Vector in C.h

typedef struct {
    size_t element_type_size;
    size_t size;
    size_t capacity;
    char* elements;
} _GenericVector;

void* _GenericVectorGetReference(_GenericVector* vector_address, size_t index) {
    if (index >= vector_address->size) return (void*)0;
    return vector_address->elements + vector_address->elements_type_size * index;
}

void _GenericVectorAssignElement(_GenericVector* vector_address, size_t index, void* element_address) {
    memcpy(_GenericVectorGetReference(vector_address, index), element_address, vector_address->elements_type_size);
}

void _GenericVectorCheckOverflow(_GenericVector* vector_address) {
    if (vector_address->size == vector_address->capacity) {
        vector_address->capacity *= 2;
        vector_address->elements = realloc(vector_address->elements,
                                           vector_address->capacity * vector_address->elements_type_size);
    }
}

void _GenericVectorCheckUnderflow(_GenericVector* vector_address) {
    if (vector_address->size <= vector_address->capacity / 2) {
        vector_address->capacity /= 2;
        vector_address->elements = realloc(vector_address->elements,
                                           vector_address->capacity * vector_address->elements_type_size);
    }
}

void _GenericVectorPushBack(_GenericVector* vector_address, void* element_address) {
    _GenericVectorCheckOverflow(vector_address);
    vector_address->size++;
    _GenericVectorAssignElement(vector_address, vector_address->size, element_address);
}

void _GenericVectorShiftRight(_GenericVector* vector_address, size_t index) {
    _GenericVectorCheckOverflow(vector_address);
    memmove(_GenericVectorGetReference(vector_address, index), _GenericVectorGetReference(vector_address, index + 1));
    vector_address->size++;
}

void _GenericVectorShiftLeft(_GenericVector* vector_address, size_t index) {
    memmove(_GenericVectorGetReference(vector_address, index), _GenericVectorGetReference(vector_address, index - 1));
    vector_address->size--;
    _GenericVectorCheckUnderflow(vector_address);
}

void _GenericVectorInsert(_GenericVector* vector_address, size_t index, void* element_address) {
    if (index > vector_address->size) return;
    _GenericVectorShiftRight(vector_address, index + 1);
    _GenericVectorAssign(vector_address, index, element_address);
}