[Model] Refactor PaddleClas module (#505)

* Refactor the PaddleClas module

* fix bug

* remove debug code

* clean unused code

* support pybind

* Update fd_tensor.h

* Update fd_tensor.cc

* temporary revert python api

* fix ci error

* fix code style problem

fastdeploy/vision/classification/ppcls/postprocessor.h

@@ -0,0 +1,55 @@
+// Copyright (c) 2022 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 "fastdeploy/vision/common/processors/transform.h"
+#include "fastdeploy/vision/common/result.h"
+
+namespace fastdeploy {
+namespace vision {
+
+namespace classification {
+/*! @brief Postprocessor object for PaddleClas serials model.
+ */
+class FASTDEPLOY_DECL PaddleClasPostprocessor {
+ public:
+  /** \brief Create a postprocessor instance for PaddleClas serials model
+   *
+   * \param[in] topk The topk result filtered by the classify confidence score, default 1
+   */
+  explicit PaddleClasPostprocessor(int topk = 1);
+
+  /** \brief Process the result of runtime and fill to ClassifyResult structure
+   *
+   * \param[in] tensors The inference result from runtime
+   * \param[in] result The output result of classification
+   * \return true if the postprocess successed, otherwise false
+   */
+  bool Run(const std::vector<FDTensor>& tensors,
+          std::vector<ClassifyResult>* result);
+
+  /// Set topk value
+  void SetTopk(int topk) { topk_ = topk; }
+
+  /// Get topk value
+  int GetTopk() const { return topk_; }
+
+ private:
+  int topk_ = 1;
+  bool initialized_ = false;
+};
+
+}  // namespace classification
+}  // namespace vision
+}  // namespace fastdeploy