hmap/Sources/HeaderMapCore/extensions/StringExtensions.swift

63 lines
2.2 KiB
Swift
Executable File

// MIT License
//
// Copyright (c) 2017 Milen Dzhumerov
//
// Permission is hereby granted, free of charge, to any person obtaining a copy
// of this software and associated documentation files (the "Software"), to deal
// in the Software without restriction, including without limitation the rights
// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
// copies of the Software, and to permit persons to whom the Software is
// furnished to do so, subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included in all
// copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
// SOFTWARE.
import Foundation
extension String {
func clangLowercasedBytes() throws -> Data {
guard let charBytes = data(using: BinaryHeaderMap.StringEncoding) else {
throw HeaderMapError.unencodableString
}
let lowercasedBytes = charBytes.map { $0.asciiLowercased() }
return Data(bytes: lowercasedBytes)
}
func clangLowercased() throws -> String? {
return try String(data: clangLowercasedBytes(), encoding: BinaryHeaderMap.StringEncoding)
}
var headerMapHash: UInt32? {
guard
let characterBytes = try? clangLowercasedBytes()
else { return nil }
return characterBytes.withUnsafeBytes {
(charBlockPointer: UnsafePointer<UInt8>) -> UInt32 in
var result = UInt32(0)
for i in 0 ..< characterBytes.count {
let charPointer = charBlockPointer.advanced(by: i)
result += UInt32(charPointer.pointee) * 13
}
return result
}
}
}
fileprivate extension UInt8 {
func asciiLowercased() -> UInt8 {
let isUppercase = (65 <= self && self <= 90)
return self + (isUppercase ? 32 : 0)
}
}