From 8d964ade3b0cfb4b317b9742cde6386a18accb0a Mon Sep 17 00:00:00 2001
From: Tess Gauthier <tessgauthier@microsoft.com>
Date: Wed, 6 Mar 2024 11:26:34 -0500
Subject: [PATCH 1/2] add div function

---
 dsc_lib/src/functions/div.rs | 77 ++++++++++++++++++++++++++++++++++++
 dsc_lib/src/functions/mod.rs |  2 +
 2 files changed, 79 insertions(+)
 create mode 100644 dsc_lib/src/functions/div.rs

diff --git a/dsc_lib/src/functions/div.rs b/dsc_lib/src/functions/div.rs
new file mode 100644
index 000000000..263adb994
--- /dev/null
+++ b/dsc_lib/src/functions/div.rs
@@ -0,0 +1,77 @@
+// Copyright (c) Microsoft Corporation.
+// Licensed under the MIT License.
+
+use crate::DscError;
+use crate::configure::context::Context;
+use crate::functions::{AcceptedArgKind, Function};
+use serde_json::Value;
+use tracing::debug;
+
+#[derive(Debug, Default)]
+pub struct Div {}
+
+impl Function for Div {
+    fn min_args(&self) -> usize {
+        2
+    }
+
+    fn max_args(&self) -> usize {
+        2
+    }
+
+    fn accepted_arg_types(&self) -> Vec<AcceptedArgKind> {
+        vec![AcceptedArgKind::Number]
+    }
+
+    fn invoke(&self, args: &[Value], _context: &Context) -> Result<Value, DscError> {
+        debug!("div function");
+        if let Some(value) = args[0].as_i64().unwrap().checked_div(args[1].as_i64().unwrap()) {
+            Ok(Value::Number(value.into()))
+        } else {
+            Err(DscError::Parser("Cannot divide by zero".to_string()))
+        }
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use crate::configure::context::Context;
+    use crate::parser::Statement;
+
+    #[test]
+    fn numbers() {
+        let mut parser = Statement::new().unwrap();
+        let result = parser.parse_and_execute("[div(8, 3)]", &Context::new()).unwrap();
+        assert_eq!(result, 2);
+    }
+
+    #[test]
+    fn nested() {
+        let mut parser = Statement::new().unwrap();
+        let result = parser.parse_and_execute("[div(18, div(9, 3))]", &Context::new()).unwrap();
+        assert_eq!(result, 6);
+    }
+
+    #[test]
+    fn invalid_one_parameter() {
+        let mut parser = Statement::new().unwrap();
+        let result = parser.parse_and_execute("[div(5)]", &Context::new());
+        assert!(result.is_err());
+    }
+
+    #[test]
+    fn invalid_div_by_zero() {
+        let mut parser = Statement::new().unwrap();
+        let result = parser.parse_and_execute("[div(5, 0)]", &Context::new());
+        assert!(result.is_err());
+    }
+
+    #[test]
+    fn overflow_input() {
+        let mut parser = Statement::new().unwrap();
+        // max value for i64 is 2^63 -1 (or 9,223,372,036,854,775,807)
+        let result = parser.parse_and_execute("[div(9223372036854775808, 2)]", &Context::new());
+        assert!(result.is_err());
+    }
+}
+
diff --git a/dsc_lib/src/functions/mod.rs b/dsc_lib/src/functions/mod.rs
index 400b82931..153e322aa 100644
--- a/dsc_lib/src/functions/mod.rs
+++ b/dsc_lib/src/functions/mod.rs
@@ -10,6 +10,7 @@ use serde_json::Value;
 pub mod base64;
 pub mod concat;
 pub mod create_array;
+pub mod div;
 pub mod envvar;
 pub mod parameters;
 pub mod resource_id;
@@ -57,6 +58,7 @@ impl FunctionDispatcher {
         functions.insert("base64".to_string(), Box::new(base64::Base64{}));
         functions.insert("concat".to_string(), Box::new(concat::Concat{}));
         functions.insert("createArray".to_string(), Box::new(create_array::CreateArray{}));
+        functions.insert("div".to_string(), Box::new(div::Div{}));
         functions.insert("envvar".to_string(), Box::new(envvar::Envvar{}));
         functions.insert("parameters".to_string(), Box::new(parameters::Parameters{}));
         functions.insert("resourceId".to_string(), Box::new(resource_id::ResourceId{}));

From a43d298dfb9b4c02ec36b0768d60871ed673794f Mon Sep 17 00:00:00 2001
From: Tess Gauthier <tessgauthier@microsoft.com>
Date: Wed, 6 Mar 2024 15:58:36 -0500
Subject: [PATCH 2/2] change unwrap call

---
 dsc_lib/src/functions/div.rs | 10 +++++++---
 1 file changed, 7 insertions(+), 3 deletions(-)

diff --git a/dsc_lib/src/functions/div.rs b/dsc_lib/src/functions/div.rs
index 263adb994..04516809a 100644
--- a/dsc_lib/src/functions/div.rs
+++ b/dsc_lib/src/functions/div.rs
@@ -25,10 +25,14 @@ impl Function for Div {
 
     fn invoke(&self, args: &[Value], _context: &Context) -> Result<Value, DscError> {
         debug!("div function");
-        if let Some(value) = args[0].as_i64().unwrap().checked_div(args[1].as_i64().unwrap()) {
-            Ok(Value::Number(value.into()))
+        if let (Some(arg1), Some(arg2)) = (args[0].as_i64(), args[1].as_i64()) {
+            if let Some(value) = arg1.checked_div(arg2) {
+                Ok(Value::Number(value.into()))
+            } else {
+                Err(DscError::Parser("Cannot divide by zero".to_string()))
+            }
         } else {
-            Err(DscError::Parser("Cannot divide by zero".to_string()))
+            Err(DscError::Parser("Invalid argument(s)".to_string()))
         }
     }
 }