06.practical.workproducer.consumer.c

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

#define BUFFER_SIZE 10

typedef struct {
        char type;  // 0 = fried chicken, 1 = French fries
        int amount; // piesces or weights
        char unit;  // 0 = piece, 1 = gram
} item;

item buffer[BUFFER_SIZE];
int first = 0;
int last = 0;

void produce(item *i){
        while ((first + 1) % BUFFER_SIZE == last) {
                // do nothing -- no free buffer item
        }
        memcpy(&buffer[first], i, sizeof(item));
        first = (first + 1) % BUFFER_SIZE;
}

item *consume() {
        item *i = malloc(sizeof(item));
        while (first == last) {
                // do nothing -- nothing to consume
        }
        memcpy(i, &buffer[last], sizeof(item));
        last = (last + 1) % BUFFER_SIZE;

        // print out to confirm
        printf("Output 3: first: %d, last: %d\n", first, last);
        return i;
}

item *initItem(char type, int amount, char unit){
        item *i = malloc(sizeof(item));
        i->amount = amount;
        i->type = type;
        i->unit = unit;
        return i;
}

int main(int argc, char const *argv[]) {
        item *input1 = initItem('0', 2, '0');
        item *input2 = initItem('1', 2, '1');

        printf("Input 1: type: %c, amount: %d, unit %c \n", input1->type, input1->amount, input1->unit);
        printf("Input 2: type: %c, amount: %d, unit %c \n", input2->type, input2->amount, input2->unit);
        printf("Initial value: first: %d, last: %d\n\n", first, last);

        // produce here
        produce(input1);
        printf("Output 1: first: %d, last: %d\n", first, last);
        produce(input2);
        printf("Output 2: first: %d, last: %d\n", first, last);

        // consume here
        consume();

        return 0;
}