CMake: add android build config

+ add missing copyright headers
+ fix README.md formatting

Change-Id: Ic01e0c4d16131db287b503c6bab99fa02f1d2e7f

CMakeLists.txt

@@ -14,7 +14,9 @@
 
 cmake_minimum_required(VERSION 2.8.7)
 
-project(sjpeg CXX)
+project(sjpeg
+        LANGUAGES C CXX)
+set(CMAKE_C_STANDARD 99)
 set(CMAKE_CXX_STANDARD 11)
 
 # Options for coder / decoder executables.
@@ -36,15 +38,16 @@ set(PROJECT_VERSION 0.1)
 
 ################################################################################
 # Android only.
+
 if(ANDROID)
-  include_directories(${ANDROID_NDK}/sources/android/cpufeatures)
-  add_library(cpufeatures STATIC
-              ${ANDROID_NDK}/sources/android/cpufeatures/cpu-features.c
+  include_directories(${SJPEG_ANDROID_NDK_PATH}/sources/android/cpufeatures)
+  add_library(cpufeatures
+    STATIC ${SJPEG_ANDROID_NDK_PATH}/sources/android/cpufeatures/cpu-features.c
   )
   target_link_libraries(cpufeatures dl)
   set(SJPEG_DEP_LIBRARIES ${SJPEG_DEP_LIBRARIES} cpufeatures)
   set(SJPEG_DEP_INCLUDE_DIRS ${SJPEG_DEP_INCLUDE_DIRS}
-      ${ANDROID_NDK}/sources/android/cpufeatures
+      ${SJPEG_ANDROID_NDK_PATH}/sources/android/cpufeatures
   )
 endif()
 
@@ -80,7 +83,7 @@ set_target_properties(sjpeg PROPERTIES POSITION_INDEPENDENT_CODE ON)
 
 # Set the version numbers.
 set_target_properties(sjpeg PROPERTIES VERSION ${PROJECT_VERSION}
-  SOVERSION ${PROJECT_VERSION})
+                      SOVERSION ${PROJECT_VERSION})
 
 # Find the standard image libraries.
 set(SJPEG_DEP_IMG_LIBRARIES)
@@ -118,9 +121,11 @@ endif()
 
 # build the utils library
 include_directories(${SJPEG_DEP_IMG_INCLUDE_DIRS})
-add_library(utils ${CMAKE_CURRENT_SOURCE_DIR}/examples/utils.cc
-  ${CMAKE_CURRENT_SOURCE_DIR}/examples/utils.h
+add_library(utils
+            ${CMAKE_CURRENT_SOURCE_DIR}/examples/utils.cc
+            ${CMAKE_CURRENT_SOURCE_DIR}/examples/utils.h
 )
+
 if(WIN32)
   # quiet warnings related to fopen, sscanf
   target_compile_definitions(utils PRIVATE _CRT_SECURE_NO_WARNINGS)

Makefile

@@ -173,6 +173,7 @@ DIST_FILES= \
          NEWS  \
          README  \
          CMakeLists.txt \
+         cmake/android.cmake \
          cmake/cpu.cmake \
          cmake/sjpegConfig.cmake.in \
          src/libsjpeg.pc.in \

README

@@ -66,7 +66,7 @@ Alternatively, one can use SjpegEstimateQuality() and
 sjpeg::EncoderParam::SetQuality() to pass a quality factor instead of using the
 matrices.
 
-sjpeg::EncoderParam is also useful for transfering some metadata to the final
+sjpeg::EncoderParam is also useful for transferring some metadata to the final
 JPEG bitstream.
 
