| 1 | use std::ops::RangeInclusive; |
| 2 | |
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| 3 | use clap::Parser; |
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| 4 | |
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| 5 | #[derive(Parser)] |
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| 6 | #[command(author, version, about, long_about = None)] |
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| 7 | struct Cli { |
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| 8 | /// Network port to use |
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| 9 | #[arg(value_parser = port_in_range)] |
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| 10 | port: u16, |
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| 11 | } |
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| 12 | |
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| 13 | fn main() { |
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| 14 | let cli = Cli::parse(); |
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| 15 | |
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| 16 | println!("PORT = {}" , cli.port); |
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| 17 | } |
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| 18 | |
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| 19 | const PORT_RANGE: RangeInclusive<usize> = 1..=65535; |
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| 20 | |
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| 21 | fn port_in_range(s: &str) -> Result<u16, String> { |
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| 22 | let port: usize = s |
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| 23 | .parse() |
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| 24 | .map_err(|_| format!("`{s}` isn't a port number" ))?; |
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| 25 | if PORT_RANGE.contains(&port) { |
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| 26 | Ok(port as u16) |
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| 27 | } else { |
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| 28 | Err(format!( |
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| 29 | "port not in range {}-{}" , |
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| 30 | PORT_RANGE.start(), |
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| 31 | PORT_RANGE.end() |
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| 32 | )) |
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| 33 | } |
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| 34 | } |
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| 35 | |
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