_realloc.c

#include "main.h"

/**
 * _realloc - function that reallocates a memory block using
 * @ptr: pointer to array
 * @old_size: old size
 * @new_size: new size
 *
 * Return: A pointer to the allocated memory
 *
 */

void *_realloc(void *ptr, unsigned int old_size, unsigned int new_size)
{
	char *s;
	char *ptr1;
	unsigned int i;

	ptr1 = (char *)ptr;

	if (ptr == NULL)
		return (malloc(new_size));
	if (new_size == 0 && ptr != NULL)
	{
		free(ptr);
		return (NULL);
	}
	if (new_size == old_size)
		return (ptr);

	s = malloc((new_size) * sizeof(char));
	if (s == NULL)
	{
		free(s);
		return (NULL);
	}

	if (new_size > old_size)
	{
		for (i = 0; i < old_size; i++)
			s[i] = ptr1[i];
	}
	if (new_size < old_size)
	{
		for (i = 0; i < new_size; i++)
			s[i] = ptr1[i];
	}
	free(ptr1);
	return (s);
}