node/lib/buffer.js at master · elarkin/node · GitHub

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// Copyright Joyent, Inc. and other Node contributors.

// Permission is hereby granted, free of charge, to any person obtaining a

// copy of this software and associated documentation files (the

// "Software"), to deal in the Software without restriction, including

// without limitation the rights to use, copy, modify, merge, publish,

// distribute, sublicense, and/or sell copies of the Software, and to permit

// persons to whom the Software is furnished to do so, subject to the

// following conditions:

// The above copyright notice and this permission notice shall be included

// in all copies or substantial portions of the Software.

// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS

// OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF

// MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN

// NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,

// DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR

// OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE

// USE OR OTHER DEALINGS IN THE SOFTWARE.

var SlowBuffer = process.binding('buffer').SlowBuffer;

var assert = require('assert');

exports.INSPECT_MAX_BYTES = 50;

function toHex(n) {

if (n < 16) return '0' + n.toString(16);

return n.toString(16);

}

SlowBuffer.prototype.inspect = function() {

var out = [],

len = this.length;

for (var i = 0; i < len; i++) {

out[i] = toHex(this[i]);

if (i == exports.INSPECT_MAX_BYTES) {

out[i + 1] = '...';

break;

}

return '<SlowBuffer ' + out.join(' ') + '>';

};

SlowBuffer.prototype.hexSlice = function(start, end) {

var len = this.length;

if (!start || start < 0) start = 0;

if (!end || end < 0 || end > len) end = len;

var out = '';

for (var i = start; i < end; i++) {

out += toHex(this[i]);

}

return out;

};

SlowBuffer.prototype.toString = function(encoding, start, end) {

encoding = String(encoding || 'utf8').toLowerCase();

start = +start || 0;

if (typeof end == 'undefined') end = this.length;

// Fastpath empty strings

if (+end == start) {

return '';

}

switch (encoding) {

case 'hex':

return this.hexSlice(start, end);

case 'utf8':

case 'utf-8':

return this.utf8Slice(start, end);

case 'ascii':

return this.asciiSlice(start, end);

case 'binary':

return this.binarySlice(start, end);

case 'base64':

return this.base64Slice(start, end);

case 'ucs2':

case 'ucs-2':

return this.ucs2Slice(start, end);

default:

throw new Error('Unknown encoding');

}

};

SlowBuffer.prototype.hexWrite = function(string, offset, length) {

offset = +offset || 0;

var remaining = this.length - offset;

if (!length) {

length = remaining;

} else {

length = +length;

if (length > remaining) {

length = remaining;

}

// must be an even number of digits

var strLen = string.length;

if (strLen % 2) {

throw new Error('Invalid hex string');

}

if (length > strLen / 2) {

length = strLen / 2;

}

for (var i = 0; i < length; i++) {

var byte = parseInt(string.substr(i * 2, 2), 16);

if (isNaN(byte)) throw new Error('Invalid hex string');

this[offset + i] = byte;

}

SlowBuffer._charsWritten = i * 2;

return i;

};

SlowBuffer.prototype.write = function(string, offset, length, encoding) {

// Support both (string, offset, length, encoding)

// and the legacy (string, encoding, offset, length)

if (isFinite(offset)) {

if (!isFinite(length)) {

encoding = length;

length = undefined;

}

} else { // legacy

var swap = encoding;

encoding = offset;

offset = length;

length = swap;

}

offset = +offset || 0;

var remaining = this.length - offset;

if (!length) {

length = remaining;

} else {

length = +length;

if (length > remaining) {

length = remaining;

}

encoding = String(encoding || 'utf8').toLowerCase();

switch (encoding) {

case 'hex':

return this.hexWrite(string, offset, length);

case 'utf8':

case 'utf-8':

return this.utf8Write(string, offset, length);

case 'ascii':

return this.asciiWrite(string, offset, length);

case 'binary':

return this.binaryWrite(string, offset, length);

case 'base64':

return this.base64Write(string, offset, length);

case 'ucs2':

case 'ucs-2':

return this.ucs2Write(string, offset, length);

default:

throw new Error('Unknown encoding');

}

};

// slice(start, end)

SlowBuffer.prototype.slice = function(start, end) {

if (end === undefined) end = this.length;

if (end > this.length) {

throw new Error('oob');

