CODEWITHSUNDEEP
javascriptnode.jsieee-754
user0103
user0103

Reputation: 1272

Parse HEX float

I have integer, for example, 4060.

How I can get HEX float (\x34\xC8\x7D\x45) from it?

JS hasn't float type, so I don't know how to do this conversion.

Thank you.

Upvotes: 5

Views: 3524

Answers (2)

robertklep
robertklep

Reputation: 203359

If you want a hex string, try this: 

> var b = new Buffer(4);
> b.writeFloatLE(4060, 0)
> b.toString('hex')
'00c07d45'

And the other way (using your input):

> Buffer('34C87D45', 'hex').readFloatLE(0)
4060.5126953125

UPDATE: new Buffer(size) has been deprecated, but it's easily replaced by Buffer.alloc(size):

var b = Buffer.alloc(4);

Upvotes: 7

user2871305
user2871305

Reputation: 1152

The above answer is no longer valid. Buffer has been deprecated (see https://nodejs.org/api/buffer.html#buffer_new_buffer_size).

New Solution:

function numToFloat32Hex(v,le)
{
    if(isNaN(v)) return false;
    var buf = new ArrayBuffer(4);
    var dv  = new DataView(buf);
    dv.setFloat32(0, v, true);
    return ("0000000"+dv.getUint32(0,!(le||false)).toString(16)).slice(-8).toUpperCase();
}

For example:

numToFloat32Hex(4060,true) // returns "00C07D45"
numToFloat32Hex(4060,false) // returns "457DC000"

Tested in Chrome and Firefox

Upvotes: 2

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