MVAngle.h

Go to the documentation of this file.

//# MVAngle.h: Class to handle angle type conversions and I/O
//# Copyright (C) 1996,1997,1998,1999,2000,2001
//# Associated Universities, Inc. Washington DC, USA.
//#
//# This library is free software; you can redistribute it and/or modify it
//# under the terms of the GNU Library General Public License as published by
//# the Free Software Foundation; either version 2 of the License, or (at your
//# option) any later version.
//#
//# This library is distributed in the hope that it will be useful, but WITHOUT
//# ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
//# FITNESS FOR A PARTICULAR PURPOSE.  See the GNU Library General Public
//# License for more details.
//#
//# You should have received a copy of the GNU Library General Public License
//# along with this library; if not, write to the Free Software Foundation,
//# Inc., 675 Massachusetts Ave, Cambridge, MA 02139, USA.
//#
//# Correspondence concerning AIPS++ should be addressed as follows:
//#        Internet email: casa-feedback@nrao.edu.
//#        Postal address: AIPS++ Project Office
//#                        National Radio Astronomy Observatory
//#                        520 Edgemont Road
//#                        Charlottesville, VA 22903-2475 USA
 
#ifndef CASA_MVANGLE_H
#define CASA_MVANGLE_H
 
 
//# Includes
#include <casacore/casa/aips.h>
#include <casacore/casa/Quanta/Quantum.h>
#include <casacore/casa/iosfwd.h>
 
namespace casacore { //# NAMESPACE CASACORE - BEGIN
 
//# Forward Declarations
class String;
class MUString;
 
//# Constants (SUN compiler does not accept non-simple default arguments)
 
// <summary>
// Class to handle angle type conversions and I/O
// </summary>
 
// <use visibility=export>
 
// <reviewed reviewer="UNKNOWN" date="before2004/08/25" tests="tMeasure" demos="">
// </reviewed>
 
