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mod data_block_data;
mod resolved_data_block;
pub use data_block_data::DataBlockData;
pub use resolved_data_block::ResolvedDataBlock;
use super::RawChannelGroup;
use crate::{
Error, Result,
blocks::{
DataBlock, DataGroupBlock, DataListBlock, HlBlock, u64_to_usize, {BlockHeader, BlockParse},
},
};
use alloc::string::ToString;
use alloc::vec::Vec;
#[cfg(feature = "compression")]
use crate::blocks::DzBlock;
#[derive(Debug, Clone)]
pub struct RawDataGroup {
pub block: DataGroupBlock,
pub channel_groups: Vec<RawChannelGroup>,
/// Whether this data group is from an unfinalized MDF file.
pub is_unfinalized: bool,
}
impl RawDataGroup {
/// Collect all data blocks referenced by this data group.
///
/// The returned vector contains the `DT` or `DV` blocks in the order they
/// appear on disk, transparently following any `DL` list chains.
///
/// For unfinalized MDF files, this will automatically use the correct
/// parsing method based on the `is_unfinalized` flag.
///
/// # Arguments
/// * `mmap` - Memory mapped file containing the MDF data
///
/// # Returns
/// A vector of [`DataBlock`] objects or an [`Error`] if parsing fails.
pub fn data_blocks<'a>(&self, mmap: &'a [u8]) -> Result<Vec<DataBlock<'a>>> {
let mut collected_blocks = Vec::new();
// Start at the group's primary data pointer
let mut current_block_address = self.block.data_block_addr;
// Guard against cyclic DL chains in corrupt files.
let mut seen_dl = alloc::collections::BTreeSet::new();
while current_block_address != 0 {
if !seen_dl.insert(current_block_address) {
return Err(Error::LinkCycle {
address: current_block_address,
});
}
let byte_offset = current_block_address as usize;
// Read the block header
let block_header = BlockHeader::from_bytes(&mmap[byte_offset..byte_offset + 24])?;
match block_header.id.as_str() {
"##DT" | "##DV" => {
// Check if this is an empty block in an unfinalized file
// (block_len == 24 means header only, but data follows anyway)
let data_block = if self.is_unfinalized && block_header.length == 24 {
// Use unfinalized parsing - read until end of file
DataBlock::from_bytes_unfinalized(&mmap[byte_offset..])?
} else {
// Normal parsing
DataBlock::from_bytes(&mmap[byte_offset..])?
};
collected_blocks.push(data_block);
// No list to follow, we're done
current_block_address = 0;
}
"##DL" => {
// Fragmented list of data blocks
let data_list_block = DataListBlock::from_bytes(&mmap[byte_offset..])?;
// Parse each fragment in this list
for &fragment_address in &data_list_block.data_block_addrs {
if fragment_address == 0 {
continue;
}
let (frag_addr, _) =
HlBlock::skip_hierarchy_blocks(mmap, fragment_address)?;
let fragment_offset = u64_to_usize(frag_addr, "DL fragment address")?;
let fragment_block = DataBlock::from_bytes(&mmap[fragment_offset..])?;
collected_blocks.push(fragment_block);
}
// Move to the next DLBLOCK in the chain (0 = end)
current_block_address = data_list_block.next_dl_addr;
}
"##HL" => {
let len = u64_to_usize(block_header.length, "##HL")?;
current_block_address =
HlBlock::next_block_addr(&mmap[byte_offset..byte_offset + len])?;
}
unexpected_id => {
return Err(Error::BlockIDError {
actual: unexpected_id.to_string(),
expected: "##DT / ##DV / ##DL / ##HL".to_string(),
});
}
}
}
Ok(collected_blocks)
}
/// Collect all data blocks, decompressing DZ blocks if needed.
///
/// This method handles both regular DT/DV blocks and compressed DZ blocks.
/// For DZ blocks, the data is decompressed and stored as owned data.
///
/// # Arguments
/// * `mmap` - Memory mapped file containing the MDF data
///
/// # Returns
/// A vector of [`ResolvedDataBlock`] objects or an [`Error`] if parsing fails.
