115 lines
3.3 KiB
Ruby
115 lines
3.3 KiB
Ruby
# $Id: vt.rb 14 2008-03-02 05:42:30Z warchild $
|
|
#
|
|
# Copyright (c) 2008, Jon Hart
|
|
# All rights reserved.
|
|
#
|
|
# Redistribution and use in source and binary forms, with or without
|
|
# modification, are permitted provided that the following conditions are met:
|
|
# * Redistributions of source code must retain the above copyright
|
|
# notice, this list of conditions and the following disclaimer.
|
|
# * Redistributions in binary form must reproduce the above copyright
|
|
# notice, this list of conditions and the following disclaimer in the
|
|
# documentation and/or other materials provided with the distribution.
|
|
# * Neither the name of the <organization> nor the
|
|
# names of its contributors may be used to endorse or promote products
|
|
# derived from this software without specific prior written permission.
|
|
#
|
|
# THIS SOFTWARE IS PROVIDED BY Jon Hart ``AS IS'' AND ANY
|
|
# EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
|
|
# WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
|
|
# DISCLAIMED. IN NO EVENT SHALL Jon Hart BE LIABLE FOR ANY
|
|
# DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
|
|
# (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
|
|
# LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
|
|
# ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
|
|
# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
|
|
# SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
|
|
#
|
|
module Racket
|
|
module Misc
|
|
# Simple class to represent a datastructure that is made up of a
|
|
# null terminted string followed by an arbitrary number of
|
|
# arbitrarily sized values, followed by a "rest" field.
|
|
class VT
|
|
# the value for this VT object
|
|
attr_accessor :value
|
|
# the array of types for this VT object
|
|
attr_accessor :types
|
|
# everything else
|
|
attr_accessor :rest
|
|
|
|
# Create a new VT which consists of a null terminated string
|
|
# followed by some number of arbitrarily sized values, as
|
|
# specified by +args+
|
|
def initialize(*args)
|
|
@lengths = args
|
|
@types = []
|
|
@value = ""
|
|
end
|
|
|
|
# Given +data+, return the value and an array
|
|
# of the types as dictated by this instance
|
|
def decode(data)
|
|
null = data.index(0x00)
|
|
value = data.unpack("a#{null}")[0]
|
|
data = data.slice(null+1, data.length)
|
|
|
|
n = 0
|
|
types = []
|
|
@lengths.each do |l|
|
|
types[n] = data.unpack("#{punpack_string(l)}")[0]
|
|
data = data.slice(l, data.length)
|
|
n += 1
|
|
end
|
|
|
|
[value, types, data]
|
|
end
|
|
|
|
# Given +data+, set the +value+ and +types+ array
|
|
# accordingly
|
|
def decode!(data)
|
|
@value, @types, @rest = self.decode(data)
|
|
end
|
|
|
|
# Return a string suitable for use elsewhere
|
|
def encode
|
|
s = "#{@value}\000"
|
|
|
|
n = 0
|
|
@lengths.each do |l|
|
|
s << [@types[n]].pack("#{punpack_string(l)}")
|
|
n += 1
|
|
end
|
|
s
|
|
end
|
|
|
|
def to_s
|
|
encode
|
|
end
|
|
|
|
def to_str
|
|
encode
|
|
end
|
|
|
|
private
|
|
# XXX: make this handle arbitrarily sized fields
|
|
def punpack_string(size)
|
|
s = ""
|
|
case size
|
|
when 1
|
|
s << "C"
|
|
when 2
|
|
s << "n"
|
|
when 4
|
|
s << "N"
|
|
else
|
|
raise ArgumentError, "Size #{s} not supported"
|
|
end
|
|
s
|
|
end
|
|
|
|
end
|
|
end
|
|
end
|
|
# vim: set ts=2 et sw=2:
|