text: 'use strict';
  
  const {
    BigInt,
    Float32Array,
    MathFloor,
    Number,
  } = primordials;
  
  const {
    ERR_BUFFER_OUT_OF_BOUNDS,
    ERR_INVALID_ARG_TYPE,
    ERR_OUT_OF_RANGE
  } = require('internal/errors').codes;
  const { validateNumber } = require('internal/validators');
  const {
    asciiSlice,
    base64Slice,
    latin1Slice,
    hexSlice,
    ucs2Slice,
    utf8Slice,
    asciiWrite,
    base64Write,
    latin1Write,
    hexWrite,
    ucs2Write,
    utf8Write
  } = internalBinding('buffer');
  const {
    untransferable_object_private_symbol,
    setHiddenValue,
  } = internalBinding('util');
  
  // Temporary buffers to convert numbers.
  const float32Array = new Float32Array(1);
  const uInt8Float32Array = new Uint8Array(float32Array.buffer);
  const float64Array = new Float64Array(1);
  const uInt8Float64Array = new Uint8Array(float64Array.buffer);
  
  // Check endianness.
  float32Array[0] = -1; // 0xBF800000
  // Either it is [0, 0, 128, 191] or [191, 128, 0, 0]. It is not possible to
  // check this with `os.endianness()` because that is determined at compile time.
  const bigEndian = uInt8Float32Array[3] === 0;
  
  function checkBounds(buf, offset, byteLength) {
    validateNumber(offset, 'offset');
    if (buf[offset] === undefined || buf[offset + byteLength] === undefined)
      boundsError(offset, buf.length - (byteLength + 1));
  }
  
  function checkInt(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 ERR_OUT_OF_RANGE('value', range, value);
    }
    checkBounds(buf, offset, byteLength);
  }
  
  function boundsError(value, length, type) {
    if (MathFloor(value) !== value) {
      validateNumber(value, type);
      throw new ERR_OUT_OF_RANGE(type || 'offset', 'an integer', value);
    }
  
    if (length < 0)
      throw new ERR_BUFFER_OUT_OF_BOUNDS();
  
    throw new ERR_OUT_OF_RANGE(type || 'offset',
                               `>= ${type ? 1 : 0} and <= ${length}`,
                               value);
  }
  
  // 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 (offset === undefined)
      throw new ERR_INVALID_ARG_TYPE('offset', 'number', offset);
    if (byteLength === 6)
      return readUInt48LE(this, offset);
    if (byteLength === 5)
      return readUInt40LE(this, offset);
    if (byteLength === 3)
      return readUInt24LE(this, offset);
    if (byteLength === 4)
      return this.readUInt32LE(offset);
    if (byteLength === 2)
      return this.readUInt16LE(offset);
    if (byteLength === 1)
      return this.readUInt8(offset);
  
    boundsError(byteLength, 6, 'byteLength');
  }
  
  function readUInt48LE(buf, offset = 0) {
    validateNumber(offset, 'offset');
    const first = buf[offset];
    const last = buf[offset + 5];
    if (first === undefined || last === undefined)
      boundsError(offset, buf.length - 6);
  
    return first +
      buf[++offset] * 2 ** 8 +
      buf[++offset] * 2 ** 16 +
      buf[++offset] * 2 ** 24 +
      (buf[++offset] + last * 2 ** 8) * 2 ** 32;
  }
  
  function readUInt40LE(buf, offset = 0) {
    validateNumber(offset, 'offset');
    const first = buf[offset];
    const last = buf[offset + 4];
    if (first === undefined || last === undefined)
      boundsError(offset, buf.length - 5);
  
    return first +
      buf[++offset] * 2 ** 8 +
      buf[++offset] * 2 ** 16 +
      buf[++offset] * 2 ** 24 +
      last * 2 ** 32;
  }
  
  function readUInt32LE(offset = 0) {
    validateNumber(offset, 'offset');
    const first = this[offset];
    const last = this[offset + 3];
    if (first === undefined || last === undefined)
      boundsError(offset, this.length - 4);
  
    return first +
      this[++offset] * 2 ** 8 +
      this[++offset] * 2 ** 16 +
      last * 2 ** 24;
  }
  
  function readUInt24LE(buf, offset = 0) {
    validateNumber(offset, 'offset');
    const first = buf[offset];
    const last = buf[offset + 2];
    if (first === undefined || last === undefined)
      boundsError(offset, buf.length - 3);
  
