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

Backport-PR-URL: #30361 PR-URL: #19691 Reviewed-By: Ben Noordhuis <[email protected]> Reviewed-By: Tiancheng "Timothy" Gu <[email protected]> Reviewed-By: Joyee Cheung <[email protected]> Reviewed-By: James M Snell <[email protected]> Reviewed-By: Ruben Bridgewater <[email protected]> Reviewed-By: Tobias Nießen <[email protected]> Reviewed-By: Matteo Collina <[email protected]>
nodejs · Feb 25, 2020 · 64744a2 · 64744a2
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diff --git a/benchmark/buffers/buffer-read.js b/benchmark/buffers/buffer-read.js
@@ -2,6 +2,10 @@
 const common = require('../common.js');
 
 const types = [
+  'BigUInt64LE',
+  'BigUInt64BE',
+  'BigInt64LE',
+  'BigInt64BE',
   'UInt8',
   'UInt16LE',
   'UInt16BE',

diff --git a/benchmark/buffers/buffer-write.js b/benchmark/buffers/buffer-write.js
@@ -2,6 +2,10 @@
 const common = require('../common.js');
 
 const types = [
+  'BigUInt64LE',
+  'BigUInt64BE',
+  'BigInt64LE',
+  'BigInt64BE',
   'UInt8',
   'UInt16LE',
   'UInt16BE',
@@ -32,11 +36,17 @@ const INT8 = 0x7f;
 const INT16 = 0x7fff;
 const INT32 = 0x7fffffff;
 const INT48 = 0x7fffffffffff;
+const INT64 = 0x7fffffffffffffffn;
 const UINT8 = 0xff;
 const UINT16 = 0xffff;
 const UINT32 = 0xffffffff;
+const UINT64 = 0xffffffffffffffffn;
 
 const mod = {
+  writeBigInt64BE: INT64,
+  writeBigInt64LE: INT64,
+  writeBigUInt64BE: UINT64,
+  writeBigUInt64LE: UINT64,
   writeInt8: INT8,
   writeInt16BE: INT16,
   writeInt16LE: INT16,
@@ -67,12 +77,23 @@ function main({ n, buf, type }) {
 
   if (!/\d/.test(fn))
     benchSpecialInt(buff, fn, n);
+  else if (/BigU?Int/.test(fn))
+    benchBigInt(buff, fn, BigInt(n));
   else if (/Int/.test(fn))
     benchInt(buff, fn, n);
   else
     benchFloat(buff, fn, n);
 }
 
+function benchBigInt(buff, fn, n) {
+  const m = mod[fn];
+  bench.start();
+  for (var i = 0n; i !== n; i++) {
+    buff[fn](i & m, 0);
+  }
+  bench.end(Number(n));
+}
+
 function benchInt(buff, fn, n) {
   const m = mod[fn];
   bench.start();

diff --git a/doc/api/buffer.md b/doc/api/buffer.md
@@ -1529,6 +1529,47 @@ deprecated: v8.0.0
 
 The `buf.parent` property is a deprecated alias for `buf.buffer`.
 
