snmalloc_sys/
lib.rs

1#![no_std]
2#![allow(non_camel_case_types)]
3
4use core::ffi::c_void;
5
6extern "C" {
7    /// Allocate the memory with the given alignment and size.
8    /// On success, it returns a pointer pointing to the required memory address.
9    /// On failure, it returns a null pointer.
10    /// The client must assure the following things:
11    /// - `alignment` is greater than zero
12    /// - `alignment` is a power of 2
13    /// The program may be forced to abort if the constrains are not full-filled.
14    pub fn sn_rust_alloc(alignment: usize, size: usize) -> *mut c_void;
15
16    /// De-allocate the memory at the given address with the given alignment and size.
17    /// The client must assure the following things:
18    /// - the memory is acquired using the same allocator and the pointer points to the start position.
19    /// - `alignment` and `size` is the same as allocation
20    /// The program may be forced to abort if the constrains are not full-filled.
21    pub fn sn_rust_dealloc(ptr: *mut c_void, alignment: usize, size: usize) -> c_void;
22
23    /// Behaves like rust_alloc, but also ensures that the contents are set to zero before being returned.
24    pub fn sn_rust_alloc_zeroed(alignment: usize, size: usize) -> *mut c_void;
25
26    /// Re-allocate the memory at the given address with the given alignment and size.
27    /// On success, it returns a pointer pointing to the required memory address.
28    /// The memory content within the `new_size` will remains the same as previous.
29    /// On failure, it returns a null pointer. In this situation, the previous memory is not returned to the allocator.
30    /// The client must assure the following things:
31    /// - the memory is acquired using the same allocator and the pointer points to the start position
32    /// - `alignment` and `old_size` is the same as allocation
33    /// - `alignment` fulfills all the requirements as `rust_alloc`
34    /// The program may be forced to abort if the constrains are not full-filled.
35    pub fn sn_rust_realloc(
36        ptr: *mut c_void,
37        alignment: usize,
38        old_size: usize,
39        new_size: usize,
40    ) -> *mut c_void;
41
42    /// Allocate `count` items of `size` length each.
43    /// Returns `null` if `count * size` overflows or on out-of-memory.
44    /// All items are initialized to zero.
45    pub fn calloc(count: usize, size: usize) -> *mut c_void;
46
47    /// Allocate `size` bytes.
48    /// Returns pointer to the allocated memory or null if out of memory.
49    /// Returns a unique pointer if called with `size` 0.
50    pub fn malloc(size: usize) -> *mut c_void;
51
52    /// Re-allocate memory to `newsize` bytes.
53    /// Return pointer to the allocated memory or null if out of memory. If null
54    /// is returned, the pointer `p` is not freed. Otherwise the original
55    /// pointer is either freed or returned as the reallocated result (in case
56    /// it fits in-place with the new size).
57    /// If `p` is null, it behaves as [`sn_malloc`]. If `newsize` is larger than
58    /// the original `size` allocated for `p`, the bytes after `size` are
59    /// uninitialized.
60    pub fn realloc(p: *mut c_void, newsize: usize) -> *mut c_void;
61
62    /// Free previously allocated memory.
63    /// The pointer `p` must have been allocated before (or be null).
64    pub fn free(p: *mut c_void);
65
66    /// Return the available bytes in a memory block.
67    pub fn sn_rust_usable_size(p: *const c_void) -> usize;
68}
69
70#[cfg(test)]
71mod tests {
72    use super::*;
73
74    #[test]
75    fn it_zero_allocs_correctly() {
76        let ptr = unsafe { sn_rust_alloc_zeroed(8, 1024) } as *mut u8 as *mut [u8; 1024];
77        unsafe {
78            assert!((*ptr).iter().all(|x| *x == 0));
79        };
80        unsafe { sn_rust_dealloc(ptr as *mut c_void, 8, 1024) };
81    }
82
83    #[test]
84    fn it_frees_memory_malloc() {
85        let ptr = unsafe { sn_rust_alloc(8, 8) } as *mut u8;
86        unsafe {
87            *ptr = 127;
88            assert_eq!(*ptr, 127)
89        };
90        unsafe { sn_rust_dealloc(ptr as *mut c_void, 8, 8) };
91    }
92
93    #[test]
94    fn it_frees_memory_sn_malloc() {
95        let ptr = unsafe { malloc(8) } as *mut u8;
96        unsafe { free(ptr as *mut c_void) };
97    }
98
99    #[test]
100    fn it_frees_memory_sn_realloc() {
101        let ptr = unsafe { malloc(8) } as *mut u8;
102        let ptr = unsafe { realloc(ptr as *mut c_void, 8) } as *mut u8;
103        unsafe { free(ptr as *mut c_void) };
104    }
105
106    #[test]
107    fn it_reallocs_correctly() {
108        let mut ptr = unsafe { sn_rust_alloc(8, 8) } as *mut u8;
109        unsafe {
110            *ptr = 127;
111            assert_eq!(*ptr, 127)
112        };
113        ptr = unsafe { sn_rust_realloc(ptr as *mut c_void, 8, 8, 16) } as *mut u8;
114        unsafe { assert_eq!(*ptr, 127) };
115        unsafe { sn_rust_dealloc(ptr as *mut c_void, 8, 16) };
116    }
117
118    #[test]
119    fn it_calculates_usable_size() {
120        let ptr = unsafe { sn_rust_alloc(32, 8) } as *mut u8;
121        let usable_size = unsafe { sn_rust_usable_size(ptr as *mut c_void) };
122        assert!(
123            usable_size >= 32,
124            "usable_size should at least equal to the allocated size"
125        );
126        unsafe { sn_rust_dealloc(ptr as *mut c_void, 32, 8) };
127    }
128}
snmalloc_sys/lib.rs

snmalloc_sys/
lib.rs
