nom.tam.fits.header.Checksum Maven / Gradle / Ivy
package nom.tam.fits.header;
/*
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/**
*
* File checksum keywords. This data dictionary contains FITS keywords that have been widely used within the
* astronomical community. It is recommended that these keywords only be used as defined here.
*
*
* See http://heasarc.gsfc.nasa.gov/docs/fcg/common_dict.html
*
*
* @author Richard van Nieuwenhoven
*/
public enum Checksum implements IFitsHeader {
/**
* The value field of the CHECKSUM keyword shall contain a 16 character string, left justified starting in column
* 12, containing the ASCII encoded complement of the checksum of the FITS HDU (Header and Data Unit). The algorithm
* shall be the 32-bit 1's complement checksum and the ASCII encoding that are described in the checksum proposal.
* The checksum is accumulated in FITS datastream order on the same HDU, identical in all respects, except that the
* value of the CHECKSUM keyword shall be set to the string '0000000000000000' (ASCII 0's, hex 30) before the
* checksum is computed.
*/
CHECKSUM(HDU.ANY, VALUE.STRING, "complement checksum for the current HDU"),
/**
* The value field of the CHECKVER keyword shall contain a string, unique in the first 8 characters, which
* distinguishes between any future alternative checksum algorithms which may be defined. The default value for a
* missing keyword shall be 'COMPLEMENT' which will represent the algorithm defined in the current proposal. It is
* recommended that this keyword be omitted from headers which implement the default ASCII encoded 32-bit 1's
* complement algorithm.
*/
CHECKVER(HDU.ANY, VALUE.STRING, "version of checksum algorithm"),
/**
* The value field of the DATASUM keyword shall be a character string containing the unsigned integer value of the
* checksum of the data records of the HDU. For dataless HDU's, this keyword may either be omitted, or the value
* field shall contain the string value '0', which is preferred. A missing DATASUM keyword asserts no knowledge of
* the checksum of the data records.
*/
DATASUM(HDU.ANY, VALUE.STRING, "checksum of the data records");
private final FitsKey key;
Checksum(HDU hdu, VALUE valueType, String comment) {
key = new FitsKey(name(), IFitsHeader.SOURCE.CHECKSUM, hdu, valueType, comment);
FitsKey.registerStandard(this);
}
@Override
public FitsKey impl() {
return key;
}
}