Fix ISO 8211 parsing of 8-byte binary format controls (b48)#10
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The binary format-control parser treated the first digit of a bWN control as a sign indicator handling only 1 (unsigned) and 2 (signed), returning null for floating-point types such as b48. This dropped the three 8-byte DCOX/DCOY/DCOZ origin-shift subfields in the S-100/S-101 DSSI field (3b48,10b14), shifting every later subfield by 12 bytes and decoding CMFX/CMFY/CMFZ as 0. Honor the second digit as the byte width and add a FloatingPoint format type for b4x/b5x (IEEE 754) so (3b48,10b14) expands to three 8-byte floating-point subfields followed by ten 4-byte unsigned integers. Adds a regression test parsing the 64-byte DSSI blob from issue #9. Fixes #9 Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
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Summary
Fixes #9.
Iso8211FieldReadermis-parsed binary format controls of the formbWNwhere the type digit is4(IEEE-754 floating-point), e.g.b48— the 8-byte origin shifts used by the S-100/S-101 DSSI field(3b48,10b14).Root cause
Iso8211DataDescriptiveRecordReader.ParseBinaryFormattreated the first digit of abWNcontrol as a sign indicator that only handled1(unsigned) and2(signed), returningnullfor any other type. Forb48the first digit is4(floating-point), so the method returnednulland the three 8-byteDCOX/DCOY/DCOZsubfields were silently dropped. This shifted every later subfield by 12 bytes, decodingCMFX/CMFY/CMFZas0and reading the record counts off by three slots.Downstream S-101 code masked the X/Y loss with a hard-coded
1e7fallback, but the Z (sounding/height) factor fell back to the S-57SOMF=10default, making charted soundings ~10× too deep.Fix
FloatingPointformat type (b4x/b5x, IEEE 754) toIso8211SubfieldFormatType.ParseBinaryFormatnow maps the type digit1→unsigned,2→signed,4/5→floating-point, and honors the second digit as the byte width — so(3b48,10b14)expands to three 8-byte floats followed by ten 4-byte unsigned ints.ConvertFloatingBinary(width 4→float, 8→double) inIso8211FieldReader; updatedToString/ByteSize.Test
Added regression test
GetSubfield_DssiFieldWith8ByteBinaryControls_DecodesCorrectly, which parses the 64-byte DSSI blob from the issue and assertsCMFX=10000000,CMFY=10000000,CMFZ=100,NOIR=85,NOPN=4800,NOMN=5.Full suite: 438/438 passing. No package version bump.