 * 'Riskiness' score:
@@ -108,6 +108,25 @@ cmake:
   . `make -j`, or
   . `mkdir build && cd build && cmake ../ && make -j`
 
+* Compiling with Android NDK
+****************************
+
+The latest NDK for Android can be retrieved from the
+Android download page: https://developer.android.com/ndk/downloads
+
+Assuming the variable NDK_ROOT is positioned correctly to point
+to the NDK's directory, the Android binaries can be built with:
+
+   . mkdir build && cd build
+   . cmake .. -DCMAKE_TOOLCHAIN_FILE=../cmake/android.cmake \
+              -DSJPEG_ANDROID_NDK_PATH=${NDK_ROOT}
+   . make -j
+
+Extra configuration option:
+
+  ANDROID_ABI: one of armeabi-v7a,armeabi-v7a with NEON,arm64-v8a,
+               x86,x86_64... (default is arm64-v8a)
+
 * Discussion list
 *****************
 

README.md

@@ -1,25 +1,27 @@
+```
                      ____ __   __ __  ____ ____  ____
                     /  __\__) /  \  \/  _ \   / /  _ \
                    _\_   \  (/      /   __/  /_/   __/
                    \_____/___/__//_/\__/_/_____/_____/
                           (__)_/  _ \/  _ \/ .__\
                           _)  \   __/   __/  /  \
                          /____/__/  \_____/_____/v1.0
+```
 
-* sjpeg: 's' stands for 'simple'.
+*   sjpeg: 's' stands for 'simple'.
 
-* sjpeg is a simple encoding library for encoding baseline JPEG files.
-  It's also a command-line tool that takes PNG or JPEG images as input
-  to produce JPEG files.
+*   sjpeg is a simple encoding library for encoding baseline JPEG files. It's
+    also a command-line tool that takes PNG or JPEG images as input to produce
+    JPEG files.
 
-* Why 'simple'? Well, the encoder used to be one single source file. And
-  not a large one, moreover. Over time it grew and was split, for readability,
-  but the spirit remains the same.
+*   Why 'simple'? Well, the encoder used to be one single source file. And not a
+    large one, moreover. Over time it grew and was split, for readability, but
+    the spirit remains the same.
 
