src/core/pool.rs

@@ -1 +1,347 @@
+type NumBuckets = u16;
 
+pub struct PoolCfg {
+    cfg: Vec<(NumBuckets, usize)>,
+}
+
+impl PoolCfg {
+    pub fn new(cfg: Vec<(NumBuckets, usize)>) -> Self {
+        PoolCfg { cfg }
+    }
+
+    pub fn sanitize(&mut self) -> usize {
+        self.cfg
+            .retain(|&(bucket_num, size)| bucket_num > 0 && size < LocalPool::MAX_SIZE);
+        self.cfg
+            .sort_unstable_by(|(_, sz0), (_, sz1)| sz0.partial_cmp(sz1).unwrap());
+        self.cfg.len()
+    }
+}
+
+type PoolSize = usize;
+
+pub struct LocalPool {
+    pool_cfg: PoolCfg,
+    pool: Vec<Vec<u8>>,
+    sizes_lists: Vec<Vec<PoolSize>>,
+}
+
+#[derive(Debug, Copy, Clone, PartialEq)]
+pub struct StoreAddr {
+    pool_idx: u16,
+    packet_idx: NumBuckets,
+}
+
+impl StoreAddr {
+    pub const INVALID_ADDR: u32 = 0xFFFFFFFF;
+
+    pub fn raw(&self) -> u32 {
+        ((self.pool_idx as u32) << 16) as u32 | self.packet_idx as u32
+    }
+}
+
+#[derive(Debug, Clone, PartialEq)]
+pub enum StoreIdError {
+    InvalidSubpool(u16),
+    InvalidPacketIdx(u16)
+}
+
+#[derive(Debug, Clone, PartialEq)]
+pub enum StoreError {
+    /// Requested data block is too large
+    DataTooLarge(usize),
+    /// The store is full. Contains the faulty subpool
+    StoreFull(u16),
+    /// Store ID is invalid. This also includes partial errors where only the subpool is invalid
+    InvalidStoreId(StoreIdError, Option<StoreAddr>),
+    /// Valid subpool and packet index, but no data is stored at the given address
+    DataDoesNotExist(StoreAddr),
+    /// Internal or configuration errors
+    InternalError(String),
+}
+
+impl LocalPool {
+    const STORE_FREE: PoolSize = PoolSize::MAX;
+    const MAX_SIZE: PoolSize = Self::STORE_FREE - 1;
+
+    pub fn new(mut cfg: PoolCfg) -> LocalPool {
+        let subpools_num = cfg.sanitize();
+        let mut local_pool = LocalPool {
+            pool_cfg: cfg,
+            pool: Vec::with_capacity(subpools_num),
+            sizes_lists: Vec::with_capacity(subpools_num),
+        };
+        for &(num_elems, elem_size) in local_pool.pool_cfg.cfg.iter() {
+            let next_pool_len = elem_size * num_elems as usize;
+            local_pool.pool.push(vec![0; next_pool_len]);
+            let next_sizes_list_len = num_elems as usize;
+            local_pool
+                .sizes_lists
+                .push(vec![Self::STORE_FREE; next_sizes_list_len]);
+        }
+        local_pool
+    }
+
+    pub fn add(&mut self, data: &[u8]) -> Result<StoreAddr, StoreError> {
+        if data.len() > Self::MAX_SIZE {
+            return Err(StoreError::DataTooLarge(data.len()));
+        }
+        let addr = self.reserve(data.len())?;
+        self.write(&addr, data)?;
+        Ok(addr)
+    }
+
+    pub fn free_element(&mut self, len: usize) -> Result<(StoreAddr, &mut [u8]), StoreError> {
+        if len > Self::MAX_SIZE {
+            return Err(StoreError::DataTooLarge(len));
+        }
+        let addr = self.reserve(len)?;
+        let raw_pos = self.raw_pos(&addr).unwrap();
+        let block = &mut self.pool.get_mut(addr.pool_idx as usize).unwrap()[raw_pos..len];
+        Ok((addr, block))
+    }
+
+    pub fn modify(&mut self, addr: &StoreAddr) -> Result<&mut [u8], StoreError> {
+        let curr_size = self.addr_check(&addr)?;
+        let raw_pos = self.raw_pos(&addr).unwrap();
+        let block = &mut self.pool.get_mut(addr.pool_idx as usize).unwrap()[raw_pos..curr_size];
+        Ok(block)
+    }
+
+    pub fn read(&self, addr: &StoreAddr) -> Result<&[u8], StoreError> {
+        let curr_size = self.addr_check(&addr)?;
+        let raw_pos = self.raw_pos(&addr).unwrap();
+        let block = &self.pool.get(addr.pool_idx as usize).unwrap()[raw_pos..curr_size];
+        Ok(block)
+    }
+
+    pub fn delete(&mut self, addr: StoreAddr) -> Result<(), StoreError> {
