new parser module

satrs-core/src/hal/std/tcp_server.rs

@@ -12,10 +12,7 @@ use crate::tmtc::{ReceivesTc, TmPacketSource};
 use thiserror::Error;
 
 // Re-export the TMTC in COBS server.
-pub use crate::hal::std::tcp_spacepackets_server::parse_buffer_for_ccsds_space_packets;
+pub use crate::hal::std::tcp_with_cobs_server::{CobsTcParser, CobsTmSender, TcpTmtcInCobsServer};
-pub use crate::hal::std::tcp_with_cobs_server::{
-    parse_buffer_for_cobs_encoded_packets, CobsTcParser, CobsTmSender, TcpTmtcInCobsServer,
-};
 
 /// Configuration struct for the generic TCP TMTC server
 ///

satrs-core/src/hal/std/tcp_spacepackets_server.rs

@@ -1,28 +1 @@
-use crate::tmtc::ReceivesTc;
 
-pub trait ApidLookup {
-    fn validate(&self, apid: u16) -> bool;
-}
-/// This function parses a given buffer for COBS encoded packets. The packet structure is
-/// expected to be like this, assuming a sentinel value of 0 as the packet delimiter:
-///
-/// 0 | ... Packet Data ... | 0 | 0 | ... Packet Data ... | 0
-///
-/// This function is also able to deal with broken tail packets at the end. If broken tail
-/// packets are detected, they are moved to the front of the buffer, and the write index for
-/// future write operations will be written to the `next_write_idx` argument.
-///
-/// The parser will write all packets which were decoded successfully to the given `tc_receiver`.
-pub fn parse_buffer_for_ccsds_space_packets<E>(
-    buf: &mut [u8],
-    _apid_lookup: &dyn ApidLookup,
-    _tc_receiver: &mut dyn ReceivesTc<Error = E>,
-    _next_write_idx: &mut usize,
-) -> Result<u32, E> {
-    let packets_found = 0;
-    for _ in 0..buf.len() {
-        todo!();
-    }
-    // Split frame at the end for a multi-packet frame. Move it to the front of the buffer.
-    Ok(packets_found)
-}

satrs-core/src/hal/std/tcp_with_cobs_server.rs

@@ -1,6 +1,5 @@
 use alloc::boxed::Box;
 use alloc::vec;
-use cobs::decode_in_place;
 use cobs::encode;
 use delegate::delegate;
 use std::io::Write;
@@ -9,6 +8,7 @@ use std::net::TcpListener;
 use std::net::TcpStream;
 use std::vec::Vec;
 
+use crate::parsers::parse_buffer_for_cobs_encoded_packets;
 use crate::tmtc::ReceivesTc;
 use crate::tmtc::TmPacketSource;
 
@@ -152,58 +152,6 @@ impl<TmError: 'static, TcError: 'static> TcpTmtcInCobsServer<TmError, TcError> {
     }
 }
 
-/// This function parses a given buffer for COBS encoded packets. The packet structure is
-/// expected to be like this, assuming a sentinel value of 0 as the packet delimiter:
-///
-/// 0 | ... Packet Data ... | 0 | 0 | ... Packet Data ... | 0
-///
-/// This function is also able to deal with broken tail packets at the end. If broken tail
-/// packets are detected, they are moved to the front of the buffer, and the write index for
-/// future write operations will be written to the `next_write_idx` argument.
-///
-/// The parser will write all packets which were decoded successfully to the given `tc_receiver`.
-pub fn parse_buffer_for_cobs_encoded_packets<E>(
-    buf: &mut [u8],
-    tc_receiver: &mut dyn ReceivesTc<Error = E>,
-    next_write_idx: &mut usize,
-) -> Result<u32, E> {
-    let mut start_index_packet = 0;
-    let mut start_found = false;
-    let mut last_byte = false;
-    let mut packets_found = 0;
-    for i in 0..buf.len() {
-        if i == buf.len() - 1 {
-            last_byte = true;
-        }
-        if buf[i] == 0 {
-            if !start_found && !last_byte && buf[i + 1] == 0 {
-                // Special case: Consecutive sentinel values or all zeroes.
-                // Skip.
-                continue;
-            }
-            if start_found {
-                let decode_result = decode_in_place(&mut buf[start_index_packet..i]);
-                if let Ok(packet_len) = decode_result {
-                    packets_found += 1;
-                    tc_receiver
-                        .pass_tc(&buf[start_index_packet..start_index_packet + packet_len])?;
-                }
-                start_found = false;
-            } else {
-                start_index_packet = i + 1;
-                start_found = true;
-            }
-        }
-    }
-    // Split frame at the end for a multi-packet frame. Move it to the front of the buffer.
-    if start_index_packet > 0 && start_found && packets_found > 0 {
-        let (first_seg, last_seg) = buf.split_at_mut(start_index_packet - 1);
-        first_seg[..last_seg.len()].copy_from_slice(last_seg);
-        *next_write_idx = last_seg.len();
-    }
-    Ok(packets_found)
-}
-
 #[cfg(test)]
 mod tests {
     use core::{

satrs-core/src/lib.rs

@@ -33,6 +33,7 @@ pub mod hk;
 pub mod mode;
 pub mod objects;
 pub mod params;
+pub mod parsers;
 pub mod pool;
 pub mod power;
 pub mod pus;

