Adding R wrapper code; see #668

dev/cmake/Modules/FindR.cmake

@@ -0,0 +1,69 @@
+# - Find R
+# This module finds the libraries corresponding to the R program
+# It is based on the code from http://github.com/usnistgov/REFPROP-wrappers which is in the public domain
+
+# This code sets the following variables:
+#
+#  R_LIBRARY             - path to the R shared library
+#  R_INCLUDE_DIRS        - include directory(ies)
+#  R_BIN_DIR             - directory that contains the R executable being used
+
+SET(R_FOUND 0)
+
+IF( "${R_BIN}" STREQUAL "")
+    MESSAGE(FATAL_ERROR "You must pass the CMake variable R_BIN pointing to the directory that contains your executable")
+ENDIF()
+
+find_program(R_EXEC
+             NAMES R
+             PATHS ${R_BIN}
+             )
+execute_process(
+    COMMAND ${R_EXEC} RHOME OUTPUT_VARIABLE R_HOME_TEXT RESULT_VARIABLE R_HOME_RESULT
+)
+MESSAGE(STATUS "R_EXEC= ${R_EXEC}")
+# Parse the output of the R path commmand, removing whitespace
+FUNCTION(chomp arg1 arg2)
+    string(REPLACE "\n" ";" arg1list ${arg1})
+    list(GET arg1list 1 arg1line)
+    string(LENGTH ${arg1line} len)
+    MATH(EXPR length ${len}-6)
+    string(SUBSTRING ${arg1line} 5 ${length} arg1path)
+    # see http://www.cmake.org/pipermail/cmake/2008-November/025423.html
+    set(${arg2} ${arg1path} PARENT_SCOPE)
+ENDFUNCTION(chomp)
+
+MESSAGE(STATUS "R_HOME_TEXT = ${R_HOME_TEXT}")
+MESSAGE(STATUS "R_HOME_RESULT = ${R_HOME_RESULT}")
+file(WRITE ${CMAKE_CURRENT_BINARY_DIR}/get_include.R R.home(component=\"include\"))
+execute_process(
+    COMMAND ${R_EXEC} --quiet -f ${CMAKE_CURRENT_BINARY_DIR}/get_include.R OUTPUT_VARIABLE R_INCLUDE_TEXT RESULT_VARIABLE R_INCLUDE_RESULT
+)
+file(REMOVE ${CMAKE_CURRENT_BINARY_DIR}/get_include.R)
+chomp(${R_INCLUDE_TEXT} R_INCLUDE_DIRS)
+MESSAGE(STATUS "R_INCLUDE = ${R_INCLUDE_DIRS} w/ RESULT=${R_INCLUDE_RESULT}")
+
+file(WRITE ${CMAKE_CURRENT_BINARY_DIR}/get_bin.R R.home(component=\"bin\"))
+execute_process(
+    COMMAND ${R_EXEC} --quiet -f ${CMAKE_CURRENT_BINARY_DIR}/get_bin.R OUTPUT_VARIABLE R_BIN_TEXT RESULT_VARIABLE R_BIN_RESULT
+)
+file(REMOVE ${CMAKE_CURRENT_BINARY_DIR}/get_bin.R)
+chomp(${R_BIN_TEXT} R_BIN_DIR)
+MESSAGE(STATUS "R_BIN_TEXT = ${R_BIN_DIR} w/ RESULT=${R_BIN_RESULT}")
+        
+find_library (
+          R_LIBRARY
+          R
+          PATHS ${R_BIN_DIR}
+          NO_DEFAULT_PATH
+          NO_CMAKE_PATH
+          )
+MESSAGE(STATUS "R_LIBRARY = ${R_LIBRARY}")
+find_package_handle_standard_args(R DEFAULT_MSG
+                                  R_LIBRARY R_INCLUDE_DIRS)
+
+MARK_AS_ADVANCED(
+  R_BIN_DIR
+  R_LIBRARY
+  R_INCLUDE_DIRS
+)