46 lines
1.5 KiB
Swift
46 lines
1.5 KiB
Swift
import Foundation
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private let DecodeTable: [UInt32] = [
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0xff, 0x44, 0xff, 0x54, 0x53, 0x52, 0x48, 0xff,
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0x4b, 0x4c, 0x46, 0x41, 0xff, 0x3f, 0x3e, 0x45,
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0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07,
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0x08, 0x09, 0x40, 0xff, 0x49, 0x42, 0x4a, 0x47,
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0x51, 0x24, 0x25, 0x26, 0x27, 0x28, 0x29, 0x2a,
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0x2b, 0x2c, 0x2d, 0x2e, 0x2f, 0x30, 0x31, 0x32,
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0x33, 0x34, 0x35, 0x36, 0x37, 0x38, 0x39, 0x3a,
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0x3b, 0x3c, 0x3d, 0x4d, 0xff, 0x4e, 0x43, 0xff,
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0xff, 0x0a, 0x0b, 0x0c, 0x0d, 0x0e, 0x0f, 0x10,
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0x11, 0x12, 0x13, 0x14, 0x15, 0x16, 0x17, 0x18,
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0x19, 0x1a, 0x1b, 0x1c, 0x1d, 0x1e, 0x1f, 0x20,
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0x21, 0x22, 0x23, 0x4f, 0xff, 0x50, 0xff, 0xff
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]
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extension String {
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func decode85() -> Data {
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var data = Data()
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var block: UInt32 = 0
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var n = 0
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for c in utf8 {
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if c >= 32, c < 128, DecodeTable[Int(c - 32)] != 0xff {
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let value = DecodeTable[Int(c - 32)]
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block = block * 85 + value
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n += 1
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if n == 5 {
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data.append(UInt8(block >> 24))
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data.append(UInt8((block >> 16) & 0xff))
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data.append(UInt8((block >> 8) & 0xff))
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data.append(UInt8(block & 0xff))
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block = 0
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n = 0
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}
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}
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}
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if n >= 4 { data.append(UInt8((block >> 16) & 0xff)) }
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if n >= 3 { data.append(UInt8((block >> 8) & 0xff)) }
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if n >= 2 { data.append(UInt8(block & 0xff)) }
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return data
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}
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}
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