|
|
|
|
#ifndef _COW_H
|
|
|
|
|
#define _COW_H
|
|
|
|
|
|
|
|
|
|
#ifdef __cplusplus
|
|
|
|
|
#define restrict __restrict__
|
|
|
|
|
#endif
|
|
|
|
|
|
|
|
|
|
#include <stdlib.h>
|
|
|
|
|
|
|
|
|
|
// Copy-on-write mapped memory.
|
|
|
|
|
typedef struct cow cow_t;
|
|
|
|
|
|
|
|
|
|
/// Create a new copy-on-write area of `size` bytes.
|
|
|
|
|
/// Writes to this instance pointer (`cow_ptr()`) are written to the allocated memory.
|
|
|
|
|
/// Writes to any cloned instances do not propagate to this instance.
|
|
|
|
|
cow_t* cow_create(size_t size);
|
|
|
|
|
/// Free a cow area. This should be called on all clones before the parent of those clones is freed.
|
|
|
|
|
void cow_free(cow_t* restrict cow);
|
|
|
|
|
/// Create a clone of this instance. Any writes to the returned pointer will not be propagated to the input one.
|
|
|
|
|
cow_t* cow_clone(const cow_t* cow);
|
|
|
|
|
|
|
|
|
|
/// Returns 1 if this instance is a clone. 0 if it is not.
|
|
|
|
|
int cow_is_fake(const cow_t* cow);
|
|
|
|
|
/// Get the size of this cow area.
|
|
|
|
|
size_t cow_size(const cow_t* cow);
|
|
|
|
|
|
|
|
|
|
/// Get the `void*` pointer to the start of the area.
|
|
|
|
|
#define cow_ptr(v) (*((void**)(v)))
|
|
|
|
|
/// Get the `T*` pointer to the start of the area.
|
|
|
|
|
#define cow_ptr_of(T, v) (*((T **)(v)))
|
|
|
|
|
///// Get the `cow_t*` back from a pointer created with cow_ptr.
|
|
|
|
|
///// NOTE: This pointer **MUST NOT** be a *copy* of a pointer created with `cow_ptr`, but the pointer returned from `cow_ptr` exactly.
|
|
|
|
|
//XXX: Too unsafe and not useful enough to warrant a function/macro.
|
|
|
|
|
//#define cow_from_ptr(p) (cow_t*)(&(p))
|
|
|
|
|
|
|
|
|
|
#ifdef __cplusplus
|
|
|
|
|
#undef restrict
|
|
|
|
|
#endif
|
|
|
|
|
|
|
|
|
|
#endif /* _COW_H */
|
