Class: MarsDateTime

Inherits:
Object
  • Object
show all
Includes:
Comparable
Defined in:
lib/marsdate.rb

Constant Summary collapse

VERSION = 
"1.0.6"
MSEC_PER_SOL = 
88775244
SOLS_PER_MYEAR = 
668.5921
MSEC_PER_DAY = 
86400000
FAKE_MSEC_PER_MYEAR = 
(668*MSEC_PER_SOL)
TimeStretch = 
MSEC_PER_SOL/MSEC_PER_DAY.to_f
Months = 
%w[ UNDEFINED
January   Gemini      February Cancer
March     Leo         April    Virgo 
May       Libra       June     Scorpio 
July      Sagittarius August   Capricorn 
September Aquarius    October  Pisces 
November  Aries       December Taurus ]
Week =

no month 0

%w[ Sunday Monday Tuesday Wednesday Thursday Friday Saturday ]
EpochMCE = 
DateTime.new(1,1,21)
EpochCE = 
DateTime.new(1,1,1)
FudgeOffset = 
67784 + 44000 + 1099 + 87 - 56
JulianDay1 =

was …24

1721443

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(*params) ⇒ MarsDateTime

Returns a new instance of MarsDateTime.



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# File 'lib/marsdate.rb', line 100

def initialize(*params)
  n = params.size
  case n
    when 3..6
      init_yms(*params)
    when 0
      init_datetime(DateTime.now)
    when 1
      case params.first
        when Integer, Float
          init_mems(params.first)
        when DateTime
          init_datetime(params.first)
      else
        raise "Expected number or DateTime" 
      end
    else
      raise "Bad params: #{params.inspect}"
  end
  compute_stretched
end

Instance Attribute Details

#day_of_week ⇒ Object (readonly)

Returns the value of attribute day_of_week.



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# File 'lib/marsdate.rb', line 37

def day_of_week
  @day_of_week
end

#dow ⇒ Object (readonly)

Returns the value of attribute dow.



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# File 'lib/marsdate.rb', line 37

def dow
  @dow
end

#epoch_sol ⇒ Object (readonly)

Returns the value of attribute epoch_sol.



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# File 'lib/marsdate.rb', line 33

def epoch_sol
  @epoch_sol
end

#mems ⇒ Object (readonly)

Returns the value of attribute mems.



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# File 'lib/marsdate.rb', line 35

def mems
  @mems
end

#mhrs ⇒ Object (readonly) Also known as: hr

Returns the value of attribute mhrs.



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# File 'lib/marsdate.rb', line 38

def mhrs
  @mhrs
end

#mmin ⇒ Object (readonly) Also known as: min

Returns the value of attribute mmin.



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# File 'lib/marsdate.rb', line 38

def mmin
  @mmin
end

#month ⇒ Object (readonly)

Returns the value of attribute month.



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# File 'lib/marsdate.rb', line 33

def month
  @month
end

#msec ⇒ Object (readonly) Also known as: sec

Returns the value of attribute msec.



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# File 'lib/marsdate.rb', line 38

def msec
  @msec
end

#shr ⇒ Object (readonly)

stretched time



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# File 'lib/marsdate.rb', line 34

def shr
  @shr
end

#smin ⇒ Object (readonly)

stretched time



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# File 'lib/marsdate.rb', line 34

def smin
  @smin
end

#sol ⇒ Object (readonly)

Returns the value of attribute sol.



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# File 'lib/marsdate.rb', line 33

def sol
  @sol
end

#ssec ⇒ Object (readonly)

stretched time



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# File 'lib/marsdate.rb', line 34

def ssec
  @ssec
end

#year ⇒ Object (readonly) Also known as: myear

Returns the value of attribute year.



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# File 'lib/marsdate.rb', line 33

def year
  @year
end

#year_sol ⇒ Object (readonly)

Returns the value of attribute year_sol.



