Add tesnor.h

paddle/framework/tensor.h

+/*
+  Copyright (c) 2016 PaddlePaddle Authors. All Rights Reserve.
+  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
+
+namespace paddle {
+namespace framework {
+
+class Tensor {
+  using paddle::platform::Place;
+  using paddle::platform::get_place;
+
+ public:
+  explicit Tensor(DDim dims) : dims_(dims), place_(get_place()) {}
+  explicit Tensor(DDim dims, Place place) : dims_(dims), place_(place) {}
+
+  template <typename T>
+  const T* data() const {
+    PADDLE_ASSERT(holder_ != nullptr);
+    PADDLE_ASSERT(holder_->Place() == place_);
+    PADDLE_ASSERT(holder_->Size() >= dims_.product() * sizeof(T));
+    return static_cast<const T*>(holder->Ptr());
+  }
+
+  template <typename T,  // must be POD types
+            typename = std::enable_if<std::is_pod<T>::value>::type>
+  T* mutable_data() {
+    if (holder_ == nullptr || holder_->Place() != place_ ||
+        holder_->Size() < dims_.product() * sizeof(T)) {
+      holder_.reset(new PlaceholderImpl(place_, dims.product() * sizeof(T)));
+    }
+    return static_cast<T*>(holder_->Ptr());
+  }
+
+  template <typename T,  // must be POD types
+            typename = std::enable_if<std::is_pod<T>::value>::type>
+  T* mutable_data(DDim dims) {
+    dims_ = dims;
+    return mutable_data<T>();
+  }
+
+  template <typename T,  // must be POD types
+            typename = std::enable_if<std::is_pod<T>::value>::type>
+  T* mutable_data(DDim dims, Place place) {
+    dims_ = dims;
+    place_ = place;
+    return mutable_data<T>();
+  }
+
+ private:
+  // Placeholder hides type T, so it doesn't appear as a template
+  // parameter of Variable.
+  struct Placeholder {
+    virtual ~Placeholder() {}
+    virtual void* Ptr() const = 0;
+    virtual Place Place() const = 0;
+    virtual size_t Size() const = 0;
+  };
+
+  template <typename T>
+  struct PlaceholderImpl : public Placeholder {
+    PlaceholderImpl(Place pl, size_t size)
+        : ptr_(memory::Alloc(pl, size), paddle::memory::Deleter(pl)),
+          place_(pl),
+          size_(size) {}
+
+    virtual void* Ptr() const { return static_cast<void*>(ptr_.get()); }
+    virtual size_t Size() const { return size_; }
+    virtual Place Place() const { return place_; }
+
+    std::unique_ptr<T, memory::Deleter> ptr_;
+    Place place_;  // record the place of ptr_.
+    size_t size_;  // size of the memory block.
+  };
+
+  std::unique_ptr<Placeholder> holder_;  // holds the memory block if allocated.
+  DDim dims_;  // could be smallers than the holder_->Size().
+  paddle::platform::Place place_;
+};
+
+}  // namespace framework
+}  // namespace paddle