JavaScript Numbers are represented as IEEE 754 double-precision floats. Unfortunately, this means they lose integer precision for values beyond +/- 2^^53. For projects that need to accurately handle 64-bit ints, such as node-thrift, a performant, Number-like class is needed. Int64 is that class.

Int64 instances look and feel much like JS-native Numbers. By way of example ... ```js // First, let's illustrate the problem ...

(0x123456789).toString(16) '123456789' // <- what we expect. (0x123456789abcdef0).toString(16) '123456789abcdf00' // <- Ugh! JS doesn't do big ints. :(

// So let's create a couple Int64s using the above values ...

// Require, of course

Int64 = require('node-int64')

// x's value is what we expect (the decimal value of 0x123456789)

x = new Int64(0x123456789) [Int64 value:4886718345 octets:00 00 00 01 23 45 67 89]

// y's value is Infinity because it's outside the range of integer // precision. But that's okay - it's still useful because it's internal // representation (octets) is what we passed in

y = new Int64('123456789abcdef0') [Int64 value:Infinity octets:12 34 56 78 9a bc de f0]

// Let's do some math. Int64's behave like Numbers. (Sorry, Int64 isn't // for doing 64-bit integer arithmetic (yet) - it's just for carrying // around int64 values

x + 1 4886718346 y + 1 Infinity

// Int64 string operations ...

'value: ' + x 'value: 4886718345' 'value: ' + y 'value: Infinity' x.toString(2) '100100011010001010110011110001001' y.toString(2) 'Infinity'

// Use JS's isFinite() method to see if the Int64 value is in the // integer-precise range of JS values

isFinite(x) true isFinite(y) false

// Get an octet string representation. (Yay, y is what we put in!)

x.toOctetString() '0000000123456789' y.toOctetString() '123456789abcdef0'

// Finally, some other ways to create Int64s ...

// Pass hi/lo words

new Int64(0x12345678, 0x9abcdef0) [Int64 value:Infinity octets:12 34 56 78 9a bc de f0]

// Pass a Buffer

new Int64(new Buffer([0x12, 0x34, 0x56, 0x78, 0x9a, 0xbc, 0xde, 0xf0])) [Int64 value:Infinity octets:12 34 56 78 9a bc de f0]

// Pass a Buffer and offset

new Int64(new Buffer([0,0,0,0,0x12, 0x34, 0x56, 0x78, 0x9a, 0xbc, 0xde, 0xf0]), 4) [Int64 value:Infinity octets:12 34 56 78 9a bc de f0]

// Pull out into a buffer

new Int64(new Buffer([0x12, 0x34, 0x56, 0x78, 0x9a, 0xbc, 0xde, 0xf0])).toBuffer()

// Or copy into an existing one (at an offset)

var buf = new Buffer(1024); new Int64(new Buffer([0x12, 0x34, 0x56, 0x78, 0x9a, 0xbc, 0xde, 0xf0])).copy(buf, 512); ```