}

if (start > end) {

throw new Error('oob');

}

return new Buffer(this, end - start, +start);

};

// Buffer

function Buffer(subject, encoding, offset) {

if (!(this instanceof Buffer)) {

return new Buffer(subject, encoding, offset);

}

var type;

// Are we slicing?

if (typeof offset === 'number') {

this.length = encoding;

this.parent = subject;

this.offset = offset;

} else {

// Find the length

switch (type = typeof subject) {

case 'number':

this.length = subject;

break;

case 'string':

this.length = Buffer.byteLength(subject, encoding);

break;

case 'object': // Assume object is an array

this.length = subject.length;

break;

default:

throw new Error('First argument needs to be a number, ' +

'array or string.');

}

if (this.length > Buffer.poolSize) {

// Big buffer, just alloc one.

this.parent = new SlowBuffer(this.length);

this.offset = 0;

} else {

// Small buffer.

if (!pool || pool.length - pool.used < this.length) allocPool();

this.parent = pool;

this.offset = pool.used;

pool.used += this.length;

}

// Treat array-ish objects as a byte array.

if (isArrayIsh(subject)) {

for (var i = 0; i < this.length; i++) {

this.parent[i + this.offset] = subject[i];

}

} else if (type == 'string') {

// We are a string

this.length = this.write(subject, 0, encoding);

}

SlowBuffer.makeFastBuffer(this.parent, this, this.offset, this.length);

}

function isArrayIsh(subject) {

return Array.isArray(subject) || Buffer.isBuffer(subject) ||

subject && typeof subject === 'object' &&

typeof subject.length === 'number';

}

exports.SlowBuffer = SlowBuffer;

exports.Buffer = Buffer;

Buffer.poolSize = 8 * 1024;

var pool;

function allocPool() {

pool = new SlowBuffer(Buffer.poolSize);

pool.used = 0;

}

// Static methods

Buffer.isBuffer = function isBuffer(b) {

return b instanceof Buffer || b instanceof SlowBuffer;

};

// Inspect

Buffer.prototype.inspect = function inspect() {

var out = [],

len = this.length;

for (var i = 0; i < len; i++) {

out[i] = toHex(this.parent[i + this.offset]);

if (i == exports.INSPECT_MAX_BYTES) {

out[i + 1] = '...';

break;

}

return '<Buffer ' + out.join(' ') + '>';

};

Buffer.prototype.get = function get(i) {

if (i < 0 || i >= this.length) throw new Error('oob');

return this.parent[this.offset + i];

};

Buffer.prototype.set = function set(i, v) {

if (i < 0 || i >= this.length) throw new Error('oob');

return this.parent[this.offset + i] = v;

};

// write(string, offset = 0, length = buffer.length-offset, encoding = 'utf8')

Buffer.prototype.write = function(string, offset, length, encoding) {

// Support both (string, offset, length, encoding)

// and the legacy (string, encoding, offset, length)

if (isFinite(offset)) {

if (!isFinite(length)) {

encoding = length;

length = undefined;

}

} else { // legacy

var swap = encoding;

encoding = offset;

offset = length;

length = swap;

}

offset = +offset || 0;

var remaining = this.length - offset;

if (!length) {

length = remaining;

} else {

length = +length;

if (length > remaining) {

length = remaining;

}

encoding = String(encoding || 'utf8').toLowerCase();

var ret;

switch (encoding) {

case 'hex':

ret = this.parent.hexWrite(string, this.offset + offset, length);

break;

case 'utf8':

case 'utf-8':

ret = this.parent.utf8Write(string, this.offset + offset, length);

break;

case 'ascii':

ret = this.parent.asciiWrite(string, this.offset + offset, length);

break;

case 'binary':

ret = this.parent.binaryWrite(string, this.offset + offset, length);

break;

case 'base64':

// Warning: maxLength not taken into account in base64Write

ret = this.parent.base64Write(string, this.offset + offset, length);

break;

case 'ucs2':

case 'ucs-2':

ret = this.parent.ucs2Write(string, this.offset + offset, length);

break;

default:

throw new Error('Unknown encoding');

}

Buffer._charsWritten = SlowBuffer._charsWritten;

return ret;

