module Fiddle::CParser

A mixin that provides methods for parsing C struct and prototype signatures.

Example¶ ↑

require 'fiddle/import'

include Fiddle::CParser
  #=> Object

parse_ctype('int')
  #=> Fiddle::TYPE_INT

parse_struct_signature(['int i', 'char c'])
  #=> [[Fiddle::TYPE_INT, Fiddle::TYPE_CHAR], ["i", "c"]]

parse_signature('double sum(double, double)')
  #=> ["sum", Fiddle::TYPE_DOUBLE, [Fiddle::TYPE_DOUBLE, Fiddle::TYPE_DOUBLE]]

Public Instance Methods

parse_ctype(ty, tymap=nil) click to toggle source

Given a String of C type ty, returns the corresponding Fiddle constant.

ty can also accept an Array of C type Strings, and will be returned in a corresponding Array.

If Hash tymap is provided, ty is expected to be the key, and the value will be the C type to be looked up.

Example:

require 'fiddle/import'

include Fiddle::CParser
  #=> Object

parse_ctype('int')
  #=> Fiddle::TYPE_INT

parse_ctype('double diff')
  #=> Fiddle::TYPE_DOUBLE

parse_ctype('unsigned char byte')
  #=> -Fiddle::TYPE_CHAR

parse_ctype('const char* const argv[]')
  #=> -Fiddle::TYPE_VOIDP

# File fiddle/lib/fiddle/cparser.rb, line 124
def parse_ctype(ty, tymap=nil)
  tymap ||= {}
  case ty
  when Array
    return [parse_ctype(ty[0], tymap), ty[1]]
  when 'void'
    return TYPE_VOID
  when /^(?:(?:signed\s+)?long\s+long(?:\s+int\s+)?|int64_t)(?:\s+\w+)?$/
    if( defined?(TYPE_LONG_LONG) )
      return TYPE_LONG_LONG
    else
      raise(RuntimeError, "unsupported type: #{ty}")
    end
  when /^(?:unsigned\s+long\s+long(?:\s+int\s+)?|uint64_t)(?:\s+\w+)?$/
    if( defined?(TYPE_LONG_LONG) )
      return -TYPE_LONG_LONG
    else
      raise(RuntimeError, "unsupported type: #{ty}")
    end
  when /^(?:signed\s+)?long(?:\s+int\s+)?(?:\s+\w+)?$/
    return TYPE_LONG
  when /^unsigned\s+long(?:\s+int\s+)?(?:\s+\w+)?$/
    return -TYPE_LONG
  when /^(?:signed\s+)?int(?:\s+\w+)?$/
    return TYPE_INT
  when /^(?:unsigned\s+int|uint)(?:\s+\w+)?$/
    return -TYPE_INT
  when /^(?:signed\s+)?short(?:\s+int\s+)?(?:\s+\w+)?$/
    return TYPE_SHORT
  when /^unsigned\s+short(?:\s+int\s+)?(?:\s+\w+)?$/
    return -TYPE_SHORT
  when /^(?:signed\s+)?char(?:\s+\w+)?$/
    return TYPE_CHAR
  when /^unsigned\s+char(?:\s+\w+)?$/
    return  -TYPE_CHAR
  when /^float(?:\s+\w+)?$/
    return TYPE_FLOAT
  when /^double(?:\s+\w+)?$/
    return TYPE_DOUBLE
  when /^size_t(?:\s+\w+)?$/
    return TYPE_SIZE_T
  when /^ssize_t(?:\s+\w+)?$/
    return TYPE_SSIZE_T
  when /^ptrdiff_t(?:\s+\w+)?$/
    return TYPE_PTRDIFF_T
  when /^intptr_t(?:\s+\w+)?$/
    return TYPE_INTPTR_T
  when /^uintptr_t(?:\s+\w+)?$/
    return TYPE_UINTPTR_T
  when /\*/, /\[[\s\d]*\]/
    return TYPE_VOIDP
  else
    ty = ty.split(' ', 2)[0]
    if( tymap[ty] )
      return parse_ctype(tymap[ty], tymap)
    else
      raise(DLError, "unknown type: #{ty}")
    end
  end
end

parse_signature(signature, tymap=nil) click to toggle source

Parses a C prototype signature

If Hash tymap is provided, the return value and the arguments from the signature are expected to be keys, and the value will be the C type to be looked up.