+        self.addr_check(&addr)?;
+        let block_size = self.pool_cfg.cfg.get(addr.pool_idx as usize).unwrap().1;
+        let raw_pos = self.raw_pos(&addr).unwrap();
+        let block = &mut self.pool.get_mut(addr.pool_idx as usize).unwrap()[raw_pos..block_size];
+        let size_list = self.sizes_lists.get_mut(addr.pool_idx as usize).unwrap();
+        size_list[addr.packet_idx as usize] = Self::STORE_FREE;
+        block.fill(0);
+        Ok(())
+    }
+
+    fn addr_check(&self, addr: &StoreAddr) -> Result<usize, StoreError> {
+        let pool_idx = addr.pool_idx as usize;
+        if pool_idx as usize >= self.pool_cfg.cfg.len() {
+            return Err(StoreError::InvalidStoreId(StoreIdError::InvalidSubpool(addr.pool_idx), Some(*addr)));
+        }
+        if addr.packet_idx >= self.pool_cfg.cfg[addr.pool_idx as usize].0 {
+            return Err(StoreError::InvalidStoreId(StoreIdError::InvalidPacketIdx(addr.packet_idx), Some(*addr)));
+        }
+        let size_list = self.sizes_lists.get(pool_idx).unwrap();
+        let curr_size = size_list[addr.packet_idx as usize];
+        if curr_size == Self::STORE_FREE {
+            return Err(StoreError::DataDoesNotExist(*addr));
+        }
+        Ok(curr_size)
+    }
+
+    fn reserve(&mut self, data_len: usize) -> Result<StoreAddr, StoreError> {
+        let subpool_idx = self.find_subpool(data_len, 0)?;
+        let (slot, size_slot_ref) = self.find_empty(subpool_idx)?;
+        *size_slot_ref = data_len;
+        Ok(StoreAddr {
+            pool_idx: subpool_idx,
+            packet_idx: slot,
+        })
+    }
+
+    fn find_subpool(&self, req_size: usize, start_at_subpool: u16) -> Result<u16, StoreError> {
+        for (i, &(_, elem_size)) in self.pool_cfg.cfg.iter().enumerate() {
+            if i < start_at_subpool as usize {
+                continue;
+            }
+            if elem_size >= req_size {
+                return Ok(i as u16);
+            }
+        }
+        Err(StoreError::DataTooLarge(req_size))
+    }
+
+    fn write(&mut self, addr: &StoreAddr, data: &[u8]) -> Result<(), StoreError> {
+        let packet_pos = self.raw_pos(addr).ok_or_else(|| {
+            StoreError::InternalError(format!(
+                "write: Error in raw_pos func with address {:?}",
+                addr
+            ))
+        })?;
+        let subpool = self.pool.get_mut(addr.pool_idx as usize).ok_or_else(|| {
+            StoreError::InternalError(format!(
+                "write: Error retrieving pool slice with address {:?}",
+                addr
+            ))
+        })?;
+        let pool_slice = &mut subpool[packet_pos..self.pool_cfg.cfg[addr.pool_idx as usize].1];
+        pool_slice.copy_from_slice(data);
+        Ok(())
+    }
+
+    fn find_empty(&mut self, subpool: u16) -> Result<(u16, &mut usize), StoreError> {
+        if let Some(size_list) = self.sizes_lists.get_mut(subpool as usize) {
+            for (i, elem_size) in size_list.iter_mut().enumerate() {
+                if *elem_size == Self::STORE_FREE {
+                    return Ok((i as u16, elem_size));
+                }
+            }
+        } else {
+            return Err(StoreError::InvalidStoreId(StoreIdError::InvalidSubpool(subpool),None));
+        }
+        Err(StoreError::StoreFull(subpool))
+    }
+
+    fn raw_pos(&self, addr: &StoreAddr) -> Option<usize> {
+        let (_, size) = self.pool_cfg.cfg.get(addr.pool_idx as usize)?;
+        Some(addr.packet_idx as usize * size)
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use crate::core::pool::{LocalPool, PoolCfg, StoreAddr, StoreError, StoreIdError};
+
+    #[test]
+    fn test_cfg() {
+        // Values where number of buckets is 0 or size is too large should be removed
