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MASSIVE String extensions performance improvements + added some more …
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…docs

in my non-scientific tests for components(separatedBy:), per the same iteration count:
Foundation's implementation took 2.5s
The old implementation of mine took 3.8s
and the new implementation takes only 1s
that's around 75% performance improvement
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@MahdiBM
MahdiBM committed Jan 28, 2022
1 parent af47a4b commit 850cb4a
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Showing 6 changed files with 90 additions and 68 deletions.
4 changes: 2 additions & 2 deletions Sources/TwitchIRC/IncomingMessage/ClearMessage.swift
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Original file line number Diff line number Diff line change
Expand Up @@ -28,8 +28,8 @@ public struct ClearMessage {

self.channel = String(channel)
/// `.unicodeScalars.dropFirst()` to remove ":", `componentsOneSplit(separatedBy: " :")`
/// normal methods like a simple `.dropFirst()` fail in rare cases.
/// Remove `.unicodeScalars` in `PrivateMessage`'s `message` and run tests to find out.
/// and other normal methods like a simple `.dropFirst()` fail in rare cases.
/// Remove `.unicodeScalars` of `PrivateMessage`'s `message` and run tests to find out.
self.message = String(message.unicodeScalars.dropFirst())

guard contentLhs.count > 2, contentLhs.last == ":" else {
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2 changes: 1 addition & 1 deletion Sources/TwitchIRC/IncomingMessage/PrivateMessage.swift
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Original file line number Diff line number Diff line change
Expand Up @@ -89,7 +89,7 @@ public struct PrivateMessage {
} /// separating with " ", then lhs contains channel name and rhs is the actual message
self.channel = channel
/// `.unicodeScalars.dropFirst()` to remove ":", `componentsOneSplit(separatedBy: " :")`
/// normal methods like a simple `.dropFirst()` fail in rare cases.
/// and other normal methods like a simple `.dropFirst()` fail in rare cases.
/// Remove `.unicodeScalars` and run tests to find out.
self.message = String(message.unicodeScalars.dropFirst())

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4 changes: 2 additions & 2 deletions Sources/TwitchIRC/IncomingMessage/UserNotice.swift
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Original file line number Diff line number Diff line change
Expand Up @@ -175,8 +175,8 @@ public struct UserNotice {
) {
self.channel = channel
/// `.unicodeScalars.dropFirst()` to remove ":", `componentsOneSplit(separatedBy: " :")`
/// normal methods like a simple `.dropFirst()` fail in rare cases.
/// Remove `.unicodeScalars` in `PrivateMessage`'s `message` and run tests to find out.
/// and other normal methods like a simple `.dropFirst()` fail in rare cases.
/// Remove `.unicodeScalars` of `PrivateMessage`'s `message` and run tests to find out.
self.message = String(message.unicodeScalars.dropFirst())
} else {
self.channel = String(contentRhs.dropFirst())
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4 changes: 2 additions & 2 deletions Sources/TwitchIRC/IncomingMessage/Whisper.swift
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Original file line number Diff line number Diff line change
Expand Up @@ -31,8 +31,8 @@ public struct Whisper {

self.receiver = receiver
/// `.unicodeScalars.dropFirst()` to remove ":", `componentsOneSplit(separatedBy: " :")`
/// normal methods like a simple `.dropFirst()` fail in rare cases.
/// Remove `.unicodeScalars` in `PrivateMessage`'s `message` and run tests to find out.
/// and other normal methods like a simple `.dropFirst()` fail in rare cases.
/// Remove `.unicodeScalars` of `PrivateMessage`'s `message` and run tests to find out.
self.message = String(message.unicodeScalars.dropFirst())

var parser = ParametersParser(String(contentLhs.dropLast(2).dropFirst()))
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1 change: 1 addition & 0 deletions Sources/TwitchIRC/OutgoingMessage/1- OutgoingMessage.swift
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Original file line number Diff line number Diff line change
Expand Up @@ -18,6 +18,7 @@ public enum OutgoingMessage {
/// Pong Twitch.
case pong

/// Serializes this message into a string that can be sent to Twitch over IRC.
public func serialize() -> String {
switch self {
case let .privateMessage(channel, message, msgIdToReply):
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143 changes: 82 additions & 61 deletions Sources/TwitchIRC/Utils/String Extensions.swift
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Original file line number Diff line number Diff line change
@@ -1,68 +1,89 @@

extension RangeReplaceableCollection where Element == Character {
extension RangeReplaceableCollection where Element == Character, Self.Index == String.Index {

/// Separates the string by the given separator only with the first matching case.
func components(separatedBy separator: String) -> [Self] {
let separatorLength = separator.count
guard separatorLength != 0 else { return [self] }
guard !(self.count < separatorLength) else { return [self] }
let selfLength = self.count
guard !(selfLength < separatorLength) else { return [self] }

let separatorChars = [Character](separator)
var endingIndices = ContiguousArray<Index>()

func oneSplit(_ string: [Character]) -> (lhs: Self, rhs: [Character])? {
guard !string.isEmpty else { return nil }

let stringLength = string.count
let maxIdx = separatorLength - 1
var lastIdx: Int? = nil

