.scan to search for a buffer

[SamyPesse]

node-binary has a method .scan:

var b = binary()
    .scan('line', new Buffer('\r\n'))
    .tap(function (vars) {
        console.log(vars.line)
    });

I'll be happy to propose a PR to add this if @deoxxa thinks it's a good idea.

[SamyPesse]

Here is a basic implementation:

function scan(name, search) {
    search = new Buffer(search, 'utf8');
    var result = new Buffer('');

    return this.loop(function(end) {
        this.buffer('tmpSearch', 1)
        .tap(function() {
            var c = this.vars.tmpSearch;
            result = Buffer.concat([result, c]);

            var toSearch = result.slice(-search.length);

            if (toSearch.compare(search) === 0) {
                delete this.vars.tmpSearch;
                this.vars[name] = result.slice(0, -search.length);
                end();
            }
        });
    });
}