class RDoc::Parser::C

# File lib/rdoc/parser/c.rb, line 167
def initialize top_level, file_name, content, options, stats
  super

  @known_classes = RDoc::KNOWN_CLASSES.dup
  @content = handle_tab_width handle_ifdefs_in @content
  @file_dir = File.dirname @file_name

  @classes           = load_variable_map :c_class_variables
  @singleton_classes = load_variable_map :c_singleton_class_variables

  # class_variable => { function => [method, ...] }
  @methods = Hash.new { |h, f| h[f] = Hash.new { |i, m| i[m] = [] } }

  # missing variable => [handle_class_module arguments]
  @missing_dependencies = {}

  # missing enclosure variable => [dependent handle_class_module arguments]
  @enclosure_dependencies = Hash.new { |h, k| h[k] = [] }
  @enclosure_dependencies.instance_variable_set :@missing_dependencies,
                                                @missing_dependencies

  @enclosure_dependencies.extend TSort

  def @enclosure_dependencies.tsort_each_node &block
    each_key(&block)
  rescue TSort::Cyclic => e
    cycle_vars = e.message.scan(/"(.*?)"/).flatten

    cycle = cycle_vars.sort.map do |var_name|
      delete var_name

      var_name, type, mod_name, = @missing_dependencies[var_name]

      "#{type} #{mod_name} (#{var_name})"
    end.join ', '

    warn "Unable to create #{cycle} due to a cyclic class or module creation"

    retry
  end

  def @enclosure_dependencies.tsort_each_child node, &block
    fetch(node, []).each(&block)
  end
end

# File lib/rdoc/parser/c.rb, line 217
def deduplicate_call_seq
  @methods.each do |var_name, functions|
    class_name = @known_classes[var_name]
    next unless class_name
    class_obj  = find_class var_name, class_name

    functions.each_value do |method_names|
      next if method_names.length == 1

      method_names.each do |method_name|
        deduplicate_method_name class_obj, method_name
      end
    end
  end
end

# File lib/rdoc/parser/c.rb, line 258
def do_aliases
  @content.scan(/rb_define_alias\s*\(
                 \s*(\w+),
                 \s*"(.+?)",
                 \s*"(.+?)"
                 \s*\)/xm) do |var_name, new_name, old_name|
    class_name = @known_classes[var_name]

    unless class_name then
      @options.warn "Enclosing class or module %p for alias %s %s is not known" % [
        var_name, new_name, old_name]
      next
    end

    class_obj = find_class var_name, class_name

    al = RDoc::Alias.new '', old_name, new_name, ''
    al.singleton = @singleton_classes.key? var_name

    comment = find_alias_comment var_name, new_name, old_name

    comment.normalize

    al.comment = comment

    al.record_location @top_level

    class_obj.add_alias al
    @stats.add_alias al
  end
end

# File lib/rdoc/parser/c.rb, line 293
def do_attrs
  @content.scan(/rb_attr\s*\(
                 \s*(\w+),
                 \s*([\w"()]+),
                 \s*([01]),
                 \s*([01]),
                 \s*\w+\);/xm) do |var_name, attr_name, read, write|
    handle_attr var_name, attr_name, read, write
  end

  @content.scan(%r%rb_define_attr\(
                           \s*([\w\.]+),
                           \s*"([^"]+)",
                           \s*(\d+),
                           \s*(\d+)\s*\);
              %xm) do |var_name, attr_name, read, write|
    handle_attr var_name, attr_name, read, write
  end
end

# File lib/rdoc/parser/c.rb, line 316
def do_boot_defclass
  @content.scan(/(\w+)\s*=\s*boot_defclass\s*\(\s*"(\w+?)",\s*(\w+?)\s*\)/) do
    |var_name, class_name, parent|
    parent = nil if parent == "0"
    handle_class_module(var_name, :class, class_name, parent, nil)
  end
end