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# File 'lib/marsdate.rb', line 33

def year_sol
  @year_sol
end

Class Method Details

.leap?(myear) ⇒ Boolean

class method for convenience

Returns:

  • (Boolean) 


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# File 'lib/marsdate.rb', line 45

def self.leap?(myear)    # class method for convenience
  return (myear % 2 == 1) if (myear % 10 != 0)
  return true if (myear % 1000 == 0)
  return false if (myear % 100 == 0)
  return true
end

.now ⇒ Object 



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# File 'lib/marsdate.rb', line 58

def self.now
  d = DateTime.now
  MarsDateTime.new(d)
end

.sols_in_month(m, year) ⇒ Object 



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# File 'lib/marsdate.rb', line 52

def self.sols_in_month(m, year)
  return 28 if m < 24
  return 25 if leap?(year)
  return 24
end

.today ⇒ Object 



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# File 'lib/marsdate.rb', line 63

def self.today
  d = DateTime.now
  MarsDateTime.new(d)
end

Instance Method Details

#+(sols) ⇒ Object 



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# File 'lib/marsdate.rb', line 224

def +(sols)
  millisec = sols * MSEC_PER_SOL
  MarsDateTime.new(@mems + millisec)
end

#-(other) ⇒ Object 



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# File 'lib/marsdate.rb', line 208

def -(other)
  case other
    when MarsDateTime
      diff = @mems - other.mems
      diff.to_f / MSEC_PER_SOL
    when DateTime
      other = MarsDateTime.new(other)
      diff = @mems - other.mems
      diff.to_f / MSEC_PER_SOL
    when Fixnum, Float
      self + (-other)
  else
    raise "Unexpected data type"
  end
end

#<=>(other) ⇒ Object 



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# File 'lib/marsdate.rb', line 229

def <=>(other)
  case other
    when MarsDateTime
      @mems <=> other.mems
    when DateTime
      @mems <=> MarsDateTime.new(other).mems
  else
    raise "Invalid comparison"
  end
end

#check_ymshms(my, mm, msol, mhr = 0, mmin = 0, msec = 0) ⇒ Object 



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# File 'lib/marsdate.rb', line 122

def check_ymshms(my, mm, msol, mhr=0, mmin=0, msec=0)
  text = ""
  text << "year #{my} is not an integer\n" unless my.is_a? Fixnum
  text << "month #{mm} is out of range" unless (1..24).include? mm
  text << "sol #{msol} is out of range" unless (1..28).include? msol
  text << "hour #{mhr} is out of range" unless (0..24).include? mhr
  text << "minute #{mmin} is out of range" unless (0..59).include? mmin
  text << "second #{msec} is out of range" unless (0..59).include? msec
  if !leap?(my) && mm == 24 && msol > 24
    text << "sol #{msol} is invalid in a non-leap year" 
  end
  raise text unless text.empty?
end

#compute_stretched ⇒ Object 



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# File 'lib/marsdate.rb', line 150

def compute_stretched
  # Handle stretched time...
  sec = @mhrs*3600 + @mmin*60 + @msec
  sec /= TimeStretch
  @shr,  sec = sec.divmod(3600)
  @smin, sec = sec.divmod(60)
  @ssec = sec.round
end

#earth_date ⇒ Object 



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# File 'lib/marsdate.rb', line 240

def earth_date
  secs = @mems/1000 + FudgeOffset
  days,secs = secs.divmod(86400)
  hrs, secs = secs.divmod(3600)
  min, secs = secs.divmod(60)
  jday = days + JulianDay1
  DateTime.jd(jday, hrs, min, secs)
end

#init_datetime(dt) ⇒ Object 



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# File 'lib/marsdate.rb', line 197

def init_datetime(dt)
  days = dt.jd - JulianDay1
  secs = days*86400 + dt.hour*3600 + dt.min*60 + dt.sec
  secs -= FudgeOffset
  init_mems(secs*1000)
end

#init_mems(mems) ⇒ Object 



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# File 'lib/marsdate.rb', line 159

def init_mems(mems)
  full_years = 0
  loop do
    millisec = FAKE_MSEC_PER_MYEAR
    millisec += MSEC_PER_SOL if leap?(full_years+1)
    break if mems < millisec
    mems -= millisec
    # puts "Subtracting #{millisec} -- one full year => #{mems}"
    full_years += 1
  end

  mspm = MSEC_PER_SOL*28
  full_months,mems = mems.divmod(mspm)
  full_days, mems  = mems.divmod(MSEC_PER_SOL)
  full_hrs, mems   = mems.divmod(3_600_000)
  full_min, mems   = mems.divmod(60_000)
  sec = mems/1000.0

  my = full_years + 1      # 1-based
  mm = full_months + 1
  ms = full_days + 1
  mhr = full_hrs           # 0-based
  mmin = full_min
  msec = sec.to_i
  frac = sec - msec        # fraction of a sec

