buffer: add {read|write}Big[U]Int64{BE|LE} methods

Backport-PR-URL: https://github.com/nodejs/node/pull/30361
PR-URL: https://github.com/nodejs/node/pull/19691
Reviewed-By: Ben Noordhuis <info@bnoordhuis.nl>
Reviewed-By: Tiancheng "Timothy" Gu <timothygu99@gmail.com>
Reviewed-By: Joyee Cheung <joyeec9h3@gmail.com>
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Ruben Bridgewater <ruben@bridgewater.de>
Reviewed-By: Tobias Nießen <tniessen@tnie.de>
Reviewed-By: Matteo Collina <matteo.collina@gmail.com>

1 files changed, 51 insertions, 0 deletions

diff --git a/test/parallel/test-buffer-bigint64.js b/test/parallel/test-buffer-bigint64.js
new file mode 100644
index 00000000000..859a40811e1
--- /dev/null
+++ b/test/parallel/test-buffer-bigint64.js
@@ -0,0 +1,51 @@
+'use strict';
+require('../common');
+const assert = require('assert');
+
+const buf = Buffer.allocUnsafe(8);
+
+['LE', 'BE'].forEach(function(endianness) {
+  // Should allow simple BigInts to be written and read
+  let val = 123456789n;
+  buf['writeBigInt64' + endianness](val, 0);
+  let rtn = buf['readBigInt64' + endianness](0);
+  assert.strictEqual(val, rtn);
+
+  // Should allow INT64_MAX to be written and read
+  val = 0x7fffffffffffffffn;
+  buf['writeBigInt64' + endianness](val, 0);
+  rtn = buf['readBigInt64' + endianness](0);
+  assert.strictEqual(val, rtn);
+
+  // Should read and write a negative signed 64-bit integer
+  val = -123456789n;
+  buf['writeBigInt64' + endianness](val, 0);
+  assert.strictEqual(val, buf['readBigInt64' + endianness](0));
+
+  // Should read and write an unsigned 64-bit integer
+  val = 123456789n;
+  buf['writeBigUInt64' + endianness](val, 0);
+  assert.strictEqual(val, buf['readBigUInt64' + endianness](0));
+
+  // Should throw a RangeError upon INT64_MAX+1 being written
+  assert.throws(function() {
+    const val = 0x8000000000000000n;
+    buf['writeBigInt64' + endianness](val, 0);
+  }, RangeError);
+
+  // Should throw a RangeError upon UINT64_MAX+1 being written
+  assert.throws(function() {
+    const val = 0x10000000000000000n;
+    buf['writeBigUInt64' + endianness](val, 0);
+  }, RangeError);
+
+  // Should throw a TypeError upon invalid input
+  assert.throws(function() {
+    buf['writeBigInt64' + endianness]('bad', 0);
+  }, TypeError);
+
+  // Should throw a TypeError upon invalid input
+  assert.throws(function() {
+    buf['writeBigUInt64' + endianness]('bad', 0);
+  }, TypeError);
+});