    return first + buf[++offset] * 2 ** 8 + last * 2 ** 16;
  }
  
  function readUInt16LE(offset = 0) {
    validateNumber(offset, 'offset');
    const first = this[offset];
    const last = this[offset + 1];
    if (first === undefined || last === undefined)
      boundsError(offset, this.length - 2);
  
    return first + last * 2 ** 8;
  }
  
  function readUInt8(offset = 0) {
    validateNumber(offset, 'offset');
    const val = this[offset];
    if (val === undefined)
      boundsError(offset, this.length - 1);
  
    return val;
  }
  
  function readUIntBE(offset, byteLength) {
    if (offset === undefined)
      throw new ERR_INVALID_ARG_TYPE('offset', 'number', offset);
    if (byteLength === 6)
      return readUInt48BE(this, offset);
    if (byteLength === 5)
      return readUInt40BE(this, offset);
    if (byteLength === 3)
      return readUInt24BE(this, offset);
    if (byteLength === 4)
      return this.readUInt32BE(offset);
    if (byteLength === 2)
      return this.readUInt16BE(offset);
    if (byteLength === 1)
      return this.readUInt8(offset);
  
    boundsError(byteLength, 6, 'byteLength');
  }
  
  function readUInt48BE(buf, offset = 0) {
    validateNumber(offset, 'offset');
    const first = buf[offset];
    const last = buf[offset + 5];
    if (first === undefined || last === undefined)
      boundsError(offset, buf.length - 6);
  
    return (first * 2 ** 8 + buf[++offset]) * 2 ** 32 +
      buf[++offset] * 2 ** 24 +
      buf[++offset] * 2 ** 16 +
      buf[++offset] * 2 ** 8 +
      last;
  }
  
  function readUInt40BE(buf, offset = 0) {
    validateNumber(offset, 'offset');
    const first = buf[offset];
    const last = buf[offset + 4];
    if (first === undefined || last === undefined)
      boundsError(offset, buf.length - 5);
  
    return first * 2 ** 32 +
      buf[++offset] * 2 ** 24 +
      buf[++offset] * 2 ** 16 +
      buf[++offset] * 2 ** 8 +
      last;
  }
  
  function readUInt32BE(offset = 0) {
    validateNumber(offset, 'offset');
    const first = this[offset];
    const last = this[offset + 3];
    if (first === undefined || last === undefined)
      boundsError(offset, this.length - 4);
  
    return first * 2 ** 24 +
      this[++offset] * 2 ** 16 +
      this[++offset] * 2 ** 8 +
      last;
  }
  
  function readUInt24BE(buf, offset = 0) {
    validateNumber(offset, 'offset');
    const first = buf[offset];
    const last = buf[offset + 2];
    if (first === undefined || last === undefined)
      boundsError(offset, buf.length - 3);
  
    return first * 2 ** 16 + buf[++offset] * 2 ** 8 + last;
  }
  
  function readUInt16BE(offset = 0) {
    validateNumber(offset, 'offset');
    const first = this[offset];
    const last = this[offset + 1];
    if (first === undefined || last === undefined)
      boundsError(offset, this.length - 2);
  
    return first * 2 ** 8 + last;
  }
  
  function readIntLE(offset, byteLength) {
    if (offset === undefined)
      throw new ERR_INVALID_ARG_TYPE('offset', 'number', offset);
    if (byteLength === 6)
      return readInt48LE(this, offset);
    if (byteLength === 5)
      return readInt40LE(this, offset);
    if (byteLength === 3)
      return readInt24LE(this, offset);
    if (byteLength === 4)
      return this.readInt32LE(offset);
    if (byteLength === 2)
      return this.readInt16LE(offset);
    if (byteLength === 1)
      return this.readInt8(offset);
  
    boundsError(byteLength, 6, 'byteLength');
  }
  
  function readInt48LE(buf, offset = 0) {
    validateNumber(offset, 'offset');
    const first = buf[offset];
    const last = buf[offset + 5];
    if (first === undefined || last === undefined)
      boundsError(offset, buf.length - 6);
  
    const val = buf[offset + 4] + last * 2 ** 8;
    return (val | (val & 2 ** 15) * 0x1fffe) * 2 ** 32 +
      first +
      buf[++offset] * 2 ** 8 +
      buf[++offset] * 2 ** 16 +
      buf[++offset] * 2 ** 24;
  }
  