+        let mut pool_cfg = PoolCfg::new(vec![(0, 0), (1, 0), (2, LocalPool::MAX_SIZE)]);
+        pool_cfg.sanitize();
+        assert_eq!(pool_cfg.cfg, vec![(1, 0)]);
+        // Entries should be ordered according to bucket size
+        pool_cfg = PoolCfg::new(vec![(16, 6), (32, 3), (8, 12)]);
+        pool_cfg.sanitize();
+        assert_eq!(pool_cfg.cfg, vec![(32, 3), (16, 6), (8, 12)]);
+        // Unstable sort is used, so order of entries with same block length should not matter
+        pool_cfg = PoolCfg::new(vec![(12, 12), (14, 16), (10, 12)]);
+        pool_cfg.sanitize();
+        assert!(
+            pool_cfg.cfg == vec![(12, 12), (10, 12), (14, 16)]
+                || pool_cfg.cfg == vec![(10, 12), (12, 12), (14, 16)]
+        );
+    }
+
+    #[test]
+    fn test_basic() {
+        // 4 buckets of 4 bytes, 2 of 8 bytes and 1 of 16 bytes
+        let pool_cfg = PoolCfg::new(vec![(4, 4), (2, 8), (1, 16)]);
+        let mut local_pool = LocalPool::new(pool_cfg);
+        // Try to access data which does not exist
+        let res = local_pool.read(&StoreAddr{
+            packet_idx: 0,
+            pool_idx: 0
+        });
+        assert!(res.is_err());
+        assert!(matches!(res.unwrap_err(), StoreError::DataDoesNotExist { .. }));
+        let mut test_buf: [u8; 16] = [0; 16];
+        for (i, val) in test_buf.iter_mut().enumerate() {
+            *val = i as u8;
+        }
+        let res = local_pool.add(test_buf.as_slice());
+        assert!(res.is_ok());
+        let addr = res.unwrap();
+        // Only the second subpool has enough storage and only one bucket
+        assert_eq!(addr, StoreAddr {
+            pool_idx: 2,
+            packet_idx: 0
+        });
+
+        // The subpool is now full and the call should fail accordingly
+        let res = local_pool.add(test_buf.as_slice());
+        assert!(res.is_err());
+        let err = res.unwrap_err();
+        assert!(matches!(err, StoreError::StoreFull {..}));
+        if let StoreError::StoreFull(subpool) = err {
+            assert_eq!(subpool, 2);
+        }
+
+        // Read back data and verify correctness
+        let res = local_pool.read(&addr);
+        assert!(res.is_ok());
+        let buf_read_back = res.unwrap();
+        assert_eq!(buf_read_back.len(), 16);
+        for (i, &val) in buf_read_back.iter().enumerate() {
+            assert_eq!(val , i as u8);
+        }
+
+        // Delete the data
+        let res = local_pool.delete(addr);
+        assert!(res.is_ok());
+
+        {
+            // Verify that the slot is free by trying to get a reference to it
+            let res = local_pool.free_element(12);
+            assert!(res.is_ok());
+            let (addr, buf_ref) = res.unwrap();
+            assert_eq!(addr, StoreAddr {pool_idx: 2, packet_idx:0});
+            assert_eq!(buf_ref.len(), 12);
+            assert_eq!(buf_ref, [0; 12]);
+            buf_ref[0] = 5;
+            buf_ref[11] = 12;
+        }
+
+        {
+            // Try to request a slot which is too large
+            let res = local_pool.free_element(20);
+            assert!(res.is_err());
+            assert_eq!(res.unwrap_err(), StoreError::DataTooLarge(20));
+
+            // Try to modify the 12 bytes requested previously
+            let res = local_pool.modify(&addr);
+            assert!(res.is_ok());
+            let buf_ref = res.unwrap();
+            assert_eq!(buf_ref[0], 5);
+            assert_eq!(buf_ref[11], 12);
+            buf_ref[0] = 0;
+            buf_ref[11] = 0;
+        }
+
+        {
+            let addr = StoreAddr{pool_idx: 3, packet_idx: 0};
+            let res = local_pool.read(&addr);
+            assert!(res.is_err());
+            let err = res.unwrap_err();
+            assert!(matches!(err, StoreError::InvalidStoreId(StoreIdError::InvalidSubpool(3), Some(_))));
+        }
+
+        {