///
/// # Feature Requirements
/// - Without `compression` feature: Returns error on DZ blocks
/// - With `compression` feature: Decompresses DZ blocks transparently
pub fn resolved_data_blocks<'a>(&self, mmap: &'a [u8]) -> Result<Vec<ResolvedDataBlock<'a>>> {
let mut collected_blocks = Vec::new();
let mut current_block_address = self.block.data_block_addr;
// Guard against cyclic DL chains in corrupt files.
let mut seen_dl = alloc::collections::BTreeSet::new();
while current_block_address != 0 {
if !seen_dl.insert(current_block_address) {
return Err(Error::LinkCycle {
address: current_block_address,
});
}
let byte_offset = current_block_address as usize;
let block_header = BlockHeader::from_bytes(&mmap[byte_offset..byte_offset + 24])?;
match block_header.id.as_str() {
"##DT" | "##DV" => {
let data_block = if self.is_unfinalized && block_header.length == 24 {
DataBlock::from_bytes_unfinalized(&mmap[byte_offset..])?
} else {
DataBlock::from_bytes(&mmap[byte_offset..])?
};
collected_blocks.push(ResolvedDataBlock {
block_id: if block_header.id == "##DT" {
"##DT"
} else {
"##DV"
},
data: DataBlockData::Borrowed(data_block.data),
});
current_block_address = 0;
}
#[cfg(feature = "compression")]
"##DZ" => {
let dz_block = DzBlock::from_bytes(&mmap[byte_offset..])?;
let decompressed = dz_block.decompress()?;
collected_blocks.push(ResolvedDataBlock {
block_id: "##DT", // DZ decompresses to DT-equivalent data
data: DataBlockData::Owned(decompressed),
});
current_block_address = 0;
}
#[cfg(not(feature = "compression"))]
"##DZ" => {
return Err(Error::BlockSerializationError(
"DZ blocks require the 'compression' feature".to_string(),
));
}
"##DL" => {
let data_list_block = DataListBlock::from_bytes(&mmap[byte_offset..])?;
for &fragment_address in &data_list_block.data_block_addrs {
if fragment_address == 0 {
continue;
}
let (frag_addr, frag_header) =
HlBlock::skip_hierarchy_blocks(mmap, fragment_address)?;
let fragment_offset = u64_to_usize(frag_addr, "DL fragment address")?;
match frag_header.id.as_str() {
"##DT" | "##DV" => {
let fragment_block =
DataBlock::from_bytes(&mmap[fragment_offset..])?;
collected_blocks.push(ResolvedDataBlock {
block_id: if frag_header.id == "##DT" {
"##DT"
} else {
"##DV"
},
data: DataBlockData::Borrowed(fragment_block.data),
});
}
#[cfg(feature = "compression")]
"##DZ" => {
let dz_block = DzBlock::from_bytes(&mmap[fragment_offset..])?;
let decompressed = dz_block.decompress()?;
collected_blocks.push(ResolvedDataBlock {
block_id: "##DT",
data: DataBlockData::Owned(decompressed),
});
}
#[cfg(not(feature = "compression"))]
"##DZ" => {
return Err(Error::BlockSerializationError(
"DZ blocks require the 'compression' feature".to_string(),
));
}
other => {
return Err(Error::BlockIDError {
actual: other.to_string(),
expected: "##DT / ##DV / ##DZ".to_string(),
});
}
}
}
current_block_address = data_list_block.next_dl_addr;
}
"##HL" => {
let len = u64_to_usize(block_header.length, "##HL")?;
current_block_address =
HlBlock::next_block_addr(&mmap[byte_offset..byte_offset + len])?;
}
unexpected_id => {
return Err(Error::BlockIDError {
actual: unexpected_id.to_string(),
expected: "##DT / ##DV / ##DL / ##DZ / ##HL".to_string(),
});
}
}
}
Ok(collected_blocks)
}
}
#[cfg(test)]
mod hl_chain_tests {
//! `##HL` may appear in the `##DG` measurement-data chain before `##DL` / `##DT`.
//! See `tests/data/sample_with_hl.mf4` (same bytes as `sample_with_hl_in_data_chain_loads`).
use super::RawDataGroup;
use crate::blocks::{BlockParse, DataGroupBlock};
#[test]
fn data_blocks_skip_hl_before_dt_in_chain() {
const SAMPLE: &[u8] = include_bytes!("../../tests/data/sample_with_hl.mf4");
const DG_OFF: usize = 1400;
let dg = DataGroupBlock::from_bytes(&SAMPLE[DG_OFF..DG_OFF + 64]).expect("DG in fixture");
let group = RawDataGroup {
block: dg,
channel_groups: Vec::new(),
is_unfinalized: false,
};
let blocks = group
.data_blocks(SAMPLE)
.expect("reader should skip ##HL and collect DT blocks");
assert!(
!blocks.is_empty(),
"fixture contains measurement data after ##HL"
);
}
}