Merge PR oxibus#17: Add decode and encode for Signal

Author: jannes922

Cargo.toml

@@ -14,8 +14,9 @@ travis-ci = { repository = "marcelbuesing/can-dbc", branch = "dev" }
 codecov = { repository = "marcelbuesing/can-dbc", branch = "dev", service = "github" }
 
 [dependencies]
-derive-getters = "0.3"
+derive-getters = "0.5"
 nom = { version = "7.1", features = ["alloc"] }
+num = { version = "0.4", default-features = false }
 serde = { version = "1.0", optional = true }
 serde_derive = { version = "1.0", optional = true }
 

src/extend/mod.rs

@@ -0,0 +1,41 @@
+mod signal;
+
+use derive_getters::Getters;
+
+/// DBC value
+#[derive(Debug, Clone, Getters)]
+pub struct Value {
+    pub(crate) name: String,
+    #[getter(rename = "raw_value")]
+    #[getter(copy)]
+    pub(crate) raw: u64,
+    #[getter(copy)]
+    pub(crate) offset: f64,
+    #[getter(copy)]
+    pub(crate) factor: f64,
+    pub(crate) unit: String,
+}
+
+unsafe impl Send for Value {}
+unsafe impl Sync for Value {}
+
+impl Value {
+    /// Get the value of the signal
+    #[inline]
+    pub fn value<T>(&self) -> T
+    where
+        T: num::NumCast + Default,
+    {
+        T::from(
+            self.raw as f64 * self.factor + self.offset
+        ).unwrap_or_default()
+    }
+    /// Get the value and unit of the signal as a string
+    #[inline]
+    pub fn value_string<T>(&self) -> String
+    where
+        T: num::NumCast + Default + std::fmt::Display,
+    {
+        format!("{} {}", self.value::<T>(), self.unit)
+    }
+}

src/extend/signal.rs

@@ -0,0 +1,162 @@
+use crate::{ByteOrder, Signal, ValueType};
+use super::Value;
+
+impl Signal {
+    /// Decodes/Extracts a signal from the message data as a [`Value`]
+    ///
+    /// # Params
+    ///
+    ///   * data: source data
+    ///
+    /// # Return
+    ///
+    ///   [`Value`] if the size of signal is not zero
+    pub fn decode_value(&self, data: &[u8]) -> Option<Value> {
+        self.decode(data)
+            .map(|v| Value {
+                name: self.name.clone(),
+                raw: v,
+                offset: self.offset,
+                factor: self.factor,
+                unit: self.unit.clone(),
+            })
+    }
+
+    /// Decodes/Extracts a signal from the message data
+    ///
+    /// # Params
+    ///
+    ///   * data: source data
+    ///
+    /// # Return
+    ///
+    ///   Raw signal value if the size of signal is not zero
+    pub fn decode(&self, data: &[u8]) -> Option<u64> {
+        if self.signal_size == 0 {
+            return None;
+        }
+
+        let len = data.len();
+        let mut result = 0;
+        match self.byte_order {
+            ByteOrder::LittleEndian => {
+                let mut src_bit = self.start_bit as usize;
+                let mut dst_bit = 0;
+                for _ in 0..self.signal_size {
+                    /* copy bit */
+                    let index = src_bit / 8;
+                    if index >= len {
+                        return None;
+                    }
+                    if (data[index] & (1 << (src_bit % 8))) > 0 {
+                        result |= 1 << dst_bit;
+                    }
+
+                    /* calculate next position */
+                    src_bit += 1;
+                    dst_bit += 1;
+                }
+            },
+            ByteOrder::BigEndian => {
+                let mut src_bit = self.start_bit as usize;
+                let mut dst_bit = self.signal_size - 1;
+                for _ in 0..self.signal_size {
+                    /* copy bit */
+                    let index = src_bit / 8;
+                    if index >= len {
+                        return None;
+                    }
+                    if (data[index] & (1 << (src_bit % 8))) > 0 {
+                        result |= 1 << dst_bit;
+                    }
+
+                    /* calculate next position */
+                    if (src_bit % 8) == 0 {
+                        src_bit += 15;
+                    }
+                    else {
+                        src_bit -= 1;
+                    }
+                    dst_bit -= 1;
+                }
+            },
+        }
+
+        match self.value_type() {
+            ValueType::Signed => {
+                if (result & (1 << (self.signal_size - 1))) > 0 {
+                    for i in self.signal_size..64 {
+                        result |= 1 << i;
+                    }
+                }
+            },
+            ValueType::Unsigned => {}
+        }
+
+        Some(result)
+    }
+
+    /// Encodes a signal into the message data
+    ///
+    /// # Params
+    ///
+    ///   * data: source data
+    ///
+    ///   * value: Raw signal value
+    pub fn encode(&self, data: &mut Vec<u8>, value: u64) {
+        if self.signal_size == 0 {
+            return;
+        }
+
+        match self.byte_order {
+            ByteOrder::LittleEndian => {
+                let mut src_bit = self.start_bit as usize;
+                let mut dst_bit = 0;
+                for _ in 0..self.signal_size {
+                    /* copy bit */
+                    let index = src_bit / 8;
+                    if index >= data.len() {
+                        data.resize(index + 1, 0);
+                    }
+                    if (value & 1 << dst_bit) > 0 {
+                        data[index] |= 1 << (src_bit % 8);
+                    }
+                    else {
+                        data[index] &= !(1 << (src_bit % 8));
+                    }
+
+                    /* calculate next position */
+                    src_bit += 1;
+                    dst_bit += 1;
+                }
+            },
+            ByteOrder::BigEndian => {
+                let mut src_bit = self.start_bit as usize;
+                let mut dst_bit = self.signal_size - 1;
+                for _ in 0..self.signal_size {
+                    /* copy bit */
+                    let index = src_bit / 8;
+                    if index >= data.len() {
+                        data.resize(index + 1, 0);
+                    }
+                    if (value & 1 << dst_bit) > 0 {
+                        data[index] |= 1 << (dst_bit % 8);
+                    }
+                    else {
+                        data[index] &= !(1 << (src_bit % 8));
+                    }
+
+                    /* calculate next position */
+                    if (src_bit % 8) == 0 {
+                        src_bit += 15;
+                    }
+                    else {
+                        src_bit -= 1;
+                    }
+                    dst_bit -= 1;
+                }
+            },
+        }
+    }
+}
+

src/lib.rs

@@ -46,6 +46,8 @@ use std::convert::TryFrom;
 use derive_getters::Getters;
 
 pub mod parser;
+mod extend;
+pub use extend::*;
 
 #[cfg(test)]
 mod tests {