feat: improve encoding & add test coverage (#31)

Author: swift1337

types/messages.ts

@@ -1,6 +1,6 @@
-import { Address, beginCell, Builder, Cell, Slice, TupleReader } from '@ton/core';
-import { DepositLog, GatewayOp, GatewayState } from './types';
-import { bufferToHexString, evmAddressToSlice, sliceToHexString } from './utils';
+import { Address, beginCell, Builder, Cell, Slice } from '@ton/core';
+import { GatewayOp } from './types';
+import { evmAddressToSlice } from './utils';
 
 // op code, query id (0)
 function newIntent(op: GatewayOp): Builder {

types/utils.spec.ts

@@ -0,0 +1,39 @@
+import { hexStringToCell, sliceToHexString } from './utils';
+
+const text =
+    'Lorem Ipsum is simply dummy text of the printing and typesetting industry.' +
+    " Lorem Ipsum has been the industry's standard dummy text ever since the 1500s," +
+    ' when an unknown printer took a galley of type and scrambled it to make a type specimen book.';
+
+describe('utils', () => {
+    it('should convert a text string to a hex string', () => {
+        // ARRANGE
+        // Given a text string in a hex format
+        const from = textToHexString(text);
+
+        // ACT
+        // Convert it into a BOC
+        const cell = hexStringToCell(from);
+
+        // ASSERT
+        // Convert cell back to hex string
+        const to = sliceToHexString(cell.beginParse());
+
+        expect(to).toBe(from);
+
+        // And convert it back to a text string
+        const text2 = hexStringToText(from);
+        expect(text2).toBe(text);
+    });
+});
+
+function textToHexString(text: string): string {
+    const buffer = Buffer.from(text, 'utf-8');
+
+    return `0x${buffer.toString('hex')}`;
+}
+
+// "0x..." -> text"
+function hexStringToText(hex: string): string {
+    return Buffer.from(hex.substring(2), 'hex').toString('utf-8');
+}

types/utils.ts

@@ -35,13 +35,12 @@ export function bufferToHexString(b: Buffer): string {
 }
 
 /**
- * Converts a Slice to a hex string
+ * Converts a Slice to a hex string (0x...)
  * @param s - Slice
- * @param bytes - Number of bytes to convert
  * @returns string (`0x...`)
  */
-export function sliceToHexString(s: Slice, bytes: number): string {
-    return bufferToHexString(s.loadBuffer(bytes));
+export function sliceToHexString(s: Slice): string {
+    return bufferToHexString(readBuffer(s));
 }
 
 /**
@@ -83,3 +82,32 @@ function writeBuffer(src: Buffer, builder: Builder) {
         builder = builder.storeBuffer(src);
     }
 }
+
+// https://github.com/ton-org/ton-core/blob/4eaced536d0a89f9374d9772884c7b52bddb68ba/src/boc/utils/strings.ts#L13
+export function readBuffer(slice: Slice) {
+    // Check consistency
+    if (slice.remainingBits % 8 !== 0) {
+        throw new Error(`Invalid string length: ${slice.remainingBits}`);
+    }
+
+    if (slice.remainingRefs !== 0 && slice.remainingRefs !== 1) {
+        throw new Error(`invalid number of refs: ${slice.remainingRefs}`);
+    }
+
+    // Read string
+    let res: Buffer;
+
+    if (slice.remainingBits === 0) {
+        res = Buffer.alloc(0);
+    } else {
+        res = slice.loadBuffer(slice.remainingBits / 8);
+    }
+
+    // Read tail
+    if (slice.remainingRefs === 1) {
+        const tail = slice.loadRef().beginParse();
+        res = Buffer.concat([res, readBuffer(tail)]);
+    }
+
+    return res;
+}