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FITSDateUtil.h
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1//# FITSDateUtil.h: Class of static functions to help with FITS dates.
2//# Copyright (C) 2002
3//# Associated Universities, Inc. Washington DC, USA.
4//#
5//# This library is free software; you can redistribute it and/or modify it
6//# under the terms of the GNU Library General Public License as published by
7//# the Free Software Foundation; either version 2 of the License, or (at your
8//# option) any later version.
9//#
10//# This library is distributed in the hope that it will be useful, but WITHOUT
11//# ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
12//# FITNESS FOR A PARTICULAR PURPOSE. See the GNU Library General Public
13//# License for more details.
14//#
15//# You should have received a copy of the GNU Library General Public License
16//# along with this library; if not, write to the Free Software Foundation,
17//# Inc., 675 Massachusetts Ave, Cambridge, MA 02139, USA.
18//#
19//# Correspondence concerning AIPS++ should be addressed as follows:
20//# Internet email: aips2-request@nrao.edu.
21//# Postal address: AIPS++ Project Office
22//# National Radio Astronomy Observatory
23//# 520 Edgemont Road
24//# Charlottesville, VA 22903-2475 USA
25//#
26//#
27//# $Id$
28
29
30#ifndef FITS_FITSDATEUTIL_H
31#define FITS_FITSDATEUTIL_H
32
33#include <casacore/casa/aips.h>
34#include <casacore/measures/Measures/MEpoch.h>
35
36namespace casacore { //# NAMESPACE CASACORE - BEGIN
37
38class String;
39class MVTime;
40
41// <summary>
42// A class with static functions to help deal with FITS dates
43// </summary>
44
45// <use visibility=export>
46
47// <reviewed reviewer="Eric Sessoms" date="2002/08/19" tests="tFITSDateUtil.cc">
48// </reviewed>
49
50// <prerequisite>
51// <li> General knowledge of FITS, particularly FITS date keywords,
52// is assumed.
53// </prerequisite>
54//
55// <etymology>
56// This is a collection of static utility functions for creating and
57// interpreting FITS date keywords (e.g. DATE-OBS).
58// </etymology>
59//
60// <synopsis>
61// Its never necessary to construct a FITSDateUtil, just use the
62// static functions to help handle FITS dates.
63// </synopsis>
64//
65// <motivation>
66// The strings that make up the value of FITS dates have a
67// precise format. This class encompasses knowlege of the formats
68// used and hopefully simplifies their creation and conversion
69// to and from Casacore MVTimes.
70// </motivation>
71//
72
74{
75public:
76 enum DateStyle {
77 // dd/mm/yy
79 // yyyy-mm-dd
81 // yyyy-mm-ddThh:mm:ss[.ss...]
83 // OLD if the current year is before 1998 AND "time" is before 1998,
84 // otherwise NEW_DATEANDTIME.
86
87 // Convert an MVTime to a FITS date string and timesys string. The
88 // time system must also be supplied.
89 // Precision is only used when the time as well as the date is used
90 // (NEW_DATEANDTIME or AUTO_PICK).
91 // The default (16) gives 10^(-10) second accuracy, 6 gives second level
92 // accuracy. Default is 10^(-6)s (1 micro-s) accuracy. 0 means date only,
93 // no time (equivalent to NEW_DATEONLY).
94 static void toFITS(String &date, String &timesys, const MVTime &time,
96 DateStyle style= AUTO_PICK, uInt precision=12);
97
98 // Convert a FITS date string and TIMESYS keyword value into an MVTime and system.
99 // Returns False if it can't decode date and timesys. It tries to convert as
100 // much as possible, for example if it can't decode timesys it still
101 // attempts to decode the time. It sets the date to Jan 1/1900 if it can't
102 // decode the time, and UTC if it can't decode timesys. If timesys is the
103 // empty string then UTC is assumed.
105 const String &date,
106 const String &timesys);
107
108 // Convert a FITS Date string to the current format. If the "in" format is
109 // already correct it is just copied through.
110 static Bool convertDateString(String &out, const String &in);
111
112
113 // Determine the precision in a FITS date string.
114 // Old style dates or no time returns 0, New style + time returns 6 + the number
115 // of decimal points, i.e. if we have a time at all we assume it is at least
116 // accurate to the second level. The result of this can be used in the call
117 // to toFITS, i.e. it has the same meaning.
118 //
119 // This is mostly meant to be a helper function for convertDateString, but
120 // it may be called by anyone.
121 static uInt findPrecision(const String &fitsDate);
122};
123
124
125} //# NAMESPACE CASACORE - END
126
127#endif
static Bool fromFITS(MVTime &time, MEpoch::Types &system, const String &date, const String &timesys)
Convert a FITS date string and TIMESYS keyword value into an MVTime and system.
@ NEW_DATEANDTIME
yyyy-mm-ddThh:mm:ss[.ss...]
@ AUTO_PICK
OLD if the current year is before 1998 AND "time" is before 1998, otherwise NEW_DATEANDTIME.
static uInt findPrecision(const String &fitsDate)
Determine the precision in a FITS date string.
static void toFITS(String &date, String &timesys, const MVTime &time, MEpoch::Types system=MEpoch::UTC, DateStyle style=AUTO_PICK, uInt precision=12)
Convert an MVTime to a FITS date string and timesys string.
static Bool convertDateString(String &out, const String &in)
Convert a FITS Date string to the current format.
Types
Types of known MEpochs Caution: The order defines the order in the translation matrix in the MCEpoch...
Definition MEpoch.h:117
String: the storage and methods of handling collections of characters.
Definition String.h:225
this file contains all the compiler specific defines
Definition mainpage.dox:28
TableExprNode time(const TableExprNode &node)
Definition ExprNode.h:1580
unsigned int uInt
Definition aipstype.h:51
TableExprNode date(const TableExprNode &node)
Definition ExprNode.h:1511
bool Bool
Define the standard types used by Casacore.
Definition aipstype.h:42