  function readInt40LE(buf, offset = 0) {
    validateNumber(offset, 'offset');
    const first = buf[offset];
    const last = buf[offset + 4];
    if (first === undefined || last === undefined)
      boundsError(offset, buf.length - 5);
  
    return (last | (last & 2 ** 7) * 0x1fffffe) * 2 ** 32 +
      first +
      buf[++offset] * 2 ** 8 +
      buf[++offset] * 2 ** 16 +
      buf[++offset] * 2 ** 24;
  }
  
  function readInt32LE(offset = 0) {
    validateNumber(offset, 'offset');
    const first = this[offset];
    const last = this[offset + 3];
    if (first === undefined || last === undefined)
      boundsError(offset, this.length - 4);
  
    return first +
      this[++offset] * 2 ** 8 +
      this[++offset] * 2 ** 16 +
      (last << 24); // Overflow
  }
  
  function readInt24LE(buf, offset = 0) {
    validateNumber(offset, 'offset');
    const first = buf[offset];
    const last = buf[offset + 2];
    if (first === undefined || last === undefined)
      boundsError(offset, buf.length - 3);
  
    const val = first + buf[++offset] * 2 ** 8 + last * 2 ** 16;
    return val | (val & 2 ** 23) * 0x1fe;
  }
  
  function readInt16LE(offset = 0) {
    validateNumber(offset, 'offset');
    const first = this[offset];
    const last = this[offset + 1];
    if (first === undefined || last === undefined)
      boundsError(offset, this.length - 2);
  
    const val = first + last * 2 ** 8;
    return val | (val & 2 ** 15) * 0x1fffe;
  }
  
  function readInt8(offset = 0) {
    validateNumber(offset, 'offset');
    const val = this[offset];
    if (val === undefined)
      boundsError(offset, this.length - 1);
  
    return val | (val & 2 ** 7) * 0x1fffffe;
  }
  
  function readIntBE(offset, byteLength) {
    if (offset === undefined)
      throw new ERR_INVALID_ARG_TYPE('offset', 'number', offset);
    if (byteLength === 6)
      return readInt48BE(this, offset);
    if (byteLength === 5)
      return readInt40BE(this, offset);
    if (byteLength === 3)
      return readInt24BE(this, offset);
    if (byteLength === 4)
      return this.readInt32BE(offset);
    if (byteLength === 2)
      return this.readInt16BE(offset);
    if (byteLength === 1)
      return this.readInt8(offset);
  
    boundsError(byteLength, 6, 'byteLength');
  }
  
  function readInt48BE(buf, offset = 0) {
    validateNumber(offset, 'offset');
    const first = buf[offset];
    const last = buf[offset + 5];
    if (first === undefined || last === undefined)
      boundsError(offset, buf.length - 6);
  
    const val = buf[++offset] + first * 2 ** 8;
    return (val | (val & 2 ** 15) * 0x1fffe) * 2 ** 32 +
      buf[++offset] * 2 ** 24 +
      buf[++offset] * 2 ** 16 +
      buf[++offset] * 2 ** 8 +
      last;
  }
  
  function readInt40BE(buf, offset = 0) {
    validateNumber(offset, 'offset');
    const first = buf[offset];
    const last = buf[offset + 4];
    if (first === undefined || last === undefined)
      boundsError(offset, buf.length - 5);
  
    return (first | (first & 2 ** 7) * 0x1fffffe) * 2 ** 32 +
      buf[++offset] * 2 ** 24 +
      buf[++offset] * 2 ** 16 +
      buf[++offset] * 2 ** 8 +
      last;
  }
  
  function readInt32BE(offset = 0) {
    validateNumber(offset, 'offset');
    const first = this[offset];
    const last = this[offset + 3];
    if (first === undefined || last === undefined)
      boundsError(offset, this.length - 4);
  
    return (first << 24) + // Overflow
      this[++offset] * 2 ** 16 +
      this[++offset] * 2 ** 8 +
      last;
  }
  
  function readInt24BE(buf, offset = 0) {
    validateNumber(offset, 'offset');
    const first = buf[offset];
    const last = buf[offset + 2];
    if (first === undefined || last === undefined)
      boundsError(offset, buf.length - 3);
  
    const val = first * 2 ** 16 + buf[++offset] * 2 ** 8 + last;
    return val | (val & 2 ** 23) * 0x1fe;
  }
  
  function readInt16BE(offset = 0) {
    validateNumber(offset, 'offset');
    const first = this[offset];
    const last = this[offset + 1];
    if (first === undefined || last === undefined)
      boundsError(offset, this.length - 2);
  
    const val = first * 2 ** 8 + last;
    return val | (val & 2 ** 15) * 0x1fffe;
  }
  