satrs-core/src/parsers.rs

@@ -0,0 +1,131 @@
+#[cfg(feature = "alloc")]
+use alloc::vec::Vec;
+use cobs::decode_in_place;
+#[cfg(feature = "alloc")]
+use hashbrown::HashSet;
+
+use crate::tmtc::ReceivesTc;
+
+/// This function parses a given buffer for COBS encoded packets. The packet structure is
+/// expected to be like this, assuming a sentinel value of 0 as the packet delimiter:
+///
+/// 0 | ... Packet Data ... | 0 | 0 | ... Packet Data ... | 0
+///
+/// This function is also able to deal with broken tail packets at the end. If broken tail
+/// packets are detected, they are moved to the front of the buffer, and the write index for
+/// future write operations will be written to the `next_write_idx` argument.
+///
+/// The parser will write all packets which were decoded successfully to the given `tc_receiver`.
+pub fn parse_buffer_for_cobs_encoded_packets<E>(
+    buf: &mut [u8],
+    tc_receiver: &mut dyn ReceivesTc<Error = E>,
+    next_write_idx: &mut usize,
+) -> Result<u32, E> {
+    let mut start_index_packet = 0;
+    let mut start_found = false;
+    let mut last_byte = false;
+    let mut packets_found = 0;
+    for i in 0..buf.len() {
+        if i == buf.len() - 1 {
+            last_byte = true;
+        }
+        if buf[i] == 0 {
+            if !start_found && !last_byte && buf[i + 1] == 0 {
+                // Special case: Consecutive sentinel values or all zeroes.
+                // Skip.
+                continue;
+            }
+            if start_found {
+                let decode_result = decode_in_place(&mut buf[start_index_packet..i]);
+                if let Ok(packet_len) = decode_result {
+                    packets_found += 1;
+                    tc_receiver
+                        .pass_tc(&buf[start_index_packet..start_index_packet + packet_len])?;
+                }
+                start_found = false;
+            } else {
+                start_index_packet = i + 1;
+                start_found = true;
+            }
+        }
+    }
+    // Split frame at the end for a multi-packet frame. Move it to the front of the buffer.
+    if start_index_packet > 0 && start_found && packets_found > 0 {
+        let (first_seg, last_seg) = buf.split_at_mut(start_index_packet - 1);
+        first_seg[..last_seg.len()].copy_from_slice(last_seg);
+        *next_write_idx = last_seg.len();
+    }
+    Ok(packets_found)
+}
+
+pub trait PacketIdLookup {
+    fn validate(&self, apid: u16) -> bool;
+}
+
+#[cfg(feature = "alloc")]
+impl PacketIdLookup for Vec<u16> {
+    fn validate(&self, apid: u16) -> bool {
+        self.contains(&apid)
+    }
+}
+
+#[cfg(feature = "alloc")]
+impl PacketIdLookup for HashSet<u16> {
+    fn validate(&self, apid: u16) -> bool {
+        self.contains(&apid)
+    }
+}
+
+impl PacketIdLookup for &[u16] {
+    fn validate(&self, apid: u16) -> bool {
+        if self.binary_search(&apid).is_ok() {
+            return true;
+        }
+        false
+    }
+}
+
+/// This function parses a given buffer for tightly packed CCSDS space packets. It uses the
+/// [PacketId] field of the CCSDS packets to detect the start of a CCSDS space packet and then
+/// uses the length field of the packet to extract CCSDS packets.
+///
+/// This function is also able to deal with broken tail packets at the end as long a the parser
+/// can read the full 6 bytes which constitue a space packet header. If broken tail packets are
+/// detected, they are moved to the front of the buffer, and the write index for future write
+/// operations will be written to the `next_write_idx` argument.
+///
+/// The parser will write all packets which were decoded successfully to the given `tc_receiver`.
+pub fn parse_buffer_for_ccsds_space_packets<E>(
+    buf: &mut [u8],
+    packet_id_lookup: &dyn PacketIdLookup,
+    tc_receiver: &mut dyn ReceivesTc<Error = E>,
+    next_write_idx: &mut usize,
+) -> Result<u32, E> {
+    let packets_found = 0;
+    let mut current_idx = 0;
+    let buf_len = buf.len();
+    loop {
+        if current_idx + 7 >= buf.len() {
+            break;
+        }
+        let packet_id = u16::from_be_bytes(buf[current_idx..current_idx + 2].try_into().unwrap());
+        if packet_id_lookup.validate(packet_id) {
+            let length_field =
+                u16::from_be_bytes(buf[current_idx + 4..current_idx + 6].try_into().unwrap());
+            let packet_size = length_field + 7;
+            if (current_idx + packet_size as usize) < buf_len {
+                tc_receiver.pass_tc(&buf[current_idx..current_idx + packet_size as usize])?;
+            } else {
+                // Move packet to start of buffer if applicable.
+                if current_idx > 0 {
+                    buf.copy_within(current_idx.., 0);
+                    *next_write_idx = current_idx;
+                }
+            }
+            current_idx += packet_size as usize;
+            continue;
+        }
+        current_idx += 1;
+    }
+    Ok(packets_found)
+}