func TestWritev(t *testing.T) {
f, err := os.Create("testwritev")
if err != nil {
panic(err)
}
defer f.Close()
data := [][]byte{[]byte("foo"), []byte("bar"), []byte("baz")}
nw, err := vectorio.Writev(f, data)
f.Seek(0, 0)
if err != nil {
t.Errorf("WritevRaw threw error: %s", err)
}
if nw != 9 {
t.Errorf("Length %d of input does not match %d written bytes", 9, nw)
}
fromdisk, err := ioutil.ReadAll(f)
if err != nil {
t.Errorf("can't read file back, %s", err)
}
should := []byte("foobarbaz")
if bytes.Compare(fromdisk, should) != 0 {
t.Errorf("contents of file don't match input, %s != %s", fromdisk, should)
}
os.Remove("testwritev")
}
func TestWritevSocket(t *testing.T) {
go func() {
ln, err := net.Listen("tcp", "127.0.0.1:9999")
if err != nil {
t.Errorf("could not listen on 127.0.0.1:9999: %s", err)
}
conn, err := ln.Accept()
if err != nil {
t.Errorf("could not accept conn: %s", err)
}
defer conn.Close()
buf := make([]byte, 9)
nr, err := conn.Read(buf)
if nr != len(buf) {
t.Errorf("read was wrong length: %d != %d", nr, len(buf))
}
good := []byte("foobarbaz")
if bytes.Compare(buf, good) != 0 {
t.Errorf("read got wrong data: %s != %s", buf, good)
} else {
t.Logf("read got correct data: %s == %s", buf, good)
}
}()
time.Sleep(1 * time.Second)
addr, _ := net.ResolveTCPAddr("tcp4", "127.0.0.1:9999")
conn, err := net.DialTCP("tcp4", nil, addr)
if err != nil {
t.Errorf("error connecting to 127.0.0.1:9999: %s", err)
} else {
t.Logf("connected to server")
}
defer conn.Close()
data := [][]byte{[]byte("foo"), []byte("bar"), []byte("baz")}
f, err := conn.File()
if err != nil {
t.Errorf("could not get file handle for TCP client: %s", err)
}
defer f.Close()
nw, err := vectorio.Writev(f, data)
f.Seek(0, 0)
if err != nil {
t.Errorf("WritevRaw threw error: %s", err)
}
if nw != 9 {
t.Errorf("Length %d of input does not match %d written bytes", len(data), nw)
} else {
t.Logf("right number of bytes written")
}
time.Sleep(1 * time.Second)
}
func ExampleVectorioCombined() {
// Create a temp file for demo purposes
f, err := ioutil.TempFile("", "vectorio")
if err != nil {
panic(err)
}
defer f.Close()
data1 := []byte("foobarbaz_buf\n")
data2 := []byte("barbazfoo_buf\n")
// This demonstrates the "buffered" form of the library, similar to bufio.
// w implements io.Writer.
w, err := vectorio.NewBufferedWritev(f)
if err != nil {
panic(err)
}
// The simple method is to just write a byte slice;
// this is converted to a syscall.Iovec and queued
// for writing
w.Write(data2)
// The user can also gain more control with WriteIovec,
// although this does not have a significant advantage over Write.
// This is what Write does on your behalf.
w.WriteIovec(syscall.Iovec{&data1[0], uint64(len(data1))})
// Flush must be called after writes are complete, to empty out
// the buffer of pending Iovec.
// Returns the total number of bytes written, as reported by the underlying syscall.
nw1, err := w.Flush()
if err != nil {
panic(err)
}
// One can also write a slice of byte slices ([][]byte) all at once.
// Note, this usage does *not* implement io.Writer, but if you have a slice
// of byte slices to write, this is a way to do that without looping.
multiple := [][]byte{
[]byte("foobarbaz_slice\n"),
[]byte("foobazbar_slice\n"),
}
// we return the number of bytes written, as reported by the underlying syscall.
nw2, err := vectorio.Writev(f, multiple)
if err != nil {
panic(err)
}
fmt.Println("Wrote", nw1+nw2, "bytes to file")
// Output:
// Wrote 60 bytes to file
}