# File lib/rdoc/parser/c.rb, line 328
def do_classes
  do_boot_defclass
  do_define_class
  do_define_class_under
  do_singleton_class
  do_struct_define_without_accessor
end

# File lib/rdoc/parser/c.rb, line 340
def do_constants
  @content.scan(%r%\Wrb_define_
                 ( variable          |
                   readonly_variable |
                   const             |
                   global_const        )
             \s*\(
               (?:\s*(\w+),)?
               \s*"(\w+)",
               \s*(.*?)\s*\)\s*;
               %xm) do |type, var_name, const_name, definition|
    var_name = "rb_cObject" if !var_name or var_name == "rb_mKernel"
    handle_constants type, var_name, const_name, definition
  end

  @content.scan(%r%
                \Wrb_curses_define_const
                \s*\(
                  \s*
                  (\w+)
                  \s*
                \)
                \s*;%xm) do |consts|
    const = consts.first

    handle_constants 'const', 'mCurses', const, "UINT2NUM(#{const})"
  end

  @content.scan(%r%
                \Wrb_file_const
                \s*\(
                  \s*
                  "([^"]+)",
                  \s*
                  (.*?)
                  \s*
                \)
                \s*;%xm) do |name, value|
    handle_constants 'const', 'rb_mFConst', name, value
  end
end

# File lib/rdoc/parser/c.rb, line 385
def do_define_class
  # The '.' lets us handle SWIG-generated files
  @content.scan(/([\w\.]+)\s* = \s*rb_define_class\s*
            \(
               \s*"(\w+)",
               \s*(\w+)\s*
            \)/mx) do |var_name, class_name, parent|
    handle_class_module(var_name, :class, class_name, parent, nil)
  end
end

# File lib/rdoc/parser/c.rb, line 399
def do_define_class_under
  @content.scan(/([\w\.]+)\s* =                  # var_name
                 \s*rb_define_class_under\s*
                 \(
                   \s* (\w+),                    # under
                   \s* "(\w+)",                  # class_name
                   \s*
                   (?:
                     ([\w\*\s\(\)\.\->]+) |      # parent_name
                     rb_path2class\("([\w:]+)"\) # path
                   )
                   \s*
                 \)
                /mx) do |var_name, under, class_name, parent_name, path|
    parent = path || parent_name

    handle_class_module var_name, :class, class_name, parent, under
  end
end

# File lib/rdoc/parser/c.rb, line 422
def do_define_module
  @content.scan(/(\w+)\s* = \s*rb_define_module\s*\(\s*"(\w+)"\s*\)/mx) do
    |var_name, class_name|
    handle_class_module(var_name, :module, class_name, nil, nil)
  end
end

# File lib/rdoc/parser/c.rb, line 432
def do_define_module_under
  @content.scan(/(\w+)\s* = \s*rb_define_module_under\s*
            \(
               \s*(\w+),
               \s*"(\w+)"
            \s*\)/mx) do |var_name, in_module, class_name|
    handle_class_module(var_name, :module, class_name, nil, in_module)
  end
end

# File lib/rdoc/parser/c.rb, line 445
def do_includes
  @content.scan(/rb_include_module\s*\(\s*(\w+?),\s*(\w+?)\s*\)/) do |c,m|
    next unless cls = @classes[c]
    m = @known_classes[m] || m

    comment = RDoc::Comment.new '', @top_level
    incl = cls.add_include RDoc::Include.new(m, comment)
    incl.record_location @top_level
  end
end

# File lib/rdoc/parser/c.rb, line 461
def do_methods
  @content.scan(%r%rb_define_
                 (
                    singleton_method |
                    method           |
                    module_function  |
                    private_method
                 )
                 \s*\(\s*([\w\.]+),
                   \s*"([^"]+)",
                   \s*(?:RUBY_METHOD_FUNC\(|VALUEFUNC\(|\(METHOD\))?(\w+)\)?,
                   \s*(-?\w+)\s*\)
                 (?:;\s*/[*/]\s+in\s+(\w+?\.(?:cpp|c|y)))?
               %xm) do |type, var_name, meth_name, function, param_count, source_file|

