Javascript - Converting between Unicode string and ArrayBuffer

Question

Does somebody know a script that is able to convert a string to a ArrayBuffer using unicode encoding?

I´m creating a browser-side eqivalent of the "Buffer" of node.js. The only encoding that is left is unicode. All others are done.

Thanks for your help!

which unicode encoding: utf-8, utf-16le, utf-16be, utf-32le, utf-32be? there are quite a few. — Dan D.
– Dan D., Commented Jan 25, 2012 at 16:56
the node.js docs say it´t the unicode BMP(Basic Multilingual Plane) encoding. — Van Coding
– Van Coding, Commented Jan 25, 2012 at 16:58
Basic Multilingual Plane is an abstraction related to unicode, but not an encoding and is related to all encodings listed above. UTF-16LE is used in Javascript browser engines and it is that, according to your answer. — kirilloid
– kirilloid, Commented Jan 25, 2012 at 17:50
@Janus Troelsen I haven't published it on github, but if you wish I can do it. But there are better ones, I think. Just search for "buffer browserify" on github and you'll find very good code. One repo is also used by node-browserify. Hope it helps. — Van Coding
– Van Coding, Commented Sep 19, 2012 at 19:03

Van Coding · Accepted Answer · 2012-01-25 17:39:51Z

8

I found it out by myself.

Decoding:

var b = new Uint8Array(str.length*2);
for(var i = 0; i < b.length; i+=2){
    var x = str.charCodeAt(i/2);
    var a = x%256;
    x -= a;
    x /= 256;
    b[i] = x;
    b[i+1] = a;
}

Encoding

var s = "";
for(var i = 0; i < this.length;){
    s += String.fromCharCode(this[i++]*256+this[i++]);
}

answered Jan 25, 2012 at 17:39

Van Coding

24.6k25 gold badges93 silver badges138 bronze badges

Sign up to request clarification or add additional context in comments.

5 Comments

kirilloid Over a year ago

s += String.fromCharCode(this[i++]*256+this[i++]); would be slow for long strings. Gather charcodes in array arr and execute String.fromCharCode.apply(arr).

kirilloid Over a year ago

Ouch, sorry. String.fromCharCode.apply(*null*, arr)

kirilloid Over a year ago

ROFL. I just faced the same problem, when transfering data from Java applet into Javascript.

J Chris A Over a year ago

some unicode characters use more than 2 bytes, so I'm not sure how you detect those etc, it's a long spec and it's been a while since I browsed it.

root-aj Over a year ago

This doesn't seem to work. sha1sum the bytes of "hello world" (in your terminal) and then convert it with that method and you'll get something completely different using the Web Crypto API. It may contain a the string, but it doesn't convert it. See gist.github.com/coolaj86/87d834cfe6ec07d2ee81 I still haven't figured it out for multi-byte characters, but I have gotten single byte characters to match sha1sums as expected.

Collectives™ on Stack Overflow

Javascript - Converting between Unicode string and ArrayBuffer

1 Answer 1

5 Comments

Your Answer

Linked

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

5 Comments

Your Answer

Sign up or log in

Post as a guest

Linked

Related