C Multi-Dimensional Array With Pointers

multi_dim_array.c

void *alloc_array(int ndims, const int dims[ndims], int size) {
    if(ndims <= 0) exit(1);
    if(ndims == 1) return calloc(dims[0], size);
    int hsize = 0, n;
    for(int n = 1, i = 0; i < ndims - 1; i += 1)
        n *= dims[i], hsize += n;
    void **head = calloc(hsize, sizeof(void*)), **ret = head;
    for(n = dims[0]; ndims > 2; ndims -= 1, dims += 1) {
        for(int i = 0, j = 0; i < n; i += 1, j += dims[1])
            head[i] = head + n + j;
        head += n, n *= dims[1];
    }
    void *data = calloc(n * dims[1], size);
    for(int i = 0, j = 0; i < n; i += 1, j += dims[1])
        head[i] = data + j * size;
    return ret;
}

void free_array(void *arr, int ndims) {
    if(ndims <= 0) exit(1);
    if(ndims == 0) return free(arr);
    void **dat = arr;
    for(; ndims > 1; ndims -= 1) dat = (void**)dat[0];
    free(dat), free(arr);
}

int main() {
    const int X = 5, Y = 2, Z = 3, W = 2;
    int ****mat = alloc_array(4, (int[4]){X, Y, Z, W}, sizeof(int));
    int mat4121 = mat[4][1][2][1];
    // ...
    free_array(mat, 4);
}