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Updating stream methodology

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This commit is contained in:
Ryan Summers 2021-06-11 16:36:19 +02:00
parent b9284451e4
commit b40ca17fea
1 changed files with 97 additions and 123 deletions
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220
src/net/data_stream.rs
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@ -7,10 +7,6 @@ use smoltcp_nal::embedded_nal::{IpAddr, Ipv4Addr, SocketAddr, UdpClientStack};
use super::NetworkReference;
use crate::hardware::design_parameters::SAMPLE_BUFFER_SIZE;
// The number of samples contained in a single block. Note that each sample corresponds ot 8 byte
// s(2 bytes per ADC/DAC code, 4 codes total).
const BLOCK_SAMPLE_SIZE: usize = 50;
// The number of data blocks that we will buffer in the queue.
const BLOCK_BUFFER_SIZE: usize = 30;
@ -56,57 +52,16 @@ pub fn setup_streaming(
(generator, stream)
}
fn serialize_blocks<'a>(
buffer: &'a mut [u8],
max_buffer_size: usize,
queue: &mut Consumer<'static, AdcDacData, BLOCK_BUFFER_SIZE>,
) -> &'a [u8] {
// While there is space in the buffer, serialize into it.
let block_size = (SAMPLE_BUFFER_SIZE / SUBSAMPLE_RATE * 2) * 2 * 2 + 8;
// Truncate the buffer to the maximum buffer size.
let buffer: &mut [u8] = if buffer.len() > max_buffer_size {
&mut buffer[..max_buffer_size]
} else {
buffer
};
// Serialize blocks into the buffer until either the buffer or the queue are exhausted.
let mut enqueued_blocks: usize = 0;
for buf in buffer.chunks_exact_mut(block_size) {
// If there are no more blocks, return the serialized data.
let data = match queue.dequeue() {
Some(data) => data,
None => break,
};
let block = DataBlock {
adcs: data.adcs,
dacs: data.dacs,
block_id: data.block_id,
block_size: SAMPLE_BUFFER_SIZE,
};
enqueued_blocks += 1;
let length = block.to_slice(buf, SUBSAMPLE_RATE);
assert!(length == block_size);
}
&buffer[..block_size * enqueued_blocks]
}
#[derive(Debug, Copy, Clone)]
pub struct AdcDacData {
block_id: u32,
adcs: [[u16; BLOCK_SAMPLE_SIZE]; 2],
dacs: [[u16; BLOCK_SAMPLE_SIZE]; 2],
block_id: u16,
adcs: [[u16; SAMPLE_BUFFER_SIZE]; 2],
dacs: [[u16; SAMPLE_BUFFER_SIZE]; 2],
}
pub struct BlockGenerator {
queue: Producer<'static, AdcDacData, BLOCK_BUFFER_SIZE>,
current_block: AdcDacData,
num_samples: usize,
current_id: u16,
}
impl BlockGenerator {
@ -115,12 +70,7 @@ impl BlockGenerator {
) -> Self {
Self {
queue,
current_block: AdcDacData {
block_id: 0,
adcs: [[0; BLOCK_SAMPLE_SIZE]; 2],
dacs: [[0; BLOCK_SAMPLE_SIZE]; 2],
},
num_samples: 0,
current_id: 0,
}
}
@ -129,47 +79,14 @@ impl BlockGenerator {
adcs: &[&mut [u16; SAMPLE_BUFFER_SIZE]; 2],
dacs: &[&mut [u16; SAMPLE_BUFFER_SIZE]; 2],
) {
let mut processed_samples = 0;
let block = AdcDacData {
block_id: self.current_id,
adcs: [*adcs[0], *adcs[1]],
dacs: [*dacs[0], *dacs[1]],
};
while processed_samples < SAMPLE_BUFFER_SIZE {
let remaining_samples = SAMPLE_BUFFER_SIZE - processed_samples;
let free_space = BLOCK_SAMPLE_SIZE - self.num_samples;
let copy_sample_length = if remaining_samples < free_space {
remaining_samples
} else {
free_space
};
let start_src = self.num_samples;
let end_src = start_src + copy_sample_length;
let start_dst = processed_samples;
let end_dst = start_dst + copy_sample_length;
self.current_block.adcs[0][start_src..end_src]
.copy_from_slice(&adcs[0][start_dst..end_dst]);
self.current_block.adcs[1][start_src..end_src]
.copy_from_slice(&adcs[1][start_dst..end_dst]);
self.current_block.dacs[0][start_src..end_src]
.copy_from_slice(&dacs[0][start_dst..end_dst]);
self.current_block.dacs[1][start_src..end_src]
.copy_from_slice(&dacs[1][start_dst..end_dst]);
self.num_samples += copy_sample_length;
// If the data block is full, push it onto the queue.
