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 increment(int)')
  #=> ["increment", Fiddle::TYPE_INT, [Fiddle::TYPE_INT]]

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:

include Fiddle::CParser
  #=> Object

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

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

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

# File ext/fiddle/lib/fiddle/cparser.rb, line 116
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 "char"
    return TYPE_CHAR
  when "unsigned char"
    return  -TYPE_CHAR
  when "short"
    return TYPE_SHORT
  when "unsigned short"
    return -TYPE_SHORT
  when "int"
    return TYPE_INT
  when "unsigned int", 'uint'
    return -TYPE_INT
  when "long"
    return TYPE_LONG
  when "unsigned long"
    return -TYPE_LONG
  when "long long"
    if( defined?(TYPE_LONG_LONG) )
      return TYPE_LONG_LONG
    else
      raise(RuntimeError, "unsupported type: #{ty}")
    end
  when "unsigned long long"
    if( defined?(TYPE_LONG_LONG) )
      return -TYPE_LONG_LONG
    else
      raise(RuntimeError, "unsupported type: #{ty}")
    end
  when "float"
    return TYPE_FLOAT
  when "double"
    return TYPE_DOUBLE
  when "size_t"
    return TYPE_SIZE_T
  when "ssize_t"
    return TYPE_SSIZE_T
  when "ptrdiff_t"
    return TYPE_PTRDIFF_T
  when "intptr_t"
    return TYPE_INTPTR_T
  when "uintptr_t"
    return TYPE_UINTPTR_T
  when /\*/, /\[\s*\]/
    return TYPE_VOIDP
  else
    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:

include Fiddle::CParser
  #=> Object

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

# File ext/fiddle/lib/fiddle/cparser.rb, line 73
def parse_signature(signature, tymap=nil)
  tymap ||= {}
  signature = signature.gsub(/\s+/, " ").strip
  case signature
  when /^([\w@\*\s]+)\(([\w\*\s\,\[\]]*)\)$/
    ret = $1
    (args = $2).strip!
    ret = ret.split(/\s+/)
    args = args.split(/\s*,\s*/)
    func = ret.pop
    if( func =~ /^\*/ )
      func.gsub!(/^\*+/,"")
      ret.push("*")
    end
    ret  = ret.join(" ")
    return [func, parse_ctype(ret, tymap), 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:

include Fiddle::CParser
  #=> Object

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

# File ext/fiddle/lib/fiddle/cparser.rb, line 24
def parse_struct_signature(signature, tymap=nil)
  if( signature.is_a?(String) )
    signature = signature.split(/\s*,\s*/)
  end
  mems = []
  tys  = []
  signature.each{|msig|
    tks = msig.split(/\s+(\*)?/)
    ty = tks[0..-2].join(" ")
    member = tks[-1]

    case ty
    when /\[(\d+)\]/
      n = $1.to_i
      ty.gsub!(/\s*\[\d+\]/,"")
      ty = [ty, n]
    when /\[\]/
      ty.gsub!(/\s*\[\]/, "*")
    end

    case member
    when /\[(\d+)\]/
      ty = [ty, $1.to_i]
      member.gsub!(/\s*\[\d+\]/,"")
    when /\[\]/
      ty = ty + "*"
      member.gsub!(/\s*\[\]/, "")
    end

    mems.push(member)
    tys.push(parse_ctype(ty,tymap))
  }
  return tys, mems
end