add CMake config package file (#4)

.github/workflows/consume.yml

@@ -0,0 +1,36 @@
+# Test consuming libbase122.
+name: Test Consuming libbase122
+on:
+  push:
+    branches: [ "master" ]
+  pull_request:
+    branches: [ "master" ]
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+    steps:
+    - uses: actions/checkout@v3
+
+    - name: Configure CMake
+      run: cmake -B ${{github.workspace}}/cmake-build -DCMAKE_BUILD_TYPE=Debug
+
+    - name: Build
+      run: cmake --build ${{github.workspace}}/cmake-build --config Debug
+
+    - name: Install
+      run: cmake --install ${{github.workspace}}/cmake-build --prefix ${{github.workspace}}/.install --config Debug
+
+    - name: Consume with CMake config file
+      working-directory: ${{github.workspace}}/test/testconsumer
+      run: |
+        cmake \
+          -DLIBBASE122_USE_CONFIG_FILE=ON \
+          -DLIBBASE122_USE_SHARED=ON \
+          -DCMAKE_PREFIX_PATH=${{github.workspace}}/.install \
+          -S. -Bcmake-build
+
+        cmake --build cmake-build
+
+        ./cmake-build/testconsumer
+      

CMakeLists.txt

@@ -33,3 +33,26 @@ install (TARGETS base122 b122 base122_shared)
 install (FILES src/base122.h TYPE INCLUDE)
 add_executable (example src/example.c)
 target_link_libraries(example base122)
+# Export CMake targets.
+set_target_properties(base122 PROPERTIES EXPORT_NAME base122::static)
+set_target_properties(base122_shared PROPERTIES EXPORT_NAME base122::shared)
+target_include_directories(base122 INTERFACE $<INSTALL_INTERFACE:include>)
+target_include_directories(base122_shared INTERFACE $<INSTALL_INTERFACE:include>)
+install (TARGETS base122 base122_shared EXPORT Base122Targets)
+install (EXPORT Base122Targets FILE Base122Targets.cmake DESTINATION lib/cmake/Base122)
+include (CMakePackageConfigHelpers)
+configure_package_config_file(
+    "${CMAKE_CURRENT_SOURCE_DIR}/cmake/Base122Config.cmake.in"
+    "${CMAKE_CURRENT_BINARY_DIR}/Base122Config.cmake"
+    INSTALL_DESTINATION "lib/cmake/Base122"
+    NO_SET_AND_CHECK_MACRO
+)
+write_basic_package_version_file(
+    "${CMAKE_CURRENT_BINARY_DIR}/Base122Version.cmake"
+    COMPATIBILITY AnyNewerVersion
+)
+install (FILES
+    "${CMAKE_CURRENT_BINARY_DIR}/Base122Config.cmake"
+    "${CMAKE_CURRENT_BINARY_DIR}/Base122Version.cmake"
+    DESTINATION "lib/cmake/Base122"
+)

README.md

@@ -37,6 +37,15 @@ cat example.jpg | b122 > encoded.b122
 cat encoded.b122 | b122 -d > decoded.jpg
 ```
 
+## Using with CMake
+
+CMake targets are exported. To use libbase122 in a CMake project:
+
+```cmake
+add_executable (app app.c)
+find_package (Base122 REQUIRED)
+target_link_libraries (app base122::static) # Or base122::shared
+```
 
 ## Contributing
 

cmake/Base122Config.cmake.in

@@ -0,0 +1,6 @@
+@PACKAGE_INIT@
+include("${CMAKE_CURRENT_LIST_DIR}/Base122Targets.cmake")
+set(SOME_DIR @PACKAGE_CMAKE_INSTALL_PREFIX@/foo)
+# `check_required_components` is used to ensure consumer did not erroneously request components.
+# No components are currently defined.
+check_required_components(Base122)

test/testconsumer/CMakeLists.txt

@@ -1,15 +1,24 @@
 cmake_minimum_required(VERSION 3.23)
 project(libbase122 LANGUAGES C)
 add_executable(testconsumer testconsumer.c)
-if (NOT DEFINED LIBBASE122_INSTALL_PATH)
-    message(FATAL_ERROR "LIBBASE122_INSTALL_PATH not defined. Define with install path to libbase122.")
-endif ()
-
 if (NOT DEFINED LIBBASE122_USE_SHARED)
     message(FATAL_ERROR "LIBBASE122_USE_SHARED not defined. Define to TRUE or FALSE.")
 endif ()
 
-if (WIN32)
+if (LIBBASE122_USE_CONFIG_FILE)
+    message (STATUS "Trying to find libbase122 with CMake config file...")
+    find_package (Base122 REQUIRED)
+    if (LIBBASE122_USE_SHARED)
+        target_link_libraries (testconsumer base122::shared)
+    else ()
+        target_link_libraries (testconsumer base122::static)
+    endif () # LIBBASE122_USE_SHARED
+elseif (WIN32)
+    if (NOT DEFINED LIBBASE122_INSTALL_PATH)
+        message(FATAL_ERROR "LIBBASE122_INSTALL_PATH not defined. Define with install path to libbase122.")
+    endif ()
+
+    message (STATUS "Trying to find libbase122 at path ${LIBBASE122_INSTALL_PATH}")
     # Convert a Windows path (e.g. C:\foo\bar) to a CMake path (e.g. C:/foo/bar)
     file(TO_CMAKE_PATH "${LIBBASE122_INSTALL_PATH}" LIBBASE122_INSTALL_PATH)
     message(STATUS "${LIBBASE122_INSTALL_PATH}")