Dynamic Array Facilities

darray.h

#ifndef DARRAY_H
#define DARRAY_H
#define DARRAY_INITIAL_CAPACITY 64

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

typedef struct darray_t {
  size_t length, capacity;
  void **elements;
} darray_t;

void *dalloc() {
  darray_t *a = malloc(sizeof(darray_t));
  if (!a) return 0;
  a->length = 0;
  a->capacity = DARRAY_INITIAL_CAPACITY;
  if (!(a->elements = calloc(DARRAY_INITIAL_CAPACITY, sizeof(void*)))) {
    free(a);
    return 0;
  }
  return a;
}

void dfree(darray_t *a) {
  free(a->elements);
  free(a);
}

void *dget(darray_t *a, size_t i) {
  return a->elements[i];
}

void *dpush(darray_t *a, void *v) {
  if (a->length >= a->capacity) {
    size_t new_capacity = a->capacity * 2;
    if (!(a->elements = realloc(a->elements, new_capacity * sizeof(void*))))
      return 0;
    memset(a->elements + a->capacity, 0, a->capacity);
    a->capacity = new_capacity;
  }
  return a->elements[a->length++] = v;
}

void *dpop(darray_t *a) {
  return a->elements[--(a->length)];
}

#define dset(a, i, v) ((a)->elements[i] = (void*)(v))
#define dpush(a, v)   (dpush((a), (void*)(long)(v)))

#endif