};

// toString(encoding, start=0, end=buffer.length)

Buffer.prototype.toString = function(encoding, start, end) {

encoding = String(encoding || 'utf8').toLowerCase();

if (typeof start == 'undefined' || start < 0) {

start = 0;

} else if (start > this.length) {

start = this.length;

}

if (typeof end == 'undefined' || end > this.length) {

end = this.length;

} else if (end < 0) {

end = 0;

}

start = start + this.offset;

end = end + this.offset;

switch (encoding) {

case 'hex':

return this.parent.hexSlice(start, end);

case 'utf8':

case 'utf-8':

return this.parent.utf8Slice(start, end);

case 'ascii':

return this.parent.asciiSlice(start, end);

case 'binary':

return this.parent.binarySlice(start, end);

case 'base64':

return this.parent.base64Slice(start, end);

case 'ucs2':

case 'ucs-2':

return this.parent.ucs2Slice(start, end);

default:

throw new Error('Unknown encoding');

}

};

// byteLength

Buffer.byteLength = SlowBuffer.byteLength;

// fill(value, start=0, end=buffer.length)

Buffer.prototype.fill = function fill(value, start, end) {

value || (value = 0);

start || (start = 0);

end || (end = this.length);

if (typeof value === 'string') {

value = value.charCodeAt(0);

}

if (!(typeof value === 'number') || isNaN(value)) {

throw new Error('value is not a number');

}

if (end < start) throw new Error('end < start');

// Fill 0 bytes; we're done

if (end === start) return 0;

if (this.length == 0) return 0;

if (start < 0 || start >= this.length) {

throw new Error('start out of bounds');

}

if (end < 0 || end > this.length) {

throw new Error('end out of bounds');

}

return this.parent.fill(value,

start + this.offset,

end + this.offset);

};

// copy(targetBuffer, targetStart=0, sourceStart=0, sourceEnd=buffer.length)

Buffer.prototype.copy = function(target, target_start, start, end) {

var source = this;

start || (start = 0);

end || (end = this.length);

target_start || (target_start = 0);

if (end < start) throw new Error('sourceEnd < sourceStart');

// Copy 0 bytes; we're done

if (end === start) return 0;

if (target.length == 0 || source.length == 0) return 0;

if (target_start < 0 || target_start >= target.length) {

throw new Error('targetStart out of bounds');

}

if (start < 0 || start >= source.length) {

throw new Error('sourceStart out of bounds');

}

if (end < 0 || end > source.length) {

throw new Error('sourceEnd out of bounds');

}

// Are we oob?

if (end > this.length) {

end = this.length;

}

if (target.length - target_start < end - start) {

end = target.length - target_start + start;

}

return this.parent.copy(target.parent,

target_start + target.offset,

start + this.offset,

end + this.offset);

};

// slice(start, end)

Buffer.prototype.slice = function(start, end) {

if (end === undefined) end = this.length;

if (end > this.length) throw new Error('oob');

if (start > end) throw new Error('oob');

return new Buffer(this.parent, end - start, +start + this.offset);

};

// Legacy methods for backwards compatibility.

Buffer.prototype.utf8Slice = function(start, end) {

return this.toString('utf8', start, end);

};

Buffer.prototype.binarySlice = function(start, end) {

return this.toString('binary', start, end);

};

Buffer.prototype.asciiSlice = function(start, end) {

return this.toString('ascii', start, end);

};

Buffer.prototype.utf8Write = function(string, offset) {

return this.write(string, offset, 'utf8');

};

Buffer.prototype.binaryWrite = function(string, offset) {

return this.write(string, offset, 'binary');

};

Buffer.prototype.asciiWrite = function(string, offset) {

return this.write(string, offset, 'ascii');

};

Buffer.prototype.readUInt8 = function(offset, noAssert) {

var buffer = this;

if (!noAssert) {

assert.ok(offset !== undefined && offset !== null,

'missing offset');

assert.ok(offset < buffer.length,

'Trying to read beyond buffer length');

}

return buffer[offset];

};

function readUInt16(buffer, offset, isBigEndian, noAssert) {

var val = 0;

if (!noAssert) {

assert.ok(typeof (isBigEndian) === 'boolean',

'missing or invalid endian');

assert.ok(offset !== undefined && offset !== null,

'missing offset');

assert.ok(offset + 1 < buffer.length,

'Trying to read beyond buffer length');

