source: doc/theses/colby_parsons_MMAth/benchmarks/waituntil/cfa/future.cfa@ 3a7aa94

#include <select.hfa>
#include <thread.hfa>
#include <future.hfa>
#include <fstream.hfa>
#include <stdio.h>
#include <time.hfa>
#include <string.h>

size_t Clients = 1, Time = 10;

size_t globalTotal = 0;
future(size_t) A, B, C;
volatile bool server_done_loop = false;
volatile bool client_done_loop = false;
volatile bool client_done = false;
volatile bool server_done = false;

volatile size_t client_count = 0;
volatile size_t client_loop_count = 0;
thread Client {};
void main( Client & this ) {
    size_t i = 0;
    for(;; i++ ) {
        waituntil( A ) { get(A); }
        and waituntil( B ) { get(B); }
        or waituntil( C ) { get(C); }

        // needs to check after waituntil for termination synchronization
        if ( client_done ) break;

        // Barrier-like synch needed to reset futures safely
        if ( __atomic_add_fetch( &client_count, 1, __ATOMIC_SEQ_CST ) == Clients ) { // synchronize reset
            client_count = 0;
            reset( A );
            reset( B );
            reset( C );
            client_done_loop = true; // unblock clients
        }
        while( !client_done_loop ) {} // client barrier
        if ( __atomic_add_fetch( &client_loop_count, 1, __ATOMIC_SEQ_CST ) == Clients ) { 
            client_done_loop = false; // reset barrier before clients can proceed past waituntil
            server_done_loop = true; // unblock server to restart iteration
            client_loop_count = 0;
        }
    }
    __atomic_fetch_add( &globalTotal, i, __ATOMIC_SEQ_CST );
}

thread Server {};
void main( Server & this ) {
    for( size_t i = 0; !server_done; i++ ) {
        if ( i % 4 == 0 ) {
            fulfil(A, i);
            fulfil(B, i);
        } else if ( i % 4 == 1 ) {
            fulfil(A, i);
            fulfil(C, i);
        } else if ( i % 4 == 2 ) {
            fulfil(B, i);
            fulfil(C, i);
        } else {
            fulfil(C, i);
        }
        while( !server_done_loop && !server_done ) {} // server barrier
        server_done_loop = false; // reset server barrier
    }
}

int main( int argc, char * argv[] ) {
    switch ( argc ) {
          case 3:
                if ( strcmp( argv[2], "d" ) != 0 ) {                    // default ?
                        Time = atoi( argv[2] );
                } // if
          case 2:
                if ( strcmp( argv[1], "d" ) != 0 ) {                    // default ?
                        Clients = atoi( argv[1] );
                        if ( Clients < 1 ) goto Usage;
                } // if
          case 1:                                                                                       // use defaults
                break;
          default:
          Usage:
                sout | "Usage: " | argv[0]
             | " [ clients (> 0) | 'd' (default " | Clients
                         | ") ] [ time (>= 0) | 'd' (default " | Time
                         | ") ]" ;
                exit( EXIT_FAILURE );
        } // switch
    processor p[Clients];

    {
        Client c[Clients];
        {
            Server s;

            sleep(Time`s);
            server_done = true;
        }
        while( available(A) || available(B) || available(C) ) {}
        client_done = true;
        fulfil( C, 0 );
    }
    printf("%zu\n", globalTotal);
}