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Add Internet and Ethernet address parsing (from strings).
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#![allow(dead_code)] | ||
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use core::result; | ||
use wire::{EthernetAddress, IpAddress, Ipv4Address}; | ||
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type Result<T> = result::Result<T, ()>; | ||
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struct Parser<'a> { | ||
data: &'a [u8], | ||
pos: usize | ||
} | ||
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impl<'a> Parser<'a> { | ||
fn new(data: &'a str) -> Parser<'a> { | ||
Parser { | ||
data: data.as_bytes(), | ||
pos: 0 | ||
} | ||
} | ||
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fn advance(&mut self) -> Result<u8> { | ||
match self.data.get(self.pos) { | ||
Some(&chr) => { | ||
self.pos += 1; | ||
Ok(chr) | ||
} | ||
None => Err(()) | ||
} | ||
} | ||
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fn try<F, T>(&mut self, f: F) -> Option<T> | ||
where F: FnOnce(&mut Parser<'a>) -> Result<T> { | ||
let pos = self.pos; | ||
match f(self) { | ||
Ok(res) => Some(res), | ||
Err(()) => { | ||
self.pos = pos; | ||
None | ||
} | ||
} | ||
} | ||
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fn accept_eof(&mut self) -> Result<()> { | ||
if self.data.len() == self.pos { | ||
Ok(()) | ||
} else { | ||
Err(()) | ||
} | ||
} | ||
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fn until_eof<F, T>(&mut self, f: F) -> Result<T> | ||
where F: FnOnce(&mut Parser<'a>) -> Result<T> { | ||
let res = f(self)?; | ||
self.accept_eof()?; | ||
Ok(res) | ||
} | ||
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fn accept_char(&mut self, chr: u8) -> Result<()> { | ||
if self.advance()? == chr { | ||
Ok(()) | ||
} else { | ||
Err(()) | ||
} | ||
} | ||
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fn accept_digit(&mut self, hex: bool) -> Result<u8> { | ||
let digit = self.advance()?; | ||
if digit >= b'0' && digit <= b'9' { | ||
Ok(digit - b'0') | ||
} else if hex && digit >= b'a' && digit <= b'f' { | ||
Ok(digit - b'a' + 10) | ||
} else if hex && digit >= b'A' && digit <= b'F' { | ||
Ok(digit - b'A' + 10) | ||
} else { | ||
Err(()) | ||
} | ||
} | ||
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fn accept_number(&mut self, max_digits: usize, max_value: u32, | ||
hex: bool) -> Result<u32> { | ||
let mut value = self.accept_digit(hex)? as u32; | ||
for _ in 1..max_digits { | ||
match self.try(|p| p.accept_digit(hex)) { | ||
Some(digit) => { | ||
value *= if hex { 16 } else { 10 }; | ||
value += digit as u32; | ||
} | ||
None => break | ||
} | ||
} | ||
if value < max_value { | ||
Ok(value) | ||
} else { | ||
Err(()) | ||
} | ||
} | ||
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fn accept_mac(&mut self) -> Result<EthernetAddress> { | ||
let mut octets = [0u8; 6]; | ||
for n in 0..6 { | ||
octets[n] = self.accept_number(2, 0x100, true)? as u8; | ||
if n != 5 { | ||
self.accept_char(b':')?; | ||
} | ||
} | ||
Ok(EthernetAddress(octets)) | ||
} | ||
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fn accept_ipv4(&mut self) -> Result<Ipv4Address> { | ||
let mut octets = [0u8; 4]; | ||
for n in 0..4 { | ||
