Swift HashDoS

main.swift

import Foundation

func randomStringWithLength (len : Int) -> NSString {
    // from http://stackoverflow.com/a/26845710/311196
    
    let letters : NSString = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789"
    
    var randomString : NSMutableString = NSMutableString(capacity: len)
    
    for (var i=0; i < len; i++){
        var length = UInt32 (letters.length)
        var rand = arc4random_uniform(length)
        randomString.appendFormat("%C", letters.characterAtIndex(Int(rand)))
    }
    
    return randomString
}

func collidingString() -> NSString {
    return NSString(format: "aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa%@aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa________________aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa",
    randomStringWithLength(15));
}

func nonCollidingString() -> NSString {
    return NSString(format: "%@aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa________________aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa",
        randomStringWithLength(15));
}

var d  = NSMutableDictionary();
var start = NSDate();

for i in 0...10000 {
    d[nonCollidingString()] = "some value"
}

println("Non-colliding: ");
println(NSDate().timeIntervalSinceDate(start));

d  = NSMutableDictionary();
start = NSDate();

for i in 0...10000 {
    d[collidingString()] = "some value"
}

println("Colliding: ");
println(NSDate().timeIntervalSinceDate(start));

Previously: Objective-C HashDoS https://gist.github.com/dchest/4467707