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use crate::error::Result;
use crate::reader::BinaryReader;
use std::io::{Read, Seek};
/// The critical preamble containing addresses and acquisition date.
#[derive(Debug)]
pub struct RawFileInfoPreamble {
pub method_file_present: bool,
pub year: u16,
pub month: u16,
pub day_of_week: u16,
pub day: u16,
pub hour: u16,
pub minute: u16,
pub second: u16,
pub millisecond: u16,
pub controller_count: u32,
/// File offset to the scan data stream.
pub data_addr: u64,
/// File offset to the first RunHeader (may be a non-MS controller in multi-controller files).
pub run_header_addr: u64,
/// All run header addresses (one per controller). Index 0 == run_header_addr.
pub run_header_addrs: Vec<u64>,
/// Second RunHeader address (for multi-controller files).
pub run_header_addr_2: u64,
}
/// Convert a proleptic Gregorian civil date to days since 1970-01-01.
///
/// Howard Hinnant's `days_from_civil` algorithm
/// (<https://howardhinnant.github.io/date_algorithms.html#days_from_civil>,
/// public domain calendar arithmetic, independent of any vendor source).
fn days_from_civil(y: i64, m: u32, d: u32) -> i64 {
let y = if m <= 2 { y - 1 } else { y };
let era = if y >= 0 { y } else { y - 399 } / 400;
let yoe = y - era * 400;
let mp = (if m > 2 { m - 3 } else { m + 9 }) as i64;
let doy = (153 * mp + 2) / 5 + d as i64 - 1;
let doe = yoe * 365 + yoe / 4 - yoe / 100 + doy;
era * 146_097 + doe - 719_468
}
/// RawFileInfo: preamble + label strings + computer name.
#[derive(Debug)]
pub struct RawFileInfo {
pub preamble: RawFileInfoPreamble,
pub label_headings: Vec<String>,
pub computer_name: String,
}
impl RawFileInfo {
pub(crate) fn read<R: Read + Seek>(r: &mut BinaryReader<R>, version: u32) -> Result<Self> {
let preamble = RawFileInfoPreamble::read(r, version)?;
// 5 label heading strings + computer name
let mut label_headings = Vec::with_capacity(5);
for _ in 0..5 {
label_headings.push(r.read_pascal_string()?);
}
let computer_name = r.read_pascal_string()?;
Ok(Self {
preamble,
label_headings,
computer_name,
})
}
}
impl RawFileInfoPreamble {
/// Convert the preamble's year/month/day/hour/minute/second/millisecond
/// fields to a Unix timestamp in seconds, or `None` if no acquisition
/// date is present (`year == 0`) or the date fields are out of range.
///
/// Like [`crate::audit_tag::AuditTag::time`], this is the instrument's
/// local wall-clock time with no timezone: interpreting the result as
/// UTC reproduces the local wall-clock value rather than a true UTC
/// instant. This is a different decoded timestamp from that audit-tag
/// FILETIME (surfaced separately by the Python bindings as
/// `RawFile.created`); the two are expected to agree since they record
/// the same acquisition event, but come from independently-decoded
/// fields.
pub fn acquisition_date(&self) -> Option<f64> {
if self.year == 0 || !(1..=12).contains(&self.month) || !(1..=31).contains(&self.day) {
return None;
}
let days = days_from_civil(self.year as i64, self.month as u32, self.day as u32);
let secs =
days * 86_400 + self.hour as i64 * 3600 + self.minute as i64 * 60 + self.second as i64;
Some(secs as f64 + self.millisecond as f64 / 1000.0)
}
pub(crate) fn read<R: Read + Seek>(r: &mut BinaryReader<R>, version: u32) -> Result<Self> {
let method_file_present = r.read_u32()? != 0;
let year = r.read_u16()?;
let month = r.read_u16()?;
let day_of_week = r.read_u16()?;
let day = r.read_u16()?;
let hour = r.read_u16()?;
let minute = r.read_u16()?;
let second = r.read_u16()?;
let millisecond = r.read_u16()?;
if version >= 64 {
// Version 66 layout
let _unk2 = r.read_u32()?;
let _data_addr_32 = r.read_u32()?; // defunct
let controller_count = r.read_u32()?;
let _controller_n2 = r.read_u32()?;
let _unk5 = r.read_u32()?;
let _unk6 = r.read_u32()?;
let _run_header_addr_32 = r.read_u32()?; // defunct
// Skip unknown_area[1]: 760 bytes
r.skip(760)?;
// Controller address table. Layout is:
// [data_addr: u64] [u32] [u32] -- scan data entry
// [run_hdr[0]: u64] [u32] [u32] -- controller 0
// [run_hdr[1]: u64] [u32] [u32] -- controller 1
// ... (for every controller beyond 2, each entry is 16 bytes
// and lives at the start of what used to be "unknown_area[2]")
// [padding zeros to fill 1048-byte region]
//
// The total region (from data_addr through the skip) is 1048 bytes for
// a 2-controller file. Each extra controller takes 16 bytes from the skip.
