From 77bacc255f0a693fa0d534e7e16e56bf95989c49 Mon Sep 17 00:00:00 2001
From: Vu Vo <vu.voth@gmail.com>
Date: Fri, 29 Oct 2021 17:16:41 +0700
Subject: [PATCH] fixbug substring3 opcode pop wrong order

---
 .../runtime/src/interpreter/opcode-list.ts     | 18 +++++++++---------
 packages/runtime/src/interpreter/opcode.ts     |  4 ++--
 .../test/src/interpreter/opcode-list.ts        |  6 +++---
 3 files changed, 14 insertions(+), 14 deletions(-)

diff --git a/packages/runtime/src/interpreter/opcode-list.ts b/packages/runtime/src/interpreter/opcode-list.ts
index 3beaab8f4..985d5532f 100644
--- a/packages/runtime/src/interpreter/opcode-list.ts
+++ b/packages/runtime/src/interpreter/opcode-list.ts
@@ -1152,19 +1152,19 @@ export class Substring extends Op {
   };
 
   execute (stack: TEALStack): void {
-    const byteString = this.assertBytes(stack.pop(), this.line);
-    const start = this.assertUint8(this.start, this.line);
     const end = this.assertUint8(this.end, this.line);
+    const start = this.assertUint8(this.start, this.line);
+    const byteString = this.assertBytes(stack.pop(), this.line);
 
-    const subString = this.subString(start, end, byteString, this.line);
+    const subString = this.subString(byteString, start, end, this.line);
     stack.push(subString);
   }
 }
 
-// pop last byte string A and two integers B and C.
-// Extract last range of bytes from A starting at B up to
-// but not including C, push the substring result. If C < B,
-// or either is larger than the string length, the program fails
+// pop a byte-array A and two integers B and C.
+// Extract a range of bytes from A starting at B up to but not including C,
+// push the substring result. If C < B, or either is larger than the array length,
+// the program fails
 // push to stack [...stack, substring]
 export class Substring3 extends Op {
   readonly line: number;
@@ -1180,11 +1180,11 @@ export class Substring3 extends Op {
   };
 
   execute (stack: TEALStack): void {
-    const byteString = this.assertBytes(stack.pop(), this.line);
     const end = this.assertBigInt(stack.pop(), this.line);
     const start = this.assertBigInt(stack.pop(), this.line);
+    const byteString = this.assertBytes(stack.pop(), this.line);
 
-    const subString = this.subString(start, end, byteString, this.line);
+    const subString = this.subString(byteString, start, end, this.line);
     stack.push(subString);
   }
 }
diff --git a/packages/runtime/src/interpreter/opcode.ts b/packages/runtime/src/interpreter/opcode.ts
index 0d3aab24e..db8daa076 100644
--- a/packages/runtime/src/interpreter/opcode.ts
+++ b/packages/runtime/src/interpreter/opcode.ts
@@ -172,12 +172,12 @@ export class Op {
 
   /**
    * Returns substring from given string (if it exists)
+   * @param byteString given string as bytes
    * @param start starting index
    * @param end ending index
-   * @param byteString given string as bytes
    * @param line line number in TEAL file
    */
-  subString (start: bigint, end: bigint, byteString: Uint8Array, line: number): Uint8Array {
+  subString (byteString: Uint8Array, start: bigint, end: bigint, line: number): Uint8Array {
     if (end < start) {
       throw new RuntimeError(RUNTIME_ERRORS.TEAL.SUBSTRING_END_BEFORE_START, { line: line });
     }
diff --git a/packages/runtime/test/src/interpreter/opcode-list.ts b/packages/runtime/test/src/interpreter/opcode-list.ts
index b805b2ce2..9129e7b15 100644
--- a/packages/runtime/test/src/interpreter/opcode-list.ts
+++ b/packages/runtime/test/src/interpreter/opcode-list.ts
@@ -1493,9 +1493,9 @@ describe("Teal Opcodes", function () {
     const stack = new Stack<StackElem>();
 
     it("should return correct substring", function () {
+      stack.push(parsing.stringToBytes("Algorand"));
       stack.push(0n);
       stack.push(4n);
-      stack.push(parsing.stringToBytes("Algorand"));
 
       const op = new Substring3([], 1);
       op.execute(stack);
@@ -1518,7 +1518,7 @@ describe("Teal Opcodes", function () {
       const start = end + 1n;
       execExpectError(
         stack,
-        [start, end, parsing.stringToBytes("Algorand")],
+        [parsing.stringToBytes("Algorand"), start, end],
         new Substring3([], 1),
         RUNTIME_ERRORS.TEAL.SUBSTRING_END_BEFORE_START
       );
@@ -1527,7 +1527,7 @@ describe("Teal Opcodes", function () {
     it("should throw error because range beyong string",
       execExpectError(
         stack,
-        [0n, 40n, parsing.stringToBytes("Algorand")],
+        [parsing.stringToBytes("Algorand"), 0n, 40n],
         new Substring3([], 1),
         RUNTIME_ERRORS.TEAL.SUBSTRING_RANGE_BEYOND
       )