+            let addr = StoreAddr{pool_idx: 2, packet_idx: 1};
+            assert_eq!(addr.raw(), 0x00020001);
+            let res = local_pool.read(&addr);
+            assert!(res.is_err());
+            let err = res.unwrap_err();
+            assert!(matches!(err, StoreError::InvalidStoreId(StoreIdError::InvalidPacketIdx(1), Some(_))));
+
+            let data_too_large = [0; 20];
+            let res = local_pool.add(data_too_large.as_slice());
+            assert!(res.is_err());
+            let err = res.unwrap_err();
+            assert_eq!(err, StoreError::DataTooLarge(20));
+
+            let res = local_pool.free_element(LocalPool::MAX_SIZE + 1);
+            assert!(res.is_err());
+            assert_eq!(res.unwrap_err(), StoreError::DataTooLarge(LocalPool::MAX_SIZE + 1));
+        }
+
+        {
+            // Reserve two smaller blocks consecutively and verify that the third reservation fails
+            let res = local_pool.free_element(8);
+            assert!(res.is_ok());
+            let (addr0, _) = res.unwrap();
+            let res = local_pool.free_element(8);
+            assert!(res.is_ok());
+            let (addr1, _) = res.unwrap();
+            let res = local_pool.free_element(8);
+            assert!(res.is_err());
+            let err = res.unwrap_err();
+            assert_eq!(err, StoreError::StoreFull(1));
+
+            // Verify that the two deletions are successful
+            assert!(local_pool.delete(addr0).is_ok());
+            assert!(local_pool.delete(addr1).is_ok());
+        }
+    }
+}

src/main.rs

@@ -1,3 +1,91 @@
-fn main() {
-    println!("Hello World")
+use std::sync::{Arc, RwLock};
+use std::thread;
+
+struct PoolDummy {
+    test_buf: [u8; 128],
+}
+
+struct PoolAccessDummy<'a> {
+    pool_dummy: &'a mut PoolDummy,
+    no_deletion: bool,
+}
+
+impl PoolAccessDummy<'_> {
+    fn modify(&mut self) -> &mut [u8] {
+        self.pool_dummy.modify()
+    }
+
+    fn release(&mut self) {
+        self.no_deletion = true;
+    }
+}
+
+impl Drop for PoolAccessDummy<'_> {
+    fn drop(&mut self) {
+        if self.no_deletion {
+            println!("Pool access: Drop with no deletion")
+        } else {
+            self.pool_dummy.delete();
+            println!("Pool access: Drop with deletion");
+        }
+    }
+}
+
+impl Default for PoolDummy {
+    fn default() -> Self {
+        PoolDummy { test_buf: [0; 128] }
+    }
+}
+
+impl PoolDummy {
+    fn modify(&mut self) -> &mut [u8] {
+        self.test_buf.as_mut_slice()
+    }
+
+    fn modify_with_accessor(&mut self) -> PoolAccessDummy {
+        PoolAccessDummy {
+            pool_dummy: self,
+            no_deletion: false,
+        }
+    }
+
+    fn read(&self) -> &[u8] {
+        self.test_buf.as_slice()
+    }
+
+    fn delete(&mut self) {
+        println!("Store content was deleted");
+    }
+}
+fn main() {
+    println!("Hello World");
+    let shared_dummy = Arc::new(RwLock::new(PoolDummy::default()));
+    let shared_clone = shared_dummy.clone();
+    let jh0 = thread::spawn(move || loop {
+        {
+            let mut dummy = shared_dummy.write().unwrap();
+            let buf = dummy.modify();
+            buf[0] = 1;
+
+            let mut accessor = dummy.modify_with_accessor();
+            let buf = accessor.modify();
+            buf[0] = 2;
+        }
+    });
+
+    let jh1 = thread::spawn(move || loop {
+        {
+            let dummy = shared_clone.read().unwrap();
+            let buf = dummy.read();
+            println!("Buffer 0: {:?}", buf[0]);
+        }
+
+        let mut dummy = shared_clone.write().unwrap();
+        let mut accessor = dummy.modify_with_accessor();
+        let buf = accessor.modify();
+        buf[0] = 3;
+        accessor.release();
+    });
+    jh0.join().unwrap();
+    jh1.join().unwrap();
 }