From: Kirill Fomichev <fanatid@ya.ru>
Date: Thu, 19 Sep 2019 15:03:03 +0000 (+0300)
Subject: add rw BigInt64 methods
X-Git-Url: https://zoso.dev/?a=commitdiff_plain;h=d8b713321bfd93c1249f30a9883d5fa91f39528f;p=buffer.git

add rw BigInt64 methods
---

diff --git a/index.js b/index.js
index 19b0468..d75d656 100644
--- a/index.js
+++ b/index.js
@@ -1187,6 +1187,48 @@ Buffer.prototype.readUInt32BE = function readUInt32BE (offset, noAssert) {
     this[offset + 3])
 }
 
+Buffer.prototype.readBigUInt64LE = defineBigIntMethod(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)
+})
+
+Buffer.prototype.readBigUInt64BE = defineBigIntMethod(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)
+})
+
 Buffer.prototype.readIntLE = function readIntLE (offset, byteLength, noAssert) {
   offset = offset >>> 0
   byteLength = byteLength >>> 0
@@ -1264,6 +1306,46 @@ Buffer.prototype.readInt32BE = function readInt32BE (offset, noAssert) {
     (this[offset + 3])
 }
 
+Buffer.prototype.readBigInt64LE = defineBigIntMethod(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)
+})
+
+Buffer.prototype.readBigInt64BE = defineBigIntMethod(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)
+})
+
 Buffer.prototype.readFloatLE = function readFloatLE (offset, noAssert) {
   offset = offset >>> 0
   if (!noAssert) checkOffset(offset, 4, this.length)
@@ -1380,6 +1462,58 @@ Buffer.prototype.writeUInt32BE = function writeUInt32BE (value, offset, noAssert
   return offset + 4
 }
 
+function wrtBigUInt64LE (buf, value, offset, min, max) {
+  checkIntBI(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 wrtBigUInt64BE (buf, value, offset, min, max) {
+  checkIntBI(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
+}
+
+Buffer.prototype.writeBigUInt64LE = defineBigIntMethod(function writeBigUInt64LE (value, offset = 0) {
+  return wrtBigUInt64LE(this, value, offset, 0n, 0xffffffffffffffffn)
+})
+
+Buffer.prototype.writeBigUInt64BE = defineBigIntMethod(function writeBigUInt64BE (value, offset = 0) {
+  return wrtBigUInt64BE(this, value, offset, 0n, 0xffffffffffffffffn)
+})
+
 Buffer.prototype.writeIntLE = function writeIntLE (value, offset, byteLength, noAssert) {
   value = +value
   offset = offset >>> 0
@@ -1476,6 +1610,14 @@ Buffer.prototype.writeInt32BE = function writeInt32BE (value, offset, noAssert)
   return offset + 4
 }
 
+Buffer.prototype.writeBigInt64LE = defineBigIntMethod(function writeBigInt64LE (value, offset = 0) {
+  return wrtBigUInt64LE(this, value, offset, -0x8000000000000000n, 0x7fffffffffffffffn)
+})
+
+Buffer.prototype.writeBigInt64BE = defineBigIntMethod(function writeBigInt64BE (value, offset = 0) {
+  return wrtBigUInt64BE(this, value, offset, -0x8000000000000000n, 0x7fffffffffffffffn)
+})
+
 function checkIEEE754 (buf, value, offset, ext, max, min) {
   if (offset + ext > buf.length) throw new RangeError('Index out of range')
   if (offset < 0) throw new RangeError('Index out of range')
@@ -1635,6 +1777,139 @@ Buffer.prototype.fill = function fill (val, start, end, encoding) {
   return this
 }
 
