class Buryspam::DateRange

Creates an appropriate date range for the following range parameters:

1. range = nil || ""         => MIN_DATE..MAX_DATE
2. range = "<date>..<date>"  => <date>..<date>
3. range = "-<date>"         => MIN_DATE..<date>
4. range = "<date>"          => <date>..MAX_DATE

Where <date> is either an absolute date or date relative to today. See ::to_date for expected date formats.

If a date range string is given (2, above) then negative relative dates refer to dates in the past and positive relative dates are in the future. A negative sign prefixing an absolute date is ignored. The two dates are swapped if they are out of order.

If only one date is given (3 and 4, above), then a negative date (relative or absolute) will generate a range from MIN_DATE to the specified date, whereas a positive date (relative or absolute) will generate a range from the specified date to MAX_DATE. In both cases a relative date is always in the past. (e.g., "1m" refers to one month ago).

MIN_DATE         NOW             MAX_DATE
 |                |               |
            -1m                           (negative relative date)
 |===========|
             |====================|
             1m                           (positive relative date)

        -2005-03-02                       (negative absolute date)
 |===========|
             |====================|
         2005-03-02                       (positive absolute date)

# File buryspam.rb, line 509
def initialize(range)
  begin
    # 1.
    if range.nil? || range.strip.empty?
      super(MIN_DATE, MAX_DATE)
    # 2.
    elsif /^(.*)\s*\.\.\s*(.*)$/.match(range)
      start, finish = to_date(range.first), to_date(range.last)
      start, finish = finish, start if start > finish
      super(start, finish)
    # 3.
    elsif range[0] == --
      super(MIN_DATE, DateRange.to_date(range))
    # 4.
    else
      super(DateRange.to_date("-" + range), MAX_DATE)
    end
  rescue ArgumentError
    raise "#$!: #{range}"
  end
end

Converts a string representing a date to a Time object. The date may either be absolute date of the form:

-?YYYY-MM-DD

(the minus sign is ignored) or a date relative to the given base date (which defaults to today).

Relative dates are of the form:

-?<num>(d|w|m|y)

where the units d, w, m, y stand for days, weeks, months and years, respectively. Negative relative dates refer to dates before the base date.

# File buryspam.rb, line 545
def self.to_date(date, base = Time.now)
  if ABS_DATE_RE.match(date)
    # Note that any '-' prefix is ignored.
    return Time.mktime($1.to_i, $2.to_i, $3.to_i)
  elsif REL_DATE_RE.match(date)
    sign, num, units = $1, $2.to_i, $3
    num = -num if sign == "-"
    base = DateTime.parse(base.to_s)
    date = case units
             when "d" then base + num
             when "w" then base + 7 * num
             when "m" then base >> num
             when "y" then base >> 12 * num
           end
    return Time.mktime(date.year, date.month, date.day,
                       date.hour, date.min, date.sec)
  else
    raise ArgumentError, "Invalid date"
  end
end