// <prerequisite>
// <li> <linkto class=Quantum>Quantum</linkto>
// </prerequisite>
//
// <etymology>
// From Measure, Value and Angle
// </etymology>
//
// <synopsis>
// An MVAngle is a simple Double, to be used for angle conversions and I/O.
// It can be constructed from a Double (in which case radians are assumed),
// or from a Quantity (<src>Quantum<Double></src>). Quantities must be in
// either angle or time units.<br>
// It has an automatic conversion to Double, so all standard mathematical
// operations can operate on it.<br>
// The class has a number of special member operations:
// <ul>
//  <li> <src>MVAngle operator()</src> will normalise the angle between
//  -180 and +180(inclusive) degrees and return the value 
//  <li> <src>MVAngle operator(Double)</src> will normalise the angle 
//  using the value specified (and return the value)
//  in fractions of a circle (this was chosen rather than radians to make
//  for easier and more precise programming) as a lower bound. I.e.
//  (-0.5) will normalise between -180 and +180 degrees, (0.) between
//  0 and 360 degrees, (-0.25) between -90 and +270 degrees,
//  (5.) between 1800 and 2160 dgrees.
//   <li> <src>MVAngle operator(MVAngle)</src> will normalise (and
//  return the normalised value) to within 180 degrees of the
//  argument value. This is useful for making a range of angles
//  contiguous.
//   <li> <src>MVAngle binorm(Double)</src> will normalise the angle in
//  steps of 180 degrees. 
//  using the value specified (and return the value)
//  in fractions of 180 degrees (this was chosen rather than radians to make
//  for easier and more precise programming) as a lower bound. I.e.
//  (-0.5) will normalise between -90 and +90 degrees, (0.) between
//  0 and 180 degrees, (10.) between 1800 and 1980 dgrees.
//   <li> <src>Double radian()</src> will return value in radians
//   <li> <src>Double degree()</src> will return value in degrees
//   <li> <src>Double circle()</src> will return value in fraction of circles
//   <li> <src>MVAngle coAngle()</src> will return 90-angle (or rather 
//      pi/2 - angle), with (0) normalisation.
//   <li> <src>Quantity get()</src> will return radians
//   <li> <src>Quantity get(Unit)</src> will return in specified units 
//      (angle or time)
// </ul>
// Output formatting is done with the <src><<</src> statement, with the
// following rules:
// <ul>
//   <li> standard output is done in the following format:
//  <src>+ddd.mm.ss.tt</src> with a floating sign. The number of
//  digits presented will be based on the precision attached to the
//  current stream
//   <li> output can be formatted by using either the <src>setFormat()</src>
//  method for global angle format setting, or the output of
//  <src>MVAngle::Format()</src> data for a once off change (see later).
//  Formats have a first argument which
//  determines the type (default, if not given, MVAngle::ANGLE, other
//  possibility MVAngle::TIME (as hh:mm:ss.tt..),
//  the second the number of digits wanted (default stream precision),
//  with a value:
//  <ul>
//    <li> <3 : ddd.. only
//    <li> <5 : ddd.mm.
//    <li> <7 : ddd.mm.ss
//    <li> >6 : with precision-6 t's added
//  </ul> 
//  comparable for time. <note role=tip> The added periods are to enable input
//  checking of the format. Look at the 'clean' types to bypass them.
//  </note>
//  The output format can be modified with modifiers (specify as
//  MVAngle::ANGLE | MVAngle::MOD (or + MVAngle::MOD)). 
//  <note role=caution>
//   For overloading/casting problems with some compilers, the
//  use of modifiers necessitates either the presence of a precision
//  (i.e. <src>(A|B, prec)</src>), or an explicit cast:
//  <src>((MVAngle::formatTypes)(A|B))</src>, or make use of
//  the provided <src>ANGLE[_CLEAN][_NO_D[M]]</src> and
//  <src>TIME[_CLEAN][_NO_H[M]].</src>
//  </note>
//
//  The modifiers can be:
//  <ul>
//   <li> <src>MVAngle::CLEAN</src> to suppress leading or trailing
//      periods (or colons for TIME), + and leading zeroes in degree
//      field for angle representation will be replaced with a space.
//      Note that the result can not be read automatically.
//   <li> <src>MVAngle::NO_D</src> (or <src>NO_H</src>) to suppress
//      the output of degrees (or hours): useful for offsets
//   <li> <src>MVAngle::NO_DM</src> (or <src>NO_HM</src>), to
//      suppress the degrees and minutes.
//   <li> <src>MVAngle::DIG2</src> to allow only 2 digits for degrees,
//      or -12 - +12 range for hours
//   <li> <src>MVAngle::LOCAL</src> to indicate local time to FITS
//      formatting only
//    <li> <src>MVAngle::FITS</src> to produce, if
//      LOCAL set, the time zone (note that if local set
//      here, as opposed to in MVTime) the angle is supposed
//      to be in local time already).
//        <li> <src>MVAngle::ALPHA</src> to use d (or h) and m instead of
//              periods or colons.
//  </ul>
//  Output in formats like <src>20'</src> can be done via the standard
//  Quantum output (e.g. <src> stream << angle.get("'") </src>).
//   <li> Available formats:
//  <ul>
//    <li> MVAngle::ANGLE in +ddd.mm.ss.ttt format
//    <li> MVAngle::TIME in hh:mm:ss.ttt format
//    <li> MVAngle::[ANGLE|TIME]_CLEAN format without superfluous periods
//    <li> MVAngle::[ANGLE|TIME][_CLEAN]_NO_[D|H][M] in format with
//      leading zero fields left empty.
//    <li> MVAngle::CLEAN modifier for suppressing superfluous periods
//    <li> MVAngle::NO_[D|H][M] modifier to suppress first field(s)
//    <li> MVAngle::DIG2 modifier to output in +dd.mm.ss.ttt format or
//      in time format in range -12 to +12h
//  </ul>
// </ul>
// The default formatting can be overwritten by a 
// <src> MVAngle::setFormat(); </src> statement; which returns an 
// MVAngle::Format
// structure, that can be used in a subsequent one to reset to previous.
// The format set holds for all MVAngle output on all streams.<br>
// Temporary formats (i.e. for one MVAngle output only), can be set by
// outputting a format (i.e. <src> stream << MVAngle::Format() << ... </src>).
// <note role=caution> A setFormat() will also reset any lingering temporary format.
// A setFormat(getFormat()) will reset without changing. Problems could
// arise in parallel processors. </note>
// Input can be read if the values are in any of the above (non-clean) output
// formats. <br>
// For other formatting practice, the output can be written to a String with
// the string() member function.<br>
// Note that using a temporary format is inherently thread-unsafe because
// the format is kept in a static variable. Another thread may overwrite
// the format just set. The only thread-safe way to format an MVTime is using
// a <src>print</src> or <src>string</src> that accepts a Format object.
//
// Strings and input can be converted to an MVAngle (or Quantity) by
// <src>Bool read(Quantity &out, const String &in)</src> and
// <src> istream >> MVAngle &</src>. In the latter case the actual
// reading is done by the String read, which reads between white-spaces.<br>
// The following input formats (note no blanks allowed) are supported
// (+stands for an optional + or -; v for an unsigned integer; dv for a
// floating number. [] indicate optional values. Separating codes are
// case insensitive):
// <ul>
//   <li> +[v].[v].[dv]    -- value in deg, arcmin, arcsec
//   <li> +[v]D[v[M[dv]]]  -- value in deg, arcmin, arcsec
//   <li> +[v]:[v[:[dv]]]  -- value in h, min, s
//   <li> +[v]H[v[M[dv]]]  -- value in h, min, s
//   <li> +[v]{D|H|:}[dv]  -- value in deg (or h), arcmin (or min)
//   <li> +dv[unit string] -- value in time or angle units. rad default
// </ul>
// Examples of valid strings:
// <srcblock>
//  5::2.59     5h + 0min + 2.59 s
//  5..2.59     5deg + 0arcmin + 2.59arcsec
//  5.259       5.259 rad
//  5..259      5deg + 259arcsec
//  5.259a      5.259 * pi * 2 *365.25 rad (normalised)
// </srcblock>
// <note role=caution> In general the input will be read as a Quantity.
// Reading of Quantities will always try to read special formats (like 
// MVAngle, MVTime) first. In
// that case problems could arise converting strings like 5d, 5::, 5hm, 5dm.
// In 'angle' mode they could have meant to be
// 5d0m, 5:0:, 5h0m, 5d0m, but they could have
// meant: days, min, hectometre, decimetre. In the same vain 5d2 could have
// meant 5d2m or 5 d<sup>2</sup>.
// To try to guess the general use, the following interpretation is made:
// <ul>
//   <li> 5d, 5:: == 5deg, 5h0m; make float (like 5.d) to make it days/min
//   <li> 5dm, 5hm == decimetre, hectometre; use 5d0m 5h0m for
//      angle
//   <li> 5d2, 5h2, 5:2 == 5d2m, 5h2m, 5:2:; use float 5 or explicit () for
//      other interpretation 
// </ul>
// </note>
// </synopsis>
//
// <example>
// See synopsis
// </example>
//
// <motivation>
// To be able to format angle-like values in user-required ways.
// </motivation>
//
// <todo asof="1997/09/16">
//   <li> Use AipsrcData once moved to aips from trial
// </todo>
 
