Fix slice

src/arrayUtils.ts

@@ -1,16 +1,16 @@
-import { method, SmartContractLib, ByteString } from 'scrypt-ts'
+import { method, SmartContractLib, ByteString, slice } from 'scrypt-ts'
 
 // A library that emulates an array interface on top of a ByteString.
 export class ArrayUtils extends SmartContractLib {
     // Get the byte at the given index.
     @method()
     static getElemAt(b: ByteString, idx: bigint): ByteString {
-        return b.slice(Number(idx) * 2, Number(idx) * 2 + 2)
+        return slice(b, idx, idx + 1n)
     }
 
     // Set the byte at the given index.
     @method()
     static setElemAt(b: ByteString, idx: bigint, val: ByteString): ByteString {
-        return b.slice(0, Number(idx) * 2) + val + b.slice(Number(idx) * 2 + 2)
+        return slice(b, 0n, idx) + val + slice(b, idx + 1n)
     }
 }

src/ec/secp256k1.ts

@@ -11,6 +11,7 @@ import {
     Utils,
     reverseByteString,
     ByteString,
+    slice,
 } from 'scrypt-ts'
 
 import { Point, Signature } from './misc'
@@ -1244,15 +1245,15 @@ export class SECP256K1 extends SmartContractLib {
     @method()
     static pubKey2Point(pubKey: PubKey): Point {
         assert(
-            pubKey.slice(0, 2) == toByteString('04'),
+            slice(pubKey, 0n, 1n) == toByteString('04'),
             'Pub key isn\'t prefixed with "04". This likely means, that it\'s not in compressed form.'
         )
         // Convert signed little endian to unsigned big endian.
         const x = Utils.fromLEUnsigned(
-            reverseByteString(pubKey.slice(2, 66), 32n)
+            reverseByteString(slice(pubKey, 1n, 33n), 32n)
         )
         const y = Utils.fromLEUnsigned(
-            reverseByteString(pubKey.slice(66, 130), 32n)
+            reverseByteString(slice(pubKey, 33n, 65n), 32n)
         )
         return {
             x: x,

src/ec/secp256r1.ts

@@ -11,6 +11,7 @@ import {
     Utils,
     reverseByteString,
     ByteString,
+    slice,
 } from 'scrypt-ts'
 
 import { Point, Signature } from './misc'
@@ -1247,15 +1248,15 @@ export class SECP256R1 extends SmartContractLib {
     @method()
     static pubKey2Point(pubKey: PubKey): Point {
         assert(
-            pubKey.slice(0, 2) == toByteString('04'),
+            slice(pubKey, 0n, 1n) == toByteString('04'),
             'Pub key isn\'t prefixed with "04". This likely means, that it\'s not in compressed form.'
         )
         // Convert signed little endian to unsigned big endian.
         const x = Utils.fromLEUnsigned(
-            reverseByteString(pubKey.slice(2, 66), 32n)
+            reverseByteString(slice(pubKey, 1n, 33n), 32n)
         )
         const y = Utils.fromLEUnsigned(
-            reverseByteString(pubKey.slice(66, 130), 32n)
+            reverseByteString(slice(pubKey, 33n, 65n), 32n)
         )
         return {
             x: x,

src/schnorr.ts

@@ -7,6 +7,7 @@ import {
     sha256,
     SmartContractLib,
     toByteString,
+    slice,
 } from 'scrypt-ts'
 import { Point } from './ec/misc'
 import { SECP256K1 } from './ec/secp256k1'
@@ -21,9 +22,9 @@ export class Schnorr extends SmartContractLib {
         msg: ByteString,
         R: Point
     ): boolean {
-        const r: ByteString = sig.slice(0, 64) // First 32 bytes
+        const r: ByteString = slice(sig, 0n, 64n) // First 32 bytes
         const s = byteString2Int(
-            reverseByteString(sig.slice(64, 128), 32n) + toByteString('00')
+            reverseByteString(slice(sig, 32n, 64n), 32n) + toByteString('00')
         )
 
         // e = Hash(r || P || msg)