pc_channel_multi.go

   1 /* pc_channel_multi.go */
   2
   3 package main
   4
   5 import (
   6         . "fmt"
   7         "crypto/rand"
   8         "time"
   9         "flag"
  10 )
  11
  12 func random_between (begin, end int64) int64 {
  13         random_byte := make([]byte, 1)
  14         rand.Read(random_byte)
  15         return int64(random_byte[0]) % (end - begin + 1) + begin
  16 }
  17
  18 func random_sleep () {
  19         time.Sleep(random_between(0, *MAX_SLEEP_TIME) * 10e7)
  20 }
  21
  22 func send (channel chan int, i int) {
  23         channel <- i
  24 }
  25
  26 func recv (channel chan int) int {
  27         return <-channel
  28 }
  29
  30 func signal (channel chan int) {
  31         if len(channel) < cap(channel) || cap(channel) == 0 {
  32                 channel <- 0
  33         }
  34 }
  35
  36 func wait (channel chan int) {
  37         <-channel
  38 }
  39
  40 var (
  41         BUFFER_SIZE = flag.Int("s", 5, "BUFFER_SIZE") // flag -s
  42         MAX_SLEEP_TIME = flag.Int64("t", 5, "MAX_SLEEP_TIME") // flag -t
  43         MAX_PRODUCTIONS = flag.Int("m", 0, "MAX_PRODUCTIONS, 0 for infinity") // flag -m
  44         N_PRODUCERS = flag.Int("p", 3, "N_PRODUCERS") // flag -p
  45         N_CONSUMERS = flag.Int("c", 3, "N_CONSUMERS") // flag -c
  46         pipe = make(chan int, *BUFFER_SIZE)
  47         quit    = make(chan int)
  48 )
  49
  50 func producer (id int) {
  51         for i := 0; i < *MAX_PRODUCTIONS || *MAX_PRODUCTIONS == 0; i++ {
  52                 Println(id, "producing:", i + id * 1e5)
  53                 send(pipe, i + id * 1e5)
  54                 random_sleep()
  55         }
  56         signal(quit)
  57 }
  58
  59 func consumer (id int) {
  60         for {
  61                 v := recv(pipe)
  62                 if closed(pipe) { // canal fechado?
  63                         break
  64                 }
  65                 Println("\t\t\t", id, "consuming:", v)
  66                 random_sleep()
  67         }
  68         signal(quit)
  69 }
  70
  71 func main () {
  72         flag.Parse() // processa flags
  73         Println("BUFFER_SIZE =", *BUFFER_SIZE)
  74         Println("MAX_SLEEP_TIME =", *MAX_SLEEP_TIME)
  75         Println("MAX_PRODUCTIONS =", *MAX_PRODUCTIONS)
  76         Println("N_PRODUCERS =", *N_PRODUCERS)
  77         Println("N_CONSUMERS =", *N_CONSUMERS)
  78         for i := 0; i < *N_PRODUCERS; i++ { // cria produtores
  79                 go producer(i + 1)
  80         }
  81         for i := 0; i < *N_CONSUMERS; i++ { // cria consumidores
  82                 go consumer(i + 1)
  83         }
  84         for i := 0; i < *N_PRODUCERS; i++ { // espera o término dos produtores
  85                 wait(quit)
  86         }
  87         close(pipe)     // fecha comunicação
  88         for i := 0; i < *N_CONSUMERS; i++ {     // espera o término dos consumidores
  89                 wait(quit)
  90         }
  91 }
  92