Add field_lt filter

libimagentryfilter/src/builtin/header/field_lt.rs

@@ -0,0 +1,60 @@
+use libimagstore::store::Entry;
+
+use builtin::header::field_path::FieldPath;
+use builtin::header::field_predicate::FieldPredicate;
+use builtin::header::field_predicate::Predicate;
+use filter::Filter;
+
+use toml::Value;
+
+struct EqLt {
+    comp: Value
+}
+
+impl Predicate for EqLt {
+
+    fn evaluate(&self, v: Value) -> bool {
+        match &self.comp {
+            &Value::Integer(i) => {
+                match v {
+                    Value::Integer(j) => i < j,
+                    Value::Float(f) => (i as f64) < f,
+                    _ => false,
+                }
+            },
+            &Value::Float(f) => {
+                match v {
+                    Value::Integer(i) => f < (i as f64),
+                    Value::Float(d) => f < d,
+                    _ => false,
+                }
+            },
+            _ => false,
+        }
+    }
+
+}
+
+/// Check whether certain header field in a entry is equal to a value
+pub struct FieldLt {
+    filter: FieldPredicate<EqLt>,
+}
+
+impl FieldLt {
+
+    pub fn new(path: FieldPath, expected_value: Value) -> FieldLt {
+        FieldLt {
+            filter: FieldPredicate::new(path, Box::new(EqLt { comp: expected_value })),
+        }
+    }
+
+}
+
+impl Filter for FieldLt {
+
+    fn filter(&self, e: &Entry) -> bool {
+        self.filter.filter(e)
+    }
+
+}
+

libimagentryfilter/src/builtin/header/mod.rs

@@ -4,5 +4,6 @@ pub mod field_grep;
 pub mod field_gt;
 pub mod field_isempty;
 pub mod field_istype;
+pub mod field_lt;
 pub mod field_path;
 pub mod field_predicate;