+### buf.readBigInt64BE(offset)
+### buf.readBigInt64LE(offset)
+<!-- YAML
+added: REPLACEME
+-->
+
+* `offset` {integer} Number of bytes to skip before starting to read. Must
+  satisfy: `0 <= offset <= buf.length - 8`. **Default:** `0`.
+* Returns: {bigint}
+
+Reads a signed 64-bit integer from `buf` at the specified `offset` with
+the specified endian format (`readBigInt64BE()` returns big endian,
+`readBigInt64LE()` returns little endian).
+
+Integers read from a `Buffer` are interpreted as two's complement signed values.
+
+### buf.readBigUInt64BE(offset)
+### buf.readBigUInt64LE(offset)
+<!-- YAML
+added: REPLACEME
+-->
+
+* `offset` {integer} Number of bytes to skip before starting to read. Must
+  satisfy: `0 <= offset <= buf.length - 8`. **Default:** `0`.
+* Returns: {bigint}
+
+Reads an unsigned 64-bit integer from `buf` at the specified `offset` with
+specified endian format (`readBigUInt64BE()` returns big endian,
+`readBigUInt64LE()` returns little endian).
+
+```js
+const buf = Buffer.from([0x00, 0x00, 0x00, 0x00, 0xff, 0xff, 0xff, 0xff]);
+
+console.log(buf.readBigUInt64BE(0));
+// Prints: 4294967295n
+
+console.log(buf.readBigUInt64LE(0));
+// Prints: 18446744069414584320n
+```
+
+
 ### buf.readDoubleBE(offset)
 ### buf.readDoubleLE(offset)
 <!-- YAML
@@ -2132,6 +2173,56 @@ console.log(`${len} bytes: ${buf.toString('utf8', 0, len)}`);
 // Prints: 12 bytes: ½ + ¼ = ¾
 ```
 
+### buf.writeBigInt64BE(value, offset)
+### buf.writeBigInt64LE(value, offset)
+<!-- YAML
+added: REPLACEME
+-->
+
+* `value` {bigint} Number to be written to `buf`.
+* `offset` {integer} Number of bytes to skip before starting to write. Must
+  satisfy: `0 <= offset <= buf.length - 8`. **Default:** `0`.
+* Returns: {integer} `offset` plus the number of bytes written.
+
+Writes `value` to `buf` at the specified `offset` with specified endian
+format (`writeBigInt64BE()` writes big endian, `writeBigInt64LE()` writes little
+endian).
+
+`value` is interpreted and written as a two's complement signed integer.
+
+```js
+const buf = Buffer.allocUnsafe(8);
+
+buf.writeBigInt64BE(0x0102030405060708n, 0);
+
+console.log(buf);
+// Prints: <Buffer 01 02 03 04 05 06 07 08>
+```
+
+### buf.writeBigUInt64BE(value, offset)
+### buf.writeBigUInt64LE(value, offset)
+<!-- YAML
+added: REPLACEME
+-->
+
+* `value` {bigint} Number to be written to `buf`.
+* `offset` {integer} Number of bytes to skip before starting to write. Must
+  satisfy: `0 <= offset <= buf.length - 8`. **Default:** `0`.
+* Returns: {integer} `offset` plus the number of bytes written.
+
+Writes `value` to `buf` at the specified `offset` with specified endian
+format (`writeBigUInt64BE()` writes big endian, `writeBigUInt64LE()` writes
+little endian).
+
+```js
+const buf = Buffer.allocUnsafe(8);
+
+buf.writeBigUInt64LE(0xdecafafecacefaden, 0);
+
+console.log(buf);
+// Prints: <Buffer de fa ce ca fe fa ca de>
+```
+
 ### buf.writeDoubleBE(value, offset)
 ### buf.writeDoubleLE(value, offset)
 <!-- YAML

diff --git a/lib/internal/buffer.js b/lib/internal/buffer.js
@@ -52,6 +52,82 @@ function boundsError(value, length, type) {
 }
 
 // Read integers.
+function readBigUInt64LE(offset = 0) {
+  validateNumber(offset, 'offset');
+  const first = this[offset];
+  const last = this[offset + 7];
+  if (first === undefined || last === undefined)
+    boundsError(offset, this.length - 8);
+
+  const lo = first +
+    this[++offset] * 2 ** 8 +
+    this[++offset] * 2 ** 16 +
+    this[++offset] * 2 ** 24;
+
+  const hi = this[++offset] +
+    this[++offset] * 2 ** 8 +
+    this[++offset] * 2 ** 16 +
+    last * 2 ** 24;
+
+  return BigInt(lo) + (BigInt(hi) << 32n);
+}
+
+function readBigUInt64BE(offset = 0) {
+  validateNumber(offset, 'offset');
+  const first = this[offset];
+  const last = this[offset + 7];
