regextest.kt

package a

val pattern = "aba"
val text = "ababa".repeat(100000)
val runs = 1000

fun occTest(): Long {
    // Warmup
    repeat(10) {
        text.occurrencesOf(pattern, ignoreCase = false, matchOverlapping = true).forEach { }
    }

    val startTime = System.currentTimeMillis()
    repeat(runs) {
        text.occurrencesOf(pattern, ignoreCase = false, matchOverlapping = true).forEach { }
    }
    val endTime = System.currentTimeMillis()

    return (endTime - startTime)
}

fun regexTest(): Long {
    // Warmup
    val regex = Regex.fromLiteral(pattern)
    repeat(10) {
        for (i in 0..text.length - 1) {
            regex.find(text, i)
        }
    }

    val startTime = System.currentTimeMillis()
    repeat(runs) {
        for (i in 0..text.length - 1) {
            regex.find(text, i)
        }
    }
    val endTime = System.currentTimeMillis()

    return (endTime - startTime)
}

fun main(args: Array<String>) {
    val occ = occTest()
    val reg = regexTest()

    print("occ: $occ ms, regex: $reg ms")
}