uk.ac.starlink.fits.ScalarColumnWriter Maven / Gradle / Ivy
package uk.ac.starlink.fits;
import java.io.DataOutput;
import java.io.IOException;
import java.math.BigDecimal;
import java.math.BigInteger;
import java.util.logging.Logger;
import uk.ac.starlink.table.ColumnInfo;
import uk.ac.starlink.table.DescribedValue;
import uk.ac.starlink.table.Tables;
/**
* ColumnWriter for writing scalar values.
* Abstract class with a factory method for providing implementations.
*
* @author Mark Taylor
* @since 10 Jul 2008
*/
abstract class ScalarColumnWriter implements ColumnWriter {
private final char formatChar_;
private final int nbyte_;
private final Number badNumber_;
private static final Logger logger_ =
Logger.getLogger( "uk.ac.starlink.fits" );
/**
* Constructor.
*
* @param formatChar TFORM type-specific format character
* @param nbyte number of bytes per scalar written
* @param badNumber numeric value used for bad values, or null
*/
protected ScalarColumnWriter( char formatChar, int nbyte,
Number badNumber ) {
formatChar_ = formatChar;
nbyte_ = nbyte;
badNumber_ = badNumber;
}
public String getFormat() {
return new String( new char[] { formatChar_ } );
}
public char getFormatChar() {
return formatChar_;
}
public int getLength() {
return nbyte_;
}
public int[] getDims() {
return null;
}
public BigDecimal getZero() {
return BigDecimal.ZERO;
}
public double getScale() {
return 1.0;
}
public Number getBadNumber() {
return badNumber_;
}
/**
* Constructs ScalarColumnWriters for specific column metadata.
*
* @param cinfo column metadata for column to be written
* @param nullableInt true if the column contains integer values which
* may be null
* @param allowSignedByte if true, bytes written as FITS signed bytes
* (TZERO=-128), if false bytes written as signed shorts
* @param padChar padding character for undersized character arrays
* @return new column writer, or null if we don't know how to do it
*/
public static ScalarColumnWriter
createColumnWriter( ColumnInfo cinfo, boolean nullableInt,
boolean allowSignedByte,
final byte padChar ) {
Class clazz = cinfo.getContentClass();
Number blankNum = null;
if ( nullableInt ) {
DescribedValue blankVal =
cinfo.getAuxDatum( Tables.NULL_VALUE_INFO );
if ( blankVal != null ) {
Object blankObj = blankVal.getValue();
if ( blankObj instanceof Number ) {
blankNum = (Number) blankObj;
}
}
}
boolean isUbyte =
Boolean.TRUE
.equals( cinfo.getAuxDatumValue( Tables.UBYTE_FLAG_INFO,
Boolean.class ) );
final BigInteger longOffset = getLongOffset( cinfo );
if ( isUbyte && clazz == Short.class ) {
final short badVal = blankNum == null ? (short) 0xff
: blankNum.shortValue();
return new ScalarColumnWriter( 'B', 1,
nullableInt ? new Short( badVal )
: null ) {
public void writeValue( DataOutput stream, Object value )
throws IOException {
short bval = ( value != null )
? ((Number) value).shortValue()
: badVal;
stream.writeByte( bval );
}
};
}
else if ( longOffset != null && clazz == String.class ) {
final long badVal = blankNum == null ? Long.MIN_VALUE
: blankNum.longValue();
final BigDecimal zeroNum = new BigDecimal( longOffset );
return new ScalarColumnWriter( 'K', 8,
nullableInt ? new Long( badVal )
: null ) {
@Override
public BigDecimal getZero() {
return zeroNum;
}
public void writeValue( DataOutput stream, Object value )
throws IOException {
long lval = value instanceof String
? getOffsetLongValue( (String) value, longOffset,
badVal )
: badVal;
stream.writeLong( lval );
}
};
}
else if ( clazz == Boolean.class ) {
return new ScalarColumnWriter( 'L', 1, null ) {
public void writeValue( DataOutput stream, Object value )
throws IOException {
byte b;
if ( Boolean.TRUE.equals( value ) ) {
b = (byte) 'T';
}
else if ( Boolean.FALSE.equals( value ) ) {
b = (byte) 'F';
}
else {
b = (byte) 0;
}
stream.writeByte( b );
}
};
}
else if ( clazz == Byte.class ) {
/* Byte is a bit tricky since a FITS byte is unsigned, while
* a byte in a StarTable (a java byte) is signed. */
if ( allowSignedByte ) {
final byte[] buf = new byte[ 1 ];
final byte badVal = blankNum == null ? (byte) 0
: blankNum.byteValue();
final BigDecimal zeroByte = new BigDecimal( -128 );
return new ScalarColumnWriter( 'B', 1,
nullableInt ? new Byte( badVal )
: null ) {
