Record< T > Struct Template Reference

#include <Record.h>

Detailed Description

template<typename T>
struct Euclid::Fits::Record< T >

Keyword-value pair with optional unit and comment.

Template Parameters

T	The value type, which can be an integer, floating point, complex, std::string, const char *, or VariantValue for run-time type deduction.

Here's a record of type double with keyword "LIGHT", value 3.0e8, unit "m/s" and comment "speed of light":

Record<double> lightSpeed {"LIGHT", 3.0e8, "m/s", "speed of light"};

In the FITS file, this record will appear in the header of an HDU as (padding blank spaces removed):

LIGHT = 3.0E8 / [m/s] speed of light

In the FITS definition, it is unclear if the "comment" encompasses only: speed of light, or also the unit, as: [m/s] speed of light. In EleFits, the former is named comment, while the latter is the raw comment. The raw comment can be get as Record::rawComment().

Such a Record can be cast to double (records of value type T can be cast to T), or more precisely, it can be sliced as its value.

double milleniumFalconSpeed = 1.5 * lightSpeed;
// Same as: 1.5 * lightSpeed.value

This is also usefull when aiming at reading record values only, and skip the keyword, unit and comment:

Record<int> theRecord = header.read<int>("KEYWORD");
int theValue = header.read<int>("KEYWORD");

The "HIERARCH" convention for extended keywords is supported. It occurs when the keyword is longer than 8 characters, or contains non-standard characters like spaces or symbols. Such records are read and written transparently as:

HIERARCH the_long_keyword = value / [unit] comment

The maximum length of such a keyword is 67 characters, which gives room for a 1-byte long value.

CFITSIO convention on long string values (more than 68 characters) is supported. When writing a long string record, the value is wrapped automatically, and each new line starts with the CONTINUE keyword. An additional "LONGSTRN" record is written to the file, to warn the file user about the CFITSIO convention.

Public Types
using	Value = T
	The value type.

Static Public Member Functions
template<typename TFrom >
static T	cast (TFrom value)
	Helper function to cast Record value types. Valid casts are: More...

Public Member Functions
	Record (const std::string &k="", T v=T(), const std::string &u="", const std::string &c="")
	Constructor. More...
template<typename TFrom >
	Record (const Record< TFrom > &other)
	Create a record from a Record of another type. More...
template<typename TFrom >
Record< T > &	assign (const std::string &k="", TFrom v=TFrom(), const std::string &u="", const std::string &c="")
	Assign new fields to the record.
template<typename U >
Record< T > &	assign (const Record< U > &other)
	Copy a Record of another type.
	operator T () const
	Slice the record as its value. More...
std::string	rawComment () const
	Get the raw comment string. More...
bool	hasLongKeyword () const
	Check whether the keyword of a record is long string (more than 8 characters). More...
bool	hasLongStringValue () const
	Check whether the value of a record is a long string (more than 68 characters). More...

Public Attributes
std::string	keyword
	The keyword.
T	value
	The value.
std::string	unit
	The unit.
std::string	comment
	The comment without the unit.

Related Functions
(Note that these are not member functions.)
template<typename T >
bool	operator== (const Record< T > &lhs, const Record< T > &rhs)
	Check whether two records are equal. More...
template<typename T >
bool	operator!= (const Record< T > &lhs, const Record< T > &rhs)
	Check whether two records are different.
template<typename T >
std::ostream &	operator<< (std::ostream &os, const Record< T > &r)
	Serialize a record.

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The documentation for this struct was generated from the following file:

• EleFitsData/EleFitsData/Record.h