def calculate(options = {})
binary = File.join Dir.tmpdir, "rb_const_gen_bin_#{Process.pid}"
Tempfile.open("#{@prefix}.const_generator") do |f|
f.puts "#include <stdio.h>"
@includes.each do |inc|
f.puts "#include <#{inc}>"
end
f.puts "#include <stddef.h>\n\n"
f.puts "int main(int argc, char **argv)\n{"
@constants.each_value do |const|
f.puts "#ifdef \#{const.name}\nprintf(\"\#{const.name} \#{const.format}\\\\n\", \#{const.cast}\#{const.name});\n#endif\n"
end
f.puts "\n\treturn 0;\n}"
f.flush
output = `gcc #{options[:cppflags]} -D_DARWIN_USE_64_BIT_INODE -D_LARGEFILE_SOURCE -D_FILE_OFFSET_BITS=64 -x c -Wall -Werror #{f.path} -o #{binary} 2>&1`
unless $?.success? then
output = output.split("\n").map { |l| "\t#{l}" }.join "\n"
raise "Compilation error generating constants #{@prefix}:\n#{output}"
end
end
output = `#{binary}`
File.unlink(binary + (FFI::Platform.windows? ? ".exe" : ""))
output.each_line do |line|
line =~ /^(\S+)\s(.*)$/
const = @constants[$1]
const.value = $2
end
missing_constants = @constants.select do |name, constant|
constant.value.nil?
end.map { |name,| name }
if @required and not missing_constants.empty? then
raise "Missing required constants for #{@prefix}: #{missing_constants.join ', '}"
end
end