#    # check for leap year...
#    if mm == 24
#      max = leap?(my) ? 25 : 24
#      diff = ms - max
#      if diff > 0
#        my, mm, ms = my+1, 1, diff
#      end
#    end

  init_yms(my, mm, ms, mhr, mmin, msec)
end

#init_yms(my, mm, msol, mhr = 0, mmin = 0, msec = 0) ⇒ Object 



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# File 'lib/marsdate.rb', line 136

def init_yms(my, mm, msol, mhr=0, mmin=0, msec=0)
  check_ymshms(my, mm, msol, mhr, mmin, msec)
  zsol = msol - 1  # z means zero-based
  zmy  = my - 1    # my means Martian year
  zesol = zmy*668 + leaps(my-1) + (mm-1)*28 + zsol
#   @mems is "Martian (time since) epoch in milliseconds"
  @mems = zesol*MSEC_PER_SOL + (mhr*3600 + mmin*60 + msec)*1000
  @year, @month, @sol, @mhrs, @mmin, @msec = my, mm, msol, mhr, mmin, msec
  @epoch_sol = zesol + 1
  @dow = (@epoch_sol-1) % 7
  @day_of_week = Week[@dow]
  @year_sol  = (mm-1)*28 + msol
end

#inspect ⇒ Object 



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# File 'lib/marsdate.rb', line 78

def inspect
  time = ('%02d' % @mhrs) + ":" + ('%02d' % @mmin) + ":" + ('%02d' % @msec)
  "#@year/#{'%02d' % @month}/#{'%02d' % @sol} " + 
  "(#@year_sol, #@epoch_sol) #@day_of_week " +
  time
end

#leap?(myear) ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/marsdate.rb', line 90

def leap?(myear)
  MarsDateTime.leap?(myear)    # DRY
end

#leaps(myr) ⇒ Object 



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# File 'lib/marsdate.rb', line 68

def leaps(myr)
  n = 0
  1.upto(myr) {|i| n+=1 if leap?(i) } 
  n
end

#month_name ⇒ Object 



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# File 'lib/marsdate.rb', line 94

def month_name
  Months[@month]
end

#strftime(fmt) ⇒ Object 



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# File 'lib/marsdate.rb', line 249

def strftime(fmt)
  str = fmt.dup
  pieces = str.scan(/(%.|[^%]+)/).flatten
  final = ""
  zmonth = '%02d' % @month
  zsol = '%02d' % @sol
  zhh = '%02d' % @mhrs  # stretched
  zmm = '%02d' % @mmin
  zss = '%02d' % @msec
  zhc = '%02d' % @shr   # canonical
  zmc = '%02d' % @smin
  zsc = '%02d' % @ssec
 
  pieces.each do |piece|
    case piece
      when "%a"; final << @day_of_week[0..2]
      when "%A"; final << @day_of_week
      when "%b"; final << month_name[0..2]
      when "%B"; final << month_name
      when "%d"; final << zsol
      when "%e"; final << ('%2d' % @sol)
      when "%F"; final << "#@year-#@month-#@sol"
      when "%H"; final << zhh
      when "%j"; final << @year_sol.to_s
      when "%m"; final << @month.to_s
      when "%M"; final << zmm
      when "%s"; final << @msec.to_s  # was: (@mems*1000).to_i.to_s
      when "%S"; final << zss
      when "%u"; final << (@dow + 1).to_s
      when "%U"; final << (@year_sol/7 + 1).to_s
      when "%w"; final << @dow.to_s
      when "%x"; final << "#@year/#{zmonth}/#{zsol}"
      when "%X"; final << "#{zhh}:#{zmm}:#{zss}"
      when "%Y"; final << @year.to_s
      when "%n"; final << "\n"
      when "%t"; final << "\t"
      when "%%"; final << "%"
      when "%P"; final << ("%02d" % @shr)
      when "%Q"; final << ("%02d" % @smin)
      when "%R"; final << ("%02d" % @ssec)
      else
        final << piece
    end
  end
  final
end

#to_s ⇒ Object 



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# File 'lib/marsdate.rb', line 85

def to_s
  time = self.strftime('%H:%M:%S [%P:%Q:%R]')
  "#@day_of_week, #{Months[@month]} #@sol, #@year at #{time}"
end

#to_yaml_properties ⇒ Object 



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# File 'lib/marsdate.rb', line 74

def to_yaml_properties
  %w[@myear @month @sol @epoch_sol @year_sol @dow @day_of_week @msme @mhrs @mmin @msec]
end

#ymshms ⇒ Object 



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# File 'lib/marsdate.rb', line 204

def ymshms
  [@year, @month, @sol, @mhrs, @mmin, @msec]
end