Example:

require 'fiddle/import'

include Fiddle::CParser
  #=> Object

parse_signature('double sum(double, double)')
  #=> ["sum", Fiddle::TYPE_DOUBLE, [Fiddle::TYPE_DOUBLE, Fiddle::TYPE_DOUBLE]]

parse_signature('void update(void (*cb)(int code))')
  #=> ["update", Fiddle::TYPE_VOID, [Fiddle::TYPE_VOIDP]]

parse_signature('char (*getbuffer(void))[80]')
  #=> ["getbuffer", Fiddle::TYPE_VOIDP, []]

# File fiddle/lib/fiddle/cparser.rb, line 84
def parse_signature(signature, tymap=nil)
  tymap ||= {}
  case compact(signature)
  when /^(?:[\w\*\s]+)\(\*(\w+)\((.*?)\)\)(?:\[\w*\]|\(.*?\));?$/
    func, args = $1, $2
    return [func, TYPE_VOIDP, split_arguments(args).collect {|arg| parse_ctype(arg, tymap)}]
  when /^([\w\*\s]+[\*\s])(\w+)\((.*?)\);?$/
    ret, func, args = $1.strip, $2, $3
    return [func, parse_ctype(ret, tymap), split_arguments(args).collect {|arg| parse_ctype(arg, tymap)}]
  else
    raise(RuntimeError,"can't parse the function prototype: #{signature}")
  end
end

parse_struct_signature(signature, tymap=nil) click to toggle source

Parses a C struct’s members

Example:

require 'fiddle/import'

include Fiddle::CParser
  #=> Object

parse_struct_signature(['int i', 'char c'])
  #=> [[Fiddle::TYPE_INT, Fiddle::TYPE_CHAR], ["i", "c"]]

parse_struct_signature(['char buffer[80]'])
  #=> [[[Fiddle::TYPE_CHAR, 80]], ["buffer"]]

# File fiddle/lib/fiddle/cparser.rb, line 35
def parse_struct_signature(signature, tymap=nil)
  if signature.is_a?(String)
    signature = split_arguments(signature, /[,;]/)
  end
  mems = []
  tys  = []
  signature.each{|msig|
    msig = compact(msig)
    case msig
    when /^[\w\*\s]+[\*\s](\w+)$/
      mems.push($1)
      tys.push(parse_ctype(msig, tymap))
    when /^[\w\*\s]+\(\*(\w+)\)\(.*?\)$/
      mems.push($1)
      tys.push(parse_ctype(msig, tymap))
    when /^([\w\*\s]+[\*\s])(\w+)\[(\d+)\]$/
      mems.push($2)
      tys.push([parse_ctype($1.strip, tymap), $3.to_i])
    when /^([\w\*\s]+)\[(\d+)\](\w+)$/
      mems.push($3)
      tys.push([parse_ctype($1.strip, tymap), $2.to_i])
    else
      raise(RuntimeError,"can't parse the struct member: #{msig}")
    end
  }
  return tys, mems
end

Private Instance Methods

compact(signature) click to toggle source

# File fiddle/lib/fiddle/cparser.rb, line 192
def compact(signature)
  signature.gsub(/\s+/, ' ').gsub(/\s*([\(\)\[\]\*,;])\s*/, '\1').strip
end

split_arguments(arguments, sep=',') click to toggle source

# File fiddle/lib/fiddle/cparser.rb, line 187
def split_arguments(arguments, sep=',')
  return [] if arguments.strip == 'void'
  arguments.scan(/([\w\*\s]+\(\*\w*\)\(.*?\)|[\w\*\s\[\]]+)(?:#{sep}\s*|$)/).collect {|m| m[0]}
end