class MVAngle {
 
 public:
 
  //# Enumerations (should mimic those in MVTime)
  // Format types
  enum formatTypes {
    ANGLE,
    TIME,
    CLEAN           = 4,
    NO_D            = 8,
    NO_DM           = NO_D+16,
    DIG2            = 1024,
    FITS            = TIME+2048,
    LOCAL           = 4096,
    USE_SPACE                   = 8192,   //# Only for MVTIme compatibility
    ALPHA                       = 16384,
    NO_H            = NO_D,
    NO_HM           = NO_DM,
    ANGLE_CLEAN         = ANGLE + CLEAN,
    ANGLE_NO_D          = ANGLE + NO_D,
    ANGLE_NO_DM         = ANGLE + NO_DM,
    ANGLE_CLEAN_NO_D        = ANGLE + CLEAN + NO_D,
    ANGLE_CLEAN_NO_DM       = ANGLE + CLEAN + NO_DM,
    TIME_CLEAN          = TIME + CLEAN,
    TIME_NO_H           = TIME + NO_H,
    TIME_NO_HM          = TIME + NO_HM,
    TIME_CLEAN_NO_H     = TIME + CLEAN + NO_H,
    TIME_CLEAN_NO_HM        = TIME + CLEAN + NO_HM ,
    MOD_MASK            = CLEAN + NO_DM + DIG2 + LOCAL + USE_SPACE + ALPHA};
  
  //# Local structure
  // Format structure
  class Format {
  public:
    friend class MVAngle;
    Format(MVAngle::formatTypes intyp = MVAngle::ANGLE,
       uInt inprec = 0) :
      typ(intyp), prec(inprec) {;};
    Format(uInt inprec) :
      typ(MVAngle::ANGLE), prec(inprec) {;};
    // Construct from type and precision (present due to overlaoding problems)
    Format(uInt intyp, uInt inprec) :
      typ((MVAngle::formatTypes) intyp), prec(inprec) {;};
  private:
    MVAngle::formatTypes typ;
    uInt prec;
  };
  