    # Ignore top-object and weird struct.c dynamic stuff
    next if var_name == "ruby_top_self"
    next if var_name == "nstr"

    var_name = "rb_cObject" if var_name == "rb_mKernel"
    handle_method(type, var_name, meth_name, function, param_count,
                  source_file)
  end

  @content.scan(%r%rb_define_global_function\s*\(
                           \s*"([^"]+)",
                           \s*(?:RUBY_METHOD_FUNC\(|VALUEFUNC\()?(\w+)\)?,
                           \s*(-?\w+)\s*\)
              (?:;\s*/[*/]\s+in\s+(\w+?\.[cy]))?
              %xm) do |meth_name, function, param_count, source_file|
    handle_method("method", "rb_mKernel", meth_name, function, param_count,
                  source_file)
  end

  @content.scan(/define_filetest_function\s*\(
                   \s*"([^"]+)",
                   \s*(?:RUBY_METHOD_FUNC\(|VALUEFUNC\()?(\w+)\)?,
                   \s*(-?\w+)\s*\)/xm) do |meth_name, function, param_count|

    handle_method("method", "rb_mFileTest", meth_name, function, param_count)
    handle_method("singleton_method", "rb_cFile", meth_name, function,
                  param_count)
  end
end

# File lib/rdoc/parser/c.rb, line 510
def do_missing
  return if @missing_dependencies.empty?

  @enclosure_dependencies.tsort.each do |in_module|
    arguments = @missing_dependencies.delete in_module

    next unless arguments # dependency on existing class

    handle_class_module(*arguments)
  end
end

# File lib/rdoc/parser/c.rb, line 525
def do_modules
  do_define_module
  do_define_module_under
end

# File lib/rdoc/parser/c.rb, line 533
def do_singleton_class
  @content.scan(/([\w\.]+)\s* = \s*rb_singleton_class\s*
                \(
                  \s*(\w+)
                \s*\)/mx) do |sclass_var, class_var|
    handle_singleton sclass_var, class_var
  end
end

# File lib/rdoc/parser/c.rb, line 545
def do_struct_define_without_accessor
  @content.scan(/([\w\.]+)\s* = \s*rb_struct_define_without_accessor\s*
            \(
               \s*"(\w+)",  # Class name
               \s*(\w+),    # Parent class
               \s*\w+,      # Allocation function
               (\s*"\w+",)* # Attributes
               \s*NULL
            \)/mx) do |var_name, class_name, parent|
    handle_class_module(var_name, :class, class_name, parent, nil)
  end
end

# File lib/rdoc/parser/c.rb, line 562
def find_alias_comment class_name, new_name, old_name
  content =~ %r%((?>/\*.*?\*/\s+))
                rb_define_alias\(\s*#{Regexp.escape class_name}\s*,
                                 \s*"#{Regexp.escape new_name}"\s*,
                                 \s*"#{Regexp.escape old_name}"\s*\);%xm

  RDoc::Comment.new($1 || '', @top_level)
end

# File lib/rdoc/parser/c.rb, line 580
def find_attr_comment var_name, attr_name, read = nil, write = nil
  attr_name = Regexp.escape attr_name

  rw = if read and write then
         /\s*#{read}\s*,\s*#{write}\s*/xm
       else
         /.*?/m
       end

  comment = if @content =~ %r%((?>/\*.*?\*/\s+))
                              rb_define_attr\((?:\s*#{var_name},)?\s*
                                              "#{attr_name}"\s*,
                                              #{rw}\)\s*;%xm then
              $1
            elsif @content =~ %r%((?>/\*.*?\*/\s+))
                                 rb_attr\(\s*#{var_name}\s*,
                                          \s*#{attr_name}\s*,
                                          #{rw},.*?\)\s*;%xm then
              $1
            elsif @content =~ %r%(/\*.*?(?:\s*\*\s*)?)
                                 Document-attr:\s#{attr_name}\s*?\n
                                 ((?>(.|\n)*?\*/))%x then
              "#{$1}\n#{$2}"
            else
              ''
            end

