, alpha2);
+      const __m128i v3 = _mm_mullo_epi16(v1, alpha1);
+      const __m128i v4 = _mm_adds_epu16(v2, v3);
+      const __m128i v5 = _mm_adds_epu16(v4, kRound);
+      const __m128i v6 = _mm_srli_epi16(v5, 8);
+      const __m128i v7 = _mm_packus_epi16(v6, zero);
+      _mm_storel_epi64((__m128i*)&ptr[x], v7);
+    }
+  }
+  width -= x;
+  if (width > 0) WebPMultRowC(ptr + x, alpha + x, width, inverse);
+}
 
 //------------------------------------------------------------------------------
-// Init function
+// Entry point
 
 extern void WebPInitAlphaProcessingSSE2(void);
 
-void WebPInitAlphaProcessingSSE2(void) {
-#if defined(WEBP_USE_SSE2)
+WEBP_TSAN_IGNORE_FUNCTION void WebPInitAlphaProcessingSSE2(void) {
+  WebPMultARGBRow = MultARGBRow;
+  WebPMultRow = MultRow;
+  WebPApplyAlphaMultiply = ApplyAlphaMultiply;
+  WebPDispatchAlpha = DispatchAlpha;
+  WebPDispatchAlphaToGreen = DispatchAlphaToGreen;
   WebPExtractAlpha = ExtractAlpha;
-#endif
 }
+
+#else  // !WEBP_USE_SSE2
+
+WEBP_DSP_INIT_STUB(WebPInitAlphaProcessingSSE2)
+
+#endif  // WEBP_USE_SSE2