  //# Friends
  // Output an angle
  friend ostream &operator<<(ostream &os, const MVAngle &meas);
  // Input an angle
  friend istream &operator>>(istream &is, MVAngle &meas);
  // Set a temporary format
  friend ostream &operator<<(ostream &os, const MVAngle::Format &form);
  
  //# Constructors
  // Default constructor: generate a zero value
  MVAngle();
  // Copy constructor
  MVAngle(const MVAngle &other);
  // Copy assignment
  MVAngle &operator=(const MVAngle &other);
  // Constructor from Double
  MVAngle(Double d);
  // Constructor from Quantum : value can be an angle or time
  // <thrown>
  //   <li> AipsError if not a time or angle
  // </thrown>
  MVAngle(const Quantity &other);
  
  // Destructor
  ~MVAngle();
  
  //# Operators
  // Conversion operator
  operator Double() const;
  // Normalisation between -180 and +180 degrees (-pi and +pi)
  const MVAngle &operator()();
  // Normalisation between 2pi*norm and 2pi*norm + 2pi
  const MVAngle &operator()(Double norm);
  // Normalisation between norm-pi and norm+pi
  const MVAngle &operator()(const MVAngle &norm);
  
  //# General member functions
  // Normalisation between pi*norm and pi*norm + pi
  const MVAngle &binorm(Double norm);
  // Check if String unit
  static Bool unitString(UnitVal &uv, String &us, MUString &in);
 
  // Make res angle Quantity from string in angle/time-like format. In the
  // case of String input, also quantities are recognised.
  // chk=True means that the entire string should be consumed.
  // throwExcp=True means that an exception is thrown in case of an error.
  // <group>
  static Bool read(Quantity &res, const String &in, Bool chk=True);
  static Bool read(Quantity &res, MUString &in, Bool chk=True);
  static Bool read(Quantity &res, const String &in, Bool chk, Bool throwExcp);
  static Bool read(Quantity &res, MUString &in, Bool chk, Bool throwExcp);
  // </group>
  // Handle a read error. An exception is thrown if indicated so.
  // Otherwise in.pop() is called and False is returned.
  static Bool handleReadError(MUString& in, Bool throwExcp);
 
  // Make co-angle (e.g. zenith distance from elevation)
  MVAngle coAngle() const;
  // Get value in given unit
  // <group>
  Double radian() const;
  Double degree() const;
  Double circle() const;
  Quantity get() const;
  Quantity get(const Unit &inunit) const;
  // </group>
  // Output data
  // <note role=warning>
  // The first function below is thread-unsafe because it uses the result of
  // the setFormat function which changes a static class member.
  // The other functions are thread-safe because the format is directly given.
  // </note>
  // <group>
  String string() const;
  String string(MVAngle::formatTypes intyp, uInt inprec = 0) const;
  String string(uInt intyp, uInt inprec) const;
  String string(uInt inprec) const;
  String string(const MVAngle::Format &form) const;
  void print(ostream &oss, const MVAngle::Format &form) const;
  void print(ostream &oss, const MVAngle::Format &form, Bool loc) const;
  // </group>
  // Set default format
  // <note role=warning>
  // It is thread-unsafe to print using the setFormat functions because they
  // change a static class member. The only thred-safe way to print a time is
  // to use the print function above. 
  // </note>
  // <group>
  static Format setFormat(MVAngle::formatTypes intyp, 
              uInt inprec = 0);
  static Format setFormat(uInt intyp, uInt inprec);
  static Format setFormat(uInt inprec = 0);
  static Format setFormat(const Format &form);
  // </group>
  // Get default format
  static Format getFormat();
  // Get code belonging to string. 0 if not known
  static MVAngle::formatTypes  giveMe(const String &in);
  // Get time zone offset (in days)
  static Double timeZone();
  
 private:
  //# Data
  // Value
  Double val;
  // Default format
  static MVAngle::Format defaultFormat;
  // Temporary format
  // <group>
  static MVAngle::Format interimFormat;
  static Bool interimSet;
  // </group>
  
  //# Member functions
};
 
// Global functions
// <summary> Global output/input functions </summary>
// Output/Input
// <group name=output>
ostream &operator<<(ostream &os, const MVAngle &meas);
istream &operator>>(istream &is, MVAngle &meas);
// Set a temporary format (thread-unsafe).
ostream &operator<<(ostream &os, const MVAngle::Format &form);
// </group>
 
 
} //# NAMESPACE CASACORE - END
 
#endif