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//! # Example
//! ```
//! let mut parser = Parser::new();
//! if let Ok(parsed) = parser.parse_slice(&buf) {
//! println!("{:?}", parsed);
//! }
//! ```
pub mod models;
#[cfg(test)]
mod tests;
use crate::parser::models::*;
use chrono::Utc;
use std::collections::HashMap;
pub type VEDirectParse = HashMap<String, Vec<u8>>;
pub struct Parser {
first_parse: bool,
parse_buf: Vec<u8>,
fields: VEDirectParse,
sum: u16,
}
impl Default for Parser {
fn default() -> Self {
Self::new()
}
}
impl Parser {
/// Create Parser instance
pub fn new() -> Self {
Parser {
first_parse: true,
parse_buf: Vec::new(),
fields: HashMap::new(),
sum: 0,
}
}
fn parse_field(data: &[u8], mut read_pos: usize) -> Result<(VEField, usize), VEError> {
if read_pos + 1 >= data.len() {
return Err(VEError::NeedMoreData);
}
if data[read_pos] == CR && data[read_pos + 1] == LF {
read_pos += 2;
match data[read_pos..].iter().position(|&c| c == TAB) {
Some(pos) => {
let label = String::from_utf8((data[read_pos..(read_pos + pos)]).to_vec())
.map_err(|e| VEError::Parse(format!("label string was invalid {}", e)))?;
read_pos = read_pos + pos + 1;
if read_pos >= data.len() {
return Err(VEError::NeedMoreData);
}
let endpos_res = data[read_pos..].iter().position(|&c| c == CR);
match endpos_res {
Some(endpos) => {
if endpos > 0 {
let value = &data[read_pos..(read_pos + endpos)];
Ok((
VEField {
label,
value: value.to_vec(),
},
read_pos + endpos,
))
} else {
Ok((VEField { label, value: vec![0] }, read_pos))
}
}
None => {
if label == "Checksum" {
Ok((
VEField {
label,
value: vec![u8::from_le(data[read_pos])],
},
read_pos + 1,
))
} else {
Err(VEError::NeedMoreData)
}
}
}
}
None => Err(VEError::NeedMoreData),
}
} else {
Err(VEError::Parse("Illegal field start".to_string()))
}
}
/// Parses victron energy protocol packet, if not complete returns VEError::NeedMoreData and stores its state
pub fn parse_slice(&mut self, data: &[u8]) -> Result<VEDirectParse, VEError> {
if self.first_parse {
// skip to first field start as we might have started somewhere in the middle
match data.iter().position(|&c| c == CR) {
Some(pos) => self.parse_buf.extend_from_slice(&data[pos..]),
None => return Err(VEError::NeedMoreData),
}
self.first_parse = false;
} else {
self.parse_buf.extend(data);
}
let mut cp = 0;
loop {
// skip hex mode messages, those can periodically occur
while cp + 1 < self.parse_buf.len() && self.parse_buf[cp] == COLON && self.parse_buf[cp + 1] == A {
match self.parse_buf[cp..].iter().position(|&c| c == CR) {
Some(pos) => {
cp += pos;
}
None => {
self.parse_buf.drain(0..cp);
return Err(VEError::NeedMoreData);
}
}
}
while cp + 3 < self.parse_buf.len()
&& self.parse_buf[cp] == CR
&& self.parse_buf[cp + 1] == LF
&& self.parse_buf[cp + 2] == COLON
&& self.parse_buf[cp + 3] == A
{
match self.parse_buf[cp + 2..].iter().position(|&c| c == CR) {
Some(pos) => {
cp = cp + pos + 2;
}
None => {
self.parse_buf.drain(0..cp);
return Err(VEError::NeedMoreData);
}
}
}
match Self::parse_field(&self.parse_buf, cp) {
Ok((field, read_pos)) => {
cp = read_pos;
self.fields.insert(field.label.clone(), field.value.clone());
self.sum = (self.sum + CR as u16) & 0xff;
self.sum = (self.sum + LF as u16) & 0xff;
for byte in field.label.to_string().as_bytes().iter() {
self.sum = (self.sum + (*byte) as u16) & 0xff;
}
self.sum = (self.sum + TAB as u16) & 0xff;
for byte in field.value.clone().iter() {
self.sum = (self.sum + (*byte) as u16) & 0xff;
}
if field.label == "Checksum" {
self.fields.insert("Checksum".to_string(), vec![u8::from_le(field.value[0])]);
self.fields
.insert("Calc_sum".to_string(), vec![u8::from_le(self.sum.try_into().unwrap())]);
self.fields
.insert("Time".to_string(), Utc::now().timestamp().to_string().as_bytes().to_vec());
let ret = self.fields.clone();
self.parse_buf.drain(0..cp);
self.fields.clear();
self.sum = 0;
return Ok(ret);
}
}
Err(VEError::NeedMoreData) => {
self.parse_buf.drain(0..cp);
return Err(VEError::NeedMoreData);
}
Err(VEError::Parse(error)) => {
self.parse_buf.clear();
self.first_parse = true;
return Err(VEError::Parse(error));
}
Err(e) => {
return Err(e);
}
}
}
}
}