let data_addr = r.read_u64()?;
let _unk7 = r.read_u32()?;
let _unk8 = r.read_u32()?;
let mut run_header_addrs = Vec::new();
// Always read at least 2 entries for compatibility
let n_read = controller_count.max(2) as usize;
for _ in 0..n_read {
let addr = r.read_u64()?;
let _unk_a = r.read_u32()?;
let _unk_b = r.read_u32()?;
run_header_addrs.push(addr);
}
let run_header_addr = run_header_addrs[0];
let run_header_addr_2 = run_header_addrs.get(1).copied().unwrap_or(0);
// Remaining padding to reach end of address-table region.
// The region size differs by file version:
// v64: 1032 bytes (data entry + up to ~2 controller entries + padding)
// v66+: 1048 bytes (one extra slot for the additional controller table)
let used_bytes = 16usize + n_read * 16;
let total_region = if version >= 66 { 1048usize } else { 1032usize };
let remaining = total_region.saturating_sub(used_bytes);
r.skip(remaining)?;
Ok(Self {
method_file_present,
year,
month,
day_of_week,
day,
hour,
minute,
second,
millisecond,
controller_count,
data_addr,
run_header_addr,
run_header_addrs,
run_header_addr_2,
})
} else {
// Pre-v64 (32-bit addresses)
let _unk2 = r.read_u32()?;
let data_addr = r.read_u32()? as u64;
let controller_count = r.read_u32()?;
let _controller_n2 = r.read_u32()?;
let _unk5 = r.read_u32()?;
let _unk6 = r.read_u32()?;
let run_header_addr = r.read_u32()? as u64;
let _unk7 = r.read_u32()?;
let _unk8 = r.read_u32()?;
let run_header_addr_2 = r.read_u32()? as u64;
// Skip unknown_area: 744 bytes
r.skip(744)?;
Ok(Self {
method_file_present,
year,
month,
day_of_week,
day,
hour,
minute,
second,
millisecond,
controller_count,
data_addr,
run_header_addr,
run_header_addrs: vec![run_header_addr, run_header_addr_2],
run_header_addr_2,
})
}
}
}
#[cfg(test)]
mod tests {
use super::*;
fn preamble(
year: u16,
month: u16,
day: u16,
hour: u16,
minute: u16,
second: u16,
millisecond: u16,
) -> RawFileInfoPreamble {
RawFileInfoPreamble {
method_file_present: false,
year,
month,
day_of_week: 0,
day,
hour,
minute,
second,
millisecond,
controller_count: 1,
data_addr: 0,
run_header_addr: 0,
run_header_addrs: Vec::new(),
run_header_addr_2: 0,
}
}
#[test]
fn days_from_civil_epoch() {
assert_eq!(days_from_civil(1970, 1, 1), 0);
}
#[test]
fn days_from_civil_reference_value() {
// Reference value from Hinnant's date algorithms writeup.
assert_eq!(days_from_civil(2000, 3, 1), 11017);
}
#[test]
fn acquisition_date_matches_known_epoch() {
let p = preamble(1970, 1, 1, 0, 0, 0, 0);
assert_eq!(p.acquisition_date(), Some(0.0));
}
#[test]
fn acquisition_date_includes_time_of_day_and_millis() {
let p = preamble(1970, 1, 1, 1, 1, 1, 500);
assert_eq!(p.acquisition_date(), Some(3661.5));
}
#[test]
fn acquisition_date_none_when_year_zero() {
let p = preamble(0, 1, 1, 0, 0, 0, 0);
assert_eq!(p.acquisition_date(), None);
}
#[test]
fn acquisition_date_none_when_month_out_of_range() {
let p = preamble(2020, 13, 1, 0, 0, 0, 0);
assert_eq!(p.acquisition_date(), None);
}
}