Files
swift-mirror/benchmark/single-source/StringEdits.swift
T
Max Moiseev 53ec0b1168 Improve StringEdits performance in absence of CharacterView
CharacterView was not Hashable, so Set could not be used as an
accumulator. String and Substring are Hashable, but using a Set as an
accumulator is still slower than first collecting all the results in an
Array and then transforming it to a Set at the end. One possible reason
why that could be the case, is that by the time conversion happens, we
already know the capacity and thus will not re-allocate and re-hash a
Set on every insertion beyong current capacity.
2017-10-05 10:43:08 -07:00

76 lines
1.8 KiB
Swift

//===--- StringEdits.swift ------------------------------------------------===//
//
// This source file is part of the Swift.org open source project
//
// Copyright (c) 2014 - 2017 Apple Inc. and the Swift project authors
// Licensed under Apache License v2.0 with Runtime Library Exception
//
// See https://swift.org/LICENSE.txt for license information
// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
//
//===----------------------------------------------------------------------===//
import TestsUtils
#if os(Linux)
import Glibc
#else
import Darwin
#endif
public let StringEdits = BenchmarkInfo(
name: "StringEdits",
runFunction: run_StringEdits,
tags: [.validation, .api, .String])
var editWords: [String] = [
"woodshed",
"lakism",
"gastroperiodynia",
]
let alphabet = "abcdefghijklmnopqrstuvwxyz"
/// All edits that are one edit away from `word`
func edits(_ word: String) -> Set<String> {
let splits = word.indices.map {
(String(word[..<$0]), String(word[$0...]))
}
var result: Array<String> = []
for (left, right) in splits {
// drop a character
result.append(left + right.dropFirst())
// transpose two characters
if let fst = right.first {
let drop1 = right.dropFirst()
if let snd = drop1.first {
result.append(left + [snd,fst] + drop1.dropFirst())
}
}
// replace each character with another
for letter in alphabet {
result.append(left + [letter] + right.dropFirst())
}
// insert rogue characters
for letter in alphabet {
result.append(left + [letter] + right)
}
}
// have to map back to strings right at the end
return Set(result)
}
@inline(never)
public func run_StringEdits(_ N: Int) {
for _ in 1...N*100 {
for word in editWords {
_ = edits(word)
}
}
}