Class: TimeParser

Inherits:
Object
  • Object
show all
Defined in:
lib/logporter/protocol/syslog3164.rb

Overview

Ruby’s core/stdlib Time.strptime is embarrasingly slow. Let’s do our own.

Constant Summary collapse

@@re_cache = 
{}
@@re_formats = 
{
  "%b" => "(?:Jan|Feb|Mar|Apr|May|Jun|Jul|Aug|Sep|Oct|Nov|Dec)",
  "%d" => "[ 1-3]?[0-9]",
  "%H" => "[0-9]{2}",
  "%M" => "[0-9]{2}",
  "%S" => "[0-9]{2}",
}

Class Method Summary collapse

Class Method Details

.strptime(string, format) ⇒ Object 



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# File 'lib/logporter/protocol/syslog3164.rb', line 15

def self.strptime(string, format)
  if @@re_cache.include?(format)
    obj = @@re_cache[format]
  else
    captures = []
    pattern = format.gsub(/%[A-z]/) do |spec|
      if @@re_formats.include?(spec)
        captures << spec
        "(#{@@re_formats[spec]})"
      else
        spec
      end
    end
    re = Regexp.new(pattern)
    obj = @@re_cache[format] = {
      :re => re,
      :captures => captures,
    }
  end

  #m = obj[:re].match(string)
  #return nil if !m

  now = Time.new
  time_array = [now.year, now.month, now.day, 0, 0, 0, 0]
  return nil unless string.scan(obj[:re]) do |*captures|
    #obj[:captures].each_with_index do |spec, i|
      #p spec => m[i + 1]
    captures.each_with_index do |spec, i|
      case spec
        when "%y"; time_array[0] = m[i + 1].to_i
        when "%b"; time_array[1] = m[i + 1]
        when "%d"; time_array[2] = m[i + 1].to_i
        when "%H"; time_array[3] = m[i + 1].to_i
        when "%M"; time_array[4] = m[i + 1].to_i
        when "%S"; time_array[5] = m[i + 1].to_i
      end # case spec
    end # each capture
  end # string.scan

  return Time.local(*time_array)
end