rusticata_macros/
macros.rs

1//! Helper macros
2
3use nom::bytes::complete::take;
4use nom::combinator::map_res;
5use nom::IResult;
6
7#[doc(hidden)]
8pub mod export {
9    pub use core::{fmt, mem, ptr};
10}
11
12/// Helper macro for newtypes: declare associated constants and implement Display trait
13#[macro_export]
14macro_rules! newtype_enum (
15    (@collect_impl, $name:ident, $($key:ident = $val:expr),* $(,)*) => {
16        $( pub const $key : $name = $name($val); )*
17    };
18
19    (@collect_disp, $name:ident, $f:ident, $m:expr, $($key:ident = $val:expr),* $(,)*) => {
20        match $m {
21            $( $val => write!($f, stringify!{$key}), )*
22            n => write!($f, "{}({} / 0x{:x})", stringify!{$name}, n, n)
23        }
24    };
25
26    // entry
27    (impl $name:ident {$($body:tt)*}) => (
28        #[allow(non_upper_case_globals)]
29        impl $name {
30            newtype_enum!{@collect_impl, $name, $($body)*}
31        }
32    );
33
34    // entry with display
35    (impl display $name:ident {$($body:tt)*}) => (
36        newtype_enum!(impl $name { $($body)* });
37
38        impl $crate::export::fmt::Display for $name {
39            fn fmt(&self, f: &mut $crate::export::fmt::Formatter) -> $crate::export::fmt::Result {
40                newtype_enum!(@collect_disp, $name, f, self.0, $($body)*)
41            }
42        }
43    );
44
45    // entry with display and debug
46    (impl debug $name:ident {$($body:tt)*}) => (
47        newtype_enum!(impl display $name { $($body)* });
48
49        impl $crate::export::fmt::Debug for $name {
50            fn fmt(&self, f: &mut $crate::export::fmt::Formatter) -> $crate::export::fmt::Result {
51                write!(f, "{}", self)
52            }
53        }
54    );
55);
56
57/// Helper macro for nom parsers: raise error if the condition is true
58///
59/// This macro is used when using custom errors
60#[macro_export]
61macro_rules! custom_check (
62  ($i:expr, $cond:expr, $err:expr) => (
63    {
64      if $cond {
65        Err(::nom::Err::Error($err))
66      } else {
67        Ok(($i, ()))
68      }
69    }
70  );
71);
72
73/// Helper macro for nom parsers: raise error if the condition is true
74///
75/// This macro is used when using `ErrorKind`
76#[macro_export]
77macro_rules! error_if (
78  ($i:expr, $cond:expr, $err:expr) => (
79    {
80      use nom::error_position;
81      if $cond {
82        Err(::nom::Err::Error(error_position!($i, $err)))
83      } else {
84        Ok(($i, ()))
85      }
86    }
87  );
88);
89
90/// Helper macro for nom parsers: raise error if input is not empty
91///
92/// Deprecated - use `nom::eof`
93#[macro_export]
94#[deprecated(since = "2.0.0")]
95macro_rules! empty (
96  ($i:expr,) => (
97    {
98      use nom::eof;
99      eof!($i,)
100    }
101  );
102);
103
104#[deprecated(since = "3.0.1", note = "please use `be_var_u64` instead")]
105/// Read an entire slice as a big-endian value.
106///
107/// Returns the value as `u64`. This function checks for integer overflows, and returns a
108/// `Result::Err` value if the value is too big.
109pub fn bytes_to_u64(s: &[u8]) -> Result<u64, &'static str> {
110    let mut u: u64 = 0;
111
112    if s.is_empty() {
113        return Err("empty");
114    };
115    if s.len() > 8 {
116        return Err("overflow");
117    }
118    for &c in s {
119        let u1 = u << 8;
120        u = u1 | (c as u64);
121    }
122
123    Ok(u)
124}
125
126/// Read a slice as a big-endian value.
127#[macro_export]
128macro_rules! parse_hex_to_u64 (
129    ( $i:expr, $size:expr ) => {
130        map_res(take($size as usize), $crate::combinator::be_var_u64)($i)
131    };
132);
133
134/// Read 3 bytes as an unsigned integer
135#[deprecated(since = "0.5.0", note = "please use `be_u24` instead")]
136#[allow(deprecated)]
137#[inline]
138pub fn parse_uint24(i: &[u8]) -> IResult<&[u8], u64> {
139    map_res(take(3usize), bytes_to_u64)(i)
140}
141
142//named!(parse_hex4<&[u8], u64>, parse_hex_to_u64!(4));
143
144/// Combination and flat_map! and take! as first combinator
145#[macro_export]
146macro_rules! flat_take (
147    ($i:expr, $len:expr, $f:ident) => ({
148        if $i.len() < $len { Err(::nom::Err::Incomplete(::nom::Needed::new($len))) }
149        else {
150            let taken = &$i[0..$len];
151            let rem = &$i[$len..];
152            match $f(taken) {
153                Ok((_,res)) => Ok((rem,res)),
154                Err(e)      => Err(e)
155            }
156        }
157    });
158    ($i:expr, $len:expr, $submac:ident!( $($args:tt)*)) => ({
159        if $i.len() < $len { Err(::nom::Err::Incomplete(::nom::Needed::new($len))) }
160        else {
161            let taken = &$i[0..$len];
162            let rem = &$i[$len..];
163            match $submac!(taken, $($args)*) {
164                Ok((_,res)) => Ok((rem,res)),
165                Err(e)      => Err(e)
166            }
167        }
168    });
169);
170
171/// Apply combinator, trying to "upgrade" error to next error type (using the `Into` or `From`
172/// traits).