  RDoc::Comment.new comment, @top_level
end

# File lib/rdoc/parser/c.rb, line 638
def find_body class_name, meth_name, meth_obj, file_content, quiet = false
  if file_content
    @body_table ||= {}
    @body_table[file_content] ||= gen_body_table file_content
    type, *args = @body_table[file_content][meth_name]
  end

  case type
  when :func_def
    comment = RDoc::Comment.new args[0], @top_level
    body = args[1]
    offset, = args[2]

    comment.remove_private if comment

    # try to find the whole body
    body = $& if /#{Regexp.escape body}[^(]*?\{.*?^\}/m =~ file_content

    # The comment block may have been overridden with a 'Document-method'
    # block. This happens in the interpreter when multiple methods are
    # vectored through to the same C method but those methods are logically
    # distinct (for example Kernel.hash and Kernel.object_id share the same
    # implementation

    override_comment = find_override_comment class_name, meth_obj
    comment = override_comment if override_comment

    comment.normalize
    find_modifiers comment, meth_obj if comment

    #meth_obj.params = params
    meth_obj.start_collecting_tokens
    tk = { :line_no => 1, :char_no => 1, :text => body }
    meth_obj.add_token tk
    meth_obj.comment = comment
    meth_obj.line    = file_content[0, offset].count("\n") + 1

    body
  when :macro_def
    comment = RDoc::Comment.new args[0], @top_level
    body = args[1]
    offset, = args[2]

    find_body class_name, args[3], meth_obj, file_content, true

    comment.normalize
    find_modifiers comment, meth_obj

    meth_obj.start_collecting_tokens
    tk = { :line_no => 1, :char_no => 1, :text => body }
    meth_obj.add_token tk
    meth_obj.comment = comment
    meth_obj.line    = file_content[0, offset].count("\n") + 1

    body
  when :macro_alias
    # with no comment we hope the aliased definition has it and use it's
    # definition

    body = find_body(class_name, args[0], meth_obj, file_content, true)

    return body if body

    @options.warn "No definition for #{meth_name}"
    false
  else # No body, but might still have an override comment
    comment = find_override_comment class_name, meth_obj

    if comment then
      comment.normalize
      find_modifiers comment, meth_obj
      meth_obj.comment = comment

      ''
    else
      @options.warn "No definition for #{meth_name}"
      false
    end
  end
end

# File lib/rdoc/parser/c.rb, line 722
def find_class(raw_name, name)
  unless @classes[raw_name]
    if raw_name =~ /^rb_m/
      container = @top_level.add_module RDoc::NormalModule, name
    else
      container = @top_level.add_class RDoc::NormalClass, name
    end

    container.record_location @top_level
    @classes[raw_name] = container
  end
  @classes[raw_name]
end

# File lib/rdoc/parser/c.rb, line 762
def find_class_comment class_name, class_mod
  comment = nil

  if @content =~ %r%
      ((?>/\*.*?\*/\s+))
      (static\s+)?
      void\s+
      Init_#{class_name}\s*(?:_\(\s*)?\(\s*(?:void\s*)?\)%xmi then
    comment = $1.sub(%r%Document-(?:class|module):\s+#{class_name}%, '')
  elsif @content =~ %r%Document-(?:class|module):\s+#{class_name}\s*?
                       (?:<\s+[:,\w]+)?\n((?>.*?\*/))%xm then
    comment = "/*\n#{$1}"
  elsif @content =~ %r%((?>/\*.*?\*/\s+))
                       ([\w\.\s]+\s* = \s+)?rb_define_(class|module)[\t (]*?"(#{class_name})"%xm then
    comment = $1
  elsif @content =~ %r%((?>/\*.*?\*/\s+))
                       ([\w\. \t]+ = \s+)?rb_define_(class|module)_under[\t\w, (]*?"(#{class_name.split('::').last})"%xm then
    comment = $1
  else
    comment = ''
  end

