Скачать или смотреть WRITING A CUSTOM MEMORY ALLOCATOR | C

include unistd.h
#include stdio.h
#include string.h

typedef struct MemoryBlock {
size_t size;
struct MemoryBlock *next;
int free;
} MemoryBlock;

#define BLOCK_SIZE sizeof(MemoryBlock)

MemoryBlock *freeList = NULL;

void *my_malloc(size_t size) {
MemoryBlock *block;

if (size = 0) {
return NULL;
}

if (!freeList) { // First allocation
block = sbrk(size + BLOCK_SIZE);
if (block == (void *)-1) {
return NULL; // sbrk failed
}
block-size = size;
block-free = 0;
block-next = NULL;
freeList = block;
} else {
// Find a free block
MemoryBlock *current = freeList;
while (current-next && !(current-free && current-size = size)) {
current = current-next;
}

if (current-free && current-size = size) {
current-free = 0;
return (void *)(current + 1);
}

block = sbrk(size + BLOCK_SIZE);
if (block == (void *)-1) {
return NULL; // sbrk failed
}
block-size = size;
block-free = 0;
block-next = NULL;
current-next = block;
}

return (void *)(block + 1);
}

void my_free(void *ptr) {
if (!ptr) {
return;
}

MemoryBlock *block = (MemoryBlock *)ptr - 1;
block-free = 1;
}

void printMemory() {
MemoryBlock *current = freeList;
printf("Memory Blocks:\n");
while (current) {
printf("Block: size=%zu, free=%d\n", current-size, current-free);
current = current-next;
}
}

int main() {
printf("Custom Memory Allocator in C\n");

int *arr = (int *)my_malloc(5 * sizeof(int));
if (!arr) {
printf("Memory allocation failed\n");
return 1;
}

for (int i = 0; i 5; i++) {
arr[i] = i + 1;
}

printf("Allocated Array: ");
for (int i = 0; i 5; i++) {
printf("%d ", arr[i]);
}
printf("\n");

my_free(arr);
printMemory();

return 0;
}