module Spruz::FileBinary

Attributes

default_options[RW]

Default options can be queried/set via this hash.

Public Instance Methods

ascii?(options = {}) click to toggle source

Returns true if #binary? returns false, false if #binary? returns true, and nil otherwise. For an explanation of options, see #binary?.

# File lib/spruz/file_binary.rb, line 55
def ascii?(options = {})
  case binary?(options)
  when true   then false
  when false  then true
  end
end
binary?(options = {}) click to toggle source

Returns true if this file is considered to be binary, false if it is not considered to be binary, and nil if it was empty.

A file is considered to be binary if the percentage of zeros exceeds options[:percentage_zeros] or the percentage of binary bytes (8-th bit is 1) exceeds options[:percentage_binary] in the buffer of size options[:buffer_size] that is checked (beginning from offset options[:offset]). If an option isn’t given the one from ::default_options is used instead.

# File lib/spruz/file_binary.rb, line 37
def binary?(options = {})
  options |= FileBinary.default_options
  old_pos = tell
  seek options[:offset], Constants::SEEK_SET
  data = read options[:buffer_size]
  !data or data.empty? and return nil
  data_size = data.size
  data.count(Constants::ZERO).to_f / data_size >
    options[:percentage_zeros] / 100.0 and return true
  data.count(Constants::BINARY).to_f / data_size >
    options[:percentage_binary] / 100.0
ensure
  old_pos and seek old_pos, Constants::SEEK_SET
end

Public Class Methods

included(modul) click to toggle source 
# File lib/spruz/file_binary.rb, line 62
def self.included(modul)
  modul.instance_eval do
    extend ClassMethods
  end
  super
end