  comment = RDoc::Comment.new comment, @top_level
  comment.normalize

  look_for_directives_in class_mod, comment

  class_mod.add_comment comment, @top_level
end

# File lib/rdoc/parser/c.rb, line 818
def find_const_comment(type, const_name, class_name = nil)
  @const_table ||= {}
  @const_table[@content] ||= gen_const_table @content
  table = @const_table[@content]

  comment =
    table[[type, const_name]] ||
    (class_name && table[class_name + "::" + const_name]) ||
    table[const_name] ||
    ''

  RDoc::Comment.new comment, @top_level
end

# File lib/rdoc/parser/c.rb, line 835
def find_modifiers comment, meth_obj
  comment.normalize
  comment.extract_call_seq meth_obj

  look_for_directives_in meth_obj, comment
end

# File lib/rdoc/parser/c.rb, line 845
def find_override_comment class_name, meth_obj
  name = Regexp.escape meth_obj.name
  prefix = Regexp.escape meth_obj.name_prefix

  comment = if @content =~ %r%Document-method:
                              \s+#{class_name}#{prefix}#{name}
                              \s*?\n((?>.*?\*/))%xm then
              "/*#{$1}"
            elsif @content =~ %r%Document-method:
                                 \s#{name}\s*?\n((?>.*?\*/))%xm then
              "/*#{$1}"
            end

  return unless comment

  RDoc::Comment.new comment, @top_level
end

# File lib/rdoc/parser/c.rb, line 613
def gen_body_table file_content
  table = {}
  file_content.scan(%r{
    ((?>/\*.*?\*/\s*)?)
    ((?:(?:\w+)\s+)?
      (?:intern\s+)?VALUE\s+(\w+)
      \s*(?:\([^)]*\))(?:[^;]|$))
  | ((?>/\*.*?\*/\s*))^\s*(\#\s*define\s+(\w+)\s+(\w+))
  | ^\s*\#\s*define\s+(\w+)\s+(\w+)
  }xm) do
    case
    when $1
      table[$3] = [:func_def, $1, $2, $~.offset(2)] if !table[$3] || table[$3][0] != :func_def
    when $4
      table[$6] = [:macro_def, $4, $5, $~.offset(5), $7] if !table[$6] || table[$6][0] == :macro_alias
    when $8
      table[$8] ||= [:macro_alias, $9]
    end
  end
  table
end

# File lib/rdoc/parser/c.rb, line 795
def gen_const_table file_content
  table = {}
  @content.scan(%r{
    ((?>^\s*/\*.*?\*/\s+))
      rb_define_(\w+)\((?:\s*(?:\w+),)?\s*
                         "(\w+)"\s*,
                         .*?\)\s*;
  | Document-(?:const|global|variable):\s
      ((?:\w+::)*\w+)
      \s*?\n((?>.*?\*/))
  }mxi) do
    case
    when $1 then table[[$2, $3]] = $1
    when $4 then table[$4] = "/*\n" + $5
    end
  end
  table
end

# File lib/rdoc/parser/c.rb, line 867
def handle_attr(var_name, attr_name, read, write)
  rw = ''
  rw += 'R' if '1' == read
  rw += 'W' if '1' == write

  class_name = @known_classes[var_name]

  return unless class_name

  class_obj = find_class var_name, class_name

  return unless class_obj

  comment = find_attr_comment var_name, attr_name
  comment.normalize

  name = attr_name.gsub(/rb_intern(?:_const)?\("([^"]+)"\)/, '\1')

  attr = RDoc::Attr.new '', name, rw, comment

  attr.record_location @top_level
  class_obj.add_attribute attr
  @stats.add_attribute attr
end

