Co-routine

Is this iterator implementation well-defined?


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

typedef struct it {
    int *start;
    int len;
    struct it *next;
} iterator_t;

static iterator_t *head = NULL;

static iterator_t *iterator(int array[], int length)
{
    static iterator_t *ptr = NULL;

    if (head == NULL) {
        head = malloc(sizeof(iterator_t));
        ptr = head;
    } else {
        ptr->next = malloc(sizeof(iterator_t));
        ptr = ptr->next;
    }

    ptr->start = array;
    ptr->len = length;
    ptr->next = NULL;

    return ptr;
}

static int iterate(iterator_t *it)
{
    static iterator_t *current = NULL;
    static int state = 0, *ptr;

    if (it != NULL) {
        /* Initialize */
        current = it;
        ptr = it->start;
        state = 0;
    } else {
        /* Co-routine */
        switch (state) {
            case 0: while (ptr != (current->start + current->len)) {
                        state = 1;
                        return *ptr;
                       
                        case 1: ++ptr;
                    }
        }
    }

    return -1;
}

int main(void)
{
    iterator_t *it, *ptr;
    int n, numbers[] = { 4, 5, 6, 0, 1, 9, 0, 0, 8 };

    it = iterator(numbers, sizeof(numbers)/sizeof(int));

    iterate(it);
    while ((n = iterate(NULL)) != -1) {
        printf("%d\n", n);
    }

    it = head;
    while (it) {
        ptr = it->next;
        free(it);
        it = ptr;
    }
    return 0;
}

>>46
Are you capable of modifying an existing linux program that handles flash? In particular, you would need to modify it in such a way that when used with a series of scripts, it could automate the book making process on our website. In addition, we would need you to be able to port the shit over to OSX.

This is because a large portion of our customer base uses this OS.