JezK
Edit File: struct_generator.rb
require 'tempfile' module FFI ## # Generates an FFI Struct layout. # # Given the @@@ portion in: # # class Zlib::ZStream < FFI::Struct # @@@ # name "struct z_stream_s" # include "zlib.h" # # field :next_in, :pointer # field :avail_in, :uint # field :total_in, :ulong # # # ... # @@@ # end # # StructGenerator will create the layout: # # layout :next_in, :pointer, 0, # :avail_in, :uint, 4, # :total_in, :ulong, 8, # # ... # # StructGenerator does its best to pad the layout it produces to preserve # line numbers. Place the struct definition as close to the top of the file # for best results. class StructGenerator @options = {} attr_accessor :size attr_reader :fields def initialize(name, options = {}) @name = name @struct_name = nil @includes = [] @fields = [] @found = false @size = nil if block_given? then yield self calculate self.class.options.merge(options) end end def self.options=(options) @options = options end def self.options @options end def calculate(options = {}) binary = File.join Dir.tmpdir, "rb_struct_gen_bin_#{Process.pid}" raise "struct name not set" if @struct_name.nil? Tempfile.open("#{@name}.struct_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{" f.puts " #{@struct_name} s;" f.puts %[ printf("sizeof(#{@struct_name}) %u\\n", (unsigned int) sizeof(#{@struct_name}));] @fields.each do |field| f.puts <<-EOF printf("#{field.name} %u %u\\n", (unsigned int) offsetof(#{@struct_name}, #{field.name}), (unsigned int) sizeof(s.#{field.name})); EOF end f.puts "\n return 0;\n}" f.flush cc = ENV['CC'] || 'gcc' output = `#{cc} #{options[:cppflags]} #{options[:cflags]} -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 @found = false output = output.split("\n").map { |l| "\t#{l}" }.join "\n" raise "Compilation error generating struct #{@name} (#{@struct_name}):\n#{output}" end end output = `#{binary}`.split "\n" File.unlink(binary + (FFI::Platform.windows? ? ".exe" : "")) sizeof = output.shift unless @size m = /\s*sizeof\([^)]+\) (\d+)/.match sizeof @size = m[1] end line_no = 0 output.each do |line| md = line.match(/.+ (\d+) (\d+)/) @fields[line_no].offset = md[1].to_i @fields[line_no].size = md[2].to_i line_no += 1 end @found = true end def field(name, type=nil) field = Field.new(name, type) @fields << field return field end def found? @found end def dump_config(io) io.puts "rbx.platform.#{@name}.sizeof = #{@size}" @fields.each { |field| io.puts field.to_config(@name) } end def generate_layout buf = "" @fields.each_with_index do |field, i| if buf.empty? buf << "layout :#{field.name}, :#{field.type}, #{field.offset}" else buf << " :#{field.name}, :#{field.type}, #{field.offset}" end if i < @fields.length - 1 buf << ",\n" end end buf end def get_field(name) @fields.find { |f| name == f.name } end def include(i) @includes << i end def name(n) @struct_name = n end end ## # A field in a Struct. class StructGenerator::Field attr_reader :name attr_reader :type attr_reader :offset attr_accessor :size def initialize(name, type) @name = name @type = type @offset = nil @size = nil end def offset=(o) @offset = o end def to_config(name) buf = [] buf << "rbx.platform.#{name}.#{@name}.offset = #{@offset}" buf << "rbx.platform.#{name}.#{@name}.size = #{@size}" buf << "rbx.platform.#{name}.#{@name}.type = #{@type}" if @type buf end end end