Added CopyFromBytes and CopyToBytes convenience methods to NDArray. Fixed typos. (#4970)

* Added CopyFromBytes and CopyToBytes convenience methods.  Fixed typos.

* Removed unneed argument check

* Use TVMArrayCopyFrom/ToBytes methods

* Moved CopyFrom/ToBytes to ndarray.cc

* CopyToBytes impl was using CopyFromBytes.  Fixed

* changed inline to TVM_DLL

* Used impl from TVMArrayCopyTo/FromBytes into NDArray CopyTo/FromBytes

* Move implementation of all CopyFrom/ToBytes into a common impls

* make arg const

* simplify method impl

include/tvm/runtime/ndarray.h

@@ -68,20 +68,38 @@ class NDArray : public ObjectRef {
   /*!
    * \brief Copy data content from another array.
    * \param other The source array to be copied from.
-   * \note The copy may happen asynchrously if it involves a GPU context.
+   * \note The copy may happen asynchronously if it involves a GPU context.
    *       TVMSynchronize is necessary.
    */
   inline void CopyFrom(const DLTensor* other);
   inline void CopyFrom(const NDArray& other);
   /*!
+ * \brief Copy data content from a byte buffer.
+ * \param data The source bytes to be copied from.
+ * \param nbytes The size of the buffer in bytes
+ *        Must be equal to the size of the NDArray.
+ * \note The copy may happen asynchronously if it involves a GPU context.
+ *       TVMSynchronize is necessary.
+ */
+  TVM_DLL void CopyFromBytes(const void* data, size_t nbytes);
+  /*!
    * \brief Copy data content into another array.
    * \param other The source array to be copied from.
-   * \note The copy may happen asynchrously if it involves a GPU context.
+   * \note The copy may happen asynchronously if it involves a GPU context.
    *       TVMSynchronize is necessary.
    */
   inline void CopyTo(DLTensor* other) const;
   inline void CopyTo(const NDArray& other) const;
   /*!
+   * \brief Copy data content into another array.
+   * \param data The source bytes to be copied from.
+   * \param nbytes The size of the data buffer.
+   *        Must be equal to the size of the NDArray.
+   * \note The copy may happen asynchronously if it involves a GPU context.
+   *       TVMSynchronize is necessary.
+   */
+  TVM_DLL void CopyToBytes(void* data, size_t nbytes) const;
+  /*!
    * \brief Copy the data to another context.
    * \param ctx The target context.
    * \return The array under another context.
@@ -182,7 +200,7 @@ class NDArray : public ObjectRef {
 
 /*!
  * \brief Save a DLTensor to stream
- * \param strm The outpu stream
+ * \param strm The output stream
  * \param tensor The tensor to be saved.
  */
 inline bool SaveDLTensor(dmlc::Stream* strm, const DLTensor* tensor);
@@ -205,7 +223,7 @@ class NDArray::ContainerBase {
   DLTensor dl_tensor;
 
   /*!
-   * \brief addtional context, reserved for recycling
+   * \brief additional context, reserved for recycling
    * \note We can attach additional content here
    *  which the current container depend on
    *  (e.g. reference to original memory when creating views).

src/runtime/ndarray.cc

@@ -60,6 +60,32 @@ inline size_t GetDataAlignment(const DLTensor& arr) {
   return align;
 }
 
+void ArrayCopyFromBytes(DLTensor* handle, const void* data, size_t nbytes) {
+  TVMContext cpu_ctx;
+  cpu_ctx.device_type = kDLCPU;
+  cpu_ctx.device_id = 0;
+  size_t arr_size = GetDataSize(*handle);
+  CHECK_EQ(arr_size, nbytes)
+      << "ArrayCopyFromBytes: size mismatch";
+  DeviceAPI::Get(handle->ctx)->CopyDataFromTo(
+      data, 0,
+      handle->data, static_cast<size_t>(handle->byte_offset),
+      nbytes, cpu_ctx, handle->ctx, handle->dtype, nullptr);
+}
+
+void ArrayCopyToBytes(const DLTensor* handle, void* data, size_t nbytes) {
+  TVMContext cpu_ctx;
+  cpu_ctx.device_type = kDLCPU;
+  cpu_ctx.device_id = 0;
+  size_t arr_size = GetDataSize(*handle);
+  CHECK_EQ(arr_size, nbytes)
+      << "ArrayCopyToBytes: size mismatch";
+  DeviceAPI::Get(handle->ctx)->CopyDataFromTo(
+      handle->data, static_cast<size_t>(handle->byte_offset),
+      data, 0,
+      nbytes, handle->ctx, cpu_ctx, handle->dtype, nullptr);
+}
+
 struct NDArray::Internal {
   // Default deleter for the container
   static void DefaultDeleter(Object* ptr_obj) {
@@ -185,6 +211,18 @@ NDArray NDArray::FromDLPack(DLManagedTensor* tensor) {
   return NDArray(GetObjectPtr<Object>(data));
 }
 
+void NDArray::CopyToBytes(void* data, size_t nbytes) const {
+  CHECK(data != nullptr);
+  CHECK(data_ != nullptr);
+  ArrayCopyToBytes(&get_mutable()->dl_tensor, data, nbytes);
+}
+
+void NDArray::CopyFromBytes(const void* data, size_t nbytes) {
+  CHECK(data != nullptr);
+  CHECK(data_ != nullptr);
+  ArrayCopyFromBytes(&get_mutable()->dl_tensor, data, nbytes);
+}
+
 void NDArray::CopyFromTo(const DLTensor* from,
                          DLTensor* to,
                          TVMStreamHandle stream) {
@@ -286,16 +324,7 @@ int TVMArrayCopyFromBytes(TVMArrayHandle handle,
                           void* data,
                           size_t nbytes) {
   API_BEGIN();
-  TVMContext cpu_ctx;
-  cpu_ctx.device_type = kDLCPU;
-  cpu_ctx.device_id = 0;
-  size_t arr_size = GetDataSize(*handle);
-  CHECK_EQ(arr_size, nbytes)
-      << "TVMArrayCopyFromBytes: size mismatch";
-  DeviceAPI::Get(handle->ctx)->CopyDataFromTo(
-      data, 0,
-      handle->data, static_cast<size_t>(handle->byte_offset),
-      nbytes, cpu_ctx, handle->ctx, handle->dtype, nullptr);
+  ArrayCopyFromBytes(handle, data, nbytes);
   API_END();
 }
 
@@ -303,15 +332,6 @@ int TVMArrayCopyToBytes(TVMArrayHandle handle,
                         void* data,
                         size_t nbytes) {
   API_BEGIN();
-  TVMContext cpu_ctx;
-  cpu_ctx.device_type = kDLCPU;
-  cpu_ctx.device_id = 0;
-  size_t arr_size = GetDataSize(*handle);
-  CHECK_EQ(arr_size, nbytes)
-      << "TVMArrayCopyToBytes: size mismatch";
-  DeviceAPI::Get(handle->ctx)->CopyDataFromTo(
-      handle->data, static_cast<size_t>(handle->byte_offset),
-      data, 0,
-      nbytes, handle->ctx, cpu_ctx, handle->dtype, nullptr);
+  ArrayCopyToBytes(handle, data, nbytes);
   API_END();
 }