173#[macro_export]
174macro_rules! upgrade_error (
175    ($i:expr, $submac:ident!( $($args:tt)*) ) => ({
176        upgrade_error!( $submac!( $i, $($args)* ) )
177    });
178    ($i:expr, $f:expr) => ({
179        upgrade_error!( call!($i, $f) )
180    });
181    ($e:expr) => ({
182        match $e {
183            Ok(o) => Ok(o),
184            Err(::nom::Err::Error(e)) => Err(::nom::Err::Error(e.into())),
185            Err(::nom::Err::Failure(e)) => Err(::nom::Err::Failure(e.into())),
186            Err(::nom::Err::Incomplete(i)) => Err(::nom::Err::Incomplete(i)),
187        }
188    });
189);
190
191/// Apply combinator, trying to "upgrade" error to next error type (using the `Into` or `From`
192/// traits).
193#[macro_export]
194macro_rules! upgrade_error_to (
195    ($i:expr, $ty:ty, $submac:ident!( $($args:tt)*) ) => ({
196        upgrade_error_to!( $ty, $submac!( $i, $($args)* ) )
197    });
198    ($i:expr, $ty:ty, $f:expr) => ({
199        upgrade_error_to!( $ty, call!($i, $f) )
200    });
201    ($ty:ty, $e:expr) => ({
202        match $e {
203            Ok(o) => Ok(o),
204            Err(::nom::Err::Error(e)) => Err(::nom::Err::Error(e.into::<$ty>())),
205            Err(::nom::Err::Failure(e)) => Err(::nom::Err::Failure(e.into::<$ty>())),
206            Err(::nom::Err::Incomplete(i)) => Err(::nom::Err::Incomplete(i)),
207        }
208    });
209);
210
211/// Nom combinator that returns the given expression unchanged
212#[macro_export]
213macro_rules! q {
214    ($i:expr, $x:expr) => {{
215        Ok(($i, $x))
216    }};
217}
218
219/// Align input value to the next multiple of n bytes
220/// Valid only if n is a power of 2
221#[macro_export]
222macro_rules! align_n2 {
223    ($x:expr, $n:expr) => {
224        ($x + ($n - 1)) & !($n - 1)
225    };
226}
227
228/// Align input value to the next multiple of 4 bytes
229#[macro_export]
230macro_rules! align32 {
231    ($x:expr) => {
232        $crate::align_n2!($x, 4)
233    };
234}
235
236#[cfg(test)]
237mod tests {
238    use nom::error::ErrorKind;
239    use nom::number::streaming::{be_u16, be_u32};
240    use nom::{error_position, Err, IResult, Needed};
241
242    #[test]
243    fn test_error_if() {
244        let empty = &b""[..];
245        let res: IResult<&[u8], ()> = error_if!(empty, true, ErrorKind::Tag);
246        assert_eq!(res, Err(Err::Error(error_position!(empty, ErrorKind::Tag))));
247    }
248
249    #[test]
250    fn test_newtype_enum() {
251        #[derive(Debug, PartialEq, Eq)]
252        struct MyType(pub u8);
253
254        newtype_enum! {
255            impl display MyType {
256                Val1 = 0,
257                Val2 = 1
258            }
259        }
260
261        assert_eq!(MyType(0), MyType::Val1);
262        assert_eq!(MyType(1), MyType::Val2);
263
264        assert_eq!(format!("{}", MyType(0)), "Val1");
265        assert_eq!(format!("{}", MyType(4)), "MyType(4 / 0x4)");
266    }
267    #[test]
268    fn test_flat_take() {
269        let input = &[0x00, 0x01, 0xff];
270        // read first 2 bytes and use correct combinator: OK
271        let res: IResult<&[u8], u16> = flat_take!(input, 2, be_u16);
272        assert_eq!(res, Ok((&input[2..], 0x0001)));
273        // read 3 bytes and use 2: OK (some input is just lost)
274        let res: IResult<&[u8], u16> = flat_take!(input, 3, be_u16);
275        assert_eq!(res, Ok((&b""[..], 0x0001)));
276        // read 2 bytes and a combinator requiring more bytes
277        let res: IResult<&[u8], u32> = flat_take!(input, 2, be_u32);
278        assert_eq!(res, Err(Err::Incomplete(Needed::new(2))));
279        // test with macro as sub-combinator
280        let res: IResult<&[u8], u16> = flat_take!(input, 2, be_u16);
281        assert_eq!(res, Ok((&input[2..], 0x0001)));
282    }
283
284    #[test]
285    fn test_q() {
286        let empty = &b""[..];
287        let res: IResult<&[u8], &str, ErrorKind> = q!(empty, "test");
288        assert_eq!(res, Ok((empty, "test")));
289    }
290
291    #[test]
292    fn test_align32() {
293        assert_eq!(align32!(3), 4);
294        assert_eq!(align32!(4), 4);
295        assert_eq!(align32!(5), 8);
296        assert_eq!(align32!(5u32), 8);
297        assert_eq!(align32!(5i32), 8);
298        assert_eq!(align32!(5usize), 8);
299    }
300}
rusticata_macros/macros.rs

rusticata_macros/
macros.rs
