EMS31_submodules/FIFOBuff/FIFOBuffChar.c

#include "FIFOBuffChar.h"

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

bool FIFOBuffChar_put(FIFOBuffChar_t *fifo, char i) // Change the function parameters to match the declaration
{
    bool ok = false;
    if ((fifo->LastEl_p == NULL) && (fifo->FirstEl_p == NULL))
    {
        // buffer is empty. add first element
        fifo->FirstEl_p = malloc(sizeof(FIFOBuffChar_element_t));
        if (fifo->FirstEl_p != NULL)
        {
            fifo->FirstEl_p->character = i;             // "value" to "character"
            fifo->FirstEl_p->nextElement = NULL;

            fifo->LastEl_p = fifo->FirstEl_p;
            fifo->size = 1;
            ok = true;
        }
        else
        {
            fifo->full = true;
            ok = false;
        }
    }
    else if ((fifo->LastEl_p != NULL) && (fifo->FirstEl_p != NULL))
    {
        // add element to exsiting buffer
        FIFOBuffChar_element_t* el = malloc(sizeof(FIFOBuffChar_element_t));
        if (el != NULL)
        {
            el->character = i;          // "value" to "character"
            el->nextElement = NULL;
            fifo->LastEl_p->nextElement = el;
            fifo->LastEl_p = el;
            fifo->size++;
            ok = true;
        }
        else
        {
            fifo->full = true;
            ok = false;
        }
    }
    else
    {
        // buffer is unhealthy. try to clear it and reinit
        if (fifo->FirstEl_p == NULL)
        {
            printf("buffer_dyn - buffer_put(): ERROR: first pointer is NULL\n");
        }
        //TODO: this while loop is unsave
        while (fifo->FirstEl_p != NULL)
        {
            FIFOBuffChar_get(fifo, NULL); // Replace buffer_get with FIFOBuffChar_get
        }
        if (fifo->LastEl_p != NULL)
        {
            free(fifo->LastEl_p);
            fifo->LastEl_p = NULL;
            printf("buffer_dyn - buffer_put(): ERROR: last pointer is NULL\n");
        }
        FIFOBuffChar_put(fifo, i); // Replace buffer_put with FIFOBuffChar_put
        ok = false;
    }
    return ok;
}

bool FIFOBuffChar_get(FIFOBuffChar_t *fifo, char *p) // Change the function parameters to match the declaration
{
    bool ok = false;
    if (fifo->FirstEl_p != NULL)
    {
        *p = fifo->FirstEl_p->character;                // "value" to "character"
        FIFOBuffChar_element_t* next = fifo->FirstEl_p->nextElement;
        free(fifo->FirstEl_p);
        // fifo->FirstEl_p = NULL;
        fifo->size--;
        fifo->full = false;
        if (next == NULL)
        {
            // this was the last element in the buffer
            if (fifo->LastEl_p == fifo->FirstEl_p)
            {
                // clear last element becouse it's the same
                fifo->LastEl_p = NULL;
                fifo->FirstEl_p = NULL;
                fifo->size = 0;
                ok = true;
            }
            else if (fifo->LastEl_p != NULL)
            {
                // buffer chain is broken; skip to last element
                fifo->FirstEl_p = fifo->LastEl_p;
                printf("buffer_dyn - buffer_get(): ERROR: next element is NULL, but it's not the last element. skip to last element\n");
                ok = false;
            }
            else
            {
                // somehow the last element is NULL
                fifo->size = 0;
                fifo->FirstEl_p = NULL;
                printf("buffer_dyn - buffer_get(): ERROR: last element pointer is NULL\n");
                ok = false;
            }
        }
        else
        {
            // set first element pointer to next element
            fifo->FirstEl_p = next;
            ok = true;
        }
    }
    else
    {
        ok = false;
    }
    return ok;
}

bool FIFOBuffChar_pop(FIFOBuffChar_t *fifo)
{
    bool ok = true;

    switch (fifo->size){
        case 0: // buffer is empty
            ok = false;
            break;

        case 1: // singel item in buffer
            // make buffer empty
            free(fifo->FirstEl_p);
            fifo->FirstEl_p = NULL;
            fifo->LastEl_p = NULL;
            fifo->size = 0;
            ok = true;
            break;

        default: // buffer is at least 2 element big
            // find the second last element
            FIFOBuffChar_element_t* secondLastEl = fifo->FirstEl_p;
            while (
                   secondLastEl->nextElement != fifo->LastEl_p
                && ((FIFOBuffChar_element_t*)secondLastEl->nextElement)->nextElement != NULL
            ){
                secondLastEl = secondLastEl->nextElement;
            }

            // remove last element
            free(fifo->LastEl_p);

            // update chain
            secondLastEl->nextElement = NULL;
            fifo->LastEl_p = secondLastEl;
            fifo->size--;
            ok = true;
            break;
    }

    return ok;
}

bool FIFOBuffChar_is_full(FIFOBuffChar_t *fifo)
{
    return fifo->full;
}

bool FIFOBuffChar_is_empty(FIFOBuffChar_t *fifo)
{
    // printf("empty %s: %s; fifo->LastEl_p = %i; fifo->FirstEl_p = %i\n",
    //     (fifo->LastEl_p == NULL) && (fifo->FirstEl_p == NULL) ? "true" : "false",
    //     (fifo->LastEl_p == fifo->FirstEl_p) ? "same" : "diff",
    //     (int) fifo->LastEl_p,
    //     (int) fifo->FirstEl_p);
    return ((fifo->LastEl_p == NULL) && (fifo->FirstEl_p == NULL));
}


FIFOBuffChar_t* FIFOBuffChar_create(void)
{
    
    // Allocate memory for a new FIFOBuffChar_t
    FIFOBuffChar_t* fifo = malloc(sizeof(FIFOBuffChar_t));
    
    if (fifo == NULL) {
        // Memory allocation failed
        return NULL;
    }
    
    // Initialize the FIFO buffer
    // Point the last element to the first one
    // Initialize other fields of the FIFOBuffChar_t struct
    
    fifo->FirstEl_p = NULL;
    fifo->LastEl_p = NULL;
    fifo->size = 0;
    fifo->full = false;

    return fifo;

}


bool FIFOBuffChar_delete(FIFOBuffChar_t *fifo)
{
    
    // Check if the buffer is already empty
    if (fifo->FirstEl_p == NULL)
    {
        // Delete all elements in the buffer
        FIFOBuffChar_element_t* currentElement = fifo->FirstEl_p;
        while (currentElement != NULL)
        {
            FIFOBuffChar_element_t* nextElement = currentElement->nextElement;
            free(currentElement);
            currentElement = nextElement;
        }
    }
    
    free(fifo);
    return true;
}


unsigned int FIFOBuffChar_getSize(FIFOBuffChar_t *fifo)
{
    return fifo->size;
}