+  if (first === undefined || last === undefined)
+    boundsError(offset, this.length - 8);
+
+  const hi = first * 2 ** 24 +
+    this[++offset] * 2 ** 16 +
+    this[++offset] * 2 ** 8 +
+    this[++offset];
+
+  const lo = this[++offset] * 2 ** 24 +
+    this[++offset] * 2 ** 16 +
+    this[++offset] * 2 ** 8 +
+    last;
+
+  return (BigInt(hi) << 32n) + BigInt(lo);
+}
+
+function readBigInt64LE(offset = 0) {
+  validateNumber(offset, 'offset');
+  const first = this[offset];
+  const last = this[offset + 7];
+  if (first === undefined || last === undefined)
+    boundsError(offset, this.length - 8);
+
+  const val = this[offset + 4] +
+    this[offset + 5] * 2 ** 8 +
+    this[offset + 6] * 2 ** 16 +
+    (last << 24); // Overflow
+  return (BigInt(val) << 32n) +
+    BigInt(first +
+      this[++offset] * 2 ** 8 +
+      this[++offset] * 2 ** 16 +
+      this[++offset] * 2 ** 24);
+}
+
+function readBigInt64BE(offset = 0) {
+  validateNumber(offset, 'offset');
+  const first = this[offset];
+  const last = this[offset + 7];
+  if (first === undefined || last === undefined)
+    boundsError(offset, this.length - 8);
+
+  const val = (first << 24) + // Overflow
+    this[++offset] * 2 ** 16 +
+    this[++offset] * 2 ** 8 +
+    this[++offset];
+  return (BigInt(val) << 32n) +
+    BigInt(this[++offset] * 2 ** 24 +
+      this[++offset] * 2 ** 16 +
+      this[++offset] * 2 ** 8 +
+      last);
+}
+
 function readUIntLE(offset, byteLength) {
   if (byteLength === 6)
     return readUInt48LE(this, offset);
@@ -454,6 +530,68 @@ function readDoubleForwards(offset = 0) {
 }
 
 // Write integers.
+function writeBigU_Int64LE(buf, value, offset, min, max) {
+  checkInt(value, min, max, buf, offset, 7);
+
+  let lo = Number(value & 0xffffffffn);
+  buf[offset++] = lo;
+  lo = lo >> 8;
+  buf[offset++] = lo;
+  lo = lo >> 8;
+  buf[offset++] = lo;
+  lo = lo >> 8;
+  buf[offset++] = lo;
+  let hi = Number(value >> 32n & 0xffffffffn);
+  buf[offset++] = hi;
+  hi = hi >> 8;
+  buf[offset++] = hi;
+  hi = hi >> 8;
+  buf[offset++] = hi;
+  hi = hi >> 8;
+  buf[offset++] = hi;
+  return offset;
+}
+
+function writeBigUInt64LE(value, offset = 0) {
+  return writeBigU_Int64LE(this, value, offset, 0n, 0xffffffffffffffffn);
+}
+
+function writeBigU_Int64BE(buf, value, offset, min, max) {
+  checkInt(value, min, max, buf, offset, 7);
+
+  let lo = Number(value & 0xffffffffn);
+  buf[offset + 7] = lo;
+  lo = lo >> 8;
+  buf[offset + 6] = lo;
+  lo = lo >> 8;
+  buf[offset + 5] = lo;
+  lo = lo >> 8;
+  buf[offset + 4] = lo;
+  let hi = Number(value >> 32n & 0xffffffffn);
+  buf[offset + 3] = hi;
+  hi = hi >> 8;
+  buf[offset + 2] = hi;
+  hi = hi >> 8;
+  buf[offset + 1] = hi;
+  hi = hi >> 8;
+  buf[offset] = hi;
+  return offset + 8;
+}
+
+function writeBigUInt64BE(value, offset = 0) {
+  return writeBigU_Int64BE(this, value, offset, 0n, 0xffffffffffffffffn);
+}
+
+function writeBigInt64LE(value, offset = 0) {
+  return writeBigU_Int64LE(
+    this, value, offset, -0x8000000000000000n, 0x7fffffffffffffffn);
+}
+
+function writeBigInt64BE(value, offset = 0) {
+  return writeBigU_Int64BE(
+    this, value, offset, -0x8000000000000000n, 0x7fffffffffffffffn);
+}
+
 function writeUIntLE(value, offset = 0, byteLength) {
   if (byteLength === 6)
     return writeU_Int48LE(this, value, offset, 0, 0xffffffffffff);
@@ -773,6 +911,14 @@ module.exports = {
   setupBufferJS,
   // Container to export all read write functions.
   readWrites: {
+    readBigUInt64LE,
+    readBigUInt64BE,
+    readBigInt64LE,
+    readBigInt64BE,
+    writeBigUInt64LE,
+    writeBigUInt64BE,
+    writeBigInt64LE,
+    writeBigInt64BE,
     readUIntLE,
     readUInt32LE,
     readUInt16LE,

diff --git a/test/parallel/test-buffer-bigint64.js 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);
+});