Документ взят из кэша поисковой машины. Адрес оригинального документа : http://www.stsci.edu/spst/UnixTransition/doc/jwst_time_util.py Дата изменения: Fri Apr 8 12:46:11 2016 Дата индексирования: Mon Apr 11 03:43:35 2016 Кодировка: Поисковые слова: rings

#
#MODULE jwst_time_util
#
#*******************************************************************
"""

**PURPOSE** --
A module for dealing with JWST times and related things.

**DEVELOPER** --
Don Chance

**MODIFICATION HISTORY** --
Initial implementation 12/10/08
replace tabs with spaces for Python 3 compatibility 2/13/12 drc & ar
strip whitespace off of input strings. drc 3/13/12
support input unicode. drc 3/13/12
modified for Python 3.2 compatibility. ar 4/26/12
remove global setting of TZ environment variable drc 4/2/13
"""
#*******************************************************************
# Force Python 2.7 to work as much like Python 3.0 as possible....
# This also makes this module incompatible with Python 2.5 and earlier.
from __future__ import print_function, division, absolute_import, unicode_literals

# Constants
MONTHS = ['jan', 'feb', 'mar', 'apr', 'may', 'jun',
'jul', 'aug', 'sep', 'oct', 'nov', 'dec']

__version__ = "4/2/13"

import time_util
import os
import datetime
import time
import re

try:
import mx.DateTime
HAS_MX = True
except ImportError:
HAS_MX = False

global old_tz
old_tz = None


def tz_set(tz='UTC'):
"""Manipulate the timezone without affecting with other things outside of this
module.
"""
import os
if 'TZ' in os.environ.keys():
old_tz = os.environ['TZ']
os.environ['TZ'] = tz
time.tzset()


def tz_unset():
"""Put the TZ environment variable back the way it was.
"""
if old_tz:
os.environ['TZ'] = old_tz
else:
del os.environ['TZ']


class jwst_time(time_util.spss_time):
"""A class for dealing with times in JWST PPS."""
ordinal_format = "%Y-%jT%H:%M:%SZ"
calendar_format = "%Y-%m-%dT%H:%M:%SZ"
SHORT_YEAR_PATTERN = re.compile('(\d\d)(.*)')
LONG_YEAR_PATTERN = re.compile('(\d\d\d\d)(.*)')
DOY_PATTERN = re.compile('.(\d\d\d)(.*)')
DD_PATTERN1 = re.compile('.(\d\d)(.*)')
SEC_PATTERN1 = re.compile('.(\d\d$)')
UTC_PATTERN = re.compile('.(\d\d)(z$)')
SEC_PATTERN3 = re.compile('.(\d\d\.\d*)(.*)')
TZ_PATTERN = re.compile('(.*)([+|-])(\d\d$)')
TZ_PATTERN2 = re.compile('(.*)([+|-])(\d\d):(\d\d$)')

def __init__(self, t=None):
"""The jwst_time constructor.

Arguments:

t -- If a number, it is assumed to be seconds since 1970. If
a string, it is assumed to be a character time in one of the
approved formats. The default will set the time to the current
system time.

NOTE: In a departure from the way spss_time handles floats and ints,
jwst_time interprets these numbers as seconds since the 1/1/1970, not as
SOGS seconds (seconds since 1/1/1980).

