github.com/cilium/ebpf@v0.10.0/ringbuf/ring_test.go (about)

     1  package ringbuf
     2  
     3  import (
     4  	"bytes"
     5  	"io"
     6  	"testing"
     7  )
     8  
     9  func TestRingBufferReader(t *testing.T) {
    10  	buf := make([]byte, 2)
    11  
    12  	ring := makeRing(2, 0)
    13  	n, err := ring.Read(buf)
    14  	if err != io.EOF {
    15  		t.Error("Expected io.EOF, got", err)
    16  	}
    17  	if n != 2 {
    18  		t.Errorf("Expected to read 2 bytes, got %d", n)
    19  	}
    20  	if !bytes.Equal(buf, []byte{0, 1}) {
    21  		t.Error("Expected [0, 1], got", buf)
    22  	}
    23  	n, err = ring.Read(buf)
    24  	if err != io.EOF {
    25  		t.Error("Expected io.EOF, got", err)
    26  	}
    27  	if n != 0 {
    28  		t.Error("Expected to read 0 bytes, got", n)
    29  	}
    30  
    31  	buf = make([]byte, 4)
    32  
    33  	ring = makeRing(4, 4)
    34  	n, err = io.ReadFull(ring, buf)
    35  	if err != nil {
    36  		t.Error("Expected nil, got", err)
    37  	}
    38  	if n != 4 {
    39  		t.Errorf("Expected to read 4 bytes, got %d", n)
    40  	}
    41  	if !bytes.Equal(buf, []byte{0, 1, 2, 3}) {
    42  		t.Error("Expected [0, 1, 2, 3], got", buf)
    43  	}
    44  	n, err = ring.Read(buf)
    45  	if err != io.EOF {
    46  		t.Error("Expected io.EOF, got", err)
    47  	}
    48  	if n != 0 {
    49  		t.Error("Expected to read 0 bytes, got", n)
    50  	}
    51  }
    52  
    53  func makeRing(size, offset int) *ringReader {
    54  	if size != 0 && (size&(size-1)) != 0 {
    55  		panic("size must be power of two")
    56  	}
    57  
    58  	ring := make([]byte, 2*size)
    59  	for i := range ring {
    60  		ring[i] = byte(i)
    61  	}
    62  
    63  	consumer := uint64(offset)
    64  	producer := uint64(len(ring)/2 + offset)
    65  
    66  	return newRingReader(&consumer, &producer, ring)
    67  }