altbitflags/
lib.rs

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
//! This crate contains macros that make creating bitfields more intuitive.
//!
//! It is an alternative way of what 'Rust Compiler Team Bitflags' do.
//! It is not similar to C bitflags but it may be a bit easier to read and use
//! in some cases. Furthermore, this crate does not conflict with
//! 'Rust Compiler Team Bitflags' and you can use both as it must be okay.
//!
//! # Example
//! ```rust
//! # #[macro_use]
//! # extern crate altbitflags;
//! #
//! // Create some structure which will act like a bitfield structure.
//! struct Something(i64);
//!
//! impl Something {
//!
//!     // Create ReadWrite flag called 'present' (or shorthand 'p').
//!     // To set a value use 'set_p' or 'set_present'.
//!     // Flag position is bit number 0.
//!     flag_rw!(p, set_p, present, set_present, 0);
//!
//!     // Create ReadOnly flag 'extended' (and 'e') at position 1.
//!     flag_ro!(e, extended, 1);
//!
//!     // Shorter version of a flag_rw! macro.
//!     flag_rw!(a, set_a, 2);
//!
//!     // Shorter version of a flag_ro! macro.
//!     flag_ro!(b, 3);
//! }
//!
//! fn main() {
//!     let mut something = Something(0);
//!
//!     // This means the same thing:
//!     if (something.p()) { /* ... */ }
//!     if (something.present()) { /* ... */ }
//!
//!     // As does this:
//!     something.set_present(true);
//!     something.set_p(true);
//! }
//! ```

/// Create read-only flag.
///
/// It accepts a name argument, optional full name argument and a number,
/// which indicates the bit number with required flag.
///
/// Later, the given flag can be accessed either by short or full name
/// in a form of a normal function.
///
/// It will work only if it's put in a structure implementation
/// where integer number with bit fields can be accessed with 'self.0'.
///
/// ReadOnly flags accepts 'self.0' to be of any integer type.
///
/// # Example
///
/// ```
/// # #![allow(unused_parens)]
/// #[macro_use]
/// extern crate altbitflags;
///
/// struct Something(i64);
///
/// impl Something {
///     flag_ro!(present, 0);
///     flag_ro!(tx, 1);
///     flag_ro!(e, extended, 2);
///
///     // It is okay to define different functions for a single bit:
///     flag_ro!(some, 3);
///     flag_ro!(some_bit, 3);
/// }
///
/// fn main() {
///     let mut something = Something(0);
///
///     if (something.present()) { /* ... */ }
///     if (something.tx()) { /* ... */ }
///
///     // These do the same thing:
///     if (something.e()) { /* ... */ }
///     if (something.extended()) { /* ... */ }
/// }
/// ```
#[macro_export]
macro_rules! flag_ro {
    ($name:ident, $pos:expr) => (
        #[inline="always"]
        pub fn $name(&self) -> bool { self.0 & (1 << $pos) != 0 }
    );

    ($name:ident, $full_name:ident, $pos:expr) => (
        flag_ro!($name, $pos);
        flag_ro!($full_name, $pos);
    );
}

/// Create read-write flag.
///
/// It accepts an name argument, optional full name argument and a number,
/// which indicates the bit number with required flag.
///
/// Later, the given flag can be accessed either by short or full name
/// like with a normal function.
///
/// It will work only if it's put in a structure implementation
/// where integer number with fields can be accessed with 'self.0'.
///
/// Currently, 'self.0' must be of type 'i64'.
///
/// # Example
///
/// ```
/// # #![allow(unused_parens)]
/// #[macro_use]
/// extern crate altbitflags;
///
/// struct Something(i64);
///
/// impl Something {
///     flag_rw!(present, set_present, 0);
///     flag_rw!(e, set_e, extended, set_extended, 1);
///
///     // It is okay to define different functions for a single bit:
///     flag_rw!(a, set_a, 2);
///     flag_rw!(b, set_b, 2);
/// }
///
/// fn main() {
///     let mut something = Something(0);
///
///     if (something.present()) { /* ... */ }
///     if (something.e()) { /* ... */ }
///
///     // These do the same thing:
///     something.set_e(true);
///     something.set_extended(true);
/// }
/// ```
#[macro_export]
macro_rules! flag_rw {
    ($name:ident, $set_name:ident, $pos:expr) => (
        flag_ro!($name, $pos);

        #[inline="always"]
        pub fn $set_name(&mut self, b: bool) {
            let x = b as i64;
            self.0 ^= (-x ^ self.0) & (1 << $pos);
        }
    );

    ($name:ident, $set_name:ident,
    $full_name:ident, $full_set_name:ident,
    $pos:expr) => (
        flag_rw!($name, $set_name, $pos);
        flag_rw!($full_name, $full_set_name, $pos);
    );
}

#[cfg(test)]
mod test;