Minimal memory tracker

memtrack.h

#define MEMTRACK_SZ 16000
struct memory_tracker {
    void* ptr[MEMTRACK_SZ];
    int opnums[MEMTRACK_SZ];
    int opnum = 0;

    // Change this to break somewhere.
    int break_opnum = -1;

    memory_tracker() {
        memset(ptr, 0, sizeof(void*) * MEMTRACK_SZ);
    }

    void* tr_malloc(void* p) {
        if (opnum == break_opnum) {
            assert(!"break_opnum hit. HALT.");
            while(1);
        }
        for (int i = 0; i < MEMTRACK_SZ; i++) {
            if (!ptr[i]) {
                ptr[i] = p;
                opnums[i] = opnum++;
                return p;
            }
        }
        assert(!"Out of tracking slots. Please increase MEMTRACK_SZ.");
        return p;
    }

    void tr_free(void* p) {
        if (opnum == break_opnum) {
            assert(!"break_opnum hit. HALT.");
            while(1);
        }
        for (int i = 0; i < MEMTRACK_SZ; i++) {
            if (ptr[i] == p) {
                ptr[i] = NULL;
                opnums[i] = opnum++;
                return;
            }
        }
        assert(!"Untracked pointer free.");
    }

    void* tr_realloc(void* old, void* p) {
        if (opnum == break_opnum) {
            assert(!"break_opnum hit. HALT.");
            while(1);
        }
        for (int i = 0; i < MEMTRACK_SZ; i++) {
            if (ptr[i] == old) {
                ptr[i] = p;
                opnums[i] = opnum++;
                return p;
            }
        }
        assert(!"Untracked pointer realloc.");
        return p;
    }

    void tr_print(void)
    {
        printf("----- tracked memory pointers -----");
        for (int i = 0; i < MEMTRACK_SZ; i++) {
            if (ptr[i]) {
                printf("  ptr: %p opnum: %d\n", ptr[i], opnums[i]);
            }
        }
    }
};