stack.c
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//
// Created by imanol on 12/25/16.
//
#include <malloc.h>
#include "stack.h"
#define EXTEND_SIZE 10
uint32_t stack_size = EXTEND_SIZE;
uint32_t stack_pos = 0;
short *stack;
void initialize_stack()
{
stack = calloc(EXTEND_SIZE,sizeof(short));
}
void extend_stack()
{
stack_size += EXTEND_SIZE;
realloc(stack,stack_size*sizeof(short));
}
void shrink_stack()
{
stack_size -= EXTEND_SIZE;
realloc(stack,stack_size*sizeof(short));
}
void push(short value)
{
stack[stack_pos++] = value;
if(stack_pos == stack_size-1)
{
extend_stack();
}
}
short pop()
{
short value = stack[stack_pos--];
if(stack_size - stack_pos == 2*EXTEND_SIZE)
{
shrink_stack();
}
return value;
}