}

if (isBigEndian) {

val = buffer[offset] << 8;

val |= buffer[offset + 1];

} else {

val = buffer[offset];

val |= buffer[offset + 1] << 8;

}

return val;

}

Buffer.prototype.readUInt16LE = function(offset, noAssert) {

return readUInt16(this, offset, false, noAssert);

};

Buffer.prototype.readUInt16BE = function(offset, noAssert) {

return readUInt16(this, offset, true, noAssert);

};

function readUInt32(buffer, offset, isBigEndian, noAssert) {

var val = 0;

if (!noAssert) {

assert.ok(typeof (isBigEndian) === 'boolean',

'missing or invalid endian');

assert.ok(offset !== undefined && offset !== null,

'missing offset');

assert.ok(offset + 3 < buffer.length,

'Trying to read beyond buffer length');

}

if (isBigEndian) {

val = buffer[offset + 1] << 16;

val |= buffer[offset + 2] << 8;

val |= buffer[offset + 3];

val = val + (buffer[offset] << 24 >>> 0);

} else {

val = buffer[offset + 2] << 16;

val |= buffer[offset + 1] << 8;

val |= buffer[offset];

val = val + (buffer[offset + 3] << 24 >>> 0);

}

return val;

}

Buffer.prototype.readUInt32LE = function(offset, noAssert) {

return readUInt32(this, offset, false, noAssert);

};

Buffer.prototype.readUInt32BE = function(offset, noAssert) {

return readUInt32(this, offset, true, noAssert);

};

* Signed integer types, yay team! A reminder on how two's complement actually

* works. The first bit is the signed bit, i.e. tells us whether or not the

* number should be positive or negative. If the two's complement value is

* positive, then we're done, as it's equivalent to the unsigned representation.

* Now if the number is positive, you're pretty much done, you can just leverage

* the unsigned translations and return those. Unfortunately, negative numbers

* aren't quite that straightforward.

* At first glance, one might be inclined to use the traditional formula to

* translate binary numbers between the positive and negative values in two's

* complement. (Though it doesn't quite work for the most negative value)

* Mainly:

* - invert all the bits

* - add one to the result

* Of course, this doesn't quite work in Javascript. Take for example the value

* of -128. This could be represented in 16 bits (big-endian) as 0xff80. But of

* course, Javascript will do the following:

* > ~0xff80

* -65409

* Whoh there, Javascript, that's not quite right. But wait, according to

* Javascript that's perfectly correct. When Javascript ends up seeing the

* constant 0xff80, it has no notion that it is actually a signed number. It

* assumes that we've input the unsigned value 0xff80. Thus, when it does the

* binary negation, it casts it into a signed value, (positive 0xff80). Then

* when you perform binary negation on that, it turns it into a negative number.

* Instead, we're going to have to use the following general formula, that works

* in a rather Javascript friendly way. I'm glad we don't support this kind of

* weird numbering scheme in the kernel.

* (BIT-MAX - (unsigned)val + 1) * -1

* The astute observer, may think that this doesn't make sense for 8-bit numbers

* (really it isn't necessary for them). However, when you get 16-bit numbers,

* you do. Let's go back to our prior example and see how this will look:

* (0xffff - 0xff80 + 1) * -1

* (0x007f + 1) * -1

* (0x0080) * -1

Buffer.prototype.readInt8 = function(offset, noAssert) {

var buffer = this;

var neg;

if (!noAssert) {

assert.ok(offset !== undefined && offset !== null,

'missing offset');

assert.ok(offset < buffer.length,

'Trying to read beyond buffer length');

}

neg = buffer[offset] & 0x80;

if (!neg) {

return (buffer[offset]);

}

return ((0xff - buffer[offset] + 1) * -1);

};

function readInt16(buffer, offset, isBigEndian, noAssert) {

var neg;

if (!noAssert) {

assert.ok(typeof (isBigEndian) === 'boolean',

'missing or invalid endian');

assert.ok(offset !== undefined && offset !== null,

'missing offset');

assert.ok(offset + 1 < buffer.length,

'Trying to read beyond buffer length');

