/usr/lib/ruby/vendor_ruby/ffi/tools/struct_generator.rb is in ruby-ffi 1.9.10debian-1build2.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 | require 'tempfile'
module FFI
##
# Generates an FFI Struct layout.
#
# Given the @@@ portion in:
#
# module 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
output = `gcc #{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
|