SPICE BSP files should be usable without needing the ANISE file equivalent
ChristopherRabotin opened this issue · comments
Use case
Although the ANISE file format provides a number of advantages compared to the BSP files, requiring users to convert their data into ANISE before using this library is a large overhead.
Effort
ANISE.rs already supports reading BSP files of some types. However, that implementation requires memory allocations. These should not be required.
Hence, the crux of this issue is to rewrite the SPK parser to not perform any memory allocations. This issue also includes providing a rewrite of some of the SPK related functions (exact list to be determined from this list). These functions must be behind a specific crate feature, e.g. spice-interop.
Verification
TDB: from the list of functions above, the tests should require rust-spice by @GregoireHENRY and make sure that the SPK functions selects return the same values. This will likely require #26 too.
I will make sure the list of SPK-related selected functions are supported in the wrapper.
The latest update can load SPK and BPC data using furnsh_spk and furnsh_bpc. I can't make those generic yet because the data is strongly typed at loading time (in order to correctly read the summary data) and they go into different variables.
Since the SPICE context only has pointers to the data, the size on the stack remains the same:
DE-0421LE-0421 -> SPKSummaryRecord { start_epoch_et_s: -3169195200.0, end_epoch_et_s: 1696852800.0, target_id: 1, center_id: 0, frame_id: 1, data_type_i: 2, start_idx: 641, end_idx: 310404 }
DE-0421LE-0421 -> SPKSummaryRecord { start_epoch_et_s: -3169195200.0, end_epoch_et_s: 1696852800.0, target_id: 2, center_id: 0, frame_id: 1, data_type_i: 2, start_idx: 310405, end_idx: 423048 }
DE-0421LE-0421 -> SPKSummaryRecord { start_epoch_et_s: -3169195200.0, end_epoch_et_s: 1696852800.0, target_id: 3, center_id: 0, frame_id: 1, data_type_i: 2, start_idx: 423049, end_idx: 567372 }
DE-0421LE-0421 -> SPKSummaryRecord { start_epoch_et_s: -3169195200.0, end_epoch_et_s: 1696852800.0, target_id: 4, center_id: 0, frame_id: 1, data_type_i: 2, start_idx: 567373, end_idx: 628976 }
DE-0421LE-0421 -> SPKSummaryRecord { start_epoch_et_s: -3169195200.0, end_epoch_et_s: 1696852800.0, target_id: 5, center_id: 0, frame_id: 1, data_type_i: 2, start_idx: 628977, end_idx: 674740 }
DE-0421LE-0421 -> SPKSummaryRecord { start_epoch_et_s: -3169195200.0, end_epoch_et_s: 1696852800.0, target_id: 6, center_id: 0, frame_id: 1, data_type_i: 2, start_idx: 674741, end_idx: 715224 }
DE-0421LE-0421 -> SPKSummaryRecord { start_epoch_et_s: -3169195200.0, end_epoch_et_s: 1696852800.0, target_id: 7, center_id: 0, frame_id: 1, data_type_i: 2, start_idx: 715225, end_idx: 750428 }
DE-0421LE-0421 -> SPKSummaryRecord { start_epoch_et_s: -3169195200.0, end_epoch_et_s: 1696852800.0, target_id: 8, center_id: 0, frame_id: 1, data_type_i: 2, start_idx: 750429, end_idx: 785632 }
DE-0421LE-0421 -> SPKSummaryRecord { start_epoch_et_s: -3169195200.0, end_epoch_et_s: 1696852800.0, target_id: 9, center_id: 0, frame_id: 1, data_type_i: 2, start_idx: 785633, end_idx: 820836 }
DE-0421LE-0421 -> SPKSummaryRecord { start_epoch_et_s: -3169195200.0, end_epoch_et_s: 1696852800.0, target_id: 10, center_id: 0, frame_id: 1, data_type_i: 2, start_idx: 820837, end_idx: 944040 }
DE-0421LE-0421 -> SPKSummaryRecord { start_epoch_et_s: -3169195200.0, end_epoch_et_s: 1696852800.0, target_id: 301, center_id: 3, frame_id: 1, data_type_i: 2, start_idx: 944041, end_idx: 1521324 }
DE-0421LE-0421 -> SPKSummaryRecord { start_epoch_et_s: -3169195200.0, end_epoch_et_s: 1696852800.0, target_id: 399, center_id: 3, frame_id: 1, data_type_i: 2, start_idx: 1521325, end_idx: 2098608 }
DE-0421LE-0421 -> SPKSummaryRecord { start_epoch_et_s: -3169195200.0, end_epoch_et_s: 1696852800.0, target_id: 199, center_id: 1, frame_id: 1, data_type_i: 2, start_idx: 2098609, end_idx: 2098620 }
DE-0421LE-0421 -> SPKSummaryRecord { start_epoch_et_s: -3169195200.0, end_epoch_et_s: 1696852800.0, target_id: 299, center_id: 2, frame_id: 1, data_type_i: 2, start_idx: 2098621, end_idx: 2098632 }
DE-0421LE-0421 -> SPKSummaryRecord { start_epoch_et_s: -3169195200.0, end_epoch_et_s: 1696852800.0, target_id: 499, center_id: 4, frame_id: 1, data_type_i: 2, start_idx: 2098633, end_idx: 2098644 }
start: 1899-07-29T00:00:00.000000074 ET length: 32 days rsize: 35 num_records: 1760 len data: 61600
[Some("de421"), None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None]
[Some("de421"), Some("de440"), Some("de438s"), None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None]
1536
[Some("de421"), None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None]
1536
Associated code:
let spice = SpiceContext::default();
let spice = spice.furnsh_spk("de421", &de421).unwrap();
println!("{:?}", spice.spk_lut);
// Now load another DE file
// WARNING: Rust won't allow us to load this other file in a scope and then unload it!
{
let bytes = file_mmap!("data/de440.bsp").unwrap();
let de440 = DAFBytes::<SPKSummaryRecord>::parse(&bytes).unwrap();
// NOTE: We assign the output because `furnsh_*` will return a clone of (pointers) of the already loaded context.
// This might sound counter intuitive but it allows the data to be loaded in a given scope and also dropped when that scope is gone.
let spice = spice.furnsh_spk("de440", &de440).unwrap();
// And another
let bytes = file_mmap!("data/de438s.bsp").unwrap();
let de440 = DAFBytes::<SPKSummaryRecord>::parse(&bytes).unwrap();
let spice = spice.furnsh_spk("de438s", &de440).unwrap();
println!("{:?}", spice.spk_lut);
println!("{}", size_of_val(&spice));
}
println!("{:?}", spice.spk_lut);
println!("{}", size_of_val(&spice));