}

val = readUInt16(buffer, offset, isBigEndian, noAssert);

neg = val & 0x8000;

if (!neg) {

return val;

}

return (0xffff - val + 1) * -1;

}

Buffer.prototype.readInt16LE = function(offset, noAssert) {

return readInt16(this, offset, false, noAssert);

};

Buffer.prototype.readInt16BE = function(offset, noAssert) {

return readInt16(this, offset, true, noAssert);

};

function readInt32(buffer, offset, isBigEndian, noAssert) {

var neg;

if (!noAssert) {

assert.ok(typeof (isBigEndian) === 'boolean',

'missing or invalid endian');

assert.ok(offset !== undefined && offset !== null,

'missing offset');

assert.ok(offset + 3 < buffer.length,

'Trying to read beyond buffer length');

}

val = readUInt32(buffer, offset, isBigEndian, noAssert);

neg = val & 0x80000000;

if (!neg) {

return (val);

}

return (0xffffffff - val + 1) * -1;

}

Buffer.prototype.readInt32LE = function(offset, noAssert) {

return readInt32(this, offset, false, noAssert);

};

Buffer.prototype.readInt32BE = function(offset, noAssert) {

return readInt32(this, offset, true, noAssert);

};

function readFloat(buffer, offset, isBigEndian, noAssert) {

if (!noAssert) {

assert.ok(typeof (isBigEndian) === 'boolean',

'missing or invalid endian');

assert.ok(offset + 3 < buffer.length,

'Trying to read beyond buffer length');

}

return require('buffer_ieee754').readIEEE754(buffer, offset, isBigEndian,

23, 4);

}

Buffer.prototype.readFloatLE = function(offset, noAssert) {

return readFloat(this, offset, false, noAssert);

};

Buffer.prototype.readFloatBE = function(offset, noAssert) {

return readFloat(this, offset, true, noAssert);

};

function readDouble(buffer, offset, isBigEndian, noAssert) {

if (!noAssert) {

assert.ok(typeof (isBigEndian) === 'boolean',

'missing or invalid endian');

assert.ok(offset + 7 < buffer.length,

'Trying to read beyond buffer length');

}

return require('buffer_ieee754').readIEEE754(buffer, offset, isBigEndian,

52, 8);

}

Buffer.prototype.readDoubleLE = function(offset, noAssert) {

return readDouble(this, offset, false, noAssert);

};

Buffer.prototype.readDoubleBE = function(offset, noAssert) {

return readDouble(this, offset, true, noAssert);

};

* We have to make sure that the value is a valid integer. This means that it is

* non-negative. It has no fractional component and that it does not exceed the

* maximum allowed value.

* value The number to check for validity

* max The maximum value

function verifuint(value, max) {

assert.ok(typeof (value) == 'number',

'cannot write a non-number as a number');

assert.ok(value >= 0,

'specified a negative value for writing an unsigned value');

assert.ok(value <= max, 'value is larger than maximum value for type');

assert.ok(Math.floor(value) === value, 'value has a fractional component');

}

Buffer.prototype.writeUInt8 = function(value, offset, noAssert) {

var buffer = this;

if (!noAssert) {

assert.ok(value !== undefined && value !== null,

'missing value');

assert.ok(offset !== undefined && offset !== null,

'missing offset');

assert.ok(offset < buffer.length,

'trying to write beyond buffer length');

verifuint(value, 0xff);

}

buffer[offset] = value;

};

function writeUInt16(buffer, value, offset, isBigEndian, noAssert) {

if (!noAssert) {

assert.ok(value !== undefined && value !== null,

'missing value');

assert.ok(typeof (isBigEndian) === 'boolean',

'missing or invalid endian');

assert.ok(offset !== undefined && offset !== null,

'missing offset');

assert.ok(offset + 1 < buffer.length,

'trying to write beyond buffer length');

verifuint(value, 0xffff);

}

if (isBigEndian) {

buffer[offset] = (value & 0xff00) >>> 8;

buffer[offset + 1] = value & 0x00ff;

} else {

buffer[offset + 1] = (value & 0xff00) >>> 8;

buffer[offset] = value & 0x00ff;

