Sha256: 5afd68460df248be579da351fdb36e078daf0343b31368ae261fd842a18e9297
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Versions: 15
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Stored size: 1.39 KB
Contents
module ZPNG
module ReadableStruct
def self.new fmt, *args
size = fmt.scan(/([a-z])(\d*)/i).map do |f,len|
[len.to_i, 1].max *
case f
when /[aAC]/ then 1
when 'v' then 2
when 'V','l' then 4
when 'Q' then 8
else raise "unknown fmt #{f.inspect}"
end
end.inject(&:+)
Struct.new( *args ).tap do |x|
x.const_set 'FORMAT', fmt
x.const_set 'SIZE', size
x.class_eval do
include InstanceMethods
end
x.extend ClassMethods
end
end
module ClassMethods
# src can be IO or String, or anything that responds to :read or :unpack
def read src, size = nil
size ||= const_get 'SIZE'
data =
if src.respond_to?(:read)
src.read(size).to_s
elsif src.respond_to?(:unpack)
src
else
raise "[?] don't know how to read from #{src.inspect}"
end
if data.size < size
$stderr.puts "[!] #{self.to_s} want #{size} bytes, got #{data.size}"
end
new(*data.unpack(const_get('FORMAT')))
end
end
module InstanceMethods
def pack
to_a.pack self.class.const_get('FORMAT')
end
def empty?
to_a.all?{ |t| t == 0 || t.nil? || t.to_s.tr("\x00","").empty? }
end
end
end # ReadableStruct
end # ZPNG
Version data entries
15 entries across 15 versions & 1 rubygems