43 lines
1.2 KiB
Swift
43 lines
1.2 KiB
Swift
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import Foundation
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extension Data {
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public var hexEncoded: String {
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return map { String(format: "%02hhx", $0) }.joined()
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}
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// Convert 0 ... 9, a ... f, A ...F to their decimal value,
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// return nil for all other input characters
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private func decodeNibble(_ u: UInt16) -> UInt8? {
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switch(u) {
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case 0x30 ... 0x39:
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return UInt8(u - 0x30)
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case 0x41 ... 0x46:
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return UInt8(u - 0x41 + 10)
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case 0x61 ... 0x66:
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return UInt8(u - 0x61 + 10)
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default:
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return nil
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}
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}
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public init?(fromHexEncodedString string: String) {
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let utf16 = string.utf16
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self.init(capacity: utf16.count/2)
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var i = utf16.startIndex
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guard utf16.count % 2 == 0 else {
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return nil
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}
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while i != utf16.endIndex {
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guard let hi = decodeNibble(utf16[i]),
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let lo = decodeNibble(utf16[utf16.index(i, offsetBy: 1, limitedBy: utf16.endIndex)!]) else {
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return nil
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}
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var value = hi << 4 + lo
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self.append(&value, count: 1)
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i = utf16.index(i, offsetBy: 2, limitedBy: utf16.endIndex)!
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}
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}
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}
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