  // Read floats
  function readFloatBackwards(offset = 0) {
    validateNumber(offset, 'offset');
    const first = this[offset];
    const last = this[offset + 3];
    if (first === undefined || last === undefined)
      boundsError(offset, this.length - 4);
  
    uInt8Float32Array[3] = first;
    uInt8Float32Array[2] = this[++offset];
    uInt8Float32Array[1] = this[++offset];
    uInt8Float32Array[0] = last;
    return float32Array[0];
  }
  
  function readFloatForwards(offset = 0) {
    validateNumber(offset, 'offset');
    const first = this[offset];
    const last = this[offset + 3];
    if (first === undefined || last === undefined)
      boundsError(offset, this.length - 4);
  
    uInt8Float32Array[0] = first;
    uInt8Float32Array[1] = this[++offset];
    uInt8Float32Array[2] = this[++offset];
    uInt8Float32Array[3] = last;
    return float32Array[0];
  }
  
  function readDoubleBackwards(offset = 0) {
    validateNumber(offset, 'offset');
    const first = this[offset];
    const last = this[offset + 7];
    if (first === undefined || last === undefined)
      boundsError(offset, this.length - 8);
  
    uInt8Float64Array[7] = first;
    uInt8Float64Array[6] = this[++offset];
    uInt8Float64Array[5] = this[++offset];
    uInt8Float64Array[4] = this[++offset];
    uInt8Float64Array[3] = this[++offset];
    uInt8Float64Array[2] = this[++offset];
    uInt8Float64Array[1] = this[++offset];
    uInt8Float64Array[0] = last;
    return float64Array[0];
  }
  
  function readDoubleForwards(offset = 0) {
    validateNumber(offset, 'offset');
    const first = this[offset];
    const last = this[offset + 7];
    if (first === undefined || last === undefined)
      boundsError(offset, this.length - 8);
  
    uInt8Float64Array[0] = first;
    uInt8Float64Array[1] = this[++offset];
    uInt8Float64Array[2] = this[++offset];
    uInt8Float64Array[3] = this[++offset];
    uInt8Float64Array[4] = this[++offset];
    uInt8Float64Array[5] = this[++offset];
    uInt8Float64Array[6] = this[++offset];
    uInt8Float64Array[7] = last;
    return float64Array[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, byteLength) {
    if (byteLength === 6)
      return writeU_Int48LE(this, value, offset, 0, 0xffffffffffff);
    if (byteLength === 5)
      return writeU_Int40LE(this, value, offset, 0, 0xffffffffff);
    if (byteLength === 3)
      return writeU_Int24LE(this, value, offset, 0, 0xffffff);
    if (byteLength === 4)
      return writeU_Int32LE(this, value, offset, 0, 0xffffffff);
    if (byteLength === 2)
      return writeU_Int16LE(this, value, offset, 0, 0xffff);
    if (byteLength === 1)
      return writeU_Int8(this, value, offset, 0, 0xff);
  
    boundsError(byteLength, 6, 'byteLength');
  }
  
  function writeU_Int48LE(buf, value, offset, min, max) {
    value = +value;
    checkInt(value, min, max, buf, offset, 5);
  
    const newVal = MathFloor(value * 2 ** -32);
    buf[offset++] = value;
    value = value >>> 8;
    buf[offset++] = value;
    value = value >>> 8;
    buf[offset++] = value;
    value = value >>> 8;
    buf[offset++] = value;
    buf[offset++] = newVal;
    buf[offset++] = (newVal >>> 8);
    return offset;
  }
  
  function writeU_Int40LE(buf, value, offset, min, max) {
    value = +value;
    checkInt(value, min, max, buf, offset, 4);
  
    const newVal = value;
    buf[offset++] = value;
    value = value >>> 8;
    buf[offset++] = value;
    value = value >>> 8;
    buf[offset++] = value;
    value = value >>> 8;
    buf[offset++] = value;
    buf[offset++] = MathFloor(newVal * 2 ** -32);
    return offset;
  }
  