for idx in 0..<stringLength {
if let lastIdxUnwrapped = lastIdx {
let nextIdx = lastIdxUnwrapped + 1
if nextIdx == maxIdx {
if string[idx] == separatorChars[nextIdx] {
let startingIdx = idx - maxIdx
let lhs = Self(string[0..<startingIdx])
let rhs = [Character](string[(idx + 1)...])
return (lhs: lhs, rhs: rhs)
} else {
if string[idx] == separatorChars[0] {
lastIdx = 0
} else {
lastIdx = nil
}
}
let separatorStartIndex = separator.startIndex
let maxIdx = separator.index(separatorStartIndex, offsetBy: separatorLength - 1)
var lastIdx: Index? = nil

for idx in self.indices {
if let lastIdxUnwrapped = lastIdx {
let nextIdx = separator.index(after: lastIdxUnwrapped)
if nextIdx == maxIdx {
if self[idx] == separator[nextIdx] {
endingIndices.append(idx)
lastIdx = nil
} else {
if string[idx] == separatorChars[nextIdx] {
lastIdx = lastIdxUnwrapped + 1
if self[idx] == separator[separatorStartIndex] {
lastIdx = separatorStartIndex
} else {
lastIdx = nil
}
}
} else {
if string[idx] == separatorChars[0] {
lastIdx = 0
if separatorLength == 1 {
let lhs = Self(string[0..<idx])
let rhs = [Character](string[(idx + 1)...])
return (lhs: lhs, rhs: rhs)
}
if self[idx] == separator[nextIdx] {
lastIdx = nextIdx
} else {
lastIdx = nil
}
}
} else {
if self[idx] == separator[separatorStartIndex] {
if separatorLength == 1 {
endingIndices.append(idx)
} else {
lastIdx = separatorStartIndex
}
}
}

return nil
}

func recursiveOneSplit(_ string: [Character]) -> [Self] {
if let (lhs, rhs) = oneSplit(string) {
return [lhs] + recursiveOneSplit(rhs)
let indicesLength = endingIndices.count
guard indicesLength != 0 else { return [self] }
let arrayLength = endingIndices.count + 1
var array = Array<Self>()
array.reserveCapacity(arrayLength)

for idx in 0..<arrayLength {
if idx == 0 {
let endingIndex = endingIndices[0]
if let upperBound = self.index(
endingIndex,
offsetBy: -separatorLength,
limitedBy: separatorStartIndex
) {
array.append(Self(self[...upperBound]))
} else {
array.append(Self())
}
} else if idx < indicesLength {
let lastIndex = endingIndices[idx - 1]
let nextIndex = endingIndices[idx]
let lowerBound = self.index(after: lastIndex)
if let upperBound = self.index(
nextIndex,
offsetBy: -separatorLength,
limitedBy: lowerBound
) {
array.append(Self(self[lowerBound...upperBound]))
} else {
array.append(Self())
}
} else {
return [Self(string)]
let afterLast = self.index(after: endingIndices.last!)
array.append(Self(self[afterLast...]))
}
}

return recursiveOneSplit([Character](self))
return array
}

/// Separates the string by the given separator only with the first matching case.
Expand All @@ -72,41 +93,41 @@ extension RangeReplaceableCollection where Element == Character {
let selfLength = self.count
guard !(selfLength < separatorLength) else { return nil }

let selfChars = [Character](self)
let separatorChars = [Character](separator)

let maxIdx = separatorLength - 1
var lastIdx: Int? = nil
let separatorStartIndex = separator.startIndex
let maxIdx = separator.index(separatorStartIndex, offsetBy: separatorLength - 1)
var lastIdx: Index? = nil

for idx in 0..<selfLength {
for idx in self.indices {
if let lastIdxUnwrapped = lastIdx {
let nextIdx = lastIdxUnwrapped + 1
let nextIdx = separator.index(after: lastIdxUnwrapped)
if nextIdx == maxIdx {
if selfChars[idx] == separatorChars[nextIdx] {
let startingIdx = idx - maxIdx
let lhs = Self(selfChars[0..<startingIdx])
let rhs = Self(selfChars[(idx + 1)...])
if self[idx] == separator[nextIdx] {
let startingIdx = self.index(idx, offsetBy: -(separatorLength - 1))
let lhs = Self(self[..<startingIdx])
let rhsLowerBound = self.index(after: idx)
let rhs = Self(self[rhsLowerBound...])
return (lhs: lhs, rhs: rhs)
} else {
if selfChars[idx] == separatorChars[0] {
lastIdx = 0
if self[idx] == separator[separatorStartIndex] {
lastIdx = separatorStartIndex
} else {
lastIdx = nil
}
}
} else {
if selfChars[idx] == separatorChars[nextIdx] {
lastIdx = lastIdxUnwrapped + 1
if self[idx] == separator[nextIdx] {
lastIdx = separator.index(after: lastIdxUnwrapped)
} else {
lastIdx = nil
}
}
} else {
if selfChars[idx] == separatorChars[0] {
lastIdx = 0
if self[idx] == separator[separatorStartIndex] {
lastIdx = separatorStartIndex
if separatorLength == 1 {
let lhs = Self(selfChars[0..<idx])
let rhs = Self(selfChars[(idx + 1)...])
let lhs = Self(self[..<idx])
let rhsLowerBound = self.index(after: idx)
let rhs = Self(self[rhsLowerBound...])
return (lhs: lhs, rhs: rhs)
}
}
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