vector implementation

vector.c

// http://www.happybearsoftware.com/implementing-a-dynamic-array.html, but with void pointers
#include "lipsynth_vector.h"

void lipsynth_vector_init(LipsynthVector *vector, size_t itemSize) {
    // initialize size and capacity
    vector->size = 0;
    vector->itemSize = itemSize;
    vector->capacity = VECTOR_INITIAL_CAPACITY;
    
    // allocate memory for vector->data
    vector->data = calloc(0, vector->itemSize * vector->capacity);
}

void lipsynth_vector_append(LipsynthVector *vector, const void* value) {
    // make sure there's room to expand into
    lipsynth_vector_double_capacity_if_full(vector);

    // append the value and increment vector->size
    memcpy(vector->data+vector->size*vector->itemSize, value, vector->itemSize);
    vector->size++;
}
void lipsynth_vector_append_zero(LipsynthVector *vector){
    lipsynth_vector_double_capacity_if_full(vector);
    memset(vector->data+vector->size*vector->itemSize, 0, vector->itemSize);
    vector->size++;
}
void* lipsynth_vector_get(LipsynthVector *vector, int index) {
    if (index >= vector->size || index < 0) {
        printf("Index %d out of bounds for vector of size %d\n", index, vector->size);
        exit(1);
    }
    // return the pointer value in this index
    return vector->data+vector->itemSize*index;
}

void lipsynth_vector_set(LipsynthVector *vector, int index, void *value) {
    // zero fill the vector up to the desired index
    while (index >= vector->size) {
        lipsynth_vector_append_zero(vector);
    }
    
    // set the value at the desired index
    memcpy(vector->data+index*vector->itemSize, value, vector->itemSize);
}

void lipsynth_vector_double_capacity_if_full(LipsynthVector *vector) {
    if (vector->size >= vector->capacity) {
        // double vector->capacity and resize the allocated memory accordingly
        vector->capacity *= 2;
        vector->data = realloc(vector->data, vector->itemSize * vector->capacity);
    }
}

void lipsynth_vector_free(LipsynthVector *vector) {
    free(vector->data);
}

vector.h

#ifndef __LipSynth__lipsynth_vector__
#define __LipSynth__lipsynth_vector__
#define VECTOR_INITIAL_CAPACITY 4

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

typedef struct {
    int size;      // slots used so far
    int capacity;  // total available slots
    void *data;     // array of integers we're storing
    size_t itemSize;
} LipsynthVector;

void lipsynth_vector_init(LipsynthVector *vector, size_t itemSize);
void lipsynth_vector_append(LipsynthVector *vector, const void* value);
void lipsynth_vector_append_zero(LipsynthVector *vector);
void *lipsynth_vector_get(LipsynthVector *vector, int index);
void lipsynth_vector_set(LipsynthVector *vector, int index, void* value);
void lipsynth_vector_double_capacity_if_full(LipsynthVector *vector);
void lipsynth_vector_free(LipsynthVector *vector);

#endif /* defined(__LipSynth__lipsynth_vector__) */