  function writeU_Int32LE(buf, value, offset, min, max) {
    value = +value;
    checkInt(value, min, max, buf, offset, 3);
  
    buf[offset++] = value;
    value = value >>> 8;
    buf[offset++] = value;
    value = value >>> 8;
    buf[offset++] = value;
    value = value >>> 8;
    buf[offset++] = value;
    return offset;
  }
  
  function writeUInt32LE(value, offset = 0) {
    return writeU_Int32LE(this, value, offset, 0, 0xffffffff);
  }
  
  function writeU_Int24LE(buf, value, offset, min, max) {
    value = +value;
    checkInt(value, min, max, buf, offset, 2);
  
    buf[offset++] = value;
    value = value >>> 8;
    buf[offset++] = value;
    value = value >>> 8;
    buf[offset++] = value;
    return offset;
  }
  
  function writeU_Int16LE(buf, value, offset, min, max) {
    value = +value;
    checkInt(value, min, max, buf, offset, 1);
  
    buf[offset++] = value;
    buf[offset++] = (value >>> 8);
    return offset;
  }
  
  function writeUInt16LE(value, offset = 0) {
    return writeU_Int16LE(this, value, offset, 0, 0xffff);
  }
  
  function writeU_Int8(buf, value, offset, min, max) {
    value = +value;
    // `checkInt()` can not be used here because it checks two entries.
    validateNumber(offset, 'offset');
    if (value > max || value < min) {
      throw new ERR_OUT_OF_RANGE('value', `>= ${min} and <= ${max}`, value);
    }
    if (buf[offset] === undefined)
      boundsError(offset, buf.length - 1);
  
    buf[offset] = value;
    return offset + 1;
  }
  
  function writeUInt8(value, offset = 0) {
    return writeU_Int8(this, value, offset, 0, 0xff);
  }
  
  function writeUIntBE(value, offset, byteLength) {
    if (byteLength === 6)
      return writeU_Int48BE(this, value, offset, 0, 0xffffffffffff);
    if (byteLength === 5)
      return writeU_Int40BE(this, value, offset, 0, 0xffffffffff);
    if (byteLength === 3)
      return writeU_Int24BE(this, value, offset, 0, 0xffffff);
    if (byteLength === 4)
      return writeU_Int32BE(this, value, offset, 0, 0xffffffff);
    if (byteLength === 2)
      return writeU_Int16BE(this, value, offset, 0, 0xffff);
    if (byteLength === 1)
      return writeU_Int8(this, value, offset, 0, 0xff);
  
    boundsError(byteLength, 6, 'byteLength');
  }
  
  function writeU_Int48BE(buf, value, offset, min, max) {
    value = +value;
    checkInt(value, min, max, buf, offset, 5);
  
    const newVal = MathFloor(value * 2 ** -32);
    buf[offset++] = (newVal >>> 8);
    buf[offset++] = newVal;
    buf[offset + 3] = value;
    value = value >>> 8;
    buf[offset + 2] = value;
    value = value >>> 8;
    buf[offset + 1] = value;
    value = value >>> 8;
    buf[offset] = value;
    return offset + 4;
  }
  
  function writeU_Int40BE(buf, value, offset, min, max) {
    value = +value;
    checkInt(value, min, max, buf, offset, 4);
  
    buf[offset++] = MathFloor(value * 2 ** -32);
    buf[offset + 3] = value;
    value = value >>> 8;
    buf[offset + 2] = value;
    value = value >>> 8;
    buf[offset + 1] = value;
    value = value >>> 8;
    buf[offset] = value;
    return offset + 4;
  }
  
  function writeU_Int32BE(buf, value, offset, min, max) {
    value = +value;
    checkInt(value, min, max, buf, offset, 3);
  
    buf[offset + 3] = value;
    value = value >>> 8;
    buf[offset + 2] = value;
    value = value >>> 8;
    buf[offset + 1] = value;
    value = value >>> 8;
    buf[offset] = value;
    return offset + 4;
  }
  
  function writeUInt32BE(value, offset = 0) {
    return writeU_Int32BE(this, value, offset, 0, 0xffffffff);
  }
  
  function writeU_Int24BE(buf, value, offset, min, max) {
    value = +value;
    checkInt(value, min, max, buf, offset, 2);
  
    buf[offset + 2] = value;
    value = value >>> 8;
    buf[offset + 1] = value;
    value = value >>> 8;
    buf[offset] = value;
    return offset + 3;
  }
  
