1.1 --- a/imiptools/dates.py	Sat Aug 15 22:56:51 2015 +0200
     1.2 +++ b/imiptools/dates.py	Sat Aug 15 22:57:17 2015 +0200
     1.3 @@ -19,6 +19,7 @@
     1.4  this program.  If not, see <http://www.gnu.org/licenses/>.
     1.5  """
     1.6  
     1.7 +from bisect import bisect_left
     1.8  from datetime import date, datetime, timedelta
     1.9  from os.path import exists
    1.10  from pytz import timezone, UnknownTimeZoneError
    1.11 @@ -470,4 +471,72 @@
    1.12  
    1.13      return to_utc_datetime(get_datetime(recurrenceid), tzid)
    1.14  
    1.15 +# Time corrections.
    1.16 +
    1.17 +def correct_datetime(dt, resolution):
    1.18 +
    1.19 +    "Correct 'dt' using the given 'resolution' details."
    1.20 +
    1.21 +    carry, hour, minute, second = correct_value((dt.hour, dt.minute, dt.second), resolution)
    1.22 +    return datetime(dt.year, dt.month, dt.day, hour, minute, second, dt.microsecond, dt.tzinfo) + \
    1.23 +           (carry and timedelta(1) or timedelta(0))
    1.24 +
    1.25 +def correct_value(value, resolution):
    1.26 +
    1.27 +    """
    1.28 +    Correct the given (hour, minute, second) tuple 'value' according to the
    1.29 +    'resolution' details.
    1.30 +    """
    1.31 +
    1.32 +    limits = 23, 59, 59
    1.33 +
    1.34 +    corrected = []
    1.35 +    reset = False
    1.36 +
    1.37 +    # Find invalid values and reset all following values.
    1.38 +
    1.39 +    for v, values, limit in zip(value, resolution, limits):
    1.40 +        if reset:
    1.41 +            if values:
    1.42 +                v = values[0]
    1.43 +            else:
    1.44 +                v = 0
    1.45 +
    1.46 +        elif values and v not in values:
    1.47 +            reset = True
    1.48 +
    1.49 +        corrected.append(v)
    1.50 +
    1.51 +    value = corrected
    1.52 +    corrected = []
    1.53 +    carry = 0
    1.54 +
    1.55 +    # Find invalid values and update them to the next valid value, updating more
    1.56 +    # significant values if the next valid value is the first in the appropriate
    1.57 +    # series.
    1.58 +
    1.59 +    for v, values, limit in zip(value, resolution, limits)[::-1]:
    1.60 +        if carry:
    1.61 +            v += 1
    1.62 +            if v > limit:
    1.63 +                if values:
    1.64 +                    v = values[0]
    1.65 +                else:
    1.66 +                    v = 0
    1.67 +                corrected.append(v)
    1.68 +                continue
    1.69 +            else:
    1.70 +                carry = 0
    1.71 +
    1.72 +        i = bisect_left(values, v)
    1.73 +        if i < len(values):
    1.74 +            v = values[i]
    1.75 +        else:
    1.76 +            v = values[0]
    1.77 +            carry = 1
    1.78 +
    1.79 +        corrected.append(v)
    1.80 +
    1.81 +    return [carry] + corrected[::-1]
    1.82 +
    1.83  # vim: tabstop=4 expandtab shiftwidth=4