feat(model): add a per-packet delay trace trait and models (#21)

Author: maxime-bruno

.gitignore

@@ -1,3 +1,5 @@
 /target
 /Cargo.lock
-.vscode
+.vscode
+
+.pre-commit-config.yaml

Cargo.toml

@@ -9,47 +9,47 @@ homepage = "https://github.com/stack-rs/netem-trace"
 repository = "https://github.com/stack-rs/netem-trace"
 keywords = ["emulation", "trace", "network", "utility", "model"]
 documentation = "https://docs.rs/netem-trace"
-categories = [
-  "network-programming",
-  "config",
-  "development-tools",
-  "simulation",
-]
-
+categories = ["network-programming", "config", "development-tools", "simulation"]
 # See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
 
 [dependencies]
 bandwidth = "0.3.0"
 dyn-clone = { version = "1.0.10", optional = true }
+human-bandwidth = { version = "0.1.3", optional = true }
+humantime-serde = { version = "1.1.1", optional = true }
 itertools = { version = "0.14.0", optional = true }
 once_cell = { version = "1.17.0", optional = true }
 rand = { version = "0.9.0", optional = true }
 rand_distr = { version = "0.5.0", optional = true }
 serde = { version = "1.0", features = ["derive"], optional = true }
-typetag = { version = "0.2.5", optional = true }
-humantime-serde = { version = "1.1.1", optional = true }
-human-bandwidth = { version = "0.1.3", optional = true }
 statrs = { version = "0.18.0", optional = true }
+typetag = { version = "0.2.5", optional = true }
 
 [dev-dependencies]
-serde_json = "1.0"
 figment = { version = "0.10.19", features = ["json"] }
-
+serde_json = "1.0"
 
 [features]
 default = ["model"]
-model = ["bw-model", "delay-model", "loss-model", "duplicate-model"]
+model = [
+    "bw-model",
+    "delay-model",
+    "delay-per-packet-model",
+    "loss-model",
+    "duplicate-model"
+]
 bw-model = ["dep:rand", "dep:rand_distr", "dep:once_cell", "dep:dyn-clone"]
 delay-model = ["dep:dyn-clone"]
+delay-per-packet-model = ["dep:dyn-clone"]
 loss-model = ["dep:dyn-clone"]
 duplicate-model = ["dep:dyn-clone"]
 serde = ["dep:serde", "dep:typetag", "bandwidth/serde"]
 mahimahi = ["dep:itertools"]
 human = [
-  "serde",
-  "dep:humantime-serde",
-  "dep:human-bandwidth",
-  "human-bandwidth/serde",
+    "serde",
+    "dep:humantime-serde",
+    "dep:human-bandwidth",
+    "human-bandwidth/serde"
 ]
 full = ["model", "mahimahi", "human", "truncated-normal"]
 truncated-normal = ["statrs"]

src/lib.rs

@@ -5,7 +5,7 @@
 //! If you want to use the pre-defined models, please enable the `model` or `bw-model` feature.
 //!
 //! And if you want read configuration from file, `serde` feature should also be enabled.
-//! We alse recommend you to enable `human` feature to make the configuration file more human-readable.
+//! We else recommend you to enable `human` feature to make the configuration file more human-readable.
 //!
 //! An example to build model from configuration:
 //!
@@ -158,7 +158,7 @@ pub type LossPattern = Vec<f64>;
 /// the packet 101 is not duplicated, then the probability of packet 102 being duplicated is still 0.8.
 ///
 /// If both packet 101 and 102 were duplicated, then the probability of packet 103 being duplicated
-/// is still 0.1, and as long as the packets were duplicated, the propability of the next packet
+/// is still 0.1, and as long as the packets were duplicated, the probability of the next packet
 /// being duplicated is always the last element - in this case, 0.1.
 pub type DuplicatePattern = Vec<f64>;
 
@@ -192,6 +192,20 @@ pub trait DelayTrace: Send {
     fn next_delay(&mut self) -> Option<(Delay, Duration)>;
 }
 
+/// This is a trait that represents a trace of per-packet delays.
+///
+/// The trace is a sequence of `delay`.
+/// The delay describes how long the packet is delayed when going through.
+///
+/// For example, if the sequence is [10ms, 20ms, 30ms],
+/// then the delay will be 10ms for the first packet, then 20ms for second, then 30ms for third.
+///
+/// The next_delay function either returns **the next delay**
+/// in the sequence, or **None** if the trace goes to end.
+pub trait DelayPerPacketTrace: Send {
+    fn next_delay(&mut self) -> Option<Delay>;
+}
+
 /// This is a trait that represents a trace of loss patterns.
 ///
 /// The trace is a sequence of `(loss_pattern, duration)` pairs.

src/model/bw.rs

@@ -989,7 +989,7 @@ impl NormalizedBwConfig {
 impl NormalizedBwConfig {
     /// This is another implementation for converting NormalizedBwConfig into NormalizedBw, where the impact
     /// of truncation (`lower_bound` and `upper_bound` field) on the mathematical expectation of the distribution
-    /// is taking account by modifing the center of the distribution.
+    /// is taking account by modifying the center of the distribution.
     ///
     /// ## Examples
     ///

src/model/delay.rs

@@ -222,7 +222,7 @@ impl DelayTrace for RepeatedDelayPattern {
                 self.current_model = Some(self.pattern[self.current_pattern].clone().into_model());
             }
             match self.current_model.as_mut().unwrap().next_delay() {
-                Some(bw) => Some(bw),
+                Some(delay) => Some(delay),
                 None => {
                     self.current_model = None;
                     self.current_pattern += 1;