#include "vector.h"

#include <assert.h>
#include <string.h>
#include <stdlib.h>
#include <errno.h>

static int vector_resize(struct vector *vec, size_t new_cap) {
    vec->data = realloc(vec->data, vec->entsize * new_cap);
    if (!vec->data) {
        vec->cap = 0;
        vec->size = 0;
        return -ENOMEM;
    }
    vec->cap = new_cap;
    return 0;
}

void vector_init(struct vector *vec, size_t entsize) {
    vec->size = 0;
    vec->cap = 0;
    vec->data = NULL;
    vec->entsize = entsize;
}

void vector_free(struct vector *vec) {
    vec->cap = 0;
    vec->size = 0;
    vec->entsize = 0;
    free(vec->data);
    vec->data = NULL;
}

void vector_release(struct vector *vec) {
    memset(vec->data, 0, vec->cap * vec->entsize);
    free(vec->data);
    vec->cap = 0;
}

void *vector_append(struct vector *vec) {
    if (vec->size == vec->cap) {
        if (vector_resize(vec, vec->cap + 8) != 0) {
            return NULL;
        }
    }
    return vec->data + vec->entsize * vec->size++;
}

void *vector_ref(struct vector *vec, size_t index) {
    assert(index < vec->size);
    return vec->data + vec->entsize * index;
}