hex2buf now returns an error in case of an odd number of characters (#2580)

* hex2buf now returns an error in case of an odd number of characters

* hex2buf throw tests

* Update packages/taquito-utils/src/taquito-utils.ts

Co-authored-by: AlirezaHaghshenas <alirezahaghshenas@gmail.com>

* parse hex string digit by digit

* fix: better handling of invalid hex strings

* Revert "parse hex string digit by digit"

This reverts commit 674f2b9.

* feat: allow 0x prefix in hex

* fix: fix a mistake in rebase

* adjusted unit tests

---------

Co-authored-by: AlirezaHaghshenas <alirezahaghshenas@gmail.com>
Co-authored-by: Davis Sawali <davis.sawali@ecadlabs.com>

Author: 3 people

packages/taquito-signer/test/taquito-signer.spec.ts

@@ -98,8 +98,8 @@ describe('inmemory-signer', () => {
       'edskS3DtVSbWbPD1yviMGebjYwWJtruMjDcfAZsH9uba22EzKeYhmQkkraFosFETmEMfFNVcDYQ5QbFerj9ozDKroXZ6mb5oxV'
     );
 
-    expect((await signer.sign('123', new Uint8Array([3]))).sig).toEqual(
-      'signvMhyzCmfN6JCYnqbtLCHdReCqwQM9viGJm1QPsiTrLGhrMi1eEmAsoXVjfNB1cJwnP9rj6i3cVCZeucqkPcsDuKmT9me'
+    expect((await signer.sign('1234', new Uint8Array([3]))).sig).toEqual(
+      'sigeeho3jK4MZKsyqcTc9mjhtz9w6enG3AFniufgUXCuXFW7VjShxLoNmxqkQSRYUwP1LHRMere5LrvxcqLgU9KmDGN356Yz'
     );
     done();
   });

packages/taquito-utils/src/taquito-utils.ts

@@ -197,12 +197,26 @@ export function encodeKeyHash(value: string) {
  * @throws {@link ValueConversionError}
  */
 export const hex2buf = (hex: string): Uint8Array => {
-  const match = hex.match(/[\da-f]{2}/gi);
-  if (match) {
-    return new Uint8Array(match.map((h) => parseInt(h, 16)));
-  } else {
-    throw new ValueConversionError(hex, 'Uint8Array');
+  if (hex.length % 2 !== 0) {
+    throw new InvalidHexStringError(hex, `: Expecting even number of characters`);
+  }
+  const hexDigits = stripHexPrefix(hex);
+  if (!hexDigits.match(/^([\da-f]{2})*$/gi)) {
+    throw new InvalidHexStringError(
+      hex,
+      `: Only characters 0-9, a-f and A-F are expected. Optionally, it can be prefixed with '0x'`
+    );
   }
+  const out = new Uint8Array(hexDigits.length / 2);
+  let j = 0;
+  for (let i = 0; i < hexDigits.length; i += 2) {
+    const v = parseInt(hexDigits.slice(i, i + 2), 16);
+    if (Number.isNaN(v)) {
+      throw new ValueConversionError(hex, 'Uint8Array');
+    }
+    out[j++] = v;
+  }
+  return out;
 };
 
 /**
@@ -351,10 +365,14 @@ export function bytes2Char(hex: string): string {
  * @param hex String value to convert to bytes
  */
 export function hex2Bytes(hex: string): Buffer {
-  if (!hex.match(/[\da-f]{2}/gi)) {
-    throw new InvalidHexStringError(hex, `: Expecting even number of characters`);
+  const hexDigits = stripHexPrefix(hex);
+  if (!hexDigits.match(/^(0x)?([\da-f]{2})*$/gi)) {
+    throw new InvalidHexStringError(
+      hex,
+      `: Expecting even number of characters: 0-9, a-z, A-Z, optionally prefixed with 0x`
+    );
   }
-  return Buffer.from(hex, 'hex');
+  return Buffer.from(hexDigits, 'hex');
 }
 
 /**

packages/taquito-utils/test/taquito-utils.spec.ts

@@ -15,6 +15,7 @@ import {
   hex2Bytes,
   b58decodeL2Address,
   encodeL2Address,
+  hex2buf,
 } from '../src/taquito-utils';
 import BigNumber from 'bignumber.js';
 
@@ -251,6 +252,43 @@ describe('Hex conversions', () => {
     expect(result).toEqual(Buffer.from('abcd', 'hex'));
   });
 
+  it('Should be able to convert hex with 0x prefix to bytes', () => {
+    const result: Buffer = hex2Bytes('0xabcd');
+
+    expect(result).toBeDefined();
+    expect(result).toEqual(Buffer.from('abcd', 'hex'));
+  });
+
+  it('Should throw an exception because of an odd number of characters', () => {
+    expect(() => hex2Bytes('abcda')).toThrow();
+  });
+
+  it('Should throw an exception because of invalid character', () => {
+    expect(() => hex2Bytes('abcq')).toThrow();
+  });
+
+  it('Should be able to convert hex to buffer', () => {
+    const result: Uint8Array = hex2buf('412D74657374');
+
+    expect(result).toBeDefined();
+    expect(result).toEqual(Uint8Array.from([65, 45, 116, 101, 115, 116]));
+  });
+
+  it('Should be able to convert hex with 0x prefix to buffer', () => {
+    const result: Uint8Array = hex2buf('0x412D74657374');
+
+    expect(result).toBeDefined();
+    expect(result).toEqual(Uint8Array.from([65, 45, 116, 101, 115, 116]));
+  });
+
+  it('Should throw an exception because of an odd number of characters (hex2buf)', () => {
+    expect(() => hex2buf('abcda')).toThrow();
+  });
+
+  it('Should throw an exception because of invalid character (hex2buf)', () => {
+    expect(() => hex2buf('abcq')).toThrow();
+  });
+
   it('should be able to get phk from tz4 Public key', () => {
     const publicKey =
       'BLpk1w1wkESXN91Ry39ZMRAhaaHJsDaMZ8wBax5QsKPEKPWTjDBk6dgKMDkoejxxPWJf52cm2osh';