demo: select

c/sys/_demo/selectdemo/select.go

@@ -0,0 +1,42 @@
+package main
+
+import (
+	"unsafe"
+
+	"github.com/goplus/llgo/c"
+	"github.com/goplus/llgo/c/os"
+	"github.com/goplus/llgo/c/sys"
+)
+
+func main() {
+	var readFds sys.FdSet
+	sys.FD_ZERO(&readFds)
+	sys.FD_SET(0, &readFds)
+
+	var tv sys.Timeval
+	tv.Sec = 5
+	tv.Usec = 0
+
+	c.Printf(c.Str("Waiting for input on stdin...\n"))
+	ret := sys.Select(1, &readFds, nil, nil, &tv)
+	if ret == -1 {
+		c.Perror(c.Str("select error"))
+		c.Exit(1)
+	} else if ret == 0 {
+		c.Printf(c.Str("Timeout occurred! No data after 5 seconds.\n"))
+	} else {
+		if sys.FD_ISSET(0, &readFds) != 0 {
+			var buffer [100]c.Char
+			n := os.Read(0, c.Pointer(&buffer[:][0]), unsafe.Sizeof(buffer)-1)
+			if n == -1 {
+				c.Perror(c.Str("read error"))
+				c.Exit(1)
+			} else if n == 0 {
+				c.Printf(c.Str("End of file\n"))
+			} else {
+				buffer[n] = c.Char(0)
+				c.Printf(c.Str("Read %ld bytes: %s\n"), n, &buffer[0])
+			}
+		}
+	}
+}

c/sys/_demo/selectdemo2/select2.go

@@ -0,0 +1,88 @@
+package main
+
+import (
+	"unsafe"
+
+	"github.com/goplus/llgo/c"
+	"github.com/goplus/llgo/c/net"
+	"github.com/goplus/llgo/c/os"
+	"github.com/goplus/llgo/c/sys"
+)
+
+const (
+	SERVER_IP   = "110.242.68.66" // Get the IP address by ping baidu.com
+	SERVER_PORT = 80
+	BUFFER_SIZE = 4096 * 1024
+)
+
+func main() {
+	var server net.SockaddrIn
+
+	sendBuf := c.Str("GET / HTTP/1.1\r\nHost: baidu.com\r\n\r\n")
+	var recvBuf [BUFFER_SIZE]c.Char
+	var bytes_sent, bytes_received c.Int
+
+	// create net
+	sock := net.Socket(net.AF_INET, net.SOCK_STREAM, 0)
+	if sock < 0 {
+		c.Perror(c.Str("Socket creation failed"))
+		return
+	}
+
+	// set server addr
+	c.Memset(c.Pointer(&server), 0, unsafe.Sizeof(server))
+	server.Family = net.AF_INET
+	server.Port = net.Htons(SERVER_PORT)
+	server.Addr.Addr = net.InetAddr(c.Str(SERVER_IP))
+
+	// connect to server
+	if net.Connect(sock, (*net.SockAddr)(c.Pointer(&server)), c.Uint(unsafe.Sizeof(server))) < 0 {
+		c.Perror(c.Str("Connect failed"))
+		return
+	}
+
+	var writefds, readfds sys.FdSet
+	var timeout sys.Timeval
+
+	//  Monitor socket writes
+	sys.FD_ZERO(&writefds)
+	sys.FD_SET(sock, &writefds)
+	timeout.Sec = 10
+	timeout.Usec = 0
+
+	// Use select to monitor the readiness of writes
+	if sys.Select(sock+1, nil, &writefds, nil, &timeout) > 0 {
+		if sys.FD_ISSET(sock, &writefds) != 0 {
+			bytes_sent = c.Int(net.Send(sock, c.Pointer(sendBuf), c.Strlen(sendBuf), 0))
+			if bytes_sent < 0 {
+				c.Perror(c.Str("send failed"))
+				return
+			}
+		}
+	} else {
+		c.Perror(c.Str("Select write error"))
+		return
+	}
+
+	// Monitor socket reads
+	sys.FD_ZERO(&readfds)
+	sys.FD_SET(sock, &readfds)
+
+	// Use select to monitor the readiness of the read operation
+	if sys.Select(sock+1, &readfds, nil, nil, &timeout) > 0 {
+		if sys.FD_ISSET(sock, &writefds) != -1 {
+			bytes_received = c.Int(net.Recv(sock, c.Pointer(&recvBuf[:][0]), BUFFER_SIZE-1, 0))
+			if bytes_received < 0 {
+				c.Perror(c.Str("receive failed"))
+				return
+			}
+			recvBuf[bytes_received] = c.Char(0)
+			c.Printf(c.Str("Received:\n%s\n"), &recvBuf[0])
+		}
+	} else {
+		c.Perror(c.Str("Select read error"))
+		return
+	}
+
+	os.Close(sock)
+}