# File lib/rdoc/parser/c.rb, line 896
def handle_class_module(var_name, type, class_name, parent, in_module)
  parent_name = @known_classes[parent] || parent

  if in_module then
    enclosure = @classes[in_module] || @store.find_c_enclosure(in_module)

    if enclosure.nil? and enclosure = @known_classes[in_module] then
      enc_type = /^rb_m/ =~ in_module ? :module : :class
      handle_class_module in_module, enc_type, enclosure, nil, nil
      enclosure = @classes[in_module]
    end

    unless enclosure then
      @enclosure_dependencies[in_module] << var_name
      @missing_dependencies[var_name] =
        [var_name, type, class_name, parent, in_module]

      return
    end
  else
    enclosure = @top_level
  end

  if type == :class then
    full_name = if RDoc::ClassModule === enclosure then
                  enclosure.full_name + "::#{class_name}"
                else
                  class_name
                end

    if @content =~ %r%Document-class:\s+#{full_name}\s*<\s+([:,\w]+)% then
      parent_name = $1
    end

    cm = enclosure.add_class RDoc::NormalClass, class_name, parent_name
  else
    cm = enclosure.add_module RDoc::NormalModule, class_name
  end

  cm.record_location enclosure.top_level

  find_class_comment cm.full_name, cm

  case cm
  when RDoc::NormalClass
    @stats.add_class cm
  when RDoc::NormalModule
    @stats.add_module cm
  end

  @classes[var_name] = cm
  @known_classes[var_name] = cm.full_name
  @store.add_c_enclosure var_name, cm
end

# File lib/rdoc/parser/c.rb, line 961
def handle_constants(type, var_name, const_name, definition)
  class_name = @known_classes[var_name]

  return unless class_name

  class_obj = find_class var_name, class_name

  unless class_obj then
    @options.warn 'Enclosing class or module %p is not known' % [const_name]
    return
  end

  comment = find_const_comment type, const_name, class_name
  comment.normalize

  # In the case of rb_define_const, the definition and comment are in
  # "/* definition: comment */" form.  The literal ':' and '\' characters
  # can be escaped with a backslash.
  if type.downcase == 'const' then
    no_match, new_definition, new_comment = comment.text.split(/(\A.*):/)

    if no_match and no_match.empty? then
      if new_definition.empty? then # Default to literal C definition
        new_definition = definition
      else
        new_definition = new_definition.gsub("\:", ":")
        new_definition = new_definition.gsub("\\", '\')
      end

      new_definition.sub!(/\A(\s+)/, '')

      new_comment = "#{$1}#{new_comment.lstrip}"

      new_comment = RDoc::Comment.new new_comment, @top_level

      con = RDoc::Constant.new const_name, new_definition, new_comment
    else
      con = RDoc::Constant.new const_name, definition, comment
    end
  else
    con = RDoc::Constant.new const_name, definition, comment
  end

  con.record_location @top_level
  @stats.add_constant con
  class_obj.add_constant con
end

# File lib/rdoc/parser/c.rb, line 1012
def handle_ifdefs_in(body)
  body.gsub(/^#ifdef HAVE_PROTOTYPES.*?#else.*?\n(.*?)#endif.*?\n/m, '\1')
end

# File lib/rdoc/parser/c.rb, line 1021
def handle_method(type, var_name, meth_name, function, param_count,
                  source_file = nil)
  class_name = @known_classes[var_name]
  singleton  = @singleton_classes.key? var_name

  @methods[var_name][function] << meth_name

  return unless class_name

  class_obj = find_class var_name, class_name

  if class_obj then
    if meth_name == 'initialize' then
      meth_name = 'new'
      singleton = true
      type = 'method' # force public
    end

    meth_obj = RDoc::AnyMethod.new '', meth_name
    meth_obj.c_function = function
    meth_obj.singleton =
      singleton || %w[singleton_method module_function].include?(type)

    p_count = Integer(param_count) rescue -1

    if source_file then
      file_name = File.join @file_dir, source_file

      if File.exist? file_name then
        file_content = File.read file_name
      else
        @options.warn "unknown source #{source_file} for #{meth_name} in #{@file_name}"
      end
    else
      file_content = @content
    end

