ej 3 cp por acabar

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <time.h>
#include "options.h"
#include <threads.h>

#define DELAY_SCALE 1000

//Added mutex to the array struct
struct array {
    int size;
    int *arr;
    mtx_t* mutex;
};

//args to create the threads
struct args {
    int id;
    int iterations;
    int delay;
    int increase;
    struct array*array;
};

//Info regarding the threads
struct thread_info {
    thrd_t id;
    struct args*args;
};


void apply_delay(int delay) {
    for(int i = 0; i < delay * DELAY_SCALE; i++); // waste time
}


int increment(int id, int iterations, int delay, struct array *arr)
{
    int pos, val;

    for(int i = 0; i < iterations; i++) {
        pos = rand() % arr->size;

        printf("%d increasing position %d\n", id, pos);

        val = arr->arr[pos];
        apply_delay(delay);

        val ++;
        apply_delay(delay);

        arr->arr[pos] = val;
        apply_delay(delay);
    }

    return 0;
}

int resta_suma(void *ptr){
    struct args*args = ptr;
    int pos1, pos2, val;

    for(int i=0; i< args->iterations; i++) {
        pos1 = rand() % args->array->size;
        printf("pos1 es %d\n",pos1);
        pos2 = rand() % args->array->size;
        printf("pos2 es %d\n",pos2);
        printf("Thread %d decrementa la posición %d e incrementa la posición %d\n",args->id, pos1, pos2);

        if(pos1<pos2){
        mtx_lock(&args->array->mutex[pos1]);
        mtx_lock(&args->array->mutex[pos2]);
        }
        else{
        mtx_lock(&args->array->mutex[pos2]);
        mtx_lock(&args->array->mutex[pos1]);
        }

        val = args->array->arr[pos1];
        apply_delay(args->delay);
        val--;
        apply_delay(args->delay);
        args->array->arr[pos1]=val;

        val = args->array->arr[pos2];
        apply_delay(args->delay);
        val++;
        apply_delay(args->delay);
        args->array->arr[pos2]=val;

        if(pos1<pos2){
        mtx_unlock(&args->array->mutex[pos1]);
        mtx_unlock(&args->array->mutex[pos2]);
        }
        else{
        mtx_unlock(&args->array->mutex[pos2]);
        mtx_unlock(&args->array->mutex[pos1]);
        }
        printf("FIN\n");
    }

    return 0;
}

//How it's supposed to work: lock the access to the array. Increment the position, add the increase to the
//  args->increase section to know how much is increased by every thread and unlock after certain delay.
int aux_increment(void*ptr){
    struct args*args = ptr;
    int pos,val;

    for(int i =0; i < args->iterations; i++) {
        pos = rand() % args->array->size;
        printf("Thread %d increasing position %d.\n", args->id, pos);
        mtx_lock(&args->array->mutex[pos]);
        val = args->array->arr[pos];
        apply_delay(args->delay);
        val++;
        args->increase ++;
        apply_delay(args->delay);
        args->array->arr[pos] = val;
        apply_delay(args->delay);
        mtx_unlock(&args->array->mutex[pos]);
    }
    return 0;
}

//Print the array to check if the corresponding amounts are correct.
void print_array(struct array*arr, struct thread_info*thred, int num_threads) {
    int total = 0;

    //Print by thread
    for(int i = 0; i < num_threads; i++) {
        printf("%d: %d.\n",i,thred[i].args->increase);
    }
    //Print by array
    for(int i = 0; i < arr->size; i++) {
        total += arr->arr[i];
        printf("%d ", arr->arr[i]);
    }

    printf("\nTotal: %d\n", total);
}

//Start threads function.
struct thread_info* start_threads(struct options opt, struct array*array){
    int i;
    struct thread_info* threads;
    printf("Creating %d threads.\n", opt.num_threads*2);
    threads = malloc(sizeof(struct thread_info)*opt.num_threads*2);

    if(threads == NULL){
        printf("Not enough memory available.\n");
        exit(1);
    }

    for(i = 0; i < opt.num_threads; i++){
        threads[i].args = malloc(sizeof(struct args));
        threads[i].args -> id = i;
        threads[i].args -> increase = 0;
        threads[i].args -> iterations = opt.iterations;
        threads[i].args -> delay = opt.delay;
        threads[i].args -> array = array;

        if( 0!= thrd_create(&threads[i].id,aux_increment,threads[i].args));
    }

    for(i = opt.num_threads; i < opt.num_threads*2; i++){
        threads[i].args = malloc(sizeof(struct args));
        threads[i].args -> id = i;
        threads[i].args -> increase = 0;
        threads[i].args -> iterations = opt.iterations;
        threads[i].args -> delay = opt.delay;
        threads[i].args -> array = array;

        if( 0!= thrd_create(&threads[i].id,resta_suma,threads[i].args));
    }

    return threads;
}

//Wait function, so we can make sure every thread has finished at the end of the program.
void wait (struct options opt, struct array*array, struct thread_info* threads){
    for(int i = 0; i < (opt.num_threads*2); i++){
        thrd_join(threads[i].id,NULL);
    }
    print_array(array,threads,opt.num_threads*2);

    for(int i = 0; i < (opt.num_threads*2); i++){
        free(threads[i].args);
    }

    free(threads);
    free(array->arr);
}

//Function that makes sure the mutex, array and threads are properly initialized.
void init_arrays(struct array*array, int size){
    array->size = size;
    array->arr = malloc(array->size*sizeof(int));
    array->mutex = malloc(size* sizeof (mtx_t));

    for(int i = 0; i<array->size; i++){
        array->arr[i] = 0;
        mtx_init(&array->mutex[i],mtx_plain);
    }
}

//Main function.
int main (int argc, char **argv)
{
    struct options       opt;
    struct array         arr;
    struct thread_info * thred;

    srand(time(NULL));

    // Default values for the options
    opt.num_threads  = 5;
    opt.size         = 10;
    opt.iterations   = 100;
    opt.delay        = 1000;

    read_options(argc, argv, &opt);


    init_arrays(&arr,opt.size);

    thred = start_threads(opt,&arr);
    wait(opt,&arr,thred);

    return 0;
}