public void writeValue( DataOutput stream, Object value )
throws IOException {
byte b = (value != null) ? ((Number) value).byteValue()
: badVal;
buf[ 0 ] = (byte) ( b ^ (byte) 0x80 );
stream.write( buf );
}
public BigDecimal getZero() {
return zeroByte;
}
};
}
else {
final short badVal = blankNum == null
? (short) ( Byte.MIN_VALUE - (short) 1 )
: blankNum.shortValue();
return new ScalarColumnWriter( 'I', 2,
nullableInt ? new Short( badVal )
: null ) {
public void writeValue( DataOutput stream, Object value )
throws IOException {
short sval = ( value != null )
? ((Number) value).shortValue()
: badVal;
stream.writeShort( sval );
}
};
}
}
else if ( clazz == Short.class ) {
final short badVal = blankNum == null ? Short.MIN_VALUE
: blankNum.shortValue();
return new ScalarColumnWriter( 'I', 2,
nullableInt ? new Short( badVal )
: null ) {
public void writeValue( DataOutput stream, Object value )
throws IOException {
short sval = ( value != null )
? ((Number) value).shortValue()
: badVal;
stream.writeShort( sval );
}
};
}
else if ( clazz == Integer.class ) {
final int badVal = blankNum == null ? Integer.MIN_VALUE
: blankNum.intValue();
return new ScalarColumnWriter( 'J', 4,
nullableInt ? new Integer( badVal )
: null ) {
public void writeValue( DataOutput stream, Object value )
throws IOException {
int ival = ( value != null )
? ((Number) value).intValue()
: badVal;
stream.writeInt( ival );
}
};
}
else if ( clazz == Long.class ) {
final long badVal = blankNum == null ? Long.MIN_VALUE
: blankNum.longValue();
return new ScalarColumnWriter( 'K', 8,
nullableInt ? new Long( badVal )
: null ) {
public void writeValue( DataOutput stream, Object value )
throws IOException {
long lval = ( value != null )
? ((Number) value).longValue()
: badVal;
stream.writeLong( lval );
}
};
}
else if ( clazz == Float.class ) {
return new ScalarColumnWriter( 'E', 4, null ) {
public void writeValue( DataOutput stream, Object value )
throws IOException {
float fval = ( value != null )
? ((Number) value).floatValue()
: Float.NaN;
stream.writeFloat( fval );
}
};
}
else if ( clazz == Double.class ) {
return new ScalarColumnWriter( 'D', 8, null ) {
public void writeValue( DataOutput stream, Object value )
throws IOException {
double dval = ( value != null )
? ((Number) value).doubleValue()
: Double.NaN;
stream.writeDouble( dval );
}
};
}
else if ( clazz == Character.class ) {
return new ScalarColumnWriter( 'A', 1, null ) {
public void writeValue( DataOutput stream, Object value )
throws IOException {
char cval = ( value != null )
? ((Character) value).charValue()
: (char) padChar;
stream.writeByte( cval );
}
};
}
else {
return null;
}
}
/**
* Acquires the long offset value for a column as a big integer,
* if it has one.
*
* @param cinfo column metadata
* @return BigInteger representation of long offset, or null
*/
static BigInteger getLongOffset( ColumnInfo cinfo ) {
Class clazz = cinfo.getContentClass();
if ( String.class.equals( clazz ) ||
String[].class.equals( clazz ) ) {
String longoffTxt =
cinfo.getAuxDatumValue( BintableStarTable.LONGOFF_INFO,
String.class );
if ( longoffTxt != null ) {
try {
return new BigInteger( longoffTxt );
}
catch ( NumberFormatException e ) {
}
}
}
return null;
}
/**
* Offsets a string value representing an integer by a given
* BigInteger offset to give a long result.
* If the string is unsuitable or the result is out of range
* for a long, a supplied bad value is returned instead.
*
* @param txt string representation of value
* @param longOffset offset value
* @param badVal result for case of error
* @return long representation of offset result, or badVal
*/
static long getOffsetLongValue( String txt, BigInteger longOffset,
long badVal ) {
if ( txt == null ) {
return badVal;
}
/* This could be coded more efficiently (exceptions are expensive),
* but it's not expected that the conversion will fail under
* the most common circumstances (FITS table column round-tripping). */
try {
return new BigInteger( txt )
.subtract( longOffset )
.longValueExact();
}
catch ( NumberFormatException e ) { // not numeric string
return badVal;
}
catch ( ArithmeticException e ) { // out of range for long
return badVal;
}
}
}
© 2015 - 2025 Weber Informatics LLC | Privacy Policy