includes

valuescript_vm/src/string_methods.rs

@@ -47,6 +47,7 @@ pub fn get_string_method(method: &str) -> Val {
     "codePointAt" => Val::Static(&CODE_POINT_AT),
     "concat" => Val::Static(&CONCAT),
     "endsWith" => Val::Static(&ENDS_WITH),
+    "includes" => Val::Static(&INCLUDES),
     _ => Val::Undefined,
   }
 }
@@ -156,6 +157,61 @@ static ENDS_WITH: NativeFunction = NativeFunction {
   },
 };
 
+static INCLUDES: NativeFunction = NativeFunction {
+  fn_: |this: &mut Val, params: Vec<Val>| -> Val {
+    match this {
+      Val::String(string_data) => {
+        let string_bytes = string_data.as_bytes();
+
+        let search_string = match params.get(0) {
+          Some(s) => s.val_to_string(),
+          _ => return Val::Bool(false),
+        };
+
+        let start_pos = match params.get(1) {
+          Some(p) => match p.to_index() {
+            // FIXME: to_index isn't quite right here
+            None => return Val::Bool(false),
+            Some(i) => i,
+          },
+          _ => 0,
+        };
+
+        let search_bytes = search_string.as_bytes();
+
+        let search_length = search_bytes.len();
+
+        if search_length == 0 {
+          // TODO: Even if start_pos is out of bounds?
+          return Val::Bool(true);
+        }
+
+        if start_pos + search_length > string_bytes.len() {
+          return Val::Bool(false);
+        }
+
+        for i in start_pos..(string_bytes.len() - search_length + 1) {
+          let mut found = true;
+
+          for j in 0..search_length {
+            if string_bytes[i + j] != search_bytes[j] {
+              found = false;
+              break;
+            }
+          }
+
+          if found {
+            return Val::Bool(true);
+          }
+        }
+
+        Val::Bool(false)
+      }
+      _ => std::panic!("Not implemented: exceptions/string indirection"),
+    }
+  },
+};
+
 fn unicode_at(bytes: &[u8], index: usize) -> Option<String> {
   match code_point_at(bytes, index) {
     Some(code_point) => Some(