aboutsummaryrefslogtreecommitdiff
path: root/src/assert_align.rs
blob: f1de642f8a0d81774a004b0bea2883fd6738d49f (plain)
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
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
/// Asserts that the types' alignments are equal.
///
/// This is useful when ensuring that pointer arithmetic is done correctly, or
/// when [FFI] requires a type to have the same alignment as some foreign type.
///
/// # Examples
///
/// A `usize` has the same alignment as any pointer type:
///
/// ```
/// # #[macro_use] extern crate static_assertions; fn main() {}
/// assert_align_eq!(usize, *const u8, *mut u8);
/// ```
///
/// The following passes because `[i32; 4]` has the same alignment as `i32`:
///
/// ```
/// # #[macro_use] extern crate static_assertions; fn main() {}
/// assert_align_eq!([i32; 4], i32);
/// ```
///
/// The following example fails to compile because `i32x4` explicitly has 4
/// times the alignment as `[i32; 4]`:
///
/// ```compile_fail
/// # #[macro_use] extern crate static_assertions; fn main() {}
/// # #[allow(non_camel_case_types)]
/// #[repr(align(16))]
/// struct i32x4([i32; 4]);
///
/// assert_align_eq!(i32x4, [i32; 4]);
/// ```
///
/// [FFI]: https://en.wikipedia.org/wiki/Foreign_function_interface
#[macro_export(local_inner_macros)]
macro_rules! assert_align_eq {
    ($x:ty, $($y:ty),+ $(,)?) => {
        const _: fn() = || {
            use $crate::_core::mem::align_of;
            const_assert_eq_usize!(align_of::<$x>() $(, align_of::<$y>())+);
        };
    };
}

/// Asserts that the types' alignments are equal.
///
/// This macro has been deprecated in favor of
/// [`assert_align_eq!`](macro.assert_align_eq.html).
#[deprecated(
    since = "1.2.0",
    note = "Please use the 'assert_align_eq' macro instead"
)]
#[macro_export(local_inner_macros)]
macro_rules! assert_eq_align {
    ($($t:tt)*) => {
        assert_align_eq!($($t)*);
    };
}

/// Asserts that the types' alignments are **not** equal.
///
/// # Examples
///
/// A `u8` does not have the same alignment as a pointer:
///
/// ```
/// # #[macro_use] extern crate static_assertions; fn main() {}
/// assert_align_ne!(u8, *const u8);
/// ```
///
/// The following example fails to compile because a `usize` has the same
/// alignment as a pointer:
///
/// ```compile_fail
/// # #[macro_use] extern crate static_assertions; fn main() {}
/// assert_align_ne!(*const u8, usize);
/// ```
#[macro_export(local_inner_macros)]
macro_rules! assert_align_ne {
    ($x:ty, $($y:ty),+ $(,)?) => {
        const _: fn() = || {
            use $crate::_core::mem::align_of;
            const_assert_ne!(align_of::<$x>() $(, align_of::<$y>())+);
        };
    };
}

/// Asserts that the types' alignments are less than each other.
///
/// # Examples
///
/// A `u8` has smaller alignment than `u16`, which has smaller alignment than
/// a pointer:
///
/// ```
/// # #[macro_use] extern crate static_assertions; fn main() {}
/// assert_align_lt!(u8, u16, *const u8);
/// ```
///
/// The following example fails to compile because a `usize` has the same
/// alignment as a pointer:
///
/// ```compile_fail
/// # #[macro_use] extern crate static_assertions; fn main() {}
/// assert_align_lt!(*const u8, usize);
/// ```
#[macro_export(local_inner_macros)]
macro_rules! assert_align_lt {
    ($x:ty, $($y:ty),+ $(,)?) => {
        const _: fn() = || {
            use $crate::_core::mem::align_of;
            const_assert_lt!(align_of::<$x>() $(, align_of::<$y>())+);
        };
    };
}

/// Asserts that the types' alignments are less than or equal to each other.
///
/// # Examples
///
/// A `u8` and `i8` have smaller alignment than any pointer type:
///
/// ```
/// # #[macro_use] extern crate static_assertions; fn main() {}
/// assert_align_le!(u8, i8, *const u8);
/// ```
///
/// The following example fails to compile because a `usize` has greater
/// alignment than `u8`:
///
/// ```compile_fail
/// # #[macro_use] extern crate static_assertions; fn main() {}
/// assert_align_le!(usize, u8);
/// ```
#[macro_export(local_inner_macros)]
macro_rules! assert_align_le {
    ($x:ty, $($y:ty),+ $(,)?) => {
        const _: fn() = || {
            use $crate::_core::mem::align_of;
            const_assert_le!(align_of::<$x>() $(, align_of::<$y>())+);
        };
    };
}

/// Asserts that the types' alignments are greater than each other.
///
/// # Examples
///
/// A pointer has greater alignment than `u16`, which has greater alignment than
/// `u8`:
///
/// ```
/// # #[macro_use] extern crate static_assertions; fn main() {}
/// assert_align_gt!(*const u8, u16, u8);
/// ```
///
/// The following example fails to compile because a `usize` has the same
/// alignment as a pointer:
///
/// ```compile_fail
/// # #[macro_use] extern crate static_assertions; fn main() {}
/// assert_align_gt!(*const u8, usize);
/// ```
#[macro_export(local_inner_macros)]
macro_rules! assert_align_gt {
    ($x:ty, $($y:ty),+ $(,)?) => {
        const _: fn() = || {
            use $crate::_core::mem::align_of;
            const_assert_gt!(align_of::<$x>() $(, align_of::<$y>())+);
        };
    };
}

/// Asserts that the types' alignments are greater than or equal to each other.
///
/// # Examples
///
/// A pointer has greater alignment than `u8` and `i8`:
///
/// ```
/// # #[macro_use] extern crate static_assertions; fn main() {}
/// assert_align_ge!(*const u8, u8, i8);
/// ```
///
/// The following example fails to compile because a `u8` has smaller alignment
/// than `usize`:
///
/// ```compile_fail
/// # #[macro_use] extern crate static_assertions; fn main() {}
/// assert_align_ge!(u8, usize);
/// ```
#[macro_export(local_inner_macros)]
macro_rules! assert_align_ge {
    ($x:ty, $($y:ty),+ $(,)?) => {
        const _: fn() = || {
            use $crate::_core::mem::align_of;
            const_assert_ge!(align_of::<$x>() $(, align_of::<$y>())+);
        };
    };
}