int64 was a workaround JS' lack of support for Int64 data types. Somewhat to my surprise, people have found it useful. However, it looks like BigInts will soon be a formally accepted feature, obsoleting the need for this package.
If a trustworthy organization or individual would like to take over as maintainer, I'm happy to hand this off. Please contact me at robert@broofa.com if you're interested. Otherwise I'll be npm-deprecating this at some future date.
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 ...
// 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=newInt64(0x123456789)[Int64value:4886718345octets:0000000123456789]// 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=newInt64('123456789abcdef0')[Int64value:Infinityoctets:123456789abcdef0]// 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+14886718346>y+1Infinity// 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>newInt64(0x12345678,0x9abcdef0)[Int64value:Infinityoctets:123456789abcdef0]// Pass a Buffer>newInt64(newBuffer([0x12,0x34,0x56,0x78,0x9a,0xbc,0xde,0xf0]))[Int64value:Infinityoctets:123456789abcdef0]// Pass a Buffer and offset>newInt64(newBuffer([0,0,0,0,0x12,0x34,0x56,0x78,0x9a,0xbc,0xde,0xf0]),4)[Int64value:Infinityoctets:123456789abcdef0]// Pull out into a buffer>newInt64(newBuffer([0x12,0x34,0x56,0x78,0x9a,0xbc,0xde,0xf0])).toBuffer()<Buffer123456789abcdef0>// Or copy into an existing one (at an offset)>varbuf=newBuffer(1024);>newInt64(newBuffer([0x12,0x34,0x56,0x78,0x9a,0xbc,0xde,0xf0])).copy(buf,512);