# "THE BEER-WARE LICENSE" (Revision 42):
# Mu Security Research Labs wrote this file. As long as you retain this notice
# you can do whatever you want with this stuff. If we meet some day, and you
# think this stuff is worth it, you can buy us a beer in return. 
# http://www.musecurity.com
# http://labs.musecurity.com
class XDR::Parser
	token IDENTIFIER NUMBER A_NAME

rule
	xdr
		: definition
		| xdr definition


	definition
		: constant_def
		| type_def
		| program_def


	program_def
		: 'program' IDENTIFIER '{' program_body '}' '=' NUMBER ';'


	program_body
		: version_def              
		| program_body version_def


	version_def
		: 'version' IDENTIFIER '{' version_body '}' '=' NUMBER ';'


	version_body
		: procedure_def
		| version_body procedure_def


	procedure_def
		: return_def IDENTIFIER '(' argument_def ')' '=' NUMBER ';'

	return_def
		: type_specifier
		| 'void'


	argument_def
		: argument_list
		| 'void'


	argument_list
		: type_specifier
		| argument_list ',' type_specifier


	constant_def
		: 'const' IDENTIFIER '=' NUMBER ';'

	type_def
		: 'typedef' declaration ';'
		| 'struct' IDENTIFIER '{' struct_body '}' ';'
		| 'enum' IDENTIFIER '{' enum_body '}' ';'
		| 'union' IDENTIFIER union_body ';'

	declaration
		: type_specifier IDENTIFIER
		| type_specifier IDENTIFIER '[' value ']'
		| type_specifier IDENTIFIER '<' value '>'
		| type_specifier IDENTIFIER '<' '>'
		| type_specifier '*' IDENTIFIER
		| 'opaque' IDENTIFIER '[' value ']'
		| 'opaque' IDENTIFIER '<' value '>'
		| 'opaque' IDENTIFIER '<' '>'
		| 'string' IDENTIFIER '<' value '>'
		| 'string' IDENTIFIER '<' '>'
		| 'struct' IDENTIFIER '*' IDENTIFIER
		| 'struct' '{' struct_body '}'
		| 'enum' '{' enum_body '}'
		| 'union' union_body

	type_specifier
		: 'unsigned' 'int'
		| 'unsigned' 'long'
		| 'unsigned' 'hyper'
		| 'unsigned'
		| 'int'
		| 'long'
		| 'hyper'
		| 'float'
		| 'double'
		| 'bool'
		| 'char'
		| IDENTIFIER

	value
		: NUMBER
		| 'TRUE'
		| 'FALSE'
		| IDENTIFIER

	struct_body
		: declaration ';'
		| struct_body declaration ';'

	enum_body
		: IDENTIFIER '=' NUMBER
		| enum_body ',' IDENTIFIER '=' NUMBER

	union_body
		: 'switch' '(' declaration ')' '{' switch_body '}'

	switch_body
		: switch_case
		| switch_case switch_default
		| switch_body switch_case
		| switch_body switch_case switch_default

	switch_case
		: 'case' value ':' case_body ';'
		| 'case' value ':'

	switch_default
		: 'default' ':' case_body ';'

	case_body
		: declaration
		| 'void'

---- inner
	AUTHOR  = "Mu Security"
	VERSION = 0.1
	LICENSE = <<-EOL
	"THE BEER-WARE LICENSE" (Revision 42):
	Mu Security Research Labs wrote this file. As long as you retain this notice
	you can do whatever you want with this stuff. If we meet some day, and you
	think this stuff is worth it, you can buy us a beer in return. 
	http://www.musecurity.com
	http://labs.musecurity.com
	EOL

	def initialize str
		@str = str
	end

	def parse
		do_parse
	end

	RE_ML_COMMENT = /\A\/\*.*?\*\//m 
	RE_COMMENT    = /\A#.*\n/
	RE_XINCLUDE   = /\A%.*\n/
	RE_WHITESPACE = /\A\s+/
	RE_KEYWORDS   = /\A(program|version|const|typedef|enum|struct|switch|union|case|default)\b/
	RE_BOOLEAN    = /\A(TRUE|FALSE)\b/
	RE_TYPES      = /\A(opaque|string|void|unsigned|int|long|hyper|float|double|bool|char)\b/
	RE_HEX_NUMBER = /\A-?0x[a-fA-F0-9]+/
	RE_NUMBER     = /\A-?\d+/
	RE_IDENTIFIER = /\A[a-zA-Z][a-zA-Z0-9_]*/
	RE_MISC       = /\A.|\n/o

	def next_token
		token = nil
		while token.nil? and not @str.empty?
			case @str
			# multi-line comments, comments and xdr include's
			when RE_ML_COMMENT
			when RE_COMMENT
			when RE_XINCLUDE
			when RE_WHITESPACE

			# keywords
			when RE_KEYWORDS
				token = [ $&, $& ]

			# true|false
			when RE_BOOLEAN
				token = [ $&, $& ]

			# types
			when RE_TYPES
				token = [ $&, $& ]

			# base-16 number
			when RE_HEX_NUMBER
				token = [ :NUMBER, $&.to_i(0) ]

			# base-10 number
			when RE_NUMBER
				token = [ :NUMBER, $&.to_i ]

			# identifier
			when RE_IDENTIFIER
				token = [ :IDENTIFIER, $& ]

			# other characters
			when RE_MISC
				token = [ $&, $& ]
			end

			@str = $'
		end

		return token if token
		return [ false, '$end' ]
	end

---- footer
if __FILE__ == $0
    open(ARGV[0]) do |ios|
        parser = XDR::Parser.new(ios.read)
        parser.parse
    end
end