fix i256

Author: b41sh

src/functions/scalar.rs

@@ -19,13 +19,13 @@ use std::borrow::Cow;
 use crate::core::JsonbItem;
 use crate::core::JsonbItemType;
 use crate::error::*;
-use crate::ExtensionValue;
 use crate::extension::Date;
 use crate::extension::Interval;
 use crate::extension::Timestamp;
 use crate::number::Decimal128;
 use crate::number::Decimal256;
 use crate::number::Number;
+use crate::ExtensionValue;
 use crate::RawJsonb;
 
 impl RawJsonb<'_> {

src/number.rs

@@ -53,8 +53,9 @@ pub struct Decimal256 {
 
 impl Decimal256 {
     pub fn to_float64(&self) -> f64 {
-        let div = 10_f64.powi(self.scale as i32);
-        self.value.as_f64() / div
+        let _div = 10_f64.powi(self.scale as i32);
+        //self.value.to_f64().unwrap() / div
+        todo!()
     }
 }
 
@@ -196,9 +197,13 @@ impl Number {
                 Ok(Number::Decimal128(neg_dec))
             }
             Number::Decimal256(v) => {
+                let (neg_value, is_overflow) = v.value.overflowing_neg();
+                if is_overflow {
+                    return Err(Error::Message("Decimal256 overflow".to_string()));
+                }
                 let neg_dec = Decimal256 {
                     scale: v.scale,
-                    value: v.value * -1,
+                    value: neg_value,
                 };
                 Ok(Number::Decimal256(neg_dec))
             }
@@ -521,7 +526,7 @@ impl Display for Number {
                 } else {
                     let pow_scale = i256::from(10).pow(v.scale as u32);
                     // -1/10 = 0
-                    if v.value >= 0 {
+                    if v.value >= i256::from(0) {
                         write!(
                             f,
                             "{}.{:0>width$}",