126 lines
4.0 KiB
Rust
126 lines
4.0 KiB
Rust
//! HDF5 Group Info message parsing (message type 0x000A).
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use crate::error::FormatError;
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/// Parsed Group Info message.
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#[derive(Debug, Clone, PartialEq)]
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pub struct GroupInfoMessage {
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/// Maximum number of links in compact storage before switching to dense.
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pub max_compact: Option<u16>,
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/// Minimum number of links in dense storage before switching back to compact.
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pub min_dense: Option<u16>,
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/// Estimated number of entries (hint).
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pub estimated_num_entries: Option<u16>,
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/// Estimated average link name length (hint).
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pub estimated_name_length: Option<u16>,
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}
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impl GroupInfoMessage {
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/// Parse a Group Info message from raw message data.
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pub fn parse(data: &[u8]) -> Result<GroupInfoMessage, FormatError> {
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if data.len() < 2 {
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return Err(FormatError::UnexpectedEof {
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expected: 2,
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available: data.len(),
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});
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}
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let version = data[0];
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if version != 0 {
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return Err(FormatError::InvalidGroupInfoVersion(version));
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}
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let flags = data[1];
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let has_link_phase = flags & 0x01 != 0;
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let has_estimated = flags & 0x02 != 0;
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let mut pos = 2;
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let (max_compact, min_dense) = if has_link_phase {
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if pos + 4 > data.len() {
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return Err(FormatError::UnexpectedEof {
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expected: pos + 4,
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available: data.len(),
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});
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}
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let mc = u16::from_le_bytes([data[pos], data[pos + 1]]);
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let md = u16::from_le_bytes([data[pos + 2], data[pos + 3]]);
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pos += 4;
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(Some(mc), Some(md))
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} else {
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(None, None)
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};
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let (estimated_num_entries, estimated_name_length) = if has_estimated {
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if pos + 4 > data.len() {
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return Err(FormatError::UnexpectedEof {
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expected: pos + 4,
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available: data.len(),
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});
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}
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let ne = u16::from_le_bytes([data[pos], data[pos + 1]]);
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let nl = u16::from_le_bytes([data[pos + 2], data[pos + 3]]);
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(Some(ne), Some(nl))
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} else {
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(None, None)
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};
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Ok(GroupInfoMessage {
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max_compact,
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min_dense,
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estimated_num_entries,
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estimated_name_length,
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})
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}
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}
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#[cfg(test)]
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mod tests {
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use super::*;
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#[test]
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fn with_link_phase_change() {
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let data = vec![0, 0x01, 8, 0, 6, 0]; // version=0, flags=1, max_compact=8, min_dense=6
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let msg = GroupInfoMessage::parse(&data).unwrap();
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assert_eq!(msg.max_compact, Some(8));
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assert_eq!(msg.min_dense, Some(6));
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assert_eq!(msg.estimated_num_entries, None);
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}
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#[test]
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fn with_estimated_entry_info() {
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let data = vec![0, 0x02, 4, 0, 16, 0]; // flags=2
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let msg = GroupInfoMessage::parse(&data).unwrap();
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assert_eq!(msg.max_compact, None);
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assert_eq!(msg.estimated_num_entries, Some(4));
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assert_eq!(msg.estimated_name_length, Some(16));
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}
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#[test]
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fn both_flags_set() {
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let data = vec![0, 0x03, 8, 0, 6, 0, 10, 0, 32, 0];
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let msg = GroupInfoMessage::parse(&data).unwrap();
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assert_eq!(msg.max_compact, Some(8));
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assert_eq!(msg.min_dense, Some(6));
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assert_eq!(msg.estimated_num_entries, Some(10));
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assert_eq!(msg.estimated_name_length, Some(32));
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}
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#[test]
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fn no_flags() {
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let data = vec![0, 0x00];
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let msg = GroupInfoMessage::parse(&data).unwrap();
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assert_eq!(msg.max_compact, None);
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assert_eq!(msg.min_dense, None);
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assert_eq!(msg.estimated_num_entries, None);
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assert_eq!(msg.estimated_name_length, None);
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}
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#[test]
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fn invalid_version() {
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let data = vec![1, 0];
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let err = GroupInfoMessage::parse(&data).unwrap_err();
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assert_eq!(err, FormatError::InvalidGroupInfoVersion(1));
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}
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}
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