[Filter/C++] Skeleton header

A few users have requested the ability to write C++ custom filters
especially for OpenCV usage.

Signed-off-by: MyungJoo Ham <myungjoo.ham@samsung.com>

diff --git a/ext/nnstreamer/tensor_filter/tensor_filter_cpp.cc b/ext/nnstreamer/tensor_filter/tensor_filter_cpp.cc
new file mode 100644 (file)
index 0000000..b31fb79
--- /dev/null
+++ b/ext/nnstreamer/tensor_filter/tensor_filter_cpp.cc
@@ -0,0 +1,139 @@
+/**
+ * GStreamer Tensor_Filter, Customized C++ Module
+ * Copyright (C) 2019 MyungJoo Ham <myungjoo.ham@samsung.com>
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Library General Public
+ * License as published by the Free Software Foundation; either
+ * version 2 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Library General Public License for more details.
+ *
+ */
+/**
+ * @file       tensor_filter_cpp.cpp
+ * @date       26 Sep 2019
+ * @brief      Tensor_filter subplugin for C++ custom filters.
+ * @see                http://github.com/nnsuite/nnstreamer
+ * @author     MyungJoo Ham <myungjoo.ham@samsung.com>
+ * @bug                No known bugs except for NYI items
+ *
+ * @note This is experimental. The API and Class definition is NOT stable.
+ *       If you want to write an OpenCV custom filter for nnstreamer, this is a good choice.
+ *
+ */
+#include <glib.h>
+#include <string.h>
+
+#include <tensor_common.h>
+#include <nnstreamer_plugin_api_filter.h>
+
+void init_filter_cpp (void) __attribute__ ((constructor));
+void fini_filter_cpp (void) __attribute__ ((destructor));
+
+#define loadClass(name, ptr) \
+  class tensor_filter_cpp *name = *(ptr); \
+  g_assert (*(ptr)); \
+  g_assert (name->validity == 0xdeafdead);
+
+/**
+ * @brief Class constructor
+ */
+tensor_filter_cpp::tensor_filter_cpp(const char *name)
+{
+  validity = 0xdeafdead;
+  this->name = g_strdup(name);
+}
+
+/**
+ * @brief Class destructor
+ */
+tensor_filter_cpp::~tensor_filter_cpp()
+{
+  g_free(name);
+}
+
+/**
+ * @brief Standard tensor_filter callback
+ */
+static int cpp_getInputDim (const GstTensorFilterProperties *prop, void **private_data, GstTensorsInfo *info)
+{
+  loadClass(cpp, private_data);
+  return cpp->getInputDim (info);
+}
+
+/**
+ * @brief Standard tensor_filter callback
+ */
+static int cpp_getOuputDim (const GstTensorFilterProperties *prop, void **private_data, GstTensorsInfo *info)
+{
+  loadClass(cpp, private_data);
+  return cpp->getOutputDim (info);
+}
+
+/**
+ * @brief Standard tensor_filter callback
+ */
+static int cpp_setInputDim (const GstTensorFilterProperties *prop, void **private_data, const GstTensorsInfo *in, GstTensorsInfo *out)
+{
+  loadClass(cpp, private_data);
+  return cpp->setInputDim (in, out);
+}
+
+/**
+ * @brief Standard tensor_filter callback
+ */
+static int cpp_invoke (const GstTensorFilterProperties *prop, void **private_data, const GstTensorMemory *input, GstTensorMemory *output)
+{
+  loadClass(cpp, private_data);
+  return cpp->invoke(input, output);
+}
+
+/**
+ * @brief Standard tensor_filter callback
+ */
+static int cpp_open (const GstTensorFilterProperties *prop, void **private_data)
+{
+  /** @todo: load the class with the given name (either file path or registered name) */
+  return 0;
+}
+
+/**
+ * @brief Standard tensor_filter callback
+ */
+static int cpp_close (const GstTensorFilterProperties *prop, void **private_data)
+{
+  /** @todo Implement This! NYI! */
+  return 0;
+}
+
+static gchar filter_subplugin_cpp[] = "cpp";
+
+static GstTensorFilterFramework NNS_support_cpp = {
+  .name = filter_subplugin_cpp,
+  .allow_in_place = FALSE,      /** @todo: support this to optimize performance later. */
+  .allocate_in_invoke = FALSE,
+  .invoke_NN = cpp_invoke,
+  .getInputDimension = cpp_getInputDim,
+  .getOutputDimension = cpp_getOutputDim,
+  .setInputDimension = cpp_setInputDim,
+  .open = cpp_open,
+  .close = cpp_close,
+};
+
+/** @brief Initialize this object for tensor_filter subplugin runtime register */
+void
+init_filter_cpp (void)
+{
+  nnstreamer_filter_probe (&NNS_support_cpp);
+}
+
+/** @brief Destruct the subplugin */
+void
+fini_filter_cpp (void)
+{
+  nnstreamer_filter_exit (NNS_support_cpp.name);
+}