octets[n] = self.accept_number(3, 0x100, false)? as u8; | ||
if n != 3 { | ||
self.accept_char(b'.')?; | ||
} | ||
} | ||
Ok(Ipv4Address(octets)) | ||
} | ||
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fn accept_ip(&mut self) -> Result<IpAddress> { | ||
if let Some(()) = self.try(|p| p.accept_eof()) { | ||
return Ok(IpAddress::Unspecified) | ||
} | ||
if let Some(ipv4) = self.try(|p| p.accept_ipv4()) { | ||
return Ok(IpAddress::Ipv4(ipv4)) | ||
} | ||
Err(()) | ||
} | ||
} | ||
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impl EthernetAddress { | ||
/// Parse a string representation of an Ethernet address. | ||
pub fn parse(s: &str) -> Result<EthernetAddress> { | ||
Parser::new(s).until_eof(|p| p.accept_mac()) | ||
} | ||
} | ||
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impl Ipv4Address { | ||
/// Parse a string representation of an IPv4 address. | ||
pub fn parse(s: &str) -> Result<Ipv4Address> { | ||
Parser::new(s).until_eof(|p| p.accept_ipv4()) | ||
} | ||
} | ||
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impl IpAddress { | ||
/// Parse a string representation of an IPv4 address. | ||
pub fn parse(s: &str) -> Result<IpAddress> { | ||
Parser::new(s).until_eof(|p| p.accept_ip()) | ||
} | ||
} | ||
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#[cfg(test)] | ||
mod test { | ||
use super::*; | ||
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#[test] | ||
fn test_mac() { | ||
assert_eq!(EthernetAddress::parse(""), Err(())); | ||
assert_eq!(EthernetAddress::parse("02:00:00:00:00:00"), | ||
Ok(EthernetAddress([0x02, 0x00, 0x00, 0x00, 0x00, 0x00]))); | ||
assert_eq!(EthernetAddress::parse("01:23:45:67:89:ab"), | ||
Ok(EthernetAddress([0x01, 0x23, 0x45, 0x67, 0x89, 0xab]))); | ||
assert_eq!(EthernetAddress::parse("cd:ef:10:00:00:00"), | ||
Ok(EthernetAddress([0xcd, 0xef, 0x10, 0x00, 0x00, 0x00]))); | ||
assert_eq!(EthernetAddress::parse("00:00:00:ab:cd:ef"), | ||
Ok(EthernetAddress([0x00, 0x00, 0x00, 0xab, 0xcd, 0xef]))); | ||
assert_eq!(EthernetAddress::parse("100:00:00:00:00:00"), Err(())); | ||
assert_eq!(EthernetAddress::parse("002:00:00:00:00:00"), Err(())); | ||
assert_eq!(EthernetAddress::parse("02:00:00:00:00:000"), Err(())); | ||
assert_eq!(EthernetAddress::parse("02:00:00:00:00:0x"), Err(())); | ||
} | ||
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#[test] | ||
fn test_ipv4() { | ||
assert_eq!(Ipv4Address::parse(""), Err(())); | ||
assert_eq!(Ipv4Address::parse("1.2.3.4"), | ||
Ok(Ipv4Address([1, 2, 3, 4]))); | ||
assert_eq!(Ipv4Address::parse("001.2.3.4"), | ||
Ok(Ipv4Address([1, 2, 3, 4]))); | ||
assert_eq!(Ipv4Address::parse("0001.2.3.4"), Err(())); | ||
assert_eq!(Ipv4Address::parse("999.2.3.4"), Err(())); | ||
assert_eq!(Ipv4Address::parse("1.2.3.4.5"), Err(())); | ||
assert_eq!(Ipv4Address::parse("1.2.3"), Err(())); | ||
assert_eq!(Ipv4Address::parse("1.2.3."), Err(())); | ||
assert_eq!(Ipv4Address::parse("1.2.3.4."), Err(())); | ||
} | ||
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#[test] | ||
fn test_ip() { | ||
assert_eq!(IpAddress::parse(""), | ||
Ok(IpAddress::Unspecified)); | ||
assert_eq!(IpAddress::parse("1.2.3.4"), | ||
Ok(IpAddress::Ipv4(Ipv4Address([1, 2, 3, 4])))); | ||
assert_eq!(IpAddress::parse("x"), Err(())); | ||
} | ||
} |