stringbench.swift

import Foundation

func measure(work:Void->Void) {
    let start = NSDate()
    for _ in 0..<100000 {
        work()
    }
    let elapsed = -(start.timeIntervalSinceNow)
    print(elapsed)
}

func testStringLoopWithIndexSuccessor()
{
    let str = "some really long string"
    let end = str.endIndex
    var idx =  str.startIndex
    
    while idx < end
    {
        let char = str[idx]
        // ... do some stuff
        idx = idx.successor()
    }
}

func testStringLoopWithAdvancedBy()
{
    let str = "some really long string"
    let len = str.characters.count
    var idx = 0
    
    while idx < len
    {
        let char = str[str.startIndex.advancedBy(idx)]
        // ... do some stuff
        idx = idx + 1
    }
}

func testStringLoopWithIndexSuccessorAndUnicodeScalarView()
{
    let str = "some really long string"
    let sca = str.unicodeScalars
    let end = sca.endIndex
    var idx = sca.startIndex
    
    while idx < end
    {
        let char = sca[idx]
        // ... do some stuff
        idx = idx.successor()
    }
}

func testStringLoopWithAdvancedByAndUnicodeScalarView()
{
    let str = "some really long string"
    let sca = str.unicodeScalars
    let len = sca.count
    var idx = 0
    
    while idx < len
    {
        let char = sca[sca.startIndex.advancedBy(idx)]
        // ... do some stuff
        idx = idx + 1
    }
}

measure { testStringLoopWithAdvancedByAndUnicodeScalarView() }
measure { testStringLoopWithIndexSuccessorAndUnicodeScalarView() }
measure { testStringLoopWithAdvancedBy() }
measure { testStringLoopWithIndexSuccessor() }