class Filesize

Constants

BINARY: Set of rules describing file sizes according to binary units.
CD: The size of a CD
DVD: The same as a DVD 5
DVD_10: The size of a double-sided single-layer DVD
DVD_14: The size of a double-sided DVD, combining a DVD-9 and a DVD-5
DVD_18: The size of a double-sided dual-layer DVD
DVD_5: The size of a common DVD
DVD_9: The size of a single-sided dual-layer DVD
Floppy: The size of a floppy disk
PREFIXES: @deprecated Please use TYPE_PREFIXES instead
SI: Set of rules describing file sizes according to SI units.
TYPE_PREFIXES
ZIP: The size of a Zip disk

Public Class Methods

from(arg) click to toggle source

Parses a string, which describes a file size, and returns a Filesize object.

@param [String] arg A file size to parse. @raise [ArgumentError] Raised if the file size cannot be parsed properly. @return [Filesize]

# File lib/filesize.rb, line 129
def from(arg)
  parts  = parse(arg)
  prefix = parts[:prefix]
  size   = parts[:size]
  type   = parts[:type]

  raise ArgumentError, "Unparseable filesize" unless type

  offset = (type[:prefixes].map { |s| s[0].chr.downcase }.index(prefix.downcase) || -1) + 1

  new(size * (type[:multiplier] ** (offset)), type)
end

new(size, type = BINARY) click to toggle source

@param [Number] size A file size, in bytes. @param [SI, BINARY] type Which type to use for conversions.

# File lib/filesize.rb, line 31
def initialize(size, type = BINARY)
  @bytes = size.to_i
  @type  = type
end

parse(string) click to toggle source

@return [Hash<:prefix, :size, :type>] @api private

# File lib/filesize.rb, line 144
def parse(string)
  type = nil
  # in this order, so we prefer binary :)
  [BINARY, SI].each { |_type|
    if string =~ _type[:regexp]
      type    =  _type
      break
    end
  }

  prefix = $2 || ''
  size   = ($1 || 0).to_f

  return { :prefix => prefix, :size => size, :type => type}
end

Public Instance Methods

*(other) click to toggle source

@return [Filesize]

# File lib/filesize.rb, line 98
def *(other)
  self.class.new(@bytes * other.to_i, @type)
end

+(other) click to toggle source

@return [Filesize]

# File lib/filesize.rb, line 88
def +(other)
  self.class.new(@bytes + other.to_i, @type)
end

-(other) click to toggle source

@return [Filesize]

# File lib/filesize.rb, line 93
def -(other)
  self.class.new(@bytes - other.to_i, @type)
end

/(other) click to toggle source

@return [Filesize]

# File lib/filesize.rb, line 103
def /(other)
  result = @bytes / other.to_f
  if other.is_a? Filesize
    result
  else
    self.class.new(result, @type)
  end
end

<=>(other) click to toggle source

# File lib/filesize.rb, line 112
def <=>(other)
  self.to_i <=> other.to_i
end

coerce(other) click to toggle source

@return [Array<self, other>] @api private

# File lib/filesize.rb, line 118
def coerce(other)
  return self, other
end

pretty() click to toggle source

Same as {#to_s} but with an automatic determination of the most sensible unit.

@return [String] @see to_s

# File lib/filesize.rb, line 73
def pretty
  size = @bytes
  if size < @type[:multiplier]
    unit = "B"
  else
    pos = (Math.log(size) / Math.log(@type[:multiplier])).floor
    pos = @type[:prefixes].size-1 if pos > @type[:prefixes].size - 1

    unit = @type[:prefixes][pos-1] + "B"
  end

  to_s(unit)
end

to(unit = 'B') click to toggle source

@param [String] unit Which unit to convert to. @return [Float] Returns the size in a given unit.

# File lib/filesize.rb, line 44
def to(unit = 'B')
  to_parts = self.class.parse(unit)
  prefix   = to_parts[:prefix]

  if prefix == 'B' or prefix.empty?
    return to_i.to_f
  end

  to_type = to_parts[:type]
  size    = @bytes

  pos = (@type[:prefixes].map { |s| s[0].chr.downcase }.index(prefix.downcase) || -1) + 1

  size = size/(to_type[:multiplier].to_f**(pos)) unless pos < 1
end

Also aliased as: to_f

to_f(unit = 'B')

Alias for: to

to_i() click to toggle source

@return [Number] Returns the size in bytes.

# File lib/filesize.rb, line 37
def to_i
  @bytes
end

Also aliased as: to_int

to_int()

Alias for: to_i

to_s(unit = 'B') click to toggle source

@param (see to_f) @return [String] Same as {#to_f}, but as a string, with the unit appended. @see to_f

# File lib/filesize.rb, line 64
def to_s(unit = 'B')
  "%.2f %s" % [to(unit).to_f.to_s, unit]
end