[Boost-bugs] [Boost C++ Libraries] #7840: Failure in posix_time_zone when specifying start date as Jn

Subject: [Boost-bugs] [Boost C++ Libraries] #7840: Failure in posix_time_zone when specifying start date as Jn
From: Boost C++ Libraries (noreply_at_[hidden])
Date: 2013-01-02 02:10:13

#7840: Failure in posix_time_zone when specifying start date as Jn
-------------------------------------------+--------------------------------
 Reporter:  andrew.lang@…                  |       Owner:  az_sw_dude
     Type:  Bugs                           |      Status:  new       
Milestone:  To Be Determined               |   Component:  date_time 
  Version:  Boost 1.50.0                   |    Severity:  Problem   
 Keywords:                                 |  
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 If you use the time zone specification "CST-2CDT,J365/00,J1/00" to create
 a boost::local_time::posix_time_zone, it fails with an exception.

 The problem appears to be in
 boost\date_time\local_time\posix_time_zone.hpp, julian_no_leap(...). The
 conversion of the start date uses this loop which has a "less than or
 equal" clause:
  while(sd >= calendar::end_of_month_day(year,sm)){
   sd -= calendar::end_of_month_day(year,sm++);
  }
 sd is the converted start specifier (365 in this case); sm is the current
 month (initialized to 1). The loop continues until sd=0 and sm=13, at
 which point end_of_month_day() throws an exception.

 Conversion of the end date uses an almost identical loop except that its
 while clause is "strictly less than":
  while(ed > calendar::end_of_month_day(year,em)){
   ed -= calendar::end_of_month_day(year,em++);
  }
 So the specifier "CST-2CDT,J1/00,J365/00" leaves ed=31 and em=12 as you
 would hope.

 In fact any start specifier at the end of a month (J31, J59,...J334) will
 fail later because it will result in sd=0 which is outside the range of
 1..31.

 This code is identical in boost 1.52.0. The fix appears to be just to use
 "strictly less than" in both loops.

-- 
Ticket URL: <https://svn.boost.org/trac/boost/ticket/7840>
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