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#include <assert.h>
#include <stdbool.h>
#include <stdio.h>
#include <stdlib.h>
#include "util.h"
/* --8<-- stack2_type */
typedef int T;
struct stack {
T *array;
size_t sz, p;
};
/* -->8-- */
/* --8<-- stack2_init */
void
stack_init(struct stack *stack)
{
stack->array = NULL;
stack->sz = 0;
stack->p = 0;
}
/* -->8-- */
/* --8<-- stack2_grow_if_needed */
static bool
stack_grow_if_needed(struct stack *stack)
{
if ( stack->p == stack->sz ) {
if ( stack->array == NULL ) {
static const size_t initial_size = 10;
if ( (stack->array = reallocarray(NULL, initial_size, sizeof stack->array[0])) != NULL ) {
stack->sz = initial_size;
stack->p = 0;
}
else {
ERROR("out of memory");
return false;
}
}
else {
const size_t new_size = stack->sz * 3 / 2;
T *new_array;
if ( (new_array = reallocarray(stack->array, new_size, sizeof stack->array[0])) != NULL ) {
stack->array = new_array;
stack->sz = new_size;
}
else {
ERROR("out of memory");
return false;
}
}
}
return true;
}
/* -->8-- */
/* --8<-- stack2_push */
bool
stack_push(struct stack *stack, T data)
{
bool success = stack_grow_if_needed(stack);
if ( success ) {
stack->array[stack->p++] = data;
}
return success;
}
/* -->8-- */
/* --8<-- stack2_pop */
bool
stack_pop(struct stack *stack, T *data)
{
if ( stack->p != 0 ) {
--stack->p;
if ( data ) {
*data = stack->array[stack->p];
}
return true;
}
else
return false;
}
/* -->8-- */
/* --8<-- stack2_empty */
bool
stack_empty(struct stack *stack)
{
return stack->p == 0;
}
/* -->8-- */
/* --8<-- stack2_free */
void
stack_free(struct stack *stack)
{
free(stack->array);
}
/* -->8-- */
void
test_stack(void)
{
struct stack stack[1];
stack_init(stack);
assert(stack_empty(stack) == true);
for ( int i = 0; i != 5; ++i )
stack_push(stack, i);
assert(stack_empty(stack) == false);
T i;
assert(stack_pop(stack, &i) == true);
assert(i == 4);
assert(stack_pop(stack, &i) == true);
assert(i == 3);
assert(stack_pop(stack, &i) == true);
assert(i == 2);
assert(stack_pop(stack, &i) == true);
assert(i == 1);
assert(stack_pop(stack, &i) == true);
assert(i == 0);
assert(stack_pop(stack, &i) == false);
assert(stack_empty(stack) == true);
assert(stack[0].sz == 10);
assert(stack[0].p == 0);
for ( int i = 0; i != 23; ++i )
stack_push(stack, i);
assert(stack[0].sz == 33);
assert(stack[0].p == 23);
stack_free(stack);
}
int
main(void)
{
test_stack();
return EXIT_SUCCESS;
}
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