1 files changed, 130 insertions, 0 deletions
diff --git a/media/libjxl/src/lib/jxl/dec_noise.cc b/media/libjxl/src/lib/jxl/dec_noise.cc
new file mode 100644
index 0000000000..d232e48c03
--- /dev/null
+++ b/media/libjxl/src/lib/jxl/dec_noise.cc
@@ -0,0 +1,130 @@
+// Copyright (c) the JPEG XL 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.
+
+#include "lib/jxl/dec_noise.h"
+
+#include <stdint.h>
+#include <stdio.h>
+#include <stdlib.h>
+
+#include <algorithm>
+#include <numeric>
+#include <utility>
+
+#undef HWY_TARGET_INCLUDE
+#define HWY_TARGET_INCLUDE "lib/jxl/dec_noise.cc"
+#include <hwy/foreach_target.h>
+#include <hwy/highway.h>
+
+#include "lib/jxl/base/compiler_specific.h"
+#include "lib/jxl/chroma_from_luma.h"
+#include "lib/jxl/image_ops.h"
+#include "lib/jxl/opsin_params.h"
+#include "lib/jxl/sanitizers.h"
+#include "lib/jxl/xorshift128plus-inl.h"
+HWY_BEFORE_NAMESPACE();
+namespace jxl {
+namespace HWY_NAMESPACE {
+
+// These templates are not found via ADL.
+using hwy::HWY_NAMESPACE::ShiftRight;
+using hwy::HWY_NAMESPACE::Vec;
+
+using D = HWY_CAPPED(float, kBlockDim);
+using DI = hwy::HWY_NAMESPACE::Rebind<int, D>;
+using DI8 = hwy::HWY_NAMESPACE::Repartition<uint8_t, D>;
+
+// Converts one vector's worth of random bits to floats in [1, 2).
+// NOTE: as the convolution kernel sums to 0, it doesn't matter if inputs are in
+// [0, 1) or in [1, 2).
+void BitsToFloat(const uint32_t* JXL_RESTRICT random_bits,
+                 float* JXL_RESTRICT floats) {
+  const HWY_FULL(float) df;
+  const HWY_FULL(uint32_t) du;
+
+  const auto bits = Load(du, random_bits);
+  // 1.0 + 23 random mantissa bits = [1, 2)
+  const auto rand12 = BitCast(df, ShiftRight<9>(bits) | Set(du, 0x3F800000));
+  Store(rand12, df, floats);
+}
+
+void RandomImage(Xorshift128Plus* rng, const Rect& rect,
+                 ImageF* JXL_RESTRICT noise) {
+  const size_t xsize = rect.xsize();
+  const size_t ysize = rect.ysize();
+
+  // May exceed the vector size, hence we have two loops over x below.
+  constexpr size_t kFloatsPerBatch =
+      Xorshift128Plus::N * sizeof(uint64_t) / sizeof(float);
+  HWY_ALIGN uint64_t batch[Xorshift128Plus::N];
+
+  const HWY_FULL(float) df;
+  const size_t N = Lanes(df);
+
+  for (size_t y = 0; y < ysize; ++y) {
+    float* JXL_RESTRICT row = rect.Row(noise, y);
+
+    size_t x = 0;
+    // Only entire batches (avoids exceeding the image padding).
+    for (; x + kFloatsPerBatch <= xsize; x += kFloatsPerBatch) {
+      rng->Fill(batch);
+      for (size_t i = 0; i < kFloatsPerBatch; i += Lanes(df)) {
+        BitsToFloat(reinterpret_cast<const uint32_t*>(batch) + i, row + x + i);
+      }
+    }
+
+    // Any remaining pixels, rounded up to vectors (safe due to padding).
+    rng->Fill(batch);
+    size_t batch_pos = 0;  // < kFloatsPerBatch
+    for (; x < xsize; x += N) {
+      BitsToFloat(reinterpret_cast<const uint32_t*>(batch) + batch_pos,
+                  row + x);
+      batch_pos += N;
+    }
+  }
+}
+void Random3Planes(size_t visible_frame_index, size_t nonvisible_frame_index,
+                   size_t x0, size_t y0, const std::pair<ImageF*, Rect>& plane0,
+                   const std::pair<ImageF*, Rect>& plane1,
+                   const std::pair<ImageF*, Rect>& plane2) {
+  HWY_ALIGN Xorshift128Plus rng(visible_frame_index, nonvisible_frame_index, x0,
+                                y0);
+  RandomImage(&rng, plane0.second, plane0.first);
+  RandomImage(&rng, plane1.second, plane1.first);
+  RandomImage(&rng, plane2.second, plane2.first);
+}
+
+// NOLINTNEXTLINE(google-readability-namespace-comments)
+}  // namespace HWY_NAMESPACE
+}  // namespace jxl
+HWY_AFTER_NAMESPACE();
+
+#if HWY_ONCE
+namespace jxl {
+
+HWY_EXPORT(Random3Planes);
+void Random3Planes(size_t visible_frame_index, size_t nonvisible_frame_index,
+                   size_t x0, size_t y0, const std::pair<ImageF*, Rect>& plane0,
+                   const std::pair<ImageF*, Rect>& plane1,
+                   const std::pair<ImageF*, Rect>& plane2) {
+  return HWY_DYNAMIC_DISPATCH(Random3Planes)(visible_frame_index,
+                                             nonvisible_frame_index, x0, y0,
+                                             plane0, plane1, plane2);
+}
+
+void DecodeFloatParam(float precision, float* val, BitReader* br) {
+  const int absval_quant = br->ReadFixedBits<10>();
+  *val = absval_quant / precision;
+}
+
+Status DecodeNoise(BitReader* br, NoiseParams* noise_params) {
+  for (float& i : noise_params->lut) {
+    DecodeFloatParam(kNoisePrecision, &i, br);
+  }
+  return true;
+}
+
+}  // namespace jxl
+#endif  // HWY_ONCE