chore: import upstream snapshot with attribution

paddle/phi/kernels/impl/load_kernel_impl.h

@@ -0,0 +1,63 @@
+// Copyright (c) 2024 PaddlePaddle Authors. All Rights Reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#pragma once
+
+#include <string>
+
+#include "paddle/phi/core/framework/dense_tensor_serialize.h"
+#include "paddle/phi/core/kernel_registry.h"
+#include "paddle/phi/core/tensor_utils.h"
+#include "paddle/phi/kernels/cast_kernel.h"
+
+namespace phi {
+
+template <typename T, typename Context>
+void LoadKernel(const Context& dev_ctx,
+                const std::string& file_path,
+                int64_t seek,
+                const std::vector<int64_t>& shape,
+                bool load_as_fp16,
+                DenseTensor* out) {
+  // FIXME(yuyang18): We save variable to local file now, but we should change
+  // it to save an output stream.
+  std::ifstream fin(file_path, std::ios::binary);
+  PADDLE_ENFORCE_EQ(
+      static_cast<bool>(fin),
+      true,
+      errors::Unavailable("Load operator fail to open file %s, please check "
+                          "whether the model file is complete or damaged.",
+                          file_path));
+  PADDLE_ENFORCE_NOT_NULL(
+      out,
+      errors::InvalidArgument("The variable to be loaded cannot be found."));
+
+  if (seek != -1) {
+    PADDLE_ENFORCE_GE(seek,
+                      0,
+                      errors::InvalidArgument(
+                          "seek with tensor must great than or equal to 0"));
+    DeserializeFromStream(fin, out, dev_ctx, seek, shape);
+  } else {
+    DeserializeFromStream(fin, out, dev_ctx);
+  }
+
+  auto in_dtype = out->dtype();
+  auto out_dtype = load_as_fp16 ? DataType::FLOAT16 : in_dtype;
+  if (in_dtype != out_dtype) {
+    CastKernel<T>(dev_ctx, *out, out_dtype, out);
+  }
+}
+
+}  // namespace phi