mm (Memory Management)

Header: udo/mm.h

Table of contents (click to go)

Macros

Enums

Unions

Structs

1. udo_mm

Functions

1. udo_mm_alloc()

2. udo_mm_sub_alloc()

3. udo_mm_sub_alloc_get_size()

4. udo_mm_free()

5. udo_mm_destroy()

API Documentation

This interface was built to force caller

to be more consciously concern about heap

based virtual memory management.

udo_mm (private)

struct udo_mm

struct udo_log_error_struct err;

size_t buff_sz;

size_t data_sz;

size_t ab_sz;

size_t offset;

err

Stores information about the error that occured

for the given context and may later be retrieved.

by caller.

buff_sz

Full size of the struct udo_mm context.

Not all bytes in the buffer are writable.

data_sz

Full size of the caller writable data.

ab_sz

The amount of available bytes the caller

can still write to.

offset

Buffer offset used when allocating new blocks

in constant time. Caller may not of used the

entire buffer before re-allocation. Member is

used to keep track of end of buffer where data

exist.

---

udo_mm_alloc

struct udo_mm *udo_mm_alloc(struct udo_mm *mm, const size_t size);

Returns pointer to an allocated block of heap

memory. The goal of this is to allocate a large

block of memory once. If re-allocation required

pass the previous large block to clone all data.

Addresses returned from function should not

be used to write to. Writable addresses

are return from a call to udo_mm_sub_alloc().

Param	Decription
mm	If NULL the inital allocation will be performed. If not NULL must pass a pointer to a struct udo_mm.
size	Size of data caller may allocate. If the size is greater than the larger block remapping of memory will occur.

Returns:

on success: Pointer to a struct udo_mm

on failure: NULL

---

udo_mm_sub_alloc

void *udo_mm_sub_alloc(struct udo_mm *mm, size_t size);

Returns pointer to an allocated block of heap

memory. From the allocated larger block of

memory sub-allocate from that larger block.

Addresses returned from function can be

used for writing.

Param	Decription
mm	Must pass a pointer to a struct udo_mm.
size	Size of buffer to sub-allocate.

Returns:

on success: Pointer to writable memory

on failure: NULL

---

udo_mm_sub_alloc_get_size

void *udo_mm_sub_alloc_get_size(const void *data);

Returns size of an allocated heap

memory sub block.

Param	Decription
data	Must pass address returned after call to udo_mm_sub_alloc().

Returns:

on success: Size of allocated sub block

on failure: (size_t)-1

---

udo_mm_free

void udo_mm_free(struct udo_mm *mm, const void *data);

Wipes the bytes at a given subregion of memory.

Shifts the memory after the subregion over to

the start of the wiped subregion.

NOTE: This function should be used sparingly

as the caller would have to keep track of the

new pointer address for every object allocated.

It’s better to only allocate memory if you know

the address it resides in won’t change. Usages

of bounded buffer for strings is encouraged.

Param	Decription
mm	Must pass a pointer to a struct udo_mm.
data	Address to the data caller wants to zero out.

---

udo_mm_destroy

void udo_mm_destroy(struct udo_mm *mm);

Free’s the large block of allocated memory created after

udo_mm_alloc() call.

Param	Decription
flops	Must pass a pointer to a struct udo_mm.