Merge pull request #20 from invariant-labs/add-checked_div

Add checked div
invariant-labs · Oct 11, 2023 · 7a1e0d0 · 7a1e0d0
2 parents 0755759 + 65de7ea
commit 7a1e0d0
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Showing 3 changed files with 41 additions and 5 deletions.
diff --git a/decimal_core/src/checked_ops.rs b/decimal_core/src/checked_ops.rs
@@ -24,6 +24,17 @@ pub fn generate_checked_ops(characteristics: DecimalCharacteristics) -> proc_mac
                     .ok_or_else(|| "checked_sub: (self - rhs) subtraction underflow")?
                 ))
             }
+
+            fn checked_div(self, rhs: Self) -> std::result::Result<Self, String> {
+                Ok(Self::new(
+                        self.get()
+                        .checked_mul(Self::one())
+                        .ok_or_else(|| "checked_div: (self * Self::one()) multiplication overflow")?
+                        .checked_div(rhs.get())
+                        .ok_or_else(|| "checked_div: ((self * Self::one()) / rhs) division by zero")?
+                    )
+                )
+            }
         }
 
         #[cfg(test)]
@@ -54,6 +65,23 @@ pub fn generate_checked_ops(characteristics: DecimalCharacteristics) -> proc_mac
                 assert_eq!(a.checked_sub(b), Ok(#struct_name::new(24)));
             }
 
+            #[test]
+            fn test_checked_div() {
+                let a = #struct_name::new(2);
+                let b = #struct_name::new(#struct_name::one());
+
+                assert_eq!(a.checked_div(b), Ok(#struct_name::new(2)));
+            }
+
+            #[test]
+            fn test_0_checked_div() {
+                let a = #struct_name::new(47);
+                let b = #struct_name::new(0);
+                let result = a.checked_div(b);
+
+                assert!(result.is_err());
+            }
+
             #[test]
             fn test_underflow_checked_sub() {
                 let min = #struct_name::new(0);

diff --git a/src/traits.rs b/src/traits.rs
@@ -40,7 +40,6 @@ pub trait Factories<T>: Sized {
     fn from_scale_up(integer: T, scale: u8) -> Self;
 }
 
-
 pub trait BetweenDecimals<T>: Sized {
     fn from_decimal(other: T) -> Self;
     fn checked_from_decimal(other: T) -> std::result::Result<Self, String>;
@@ -70,4 +69,5 @@ pub trait ByNumber<B>: Sized {
 pub trait CheckedOps: Sized {
     fn checked_add(self, rhs: Self) -> std::result::Result<Self, String>;
     fn checked_sub(self, rhs: Self) -> std::result::Result<Self, String>;
+    fn checked_div(self, rhs: Self) -> std::result::Result<Self, String>;
 }
diff --git a/src/walkthrough.rs b/src/walkthrough.rs
@@ -86,12 +86,19 @@ mod walkthrough {
             let result = percentage.checked_sub(Percentage::new(10));
             assert_eq!(result, Ok(Percentage::new(90)));
         }
+        // checked_div
+        {
+            let result = Price::from_integer(99).checked_div(Price::from_scale(5, 1));
+            assert_eq!(result, Ok(Price::from_integer(198)));
+        }
         // checked big div
         {
             let price = Price::max_instance().checked_big_div(Price::new(50000));
-            assert_eq!(price, Ok(Price::new(68056473384187692692674921486353642291)));
+            assert_eq!(
+                price,
+                Ok(Price::new(68056473384187692692674921486353642291))
+            );
         }
-
         // checked_from_scale
         {
             let overflow_err =
@@ -109,7 +116,8 @@ mod walkthrough {
         }
         // checked_from_scale_to_value
         {
-            let result =  Price::checked_from_scale_to_value(max_price_value, price_scale - 1).unwrap();
+            let result =
+                Price::checked_from_scale_to_value(max_price_value, price_scale - 1).unwrap();
             assert_eq!(
                 result,
                 U256::from_dec_str("3402823669209384634633746074317682114550").unwrap()
@@ -125,7 +133,7 @@ mod walkthrough {
         }
         // checked_from_decimal_to_value
         {
-            let result =  Price::checked_from_decimal_to_value(Price::max_instance()).unwrap();
+            let result = Price::checked_from_decimal_to_value(Price::max_instance()).unwrap();
             assert_eq!(result, U256::from(Price::max_value()));
         }
         // checked_big_div_by_number & checked_big_div_by_number_up