LogAn/lib/cstruct.rb

49 lines
1.3 KiB
Ruby

class CStruct
def self.new *p
pre = p.pop if p.last.kind_of? Hash
Class.new do
include CStruct::Mix
eval <<-EOF
attr_accessor #{p.map{|n,v| ":#{n}" }.join', '}
def self._directives
["#{p.map{|n,v|"#{v}"}.join}", #{post}]
end
def initialize data = nil
#{p.map{|n,v|"@#{n}"}.join', '} = _parse data
end
def _create
super #{p.map{|n,v|"@#{n}"}.join', '}
end
EOF
end
end
end
module CStruct::Mix
def _parse data = nil
return unless data
pre, pos = self.class._directives
if pos.nil? or pos == 0 then data.unpack pre
elsif pos == 1 then data.unpack pre+'a*'
else
# Statisch lange Daten, Laengen von var und der Rest in var
(*dat, var) = data.unpack pre + ('N'*(pos-1)) + 'a*'
dat[ 0...-pos ] + # Statisch lange Daten
var.unpack( # Variabel lange Daten
dat[ -pos...-1 ].inject( data.length-var.length) {|i,j|
j.push i-j.last # Differenzieren
}.map {|i| "a#{i}" }.join) # Packstring zusammensetzen
end
end
def _create *data
pre, pos = self.class._directives
if pos.nil? or pos == 0 then data.pack pre
elsif pos == 1 then data.pack pre+'a*'
else
r = data[ 0...-pos ].pack pre
r += data[ -pos..-1 ].inject( [r.length]) {|i,j| j.push i+j.last}[1...-1].pack 'N*'
r + data[ -pos..-1 ].pack( 'a*'*(pos-1))
end
end
end