  function writeU_Int16BE(buf, value, offset, min, max) {
    value = +value;
    checkInt(value, min, max, buf, offset, 1);
  
    buf[offset++] = (value >>> 8);
    buf[offset++] = value;
    return offset;
  }
  
  function writeUInt16BE(value, offset = 0) {
    return writeU_Int16BE(this, value, offset, 0, 0xffff);
  }
  
  function writeIntLE(value, offset, byteLength) {
    if (byteLength === 6)
      return writeU_Int48LE(this, value, offset, -0x800000000000, 0x7fffffffffff);
    if (byteLength === 5)
      return writeU_Int40LE(this, value, offset, -0x8000000000, 0x7fffffffff);
    if (byteLength === 3)
      return writeU_Int24LE(this, value, offset, -0x800000, 0x7fffff);
    if (byteLength === 4)
      return writeU_Int32LE(this, value, offset, -0x80000000, 0x7fffffff);
    if (byteLength === 2)
      return writeU_Int16LE(this, value, offset, -0x8000, 0x7fff);
    if (byteLength === 1)
      return writeU_Int8(this, value, offset, -0x80, 0x7f);
  
    boundsError(byteLength, 6, 'byteLength');
  }
  
  function writeInt32LE(value, offset = 0) {
    return writeU_Int32LE(this, value, offset, -0x80000000, 0x7fffffff);
  }
  
  function writeInt16LE(value, offset = 0) {
    return writeU_Int16LE(this, value, offset, -0x8000, 0x7fff);
  }
  
  function writeInt8(value, offset = 0) {
    return writeU_Int8(this, value, offset, -0x80, 0x7f);
  }
  
  function writeIntBE(value, offset, byteLength) {
    if (byteLength === 6)
      return writeU_Int48BE(this, value, offset, -0x800000000000, 0x7fffffffffff);
    if (byteLength === 5)
      return writeU_Int40BE(this, value, offset, -0x8000000000, 0x7fffffffff);
    if (byteLength === 3)
      return writeU_Int24BE(this, value, offset, -0x800000, 0x7fffff);
    if (byteLength === 4)
      return writeU_Int32BE(this, value, offset, -0x80000000, 0x7fffffff);
    if (byteLength === 2)
      return writeU_Int16BE(this, value, offset, -0x8000, 0x7fff);
    if (byteLength === 1)
      return writeU_Int8(this, value, offset, -0x80, 0x7f);
  
    boundsError(byteLength, 6, 'byteLength');
  }
  
  function writeInt32BE(value, offset = 0) {
    return writeU_Int32BE(this, value, offset, -0x80000000, 0x7fffffff);
  }
  
  function writeInt16BE(value, offset = 0) {
    return writeU_Int16BE(this, value, offset, -0x8000, 0x7fff);
  }
  
  // Write floats.
  function writeDoubleForwards(val, offset = 0) {
    val = +val;
    checkBounds(this, offset, 7);
  
    float64Array[0] = val;
    this[offset++] = uInt8Float64Array[0];
    this[offset++] = uInt8Float64Array[1];
    this[offset++] = uInt8Float64Array[2];
    this[offset++] = uInt8Float64Array[3];
    this[offset++] = uInt8Float64Array[4];
    this[offset++] = uInt8Float64Array[5];
    this[offset++] = uInt8Float64Array[6];
    this[offset++] = uInt8Float64Array[7];
    return offset;
  }
  
  function writeDoubleBackwards(val, offset = 0) {
    val = +val;
    checkBounds(this, offset, 7);
  
    float64Array[0] = val;
    this[offset++] = uInt8Float64Array[7];
    this[offset++] = uInt8Float64Array[6];
    this[offset++] = uInt8Float64Array[5];
    this[offset++] = uInt8Float64Array[4];
    this[offset++] = uInt8Float64Array[3];
    this[offset++] = uInt8Float64Array[2];
    this[offset++] = uInt8Float64Array[1];
    this[offset++] = uInt8Float64Array[0];
    return offset;
  }
  
  function writeFloatForwards(val, offset = 0) {
    val = +val;
    checkBounds(this, offset, 3);
  
    float32Array[0] = val;
    this[offset++] = uInt8Float32Array[0];
    this[offset++] = uInt8Float32Array[1];
    this[offset++] = uInt8Float32Array[2];
    this[offset++] = uInt8Float32Array[3];
    return offset;
  }
  
