the-algorithm/navi/thrift_bpr_adapter/thrift/src/decoder.rs

// A feature value can be one of these
enum FeatureVal {
  Empty,
  U8Vector(Vec<u8>),
  FloatVector(Vec<f32>),
}

// A Feature has a name and a value
// The name for now is 'id' of type string
// Eventually this needs to be flexible - example to accomodate feature-id
struct Feature {
  id: String,
  val: FeatureVal,
}

impl Feature {
  fn new() -> Feature {
    Feature {
      id: String::new(),
      val: FeatureVal::Empty
    }
  }
}

// A single inference record will have multiple features
struct Record {
  fields: Vec<Feature>,
}

impl Record {
  fn new() -> Record {
    Record { fields: vec![] }
  }
}

// This is the main API used by external components
// Given a serialized input, decode it into Records
fn decode(input: Vec<u8>) -> Vec<Record> {
  // For helping define the interface
  vec![get_random_record(), get_random_record()]
}

// Used for testing the API, will be eventually removed
fn get_random_record() -> Record {
  let mut record: Record = Record::new();

  let f1: Feature = Feature {
    id: String::from("continuous_features"),
    val: FeatureVal::FloatVector(vec![1.0f32; 2134]),
  };

  record.fields.push(f1);

  let f2: Feature = Feature {
    id: String::from("user_embedding"),
    val: FeatureVal::FloatVector(vec![2.0f32; 200]),
  };

  record.fields.push(f2);

  let f3: Feature = Feature {
    id: String::from("author_embedding"),
    val: FeatureVal::FloatVector(vec![3.0f32; 200]),
  };

  record.fields.push(f3);

  let f4: Feature = Feature {
    id: String::from("binary_features"),
    val: FeatureVal::U8Vector(vec![4u8; 43]),
  };

  record.fields.push(f4);

  record
}