diff --git a/ext/nnstreamer/tensor_filter/tensor_filter_cpp.h b/ext/nnstreamer/tensor_filter/tensor_filter_cpp.h
new file mode 100644 (file)
index 0000000..6971850
--- /dev/null
+++ b/ext/nnstreamer/tensor_filter/tensor_filter_cpp.h
@@ -0,0 +1,70 @@
+/**
+ * GStreamer Tensor_Filter, Customized C++ Module
+ * Copyright (C) 2019 MyungJoo Ham <myungjoo.ham@samsung.com>
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Library General Public
+ * License as published by the Free Software Foundation; either
+ * version 2 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Library General Public License for more details.
+ *
+ */
+/**
+ * @file       tensor_filter_cpp.h
+ * @date       24 Sep 2019
+ * @brief      Custom tensor processing interface for C++ codes.
+ * @see                http://github.com/nnsuite/nnstreamer
+ * @author     MyungJoo Ham <myungjoo.ham@samsung.com>
+ * @bug                No known bugs except for NYI items
+ *
+ * How To for NNdevelopers (C++ subplugin writers):
+ *
+ * @todo Write This
+ *
+ * @note This is experimental. The API and Class definition is NOT stable.
+ *       If you want to write an OpenCV custom filter for nnstreamer, this is a good choice.
+ *
+ * To Packagers:
+ *
+ * This is to be exposed with "nnstreamer-c++-dev"
+ */
+#ifndef __NNS_TENSOR_FITLER_CPP_H__
+#define __NNS_TENSOR_FITLER_CPP_H__
+
+#include <stdint.h>
+
+#ifdef __cplusplus
+/**
+ * @brief This allows to have a c++ class inserted as a filter in a neural network pipeline of nnstreamer
+ * @note This is experimental.
+ */
+class tensor_filter_cpp {
+  private:
+    const uint32_t validity;
+    const char *name; /**< The name of this C++ custom filter, searchable with "model" property */
+
+  public:
+    tensor_filter_cpp(const char *modelName); /**< modelName is the model property of tensor_filter, which could be the path to the model file (requires proper extension name) or the registered model name at runtime. */
+    ~tensor_filter_cpp();
+
+    /** C++ plugin writers need to fill {getInput/Output} inclusive-or {setInput} */
+    virtual int getInputDim(GstTensorsInfo *info) = 0;
+    virtual int getOutputDim(GstTensorsInfo *info) = 0;
+
+    virtual int setIutputDim(const GstTensorsInfo *in, GstTensorsInfo *out) = 0;
+
+    bool allocate_before_invoke; /**< TRUE, if you want nnstreamer to preallocate output buffers before calling invoke */
+    virtual int invoke(const GstTensorMemory *in, GstTensorMemory *out) = 0;
+
+    /** API */
+    static int tensor_filter_cpp_register (class tensor_filter_cpp *filter) final; /**< Register a C++ custom filter with this API if you want to register it at runtime. (or at the constructor of a shared object if you want to load it dynamically.) This should be invoked before initialized (constructed) by tensor_filter at run-time. */
+
+};
+
+#endif /* __cplusplus */
+
+#endif /* __NNS_TENSOR_FITLER_CPP_H__ */