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//! RINEX compression module
use crate::{
epoch::epoch_decompose as epoch_decomposition,
error::FormattingError,
hatanaka::{NumDiff, TextDiff},
observation::{HeaderFields, Record},
prelude::{Constellation, Observable, SV},
BufWriter,
};
use std::{collections::HashMap, io::Write};
use itertools::Itertools;
pub type Compressor = CompressorExpert<5>;
pub struct CompressorExpert<const M: usize> {
/// True (by default) if this a CRINEX3 compressor.
/// Modify this before getting started!
pub v3: bool,
/// True when epoch descriptor should be compressed.
/// True on first epoch.
epoch_compression: bool,
/// Readable Epoch being compressed
epoch_buf: String,
/// Readable flags being compressed
flags_buf: String,
/// Epoch [TextDiff]
epoch_diff: TextDiff,
/// Flags kernel, per SV
flags_diff: HashMap<SV, TextDiff>,
/// Flag textdiff
/// Compression kernels (per SV and signal)
sv_kernels: HashMap<(SV, Observable), NumDiff<M>>,
// /// Clock [NumDiff]
// clock_diff: NumDiff<M>,
}
impl<const M: usize> Default for CompressorExpert<M> {
fn default() -> Self {
Self {
v3: true,
epoch_compression: false,
epoch_diff: TextDiff::new(""),
epoch_buf: String::with_capacity(128),
flags_buf: String::with_capacity(128),
sv_kernels: HashMap::with_capacity(8),
flags_diff: HashMap::with_capacity(8),
}
}
}
impl<const M: usize> CompressorExpert<M> {
/// Format [Record] using mutable [CompressorExpert].
/// Compressed bytes are dumped in mutable [BufWriter].
/// This permits the RNX2CRX compression ops.
pub fn format<W: Write>(
&mut self,
w: &mut BufWriter<W>,
record: &Record,
header: &HeaderFields,
) -> Result<(), FormattingError> {
for (k, v) in record.iter() {
if !k.flag.is_ok() {
// TODO not 100% correct, verify > 1
self.epoch_compression = false;
}
let (y, m, d, hh, mm, ss, ns) = epoch_decomposition(k.epoch);
// form unique SV list
let svnn = v
.signals
.iter()
.map(|sig| sig.sv)
.unique()
.sorted()
.collect::<Vec<_>>();
if !self.epoch_compression {
if self.v3 {
write!(w, "> ")?;
} else {
write!(w, "&")?;
}
} else {
if self.v3 {
write!(w, " ")?;
} else {
write!(w, " ")?;
}
}
if self.v3 {
self.epoch_buf.push_str(&format!(
"{:04} {:02} {:02} {:02} {:02} {:02}.{:07} {}{:3} ",
y,
m,
d,
hh,
mm,
ss,
ns / 100,
k.flag,
svnn.len(),
));
} else {
self.epoch_buf.push_str(&format!(
"{:02} {:02} {:02} {:02} {:02} {:02}.{:07} {}{:3} ",
y,
m,
d,
hh,
mm,
ss,
ns / 100,
k.flag,
svnn.len(),
));
}
// Append each SV to epoch description
for sv in svnn.iter() {
self.epoch_buf.push_str(&format!("{:x}", sv));
}
// Epoch compression
if !self.epoch_compression {
self.epoch_diff.force_init(&self.epoch_buf);
writeln!(w, "{}", self.epoch_buf.trim_end())?;
} else {
let compressed = self.epoch_diff.compress(&self.epoch_buf);
writeln!(w, "{}", compressed.trim_end())?;
}
if let Some(clk) = v.clock {
// TODO: clock is not correctly supported yet
if !self.epoch_compression {
writeln!(w, "{}", clk.offset_s)?;
}
} else {
// No clock: BLANKed line
write!(w, "\n")?;
}
// For each SV
for sv in svnn.iter() {
// Following header specs
let sv_observables = header.codes.get(&sv.constellation);
let sv_observables = match sv_observables {
Some(observables) => observables, // correctly identified,
None => {
// handles SBAS case
if sv.constellation.is_sbas() {
match header.codes.get(&Constellation::SBAS) {
Some(observables) => observables,
None => {
// correctly formatted RINEX will never
// end up here
continue;
},
}
} else {
// correctly formatted RINEX will never
// end up here
continue;
}
},
};
for observable in sv_observables.iter() {
if let Some(signal) = v
.signals
.iter()
.filter(|sig| sig.sv == *sv && &sig.observable == observable)
.reduce(|k, _| k)
{
let quantized = (signal.value * 1000.0).round() as i64;
// retrieve or build compression kernel
if let Some((_, sv_kernel)) = self
.sv_kernels
.iter_mut()
.filter(|((sv, obs), _)| *sv == signal.sv && obs == &signal.observable)
.reduce(|k, _| k)
{
let compressed = sv_kernel.compress(quantized);
write!(w, "{} ", compressed)?;
} else {
// first encounter: build kernel
let kernel = NumDiff::<M>::new(quantized, 3);
self.sv_kernels
.insert((signal.sv, signal.observable.clone()), kernel);
write!(w, "{}&{} ", 3, quantized)?;
}
if let Some(lli) = signal.lli {
self.flags_buf.push_str(&format!("{}", lli.bits() as u8));
} else {
self.flags_buf.push_str(" ");
}
if let Some(snr) = signal.snr {
self.flags_buf.push_str(&format!("{}", snr as u8));
} else {
self.flags_buf.push_str(" ");
}
} else {
// BLANK is a single ' '
write!(w, "{}", ' ')?;
self.flags_buf.push_str(" ");
}
}
// Flags compression
if let Some(flags_kernel) = self.flags_diff.get_mut(&sv) {
let compressed = flags_kernel.compress(&self.flags_buf);
writeln!(w, "{}", compressed)?;
} else {
let mut kernel = TextDiff::new("");
let compressed = kernel.compress(&self.flags_buf);
writeln!(w, "{}", compressed)?;
self.flags_diff.insert(*sv, kernel);
}
self.flags_buf.clear();
}
// prepare for next epoch
self.epoch_compression = true;
self.epoch_buf.clear();
}
Ok(())
}
}