**Raises** -- TypeError - Raised when the input is something
other than an int, float, string, or another jwst_time.
"""
JWSTTimeError = """jwst_time constructor requires an
int, float, string, another jwst_time, or a list of [, ]."""
if t is None:
self.syssec = time.time()
elif (isinstance(t, int)
or isinstance(t, float)):
self.syssec = t
elif isinstance(t, str):
self.syssec = jwst_time.dtdict_to_syssec(jwst_time.parse_string(t.strip()))
elif isinstance(t, unicode):
self.syssec = jwst_time.dtdict_to_syssec(jwst_time.parse_string(t.strip().encode('ascii', 'replace')))
elif isinstance(t, jwst_time) or isinstance(t, time_util.spss_time):
self.syssec = t.syssec
elif isinstance(t, list):
if len(t) == 2:
if t[1] == 'systemtime':
self.syssec = t[0]
else:
JWSTTimeError = """Unsupported Input time reference '%s'""" % t[1]
raise TypeError(JWSTTimeError)
else:
JWSTTimeError = """List Input time requires 2 elements got %s""" % len(t)
raise TypeError(JWSTTimeError)
elif isinstance(t, datetime.datetime):
jwst_time.set_jwst_character_time(self, t.strftime(self.ordinal_format))
elif HAS_MX and type(t) == type(mx.DateTime.DateTime(2001)):
self.syssec = t.ticks()
else:
raise TypeError(JWSTTimeError)

def get_localtime(self):
return localtime(int(self))

def __repr__(self):
"""The string representation of an jwst_time.

**Returns** -- The JWST character time
will be printed.
"""
return time.strftime(self.calendar_format, time.gmtime(self.syssec))

def __sub__(self, other):
"""Operator overloading for subtraction.

**Returns** -- A delta_time when two jwst_times are subtracted.
Subtracting a float, int, or delta_time from a jwst_time
returns an jwst_time.
"""
if isinstance(other, time_util.spss_time):
return time_util.delta_time(self.syssec - other.syssec)
elif isinstance(other, time_util.delta_time):
return jwst_time(self.syssec - other.delta)
elif (isinstance(other, int)
or isinstance(other, float)):
return jwst_time(self.syssec - other)
else:
JWSTTimeError = """Only ints, floats, delta_times, spss_times
and other jwst_times may be subtracted from an
jwst_time."""
raise TypeError(JWSTTimeError)

def __add__(self, other):
"""Operator overloading for addition.

**Returns** -- When an jwst_time and a delta, int, or float
are added, an jwst_time object will be returned.
"""
if isinstance(other, time_util.delta_time):
return jwst_time(self.syssec + other.delta)
elif (isinstance(other, int)
or isinstance(other, float)):
return jwst_time(self.syssec + other)
else:
JWSTTimeError = """Only ints, floats, and delta_times
may be added to an jwst_time."""
raise TypeError(JWSTTimeError)

def __float__(self):
"""Seconds since Jan 1, 1970 returned
as a float.
"""
return float(self.syssec)

def __int__(self):
"""Seconds since Jan 1, 1970 returned
as an int.
"""
return int(self.syssec)

@staticmethod
def parse_string(stime):
"""Parse a string containing a time.
"""
year = 0
month = 0
doy = 0
day = 0
hour = 0
minute = 0
second = 0
tz_offset = 0
sign = 1

tz_set()

stime = stime.strip()

# Strip out the year.
long_year_pattern = jwst_time.LONG_YEAR_PATTERN.match(stime)
short_year_pattern = jwst_time.SHORT_YEAR_PATTERN.match(stime)
if long_year_pattern:
year = int(long_year_pattern.groups()[0])
rest = long_year_pattern.groups()[1]
elif short_year_pattern:
year = 2000 + int(short_year_pattern.groups()[0])
rest = short_year_pattern.groups()[1]
else:
raise ValueError('illegal datetime format: ' + stime)

# Next, get the month.
doy_pattern = jwst_time.DOY_PATTERN.match(rest)
number_month_pattern = jwst_time.DD_PATTERN1.match(rest)
if rest and rest[1:4].lower() in MONTHS:
month = MONTHS.index(rest[1:4].lower()) + 1
rest = rest[4:]
elif rest and doy_pattern:
doy = int(doy_pattern.groups()[0])
rest = doy_pattern.groups()[1]
elif rest and number_month_pattern:
month = int(number_month_pattern.groups()[0])
rest = number_month_pattern.groups()[1]
else:
month = 1