 # The sjpeg library:
 
-The main header is src/sjpeg.h.
-This is mainly just one function to call, defined in src/sjpeg.h
+The main header is src/sjpeg.h. This is mainly just one function to call,
+defined in src/sjpeg.h
 
 ```
 size_t SjpegCompress(const uint8_t* rgb, int width, int height,
@@ -43,31 +45,33 @@ as well as functions with a C++ string-based API.
 The library comes primarily with a plain-C API, but a C++ version is available
 too, that uses `std::string` as interface.
 
-`SjpegFreeBuffer()` can be called release the buffers returned by `SjpegEncode()`
-and `SjpegCompress()`.
+`SjpegFreeBuffer()` can be called release the buffers returned by
+`SjpegEncode()` and `SjpegCompress()`.
 
 Also included in the library: some helper functions to inspect JPEG bitstream.
-They are meant to help re-processing a JPEG source:
-  `SjpegDimensions()`: quickly get the JPEG picture dimensions.
-  `SjpegFindQuantizer()`: return the quantization matrices
-  `SjpegEstimateQuality()`: return an estimate of the encoding quality
+They are meant to help re-processing a JPEG source: `SjpegDimensions()`: quickly
+get the JPEG picture dimensions. `SjpegFindQuantizer()`: return the quantization
+matrices `SjpegEstimateQuality()`: return an estimate of the encoding quality
 
 ## SjpegEncodeParam interface:
 
 This should be the most fine-tuned use of the library: SjpegEncodeParam gives
 access to a lot of fine controls (C++ only). See `src/sjpeg.h` for details.
 
-In particular, using SjpegEncodeParam is the recommended way of re-compressing
-a JPEG input. Here is the recipe:
+In particular, using SjpegEncodeParam is the recommended way of re-compressing a
+JPEG input. Here is the recipe:
 
-* use `SjpegFindQuantizer` to extract the quantization matrices from the source
-* use `SjpegEncodeParam::SetQuantMatrix()` to transfer them to the encoding parameters (with a reduction factor if necessary)
-* call `sjpeg::SjpegEncode()` with this parameter
+*   use `SjpegFindQuantizer` to extract the quantization matrices from the
+    source
+*   use `SjpegEncodeParam::SetQuantMatrix()` to transfer them to the encoding
+    parameters (with a reduction factor if necessary)
+*   call `sjpeg::SjpegEncode()` with this parameter
 
 Alternately, one can use `SjpegEstimateQuality()` and
-`SjpegEncodeParam::SetQuality()` to pass a quality factor instead of the matrices.
+`SjpegEncodeParam::SetQuality()` to pass a quality factor instead of the
+matrices.
 
-`SjpegEncodeParam` is also useful for transfering some metadata to the final
+`SjpegEncodeParam` is also useful for transferring some metadata to the final
 JPEG bitstream.
 
 ## 'Riskiness' score:
@@ -85,9 +89,9 @@ which returns a recommendation for 'yuv_mode' to use in the above API.
 
 `examples/sjpeg` is a very simple tool to compress a PNG/JPEG file to JPEG.
 
-`sjpeg in.png -o out.jpg -q 70     # compress the PNG source with quality 70`
+`sjpeg in.png -o out.jpg -q 70 # compress the PNG source with quality 70`
 
-`sjpeg in.jpg -o out.jpg -r 90     # recompress JPEG input to ~90% `
+`sjpeg in.jpg -o out.jpg -r 90 # recompress JPEG input to ~90%`
 
 sjpeg has various options to change the encoding method. Just try `sjpeg -h`.
 
@@ -104,14 +108,33 @@ from `SjpegEncodeParam` can be triggered from the keyboard.
 
 Please read the instructions in the INSTALL file.
 
-Basically, you can use the supplied Makefile or generate your build with
-cmake:
+Basically, you can use the supplied Makefile or generate your build with cmake:
+
+*   `make -j`, or
+*   `mkdir build && cd build && cmake ../ && make -j`
+
+## Compiling with Android NDK
+
+The latest NDK for Android can be retrieved from the Android
+[download page](https://developer.android.com/ndk/downloads).
+
+Assuming the variable NDK_ROOT is positioned correctly to point to the NDK's
+directory, the Android binaries can be built with:
+
+```shell
+$ mkdir build && cd build
+$ cmake .. -DCMAKE_TOOLCHAIN_FILE=../cmake/android.cmake \
+           -DSJPEG_ANDROID_NDK_PATH=${NDK_ROOT}
+$ make -j
+```
+
+Extra configuration option:
 
-* `make -j`, or
-* `mkdir build && cd build && cmake ../ && make -j`
+*   `ANDROID_ABI`: one of armeabi-v7a,armeabi-v7a with
+    NEON,arm64-v8a,x86,x86_64... (default is arm64-v8a)
 
 # Discussion list
 
 The following forum can be used to report bugs or just discuss sjpeg:
 
-[https://groups.google.com/forum/#!forum/sjpeg]([https://groups.google.com/forum/#!forum/sjpeg)
+[https://groups.google.com/forum/#!forum/sjpeg](https://groups.google.com/forum/#!forum/sjpeg)

cmake/cpu.cmake

@@ -1,3 +1,17 @@
+# Copyright 2021 Google LLC.
+#
+# 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
+#
+#      https://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.
+
 ## Check for SIMD extensions.
 
 function(sjpeg_check_compiler_flag SJPEG_SIMD_DEFINE ENABLE_SIMD)

tests/test_cmd.sh

@@ -1,4 +1,19 @@
 #!/bin/sh
+# Copyright 2021 Google LLC
+#
+# 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.
+# ------------------------------------------------------------------------------
+
 # tests for command lines
 
 SJPEG=../examples/sjpeg

tests/test_png_jpg.sh

@@ -1,4 +1,19 @@
 #!/bin/sh
+# Copyright 2021 Google LLC
+#
+# 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.
+# ------------------------------------------------------------------------------
+
 # tests for JPEG/PNG/PPM -> JPEG -> JPEG chain
 
 SJPEG=../examples/sjpeg