michael@0: String.prototype.repeat = function(num) {
michael@0:     return new Array(num + 1).join(this);
michael@0: }
michael@0: 
michael@0: function set_to_length(length, frag_size)
michael@0: {
michael@0:     var fragment = "'" + "x".repeat(frag_size) + "' + ";
michael@0:     var frags = Math.floor((length - 1)/frag_size);
michael@0:     var code = "var x = " + fragment.repeat(frags) + "'" +
michael@0:         "x".repeat(length - frags * frag_size) + "';";
michael@0: 
michael@0:     try {
michael@0:         eval(code);
michael@0:     }
michael@0:     catch(err) {
michael@0:         if (err.message && err.message == "Out of memory")
michael@0:             return -1;
michael@0:         if (err == "out of memory")
michael@0:             return -1;
michael@0:         throw(err); /* Oops, broke something. */
michael@0:     }
michael@0: 
michael@0:     return code.length;
michael@0: }
michael@0: 
michael@0: var first_fail;
michael@0: var first_pass;
michael@0: var frag_size;
michael@0: var pass_code_length;
michael@0: 
michael@0: function search_up()
michael@0: {
michael@0:     if (set_to_length(first_fail, frag_size) < 0) {
michael@0:         setTimeout(binary_search, 0);
michael@0:         return;
michael@0:     }
michael@0: 
michael@0:     first_fail *= 2;
michael@0: }
michael@0: 
michael@0: function binary_search()
michael@0: {
michael@0:     if (first_fail - first_pass > 1) {
michael@0:         var length = (first_pass + first_fail) / 2;
michael@0:         var code_len = set_to_length(length, frag_size);
michael@0:         if (code_len > 0) {
michael@0:             first_pass = length;
michael@0:             pass_code_length = code_len;
michael@0:         } else
michael@0:             first_fail = length;
michael@0:         setTimeout(binary_search, 0);
michael@0:         return;
michael@0:     }
michael@0: }
michael@0: 
michael@0: function run_find_limit()
michael@0: {
michael@0:     frag_size = 64;
michael@0:     first_fail = 65536; /* A guess */
michael@0:     first_pass = 0;
michael@0:     pass_code_length = 0;
michael@0: 
michael@0:     for (var i=0; i<5; i++)
michael@0: 	search_up(0);
michael@0: }
michael@0: 
michael@0: run_find_limit();