# Now get the day of the month
if not doy and month and rest:
day_pattern = jwst_time.DD_PATTERN1.match(rest)
if day_pattern:
day = int(day_pattern.groups()[0])
rest = day_pattern.groups()[1]
elif not doy:
day = 1

# Strip off the time zone info
time_zone_pattern_hours = jwst_time.TZ_PATTERN.match(rest) or jwst_time.TZ_PATTERN2.match(rest)
if time_zone_pattern_hours:
rest = time_zone_pattern_hours.groups()[0]
if time_zone_pattern_hours.groups()[1] == '-':
sign = -1
tz_offset = int(time_zone_pattern_hours.groups()[2]) * 60
tz_minutes = time_zone_pattern_hours.groups()[3:]
if tz_minutes:
tz_offset += int(time_zone_pattern_hours.groups()[3])

tz_offset *= sign*60

# Hours
if rest:
hour_pattern = jwst_time.DD_PATTERN1.match(rest)
if hour_pattern:
hour = int(hour_pattern.groups()[0])
rest = hour_pattern.groups()[1]
else:
raise ValueError('illegal datetime format: ' + stime)

# Minutes
if rest:
minute_pattern = jwst_time.DD_PATTERN1.match(rest)
if minute_pattern:
minute = int(minute_pattern.groups()[0])
rest = minute_pattern.groups()[1]
else:
raise ValueError('illegal datetime format: ' + stime)

# Seconds
if rest:
second_pattern = jwst_time.SEC_PATTERN1.match(rest) or jwst_time.UTC_PATTERN.match(rest)
if second_pattern:
second = int(second_pattern.groups()[0])
rest = ''
else:
second_pattern = jwst_time.SEC_PATTERN3.match(rest) or jwst_time.DD_PATTERN1.match(rest)
if second_pattern:
second = int(float(second_pattern.groups()[0]) + 0.5)
rest = second_pattern.groups()[1]

if doy:
month = day = 1

tz_unset()

return {'year': year,
'month': month,
'doy': doy,
'day': day,
'hour': hour,
'minute': minute,
'second': second,
'tz_offset': tz_offset}

@staticmethod
def dtdict_to_syssec(dict):
#print dict
tz_set()
if dict.get('doy', 0) == 0:
strtime = "%i %02i %02i %02i %02i %02i" % (dict['year'],
dict['month'],
dict['day'],
dict['hour'],
dict['minute'],
dict['second'])
#print strtime
syssec = int(time.mktime(time.strptime(strtime, "%Y %m %d %H %M %S")) + 0.5) - dict.get('tz_offset', 0)
else:
strtime = "%i %03i %02i %02i %02i" % (dict['year'],
dict['doy'],
dict['hour'],
dict['minute'],
dict['second'])
syssec = int(time.mktime(time.strptime(strtime, "%Y %j %H %M %S")) + 0.5) - dict.get('tz_offset', 0)
tz_unset()
return syssec


class localtime(jwst_time):
def __init__(self, t=None, timezone=None):
if timezone:
self.timezone = timezone
else:
self.timezone = time_util.LOCAL_TIMEZONE

jwst_time.__init__(self, t)

def __repr__(self):
return self.strftime('%Y-%m-%dT%H:%M:%S') + self.get_tz_offset_str()

def set_timezone(self, tz):
self.timezone = tz

def get_tz_offset(self):
tz_set(self.timezone)

isdst = time.localtime(self.syssec).tm_isdst

tz_unset()

if isdst == 0 or isdst == -1:
return time.timezone
elif isdst == 1:
return time.altzone

def get_tz_offset_str(self):
tz = self.get_tz_offset()
if tz == 0:
return "Z"
elif tz > 0:
sgn = "-"
else:
sgn = "+"
tz = -1*tz
return sgn+"%02i:%02i" % (tz//3600, (tz % 3600)//60)

def get_timezone(self):
return self.timezone

def strftime(self, format):
tz_set(self.timezone)
lt = time.strftime(format, time.localtime(self.syssec))
tz_unset()
return lt