MM – C Memory Manager / Arena Allocator

A lightweight, arena-based thread-safe memory manager for C.

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Features

• Thread Safe

• Multiple memory arenas support

• 8-byte aligned allocations

• malloc / free / realloc equivalents

• Block splitting and defragmentation

• Optional freestanding mode (no stdlib)

• Simple return codes: success, no space, arena exists

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Quick Start – Add Arena & Alloc

#include <mm/mm.h>
#include <stdio.h>

int main() {
    mm_init();
    
    char mem[1024];
    mm_add_arena(mem, sizeof(mem));

    int* x = mm_alloc(sizeof(int));
    *x = 42;
    printf("%d\n", *x);

    mm_free(x);
    return 0;
}

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Realloc Example

mm_init();
int* arr = mm_alloc(4 * sizeof(int));
for (int i = 0; i < 4; i++) arr[i] = i;

// Grow array
arr = mm_realloc(arr, 8 * sizeof(int));
for (int i = 4; i < 8; i++) arr[i] = i;

mm_free(arr);

Private Arena

char b[0x1000];
mm_arena a = { 0u }; 
mm_arena_init(&a, b, sizeof(b));
void* p = mm_arena_alloc(&a, 0x100u);
p = mm_arena_realloc(&a, p, 0x200u);
mm_arena_free(&a, p);

License

MIT