+// CUSTOM ERRORS
+// =============
+
+// Simplified versions from Node, changed for Buffer-only usage
+var errors = {}
+function E (sym, getMessage, Base) {
+  errors[sym] = class NodeError extends Base {
+    constructor () {
+      super()
+
+      Object.defineProperty(this, 'message', {
+        value: getMessage.apply(this, arguments),
+        writable: true,
+        configurable: true
+      })
+
+      // Add the error code to the name to include it in the stack trace.
+      this.name = `${this.name} [${sym}]`
+      // Access the stack to generate the error message including the error code
+      // from the name.
+      this.stack // eslint-disable-line no-unused-expressions
+      // Reset the name to the actual name.
+      delete this.name
+    }
+
+    get code () {
+      return sym
+    }
+
+    set code (value) {
+      Object.defineProperty(this, 'code', {
+        configurable: true,
+        enumerable: true,
+        value,
+        writable: true
+      })
+    }
+
+    toString () {
+      return `${this.name} [${sym}]: ${this.message}`
+    }
+  }
+}
+
+E('ERR_BUFFER_OUT_OF_BOUNDS',
+  function (name) {
+    if (name) {
+      return `${name} is outside of buffer bounds`
+    }
+
+    return 'Attempt to access memory outside buffer bounds'
+  }, RangeError)
+E('ERR_INVALID_ARG_TYPE',
+  function (name, actual) {
+    return `The "${name}" argument must be of type number. Received type ${typeof actual}`
+  }, TypeError)
+E('ERR_OUT_OF_RANGE',
+  function (str, range, input) {
+    let msg = `The value of "${str}" is out of range.`
+    let received = input
+    if (Number.isInteger(input) && Math.abs(input) > 2 ** 32) {
+      received = addNumericalSeparator(String(input))
+    } else if (typeof input === 'bigint') {
+      received = String(input)
+      if (input > 2n ** 32n || input < -(2n ** 32n)) {
+        received = addNumericalSeparator(received)
+      }
+      received += 'n'
+    }
+    msg += ` It must be ${range}. Received ${received}`
+    return msg
+  }, RangeError)
+
+function addNumericalSeparator (val) {
+  let res = ''
+  let i = val.length
+  const start = val[0] === '-' ? 1 : 0
+  for (; i >= start + 4; i -= 3) {
+    res = `_${val.slice(i - 3, i)}${res}`
+  }
+  return `${val.slice(0, i)}${res}`
+}
+
+// CHECK FUNCTIONS
+// ===============
+
+function checkBounds (buf, offset, byteLength) {
+  validateNumber(offset, 'offset')
+  if (buf[offset] === undefined || buf[offset + byteLength] === undefined) {
+    boundsError(offset, buf.length - (byteLength + 1))
+  }
+}
+
+function checkIntBI (value, min, max, buf, offset, byteLength) {
+  if (value > max || value < min) {
+    const n = typeof min === 'bigint' ? 'n' : ''
+    let range
+    if (byteLength > 3) {
+      if (min === 0 || min === 0n) {
+        range = `>= 0${n} and < 2${n} ** ${(byteLength + 1) * 8}${n}`
+      } else {
+        range = `>= -(2${n} ** ${(byteLength + 1) * 8 - 1}${n}) and < 2 ** ` +
+                `${(byteLength + 1) * 8 - 1}${n}`
+      }
+    } else {
+      range = `>= ${min}${n} and <= ${max}${n}`
+    }
+    throw new errors.ERR_OUT_OF_RANGE('value', range, value)
+  }
+  checkBounds(buf, offset, byteLength)
+}
+
+function validateNumber (value, name) {
+  if (typeof value !== 'number') {
+    throw new errors.ERR_INVALID_ARG_TYPE(name, 'number', value)
+  }
+}
+
+function boundsError (value, length, type) {
+  if (Math.floor(value) !== value) {
+    validateNumber(value, type)
+    throw new errors.ERR_OUT_OF_RANGE(type || 'offset', 'an integer', value)
+  }
+
+  if (length < 0) {
+    throw new errors.ERR_BUFFER_OUT_OF_BOUNDS()
+  }
+
+  throw new errors.ERR_OUT_OF_RANGE(type || 'offset',
+                                    `>= ${type ? 1 : 0} and <= ${length}`,
+                                    value)
+}
+
 // HELPER FUNCTIONS
 // ================
 
@@ -1797,3 +2072,12 @@ var hexSliceLookupTable = (function () {
   }
   return table
 })()
+
+// Return not function with Error if BigInt not supported
+function defineBigIntMethod (fn) {
+  return typeof BigInt === 'undefined' ? BufferBigIntNotDefined : fn
+}
+
+function BufferBigIntNotDefined () {
+  throw new Error('BigInt not supported')
+}
diff --git a/package.json b/package.json
index 9d9c6e0..bad6015 100644
--- a/package.json
+++ b/package.json
@@ -69,6 +69,9 @@
     "update-authors": "./bin/update-authors.sh"
   },
   "standard": {
+    "globals": [
+      "BigInt"
+    ],
     "ignore": [
       "test/node/**/*.js",
       "test/common.js",
diff --git a/test/node/test-buffer-bigint64.js b/test/node/test-buffer-bigint64.js
new file mode 100644
index 0000000..b11632f
--- /dev/null
+++ b/test/node/test-buffer-bigint64.js
@@ -0,0 +1,55 @@
+'use strict'
+var Buffer = require('../../').Buffer
+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)
+  }, {
+    code: 'ERR_OUT_OF_RANGE',
+    message: 'The value of "value" is out of range. It must be ' +
+             '>= 0n and < 2n ** 64n. Received 18_446_744_073_709_551_616n'
+  })
+
+  // 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)
+})