Added safemath i128

package.json

@@ -1,6 +1,6 @@
 {
     "name": "@btc-vision/btc-runtime",
-    "version": "1.4.3",
+    "version": "1.4.4",
     "description": "Bitcoin Smart Contract Runtime",
     "main": "btc/index.ts",
     "scripts": {

runtime/index.ts

@@ -38,6 +38,7 @@ export * from './lang/Definitions';
 export * from './types/Address';
 export * from './types/Revert';
 export * from './types/SafeMath';
+export * from './types/SafeMathI128';
 
 /** Math */
 export * from './math/abi';

runtime/types/SafeMathI128.ts

@@ -0,0 +1,146 @@
+import { i128 } from '@btc-vision/as-bignum/assembly';
+
+export class SafeMathI128 {
+    public static readonly ZERO: i128 = i128.fromI32(0);
+    public static readonly ONE: i128 = i128.fromI32(1);
+    public static readonly NEG_ONE: i128 = i128.fromI32(-1);
+
+    public static readonly MIN: i128 = i128.Min;
+    public static readonly MAX: i128 = i128.Max;
+
+    /**
+     * Safe addition for i128.
+     * Throws if (a + b) overflows or underflows the signed 128-bit range.
+     */
+    public static add(a: i128, b: i128): i128 {
+        let c = i128.add(a, b);
+
+        // Overflow check for 2's complement:
+        // If a and b have the same sign, but c differs, overflow occurred.
+        // We can detect sign mismatch using ((a ^ c) & (b ^ c)) < 0
+        // (i.e., the sign bit is set in that expression).
+        if (((a ^ c) & (b ^ c)).isNeg()) {
+            throw new Error('SafeMathI128: addition overflow');
+        }
+
+        return c;
+    }
+
+    /**
+     * Safe subtraction for i128.
+     * Throws if (a - b) overflows or underflows the signed 128-bit range.
+     */
+    public static sub(a: i128, b: i128): i128 {
+        let c = i128.sub(a, b);
+
+        // Subtraction is (a + (-b)). We can do a direct check like:
+        // If (a ^ b) & (a ^ c) has sign bit set => overflow.
+        if (((a ^ b) & (a ^ c)).isNeg()) {
+            throw new Error('SafeMathI128: subtraction overflow');
+        }
+
+        return c;
+    }
+
+    /*public static mul(a: i128, b: i128): i128 {
+        // Quick check: if either is ZERO, product is ZERO => no overflow
+        if (a == SafeMathI128.ZERO || b == SafeMathI128.ZERO) {
+            return SafeMathI128.ZERO;
+        }
+
+        let c = i128.mul(a, b);
+
+        // Check overflow: c / b should be exactly a (if b != 0).
+        // Also watch for the i128 edge case: MIN * -1 => possible overflow if not representable.
+        // We'll rely on the division check:
+        if (b != SafeMathI128.ZERO) {
+            let divCheck = i128.div(c, b);
+            if (divCheck != a) {
+                throw new Error('SafeMathI128: multiplication overflow');
+            }
+        }
+
+        return c;
+    }*/
+
+    /*public static div(a: i128, b: i128): i128 {
+        if (b == SafeMathI128.ZERO) {
+            throw new Error('SafeMathI128: division by zero');
+        }
+
+        // Check i128 edge case: MIN / -1 => possible overflow if no corresponding positive.
+        if (a == SafeMathI128.MIN && b == SafeMathI128.NEG_ONE) {
+            throw new Error('SafeMathI128: division overflow (MIN / -1)');
+        }
+
+        return i128.div(a, b);
+    }*/
+
+    /*public static mod(a: i128, b: i128): i128 {
+        if (b == SafeMathI128.ZERO) {
+            throw new Error('SafeMathI128: modulo by zero');
+        }
+        // Similar edge case as division:
+        if (a == SafeMathI128.MIN && b == SafeMathI128.NEG_ONE) {
+            // Some implementations might treat MIN % -1 == 0,
+            // but if the library doesn't, you may handle it similarly to division.
+            // We'll assume we throw to be safe:
+            throw new Error('SafeMathI128: modulo overflow (MIN % -1)');
+        }
+
+        // Use i128.rem, i128.mod, or the operator as appropriate.
+        return i128.rem(a, b);
+    }*/
+
+    /**
+     * Increment an i128 by 1 with overflow check.
+     */
+    public static inc(value: i128): i128 {
+        return SafeMathI128.add(value, SafeMathI128.ONE);
+    }
+
+    /**
+     * Decrement an i128 by 1 with underflow check.
+     */
+    public static dec(value: i128): i128 {
+        return SafeMathI128.sub(value, SafeMathI128.ONE);
+    }
+
+    /**
+     * Return the absolute value of x, throwing if x == MIN (since |MIN| might not be representable).
+     */
+    public static abs(x: i128): i128 {
+        if (x.isNeg()) {
+            // If x == MIN, -x can overflow.
+            if (x == SafeMathI128.MIN) {
+                throw new Error('SafeMathI128: abs overflow on MIN');
+            }
+            return x.neg();
+        }
+        return x;
+    }
+
+    /**
+     * Return the negation of x, throwing if x == MIN.
+     */
+    public static neg(x: i128): i128 {
+        if (x == SafeMathI128.MIN) {
+            throw new Error('SafeMathI128: neg overflow on MIN');
+        }
+        return x.neg();
+    }
+
+    /**
+     * Returns the smaller of two i128s.
+     */
+    public static min(a: i128, b: i128): i128 {
+        return i128.lt(a, b) ? a : b;
+    }
+
+    /**
+     * Returns the larger of two i128s.
+     */
+    public static max(a: i128, b: i128): i128 {
+        return i128.gt(a, b) ? a : b;
+    }
+}