if self.num_samples == BLOCK_SAMPLE_SIZE {
// Note: We silently ignore dropped blocks here. The queue can fill up if the
// service routing isn't being called often enough.
self.queue.enqueue(self.current_block).ok();
self.current_block.block_id =
self.current_block.block_id.wrapping_add(1);
self.num_samples = 0;
}
processed_samples += copy_sample_length;
}
self.current_id = self.current_id.wrapping_add(1);
self.queue.enqueue(block).ok();
}
}
@ -181,31 +98,86 @@ pub struct DataStream {
buffer: [u8; 1024],
}
struct DataBlock {
block_id: u32,
block_size: usize,
adcs: [[u16; BLOCK_SAMPLE_SIZE]; 2],
dacs: [[u16; BLOCK_SAMPLE_SIZE]; 2],
// Datapacket format:
//
// Header:
// [0..2]: Start block ID (u16)
// [2..3]: Num Blocks present (u8) <N>
// [3..4]: Batch Size (u8) <BS>
//
// Following the header, batches are added sequentially. Each batch takes the form of:
// [<BS>*0..<BS>*2]: ADC0
// [<BS>*2..<BS>*4]: ADC1
// [<BS>*4..<BS>*6]: DAC0
// [<BS>*6..<BS>*8]: DAC1
struct DataPacket<'a> {
buf: &'a mut [u8],
subsample_rate: usize,
start_id: Option<u16>,
num_blocks: u8,
write_index: usize,
}
impl DataBlock {
pub fn to_slice(self, buf: &mut [u8], subsample: usize) -> usize {
let block_size = self.block_size / subsample;
buf[0..4].copy_from_slice(&self.block_id.to_be_bytes());
buf[4..8].copy_from_slice(&block_size.to_be_bytes());
impl<'a> DataPacket<'a> {
pub fn new(buf: &'a mut [u8], subsample_rate: usize) -> Self {
Self {
buf,
start_id: None,
num_blocks: 0,
subsample_rate,
write_index: 4,
}
}
let mut offset: usize = 8;
for device in &[self.adcs, self.dacs] {
pub fn add_batch(&mut self, batch: &AdcDacData) -> Result<(), ()> {
// Check that the block is sequential.
if let Some(id) = &self.start_id {
if batch.block_id != id.wrapping_add(self.num_blocks.into()) {
return Err(());
}
} else {
// Otherwise, this is the first block. Record the strt ID.
self.start_id = Some(batch.block_id);
}
// Check that there is space for the block.
let block_size_bytes = SAMPLE_BUFFER_SIZE / self.subsample_rate * 4 * 2;
if self.buf.len() - self.get_packet_size() < block_size_bytes {
return Err(());
}
// Copy the samples into the buffer.
for device in &[batch.adcs, batch.dacs] {
for channel in device {
for sample in channel.iter().step_by(subsample) {
buf[offset..offset + 2]
for sample in channel.iter().step_by(self.subsample_rate) {
self.buf[self.write_index..self.write_index + 2]
.copy_from_slice(&sample.to_be_bytes());
offset += 2;
self.write_index += 2;
}
}
}
offset
Ok(())
}
fn get_packet_size(&self) -> usize {
let header_length = 4;
let block_sample_size = SAMPLE_BUFFER_SIZE / self.subsample_rate;
let block_size_bytes = block_sample_size * 2 * 4;
block_size_bytes * self.num_blocks as usize + header_length
}
pub fn finish(self) -> usize {
let block_sample_size = SAMPLE_BUFFER_SIZE / self.subsample_rate;
// Write the header into the block.
self.buf[0..2].copy_from_slice(&self.start_id.unwrap().to_be_bytes());
self.buf[2] = self.num_blocks;
self.buf[3] = block_sample_size as u8;
// Return the length of the packet to transmit.
self.get_packet_size()
}
}
@ -285,21 +257,23 @@ impl DataStream {
}
if self.queue.ready() {
let mut handle = self.socket.borrow_mut().unwrap();
let capacity = self
.stack
.lock(|stack| {
stack.with_udp_socket(handle, |socket| {
socket.payload_send_capacity()
})
})
.unwrap();
// Dequeue data from the queue into a larger block structure.
let mut packet = DataPacket::new(&mut self.buffer, SUBSAMPLE_RATE);
while self.queue.ready() {
// Note(unwrap): We check above that the queue is ready before calling this.
if packet.add_batch(self.queue.peek().unwrap()).is_err() {
// If we cannot add another batch, break out of the loop and send the packet.
break;
}
let data =
serialize_blocks(&mut self.buffer, capacity, &mut self.queue);
// Remove the batch that we just added.
self.queue.dequeue();
}
// Transmit the data block.
self.stack.send(&mut handle, &data).ok();
let mut handle = self.socket.borrow_mut().unwrap();
let size = packet.finish();
self.stack.send(&mut handle, &self.buffer[..size]).ok();
}
}
}