stack.c

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#include <stdlib.h>
 
#include "stack.h"
 
static StackEntry* StackEntry_Create(void* item)
{
    StackEntry* entry = calloc(1, sizeof(StackEntry));
    if (entry != NULL)
    {
        entry->item = item;
    }
 
    return entry;
}
 
static void StackEntry_Destroy(StackEntry* entry)
{
    free(entry);
}
 
// Stack_Push()
void Stack_Push(StackEntry** stack, void* item)
{
    if (stack != NULL && item != NULL)
    {
        StackEntry* entry = StackEntry_Create(item);
        if (entry != NULL)
        {
            if (*stack != NULL)
            {
                entry->next = *stack;
                *stack = entry;
            }
            else
            {
                *stack = entry;
            }
        }
    }
}
 
// Stack_Pop()
void* Stack_Pop(StackEntry** stack)
{
    void* item = NULL;
    if (stack != NULL)
    {
        StackEntry* entry = *stack;
        if (entry != NULL)
        {
            item = entry->item;
            *stack = entry->next;
            StackEntry_Destroy(entry);
        }
    }
    return item;
}
 
// Stack_IsEmpty()
bool Stack_IsEmpty(StackEntry** stack)
{
    return stack == NULL || *stack == NULL;
}