metasploit-framework/lib/racket/misc/lv.rb

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# $Id: lv.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 data structures that
# consist of an arbitrary number of length value pairs.
class LV
# An array containing the values parsed from this LV
attr_accessor :values
# The lengths of the values parsed from this LV
attr_accessor :lengths
# everything else
attr_accessor :rest
# Create a new LV object whose L sizes are specified in +args+
def initialize(*args)
@sizes = args
@values = []
@lengths = []
end
def decode(data)
n = 0
values = []
lengths = []
@sizes.each do |s|
# XXX: raise an error here if there is not enough data to
# unpack this next LV
lengths[n] = data.unpack("#{punpack_string(s)}")[0]
data = data.slice(s, data.length)
values[n] = data.unpack("a#{lengths[n]}")[0]
data = data.slice(lengths[n], data.length)
n += 1
end
# data now contains "rest"
[lengths, values, data]
end
def decode!(data)
@lengths, @values, @rest = self.decode(data)
end
def encode
n = 0
s = ""
@lengths.each do |l|
s << [l].pack("#{punpack_string(@sizes[n])}")
s << [@values[n]].pack("a#{l}")
n += 1
end
s
end
def to_s
encode
end
def to_str
encode
end
private
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
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