PostgreSQLData+Data.swift

extension Data: PostgreSQLDataConvertible {
    /// See `PostgreSQLDataConvertible`.
    public static func convertFromPostgreSQLData(_ data: PostgreSQLData) throws -> Data {
        guard case .bytea = data.type else {
            throw PostgreSQLError.decode(self, from: data)
        }
        switch data.storage{
        case .text(let string): return Data(hexString: .init(string.dropFirst(2)))
        case .binary(let value): return value
        case .null: throw PostgreSQLError.decode(self, from: data)
        }
    }

    /// See `PostgreSQLDataConvertible`.
    public func convertToPostgreSQLData() throws -> PostgreSQLData {
        return PostgreSQLData(.bytea, binary: self)
    }
}

extension Data {
    /// Initialize data from a hex string.
    internal init(hexString: String) {
        var data = Data()

        var gen = hexString.makeIterator()
        while let c1 = gen.next(), let c2 = gen.next() {
            let s = String([c1, c2])
            guard let d = UInt8(s, radix: 16) else {
                break
            }

            data.append(d)
        }

        self.init(data)
    }
}