Merge pull request #16724 from liqi-c:3.4-tengine

* Add Tengine support .

* Modify printf to CV_LOG_WARNING

* a few minor fixes in the code

* Renew Tengine version

* Add header file for CV_LOG_WARNING

* Add #ifdef HAVE_TENGINE in tengine_graph_convolution.cpp

* remove trailing whitespace

* Remove trailing whitespace

* Modify for compile problem

* Modify some code style error

* remove whitespace

* Move some code style problem

* test

* add ios limit and build problem

* Modified as alalek suggested

* Add cmake 2.8 support

* modify cmake 3.5.1 problem

* test and set BUILD_ANDROID_PROJECTS OFF

* remove some compile error

* remove some extra code in tengine

* close test.

* Test again

* disable android.

* delete ndk version judgement

* Remove setenv() call . and add License information

* Set tengine default OFF. Close test .

Co-authored-by: Vadim Pisarevsky <vadim.pisarevsky@gmail.com>

3rdparty/libtengine/tengine.cmake

@@ -0,0 +1,90 @@
+# COPYRIGHT
+# Licensed to the Apache Software Foundation (ASF) under one
+# or more contributor license agreements.  See the NOTICE file
+# distributed with this work for additional information
+# regarding copyright ownership.  The ASF licenses this file
+# to you 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.
+#
+# Copyright (c) 2020, OPEN AI LAB
+# Author: qtang@openailab.com or https://github.com/BUG1989
+#         qli@openailab.com
+#         sqfu@openailab.com
+#
+
+SET(TENGINE_VERSION "tengine-opencv")
+SET(OCV_TENGINE_DSTDIRECTORY ${OpenCV_BINARY_DIR}/3rdparty/libtengine)
+SET(DEFAULT_OPENCV_TENGINE_SOURCE_PATH ${OCV_TENGINE_DSTDIRECTORY}/Tengine-${TENGINE_VERSION})
+
+IF(EXISTS ${DEFAULT_OPENCV_TENGINE_SOURCE_PATH})
+	MESSAGE(STATUS "Tengine is exist already  .")
+
+	SET(Tengine_FOUND ON)
+	set(BUILD_TENGINE ON)
+ELSE()
+	SET(OCV_TENGINE_FILENAME "${TENGINE_VERSION}.zip")#name2
+	SET(OCV_TENGINE_URL "https://github.com/OAID/Tengine/archive/") #url2
+	SET(tengine_md5sum 9c80d91dc8413911522ec80cde013ae2) #md5sum2
+
+	MESSAGE(STATUS "**** TENGINE DOWNLOAD BEGIN ****")
+	ocv_download(FILENAME ${OCV_TENGINE_FILENAME}
+						HASH ${tengine_md5sum}
+						URL
+						"${OPENCV_TENGINE_URL}"
+						"$ENV{OPENCV_TENGINE_URL}"
+						"${OCV_TENGINE_URL}"
+						DESTINATION_DIR ${OCV_TENGINE_DSTDIRECTORY}
+						ID TENGINE
+						STATUS res
+						UNPACK RELATIVE_URL)
+
+	if (NOT res)
+		MESSAGE(STATUS "TENGINE DOWNLOAD FAILED .Turning Tengine_FOUND off.")
+		SET(Tengine_FOUND OFF)
+	else ()
+		MESSAGE(STATUS "TENGINE DOWNLOAD success . ")
+
+		SET(Tengine_FOUND ON)
+		set(BUILD_TENGINE ON)
+	endif()
+ENDIF()
+
+if (BUILD_TENGINE)
+	set(HAVE_TENGINE 1)
+
+	# android system
+	if(ANDROID)
+	   if(${ANDROID_ABI} STREQUAL "armeabi-v7a")
+			   set(CONFIG_ARCH_ARM32 ON)
+	   elseif(${ANDROID_ABI} STREQUAL "arm64-v8a")
+			   set(CONFIG_ARCH_ARM64 ON)
+	   endif()
+	endif()
+
+	# linux system
+	if(CMAKE_SYSTEM_PROCESSOR STREQUAL arm)
+		   set(CONFIG_ARCH_ARM32 ON)
+	elseif(CMAKE_SYSTEM_PROCESSOR STREQUAL aarch64) ## AARCH64
+		   set(CONFIG_ARCH_ARM64 ON)
+	endif()
+
+	SET(DEFAULT_OPENCV_TENGINE_SOURCE_PATH ${OCV_TENGINE_DSTDIRECTORY}/Tengine-${TENGINE_VERSION})
+	set(BUILT_IN_OPENCV ON) ## set for tengine compile discern .
+	set(Tengine_INCLUDE_DIR  ${DEFAULT_OPENCV_TENGINE_SOURCE_PATH}/core/include)
+	set(Tengine_LIB   ${CMAKE_BINARY_DIR}/lib/${ANDROID_ABI}/libtengine.a)
+	if ( IS_DIRECTORY ${DEFAULT_OPENCV_TENGINE_SOURCE_PATH})
+		add_subdirectory("${DEFAULT_OPENCV_TENGINE_SOURCE_PATH}" ${OCV_TENGINE_DSTDIRECTORY}/build)
+	endif()
+endif()
+
+