}

Buffer.prototype.writeUInt16LE = function(value, offset, noAssert) {

writeUInt16(this, value, offset, false, noAssert);

};

Buffer.prototype.writeUInt16BE = function(value, offset, noAssert) {

writeUInt16(this, value, offset, true, noAssert);

};

function writeUInt32(buffer, value, offset, isBigEndian, noAssert) {

if (!noAssert) {

assert.ok(value !== undefined && value !== null,

'missing value');

assert.ok(typeof (isBigEndian) === 'boolean',

'missing or invalid endian');

assert.ok(offset !== undefined && offset !== null,

'missing offset');

assert.ok(offset + 3 < buffer.length,

'trying to write beyond buffer length');

verifuint(value, 0xffffffff);

}

if (isBigEndian) {

buffer[offset] = (value >>> 24) & 0xff;

buffer[offset + 1] = (value >>> 16) & 0xff;

buffer[offset + 2] = (value >>> 8) & 0xff;

buffer[offset + 3] = value & 0xff;

} else {

buffer[offset + 3] = (value >>> 24) & 0xff;

buffer[offset + 2] = (value >>> 16) & 0xff;

buffer[offset + 1] = (value >>> 8) & 0xff;

buffer[offset] = value & 0xff;

}

Buffer.prototype.writeUInt32LE = function(value, offset, noAssert) {

writeUInt32(this, value, offset, false, noAssert);

};

Buffer.prototype.writeUInt32BE = function(value, offset, noAssert) {

writeUInt32(this, value, offset, true, noAssert);

};

* We now move onto our friends in the signed number category. Unlike unsigned

* numbers, we're going to have to worry a bit more about how we put values into

* arrays. Since we are only worrying about signed 32-bit values, we're in

* slightly better shape. Unfortunately, we really can't do our favorite binary

* & in this system. It really seems to do the wrong thing. For example:

* > -32 & 0xff

* 224

* What's happening above is really: 0xe0 & 0xff = 0xe0. However, the results of

* this aren't treated as a signed number. Ultimately a bad thing.

* What we're going to want to do is basically create the unsigned equivalent of

* our representation and pass that off to the wuint* functions. To do that

* we're going to do the following:

* - if the value is positive

* we can pass it directly off to the equivalent wuint

* - if the value is negative

* we do the following computation:

* mb + val + 1, where

* mb is the maximum unsigned value in that byte size

* val is the Javascript negative integer

* As a concrete value, take -128. In signed 16 bits this would be 0xff80. If

* you do out the computations:

* 0xffff - 128 + 1

* 0xffff - 127

* 0xff80

* You can then encode this value as the signed version. This is really rather

* hacky, but it should work and get the job done which is our goal here.

* A series of checks to make sure we actually have a signed 32-bit number

function verifsint(value, max, min) {

assert.ok(typeof (value) == 'number',

'cannot write a non-number as a number');

assert.ok(value <= max, 'value larger than maximum allowed value');

assert.ok(value >= min, 'value smaller than minimum allowed value');

assert.ok(Math.floor(value) === value, 'value has a fractional component');

}

function verifIEEE754(value, max, min) {

assert.ok(typeof (value) == 'number',

'cannot write a non-number as a number');

assert.ok(value <= max, 'value larger than maximum allowed value');

assert.ok(value >= min, 'value smaller than minimum allowed value');

}

Buffer.prototype.writeInt8 = function(value, offset, noAssert) {

var buffer = this;

if (!noAssert) {

assert.ok(value !== undefined && value !== null,

'missing value');

assert.ok(offset !== undefined && offset !== null,

'missing offset');

assert.ok(offset < buffer.length,

'Trying to write beyond buffer length');

verifsint(value, 0x7f, -0xf0);

}

if (value >= 0) {

buffer.writeUInt8(value, offset, noAssert);

} else {

buffer.writeUInt8(0xff + value + 1, offset, noAssert);

}

};

function writeInt16(buffer, value, offset, isBigEndian, noAssert) {

if (!noAssert) {

assert.ok(value !== undefined && value !== null,

'missing value');

assert.ok(typeof (isBigEndian) === 'boolean',

'missing or invalid endian');

assert.ok(offset !== undefined && offset !== null,

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node/lib/buffer.js at master · elarkin/node · GitHub

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