dayAge_calc.py

#!/usr/bin/env python
# -*- coding: utf-8 -*-
# 

Gb_showErr      = 1
Gb_forceErr     = 0
Gstr_forceErr   = "<error>"
Gstr_ageInput   = "-x"

Gstr_synopsis 	= """
NAME

	dayAge_calc.py

SYNOPSIS

        dayAge_calc.py	[-n] [-N <forceError>] -i <ageString>	

DESCRIPTION

	'dayAge_calc.py' accepts as input an <ageString> of format 'XXXA' where
        'X' denotes a numeric character [0-9] and 'A' denotes a modifier and is
        either 'D' (for Days), 'M' (for Months), or 'Y' (for Years).

        The script simply calculates the number of days denoted by its input
        string and echoes to stdout.
	
ARGUMENTS

        -n (OPTIONAL)
        If specified, suppress printing output stderr messages. This is useful
        if the script is called from 'awk' and there is no simple mechanism
        for filtering to /dev/null.

        -N <forceError> (OPTIONAL)
        If specified, and if any error has occurred, print <forceError> to
        <stdout> irrespective of '-n'.

	-i <ageString>
	The age string to process. 
		
PRECONDITIONS

        o The <ageString> must be of form 'XXXA' as described above.
	
POSTCONDITIONS

	o The equivalent number of days denoted by the <ageString> is returned.
        
HISTORY

17 July 2009
o Initial development implementation.

"""

import 	os
import	sys
import	getopt
import  string

dictErr = {
    'ageStringLen'        : {
        'action'        : 'checking the input <ageString>, ', 
        'error'         : 'I counted the wrong number of characters.', 
        'exitCode'      : 10
                            },
    'ageSpec'           : {
        'action'        : 'checking the input <ageString>, ', 
        'error'         : "it doesn't look like it was specified. Did you use '-i <ageString>'?", 
        'exitCode'      : 10
                            },
    'comArgs'          : {
        'action'        : 'checking command line arguments,', 
        'error'         : 'it seems that you have wrong number of arguments.', 
        'exitCode'      : 11
                            },
    'ageStringF'         : {
        'action'        : 'checking age modifier, I read an incorrect character.', 
        'error'         : 'Modifier is either "D" for days, "M" for months, "Y" for years."', 
        'exitCode'      : 12
                            }
}

Gstr_SELF       = sys.argv[0]

def synopsis_show():
    print "%s" % Gstr_synopsis

def error_exit(astr_key):
    if Gb_showErr:
        print >>sys.stderr, Gstr_SELF
        print >>sys.stderr, "\n"
        print >>sys.stderr, "\tSorry, but some error occurred."
        print >>sys.stderr, "\tWhile " + dictErr[astr_key]['action']
        print >>sys.stderr, "\t" + dictErr[astr_key]['error']
        print >>sys.stderr, "\n"
        print >>sys.stderr, "Exiting to system with code %d.\n" % dictErr[astr_key]['exitCode']
    if Gb_forceErr:
        print Gstr_forceErr
    sys.exit(dictErr[astr_key]['exitCode'])

def fatal(astr_key, astr_extraMsg=""):
    if len(astr_extraMsg): print astr_extraMsg
    error_exit( astr_key)

try:
        
    opts, remargs   = getopt.getopt(sys.argv[1:], 'xni:N:')
except getopt.GetoptError:
    if Gb_showErr: print Gstr_forceErr
    sys.exit(1)

verbose         = 0

for o, a in opts:
        
    if (o == '-x'):
        synopsis_show()
        sys.exit(1)
    if (o == '-n'):
        Gb_showErr      = 0
    if (o == '-N'):
        Gb_forceErr     = 1
        Gstr_forceErr   = a
    if (o == '-i'):
        Gstr_ageInput   = a

if Gstr_ageInput == "-x": fatal('ageSpec')
if len(Gstr_ageInput) != 4:
    if Gb_showErr:
        print >>sys.stderr, "Invalid length of <ageString>. Must be of form 'XXXM' where"
        print >>sys.stderr, "'X' is a number and 'A' is either 'D', 'W', 'M', or 'Y'."
        print >>sys.stderr, "\n"
        print >>sys.stderr, "Examples of valid <ageStrings>: 034D, 002W, 007Y, etc."
        print >>sys.stderr, "\n"
    fatal('ageStringLen')

Gstr_ageString  = Gstr_ageInput[0:3]

Gstr_ageFact    = Gstr_ageInput[3]
if Gstr_ageFact != 'D' and Gstr_ageFact != 'M' and Gstr_ageFact != 'Y' and Gstr_ageFact != 'W':
    fatal('ageStringF')

Gf_ageInput     = string.atof(Gstr_ageString)
Gf              = Gf_ageInput
Gf_ageInDays    = {

    'D' : lambda Gf:    Gf * 1.0,
    'W' : lambda Gf:    Gf * 7.0,
    'M' : lambda Gf:    Gf * 30.42,
    'Y' : lambda Gf:    Gf * 365.25

} [Gstr_ageFact](Gf)
 
print "%d" % Gf_ageInDays,

sys.exit(0)