  function writeFloatBackwards(val, offset = 0) {
    val = +val;
    checkBounds(this, offset, 3);
  
    float32Array[0] = val;
    this[offset++] = uInt8Float32Array[3];
    this[offset++] = uInt8Float32Array[2];
    this[offset++] = uInt8Float32Array[1];
    this[offset++] = uInt8Float32Array[0];
    return offset;
  }
  
  class FastBuffer extends Uint8Array {}
  
  function addBufferPrototypeMethods(proto) {
    proto.readBigUInt64LE = readBigUInt64LE,
    proto.readBigUInt64BE = readBigUInt64BE,
    proto.readBigInt64LE = readBigInt64LE,
    proto.readBigInt64BE = readBigInt64BE,
    proto.writeBigUInt64LE = writeBigUInt64LE,
    proto.writeBigUInt64BE = writeBigUInt64BE,
    proto.writeBigInt64LE = writeBigInt64LE,
    proto.writeBigInt64BE = writeBigInt64BE,
  
    proto.readUIntLE = readUIntLE;
    proto.readUInt32LE = readUInt32LE;
    proto.readUInt16LE = readUInt16LE;
    proto.readUInt8 = readUInt8;
    proto.readUIntBE = readUIntBE;
    proto.readUInt32BE = readUInt32BE;
    proto.readUInt16BE = readUInt16BE;
    proto.readIntLE = readIntLE;
    proto.readInt32LE = readInt32LE;
    proto.readInt16LE = readInt16LE;
    proto.readInt8 = readInt8;
    proto.readIntBE = readIntBE;
    proto.readInt32BE = readInt32BE;
    proto.readInt16BE = readInt16BE;
  
    proto.writeUIntLE = writeUIntLE;
    proto.writeUInt32LE = writeUInt32LE;
    proto.writeUInt16LE = writeUInt16LE;
    proto.writeUInt8 = writeUInt8;
    proto.writeUIntBE = writeUIntBE;
    proto.writeUInt32BE = writeUInt32BE;
    proto.writeUInt16BE = writeUInt16BE;
    proto.writeIntLE = writeIntLE;
    proto.writeInt32LE = writeInt32LE;
    proto.writeInt16LE = writeInt16LE;
    proto.writeInt8 = writeInt8;
    proto.writeIntBE = writeIntBE;
    proto.writeInt32BE = writeInt32BE;
    proto.writeInt16BE = writeInt16BE;
  
    proto.readFloatLE = bigEndian ? readFloatBackwards : readFloatForwards;
    proto.readFloatBE = bigEndian ? readFloatForwards : readFloatBackwards;
    proto.readDoubleLE = bigEndian ? readDoubleBackwards : readDoubleForwards;
    proto.readDoubleBE = bigEndian ? readDoubleForwards : readDoubleBackwards;
    proto.writeFloatLE = bigEndian ? writeFloatBackwards : writeFloatForwards;
    proto.writeFloatBE = bigEndian ? writeFloatForwards : writeFloatBackwards;
    proto.writeDoubleLE = bigEndian ? writeDoubleBackwards : writeDoubleForwards;
    proto.writeDoubleBE = bigEndian ? writeDoubleForwards : writeDoubleBackwards;
  
    proto.asciiSlice = asciiSlice;
    proto.base64Slice = base64Slice;
    proto.latin1Slice = latin1Slice;
    proto.hexSlice = hexSlice;
    proto.ucs2Slice = ucs2Slice;
    proto.utf8Slice = utf8Slice;
    proto.asciiWrite = asciiWrite;
    proto.base64Write = base64Write;
    proto.latin1Write = latin1Write;
    proto.hexWrite = hexWrite;
    proto.ucs2Write = ucs2Write;
    proto.utf8Write = utf8Write;
  }
  
  // This would better be placed in internal/worker/io.js, but that doesn't work
  // because Buffer needs this and that would introduce a cyclic dependency.
  function markAsUntransferable(obj) {
    if ((typeof obj !== 'object' && typeof obj !== 'function') || obj === null)
      return;  // This object is a primitive and therefore already untransferable.
    setHiddenValue(obj, untransferable_object_private_symbol, true);
  }
  
  module.exports = {
    FastBuffer,
    addBufferPrototypeMethods,
    markAsUntransferable,
  };
  