    body = find_body class_name, function, meth_obj, file_content

    if body and meth_obj.document_self then
      meth_obj.params = if p_count < -1 then # -2 is Array
                          '(*args)'
                        elsif p_count == -1 then # argc, argv
                          rb_scan_args body
                        else
                          "(#{(1..p_count).map { |i| "p#{i}" }.join ', '})"
                        end


      meth_obj.record_location @top_level
      class_obj.add_method meth_obj
      @stats.add_method meth_obj
      meth_obj.visibility = :private if 'private_method' == type
    end
  end
end

# File lib/rdoc/parser/c.rb, line 1081
def handle_singleton sclass_var, class_var
  class_name = @known_classes[class_var]

  @known_classes[sclass_var]     = class_name
  @singleton_classes[sclass_var] = class_name
end

# File lib/rdoc/parser/c.rb, line 1091
def handle_tab_width(body)
  if /\t/ =~ body
    tab_width = @options.tab_width
    body.split(/\n/).map do |line|
      1 while line.gsub!(/\t+/) do
        ' ' * (tab_width * $&.length - $`.length % tab_width)
      end && $~
      line
    end.join "\n"
  else
    body
  end
end

# File lib/rdoc/parser/c.rb, line 1109
def load_variable_map map_name
  return {} unless files = @store.cache[map_name]
  return {} unless name_map = files[@file_name]

  class_map = {}

  name_map.each do |variable, name|
    next unless mod = @store.find_class_or_module(name)

    class_map[variable] = if map_name == :c_class_variables then
                            mod
                          else
                            name
                          end
    @known_classes[variable] = name
  end

  class_map
end

# File lib/rdoc/parser/c.rb, line 1138
def look_for_directives_in context, comment
  @preprocess.handle comment, context do |directive, param|
    case directive
    when 'main' then
      @options.main_page = param
      ''
    when 'title' then
      @options.default_title = param if @options.respond_to? :default_title=
      ''
    end
  end

  comment
end

# File lib/rdoc/parser/c.rb, line 1157
def rb_scan_args method_body
  method_body =~ /rb_scan_args\((.*?)\)/m
  return '(*args)' unless $1

  $1.split(/,/)[2] =~ /"(.*?)"/ # format argument
  format = $1.split(//)

  lead = opt = trail = 0

  if format.first =~ /\d/ then
    lead = $&.to_i
    format.shift
    if format.first =~ /\d/ then
      opt = $&.to_i
      format.shift
      if format.first =~ /\d/ then
        trail = $&.to_i
        format.shift
        block_arg = true
      end
    end
  end

  if format.first == '*' and not block_arg then
    var = true
    format.shift
    if format.first =~ /\d/ then
      trail = $&.to_i
      format.shift
    end
  end

  if format.first == ':' then
    hash = true
    format.shift
  end

  if format.first == '&' then
    block = true
    format.shift
  end

  # if the format string is not empty there's a bug in the C code, ignore it

  args = []
  position = 1

  (1...(position + lead)).each do |index|
    args << "p#{index}"
  end

  position += lead

  (position...(position + opt)).each do |index|
    args << "p#{index} = v#{index}"
  end

  position += opt

  if var then
    args << '*args'
    position += 1
  end

  (position...(position + trail)).each do |index|
    args << "p#{index}"
  end

  position += trail

  if hash then
    args << "p#{position} = {}"
  end

  args << '&block' if block

  "(#{args.join ', '})"
end

# File lib/rdoc/parser/c.rb, line 1240
def remove_commented_out_lines
  @content = @content.gsub(%r%//.*rb_define_%, '//')
end

# File lib/rdoc/parser/c.rb, line 1248
def scan
  remove_commented_out_lines

  do_modules
  do_classes
  do_missing

  do_constants
  do_methods
  do_includes
  do_aliases
  do_attrs

  deduplicate_call_seq

  @store.add_c_variables self

  @top_level
end