Module: FunWith::Files::Utils::ByteSize

Defined in:
lib/fun_with/files/utils/byte_size.rb

Constant Summary collapse

UNITS = 
{
  :B => 1,
  :KB => 1_000,
  :MB => 1_000_000,
  :GB => 1_000_000_000,
  :TB => 1_000_000_000_000,
  :PB => 1_000_000_000_000_000,
  :EB => 1_000_000_000_000_000_000,
  :ZB => 1_000_000_000_000_000_000_000
}
UNIT_STANDARDIZERS = 
{ "" => :B, "B" => :B, "b" => :B }

Instance Method Summary collapse

Instance Method Details

#convert(expr, units = :B) ⇒ Object 



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# File 'lib/fun_with/files/utils/byte_size.rb', line 35

def convert( expr, units = :B )
  to_units( to_bytes( expr ), units )
end

#humanize_bytes(bytes) ⇒ Object 



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# File 'lib/fun_with/files/utils/byte_size.rb', line 96

def humanize_bytes( bytes )
  return "?" unless bytes.is_a?( Integer ) && bytes >= 0
    
  bytes = bytes.to_f
    
  if bytes > 1_000_000_000
    exp = "G"
    amt = bytes / 1_000_000_000
  elsif bytes > 1_000_000
    exp = "M"
    amt = bytes / 1_000_000
  elsif bytes > 1_000
    exp = "K"
    amt = bytes / 1_000
  else
    exp = "B"
    amt = bytes
  end
    
  if amt > 10
    digits = 0
  elsif amt > 1
    digits = 1
  end
    
  sprintf( "%0.#{digits}f", amt ) + exp
end

#limited_precision_value(f, d) ⇒ Object

returns a string of numbers, representing the float d - number of figures after the zero (max)



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# File 'lib/fun_with/files/utils/byte_size.rb', line 126

def limited_precision_value( f, d )
  # 4, 1234.5 -> 1234
  # 4, 123.45 -> 123.4
  # 4, 12.3423 -> 12.34
  # 4, 0.0001  -> 0.0001 ->  - 1234.5, 123.45, 12.345, 1.2345 0.1234 0.0123
  # 2 - 1234, 123, 12.3, 1.23, 0.12, 0.01
  # 1 - 12.3, 12, 1
  # 0 - 12, 1, 0
  #
  #
  #
  #
  #
end

#standardize_unit(unit) ⇒ Object 



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# File 'lib/fun_with/files/utils/byte_size.rb', line 83

def standardize_unit( unit )
  # So the caller can add a space if desired, but ultimately it might be
  # better to offer more flexible formatting options.
  unit = unit.strip if unit.respond_to?(:strip)   
  
  if UNIT_STANDARDIZERS.has_key?( unit )
    UNIT_STANDARDIZERS[unit]
  else
    raise ArgumentError.new( "ByteSize.to_units doesn't understand the unit #{unit.inspect}(unit.class)" )
  end
end

#to_bytes(expr) ⇒ Object

Takes a string of the form “<NUMBER><UNIT>” and returns the number of bytes represented. See UNITS constant for valid constants



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# File 'lib/fun_with/files/utils/byte_size.rb', line 42

def to_bytes( expr )
  regexp = /^\s*(?<num>\d+(\.\d+)?)\s*(?<unit>(k|m|g|t|p|z|)b?)\s*$/i
  
  if m = expr.upcase.match( regexp )
    num   = m[:num].to_f
    units = standardize_unit( m[:unit] )
    # units = case units.length
    #         when 0
    #           :B
    #         when 1
    #           (units == "B" ? units : units + "B").to_sym
    #         when 2
    #           units.to_sym
    #         end
    debugger unless UNITS.has_key?(units)
    (num * UNITS[units]).to_i
  else
    raise ArgumentError.new( "#{expr} is not in a format that to_bytes recognizes")
  end
end

#to_units(byte_count, unit) ⇒ Object

Looking for a human-friendly vibe more than accuracy. At most one unit of post-decimal precision, and only for small numbers. If the tenths place is a zero, the trailing zero is dropped.



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# File 'lib/fun_with/files/utils/byte_size.rb', line 67

def to_units( byte_count, unit )
  num = byte_count.to_f / UNITS[standardize_unit(unit)]
  # the first comparison gets rid of leading zeros
  # the second comparison prevents the decimal from being printed 
  # when it doesn't make a big difference
  if num == num.to_i || num >= 100        # 9.9k 10k
    num_str = num.to_i.to_s
  else
    num_str = sprintf( "%0.01f", num )
  end
  
  num_str = num_str[0..-3] if num_str[-2..-1] == ".0"
  
  num_str + unit.to_s
end