Add support for PDS3 Spreadsheets that use record value offsets

[jordanpadams]

This ticket will deal with updating the Transform Tool to support PDS3 Spreadsheet objects that contain a record offset value instead of a byte offset value in the pointer statement.

The tool currently outputs the following error when trying to perform a PDS3 table to CSV transformation:

C:\Users\slavney\Documents\Work_files\Mission_Operations\MSL\PDS3to4\ForSean\APXS>transform apa_402284882rsp00540043232_______p1.lbl -f pds4-label -o apa_pds4label
gov.nasa.pds.transform.TransformException: Error occurred while generating PDS4 label: Invocation of method 'parseInt' in  class java.lang.Integer threw exception java.lang.NumberFormatException: null at /gov/nasa/pds/transform/util/generic-pds3_to_pds4.vm[line 596, column 55]
        at gov.nasa.pds.transform.product.Pds3LabelTransformer.transform(Pds3LabelTransformer.java:91)
        at gov.nasa.pds.transform.product.Pds3LabelTransformer.transform(Pds3LabelTransformer.java:103)
        at gov.nasa.pds.transform.TransformLauncher.doTransformation(TransformLauncher.java:425)
        at gov.nasa.pds.transform.TransformLauncher.processMain(TransformLauncher.java:460)
        at gov.nasa.pds.transform.TransformLauncher.main(TransformLauncher.java:479)
outputs = []
PDS Transform Tool Log

Version                     Version 1.6.0
Time                        Thu, Nov 30 2017 at 02:17:36 PM
Target                      [file:/C:/Users/slavney/Documents/Work_files/Mission_Operations/MSL/PDS3to4/ForSean/APXS/apa_402284882rsp00540043232_______p1.lbl]
Output Directory            apa_pds4label
Index                       1
Format Type                 pds4-label

INFO:   [C:\Users\slavney\Documents\Work_files\Mission_Operations\MSL\PDS3to4\ForSean\APXS\apa_402284882rsp00540043232_______p1.lbl] Transforming label file: C:\Users\slavney\Documents\Work_files\Mission_Operations\MSL\PDS3to4\ForSean\APXS\apa_402284882rsp00540043232_______p1.lbl
ERROR:   [file:/C:/Users/slavney/Documents/Work_files/Mission_Operations/MSL/PDS3to4/ForSean/APXS/apa_402284882rsp00540043232_______p1.lbl] Error occurred while generating PDS4 label: Invocation of method 'parseInt' in  class java.lang.Integer threw exception java.lang.NumberFormatException: null at /gov/nasa/pds/transform/util/generic-pds3_to_pds4.vm[line 596, column 55]

The issue is that when the tool sees a record value in a pointer statement like so:

^SPREADSHEET = ("APA_402284882RSP00540043232_______P1.CSV",2)

it calculates the actual start byte location of the data by using the RECORD_BYTES value. However, this element does not exist in the label so it errors out. Changing this pointer statement with using a BYTE offset value instead, transformation is successful:

^SPREADSHEET = ("APA_402284882RSP00540043232_______P1.CSV",130 <BYTES>)

This update will involve having to read in the data file to determine the starting byte location of the data so that the PDS4 label will get populated with the correct offset value when describing the table object.

apa_402284882rsp00540043232_______p1.csv.txt
apa_402284882rsp00540043232_______p1.lbl.txt