1 files changed, 168 insertions, 0 deletions
diff --git a/libgo/go/crypto/block/xor_test.go b/libgo/go/crypto/block/xor_test.go
new file mode 100644
index 000000000..50f6bb08d
--- /dev/null
+++ b/libgo/go/crypto/block/xor_test.go
@@ -0,0 +1,168 @@
+// Copyright 2009 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package block
+
+import (
+	"bytes"
+	"fmt"
+	"io"
+	"testing"
+	"testing/iotest"
+)
+
+// Simple "pseudo-random" stream for testing.
+type incStream struct {
+	buf []byte
+	n   byte
+}
+
+func newIncStream(blockSize int) *incStream {
+	x := new(incStream)
+	x.buf = make([]byte, blockSize)
+	return x
+}
+
+func (x *incStream) Next() []byte {
+	x.n++
+	for i := range x.buf {
+		x.buf[i] = x.n
+		x.n++
+	}
+	return x.buf
+}
+
+func testXorWriter(t *testing.T, maxio int) {
+	var plain, crypt [256]byte
+	for i := 0; i < len(plain); i++ {
+		plain[i] = byte(i)
+	}
+	b := new(bytes.Buffer)
+	for block := 1; block <= 64 && block <= maxio; block *= 2 {
+		// compute encrypted version
+		n := byte(0)
+		for i := 0; i < len(crypt); i++ {
+			if i%block == 0 {
+				n++
+			}
+			crypt[i] = plain[i] ^ n
+			n++
+		}
+
+		for frag := 0; frag < 2; frag++ {
+			test := fmt.Sprintf("block=%d frag=%d maxio=%d", block, frag, maxio)
+			b.Reset()
+			r := bytes.NewBuffer(plain[0:])
+			s := newIncStream(block)
+			w := newXorWriter(s, b)
+
+			// copy plain into w in increasingly large chunks: 1, 1, 2, 4, 8, ...
+			// if frag != 0, move the 1 to the end to cause fragmentation.
+			if frag == 0 {
+				_, err := io.Copyn(w, r, 1)
+				if err != nil {
+					t.Errorf("%s: first Copyn: %s", test, err)
+					continue
+				}
+			}
+			for n := 1; n <= len(plain)/2; n *= 2 {
+				_, err := io.Copyn(w, r, int64(n))
+				if err != nil {
+					t.Errorf("%s: Copyn %d: %s", test, n, err)
+				}
+			}
+
+			// check output
+			crypt := crypt[0 : len(crypt)-frag]
+			data := b.Bytes()
+			if len(data) != len(crypt) {
+				t.Errorf("%s: want %d bytes, got %d", test, len(crypt), len(data))
+				continue
+			}
+
+			if string(data) != string(crypt) {
+				t.Errorf("%s: want %x got %x", test, data, crypt)
+			}
+		}
+	}
+}
+
+
+func TestXorWriter(t *testing.T) {
+	// Do shorter I/O sizes first; they're easier to debug.
+	for n := 1; n <= 256 && !t.Failed(); n *= 2 {
+		testXorWriter(t, n)
+	}
+}
+
+func testXorReader(t *testing.T, maxio int) {
+	var readers = []func(io.Reader) io.Reader{
+		func(r io.Reader) io.Reader { return r },
+		iotest.OneByteReader,
+		iotest.HalfReader,
+	}
+	var plain, crypt [256]byte
+	for i := 0; i < len(plain); i++ {
+		plain[i] = byte(255 - i)
+	}
+	b := new(bytes.Buffer)
+	for block := 1; block <= 64 && block <= maxio; block *= 2 {
+		// compute encrypted version
+		n := byte(0)
+		for i := 0; i < len(crypt); i++ {
+			if i%block == 0 {
+				n++
+			}
+			crypt[i] = plain[i] ^ n
+			n++
+		}
+
+		for mode := 0; mode < len(readers); mode++ {
+			for frag := 0; frag < 2; frag++ {
+				test := fmt.Sprintf("block=%d mode=%d frag=%d maxio=%d", block, mode, frag, maxio)
+				s := newIncStream(block)
+				b.Reset()
+				r := newXorReader(s, readers[mode](bytes.NewBuffer(crypt[0:maxio])))
+
+				// read from crypt in increasingly large chunks: 1, 1, 2, 4, 8, ...
+				// if frag == 1, move the 1 to the end to cause fragmentation.
+				if frag == 0 {
+					_, err := io.Copyn(b, r, 1)
+					if err != nil {
+						t.Errorf("%s: first Copyn: %s", test, err)
+						continue
+					}
+				}
+				for n := 1; n <= maxio/2; n *= 2 {
+					_, err := io.Copyn(b, r, int64(n))
+					if err != nil {
+						t.Errorf("%s: Copyn %d: %s", test, n, err)
+					}
+				}
+
+				// check output
+				data := b.Bytes()
+				crypt := crypt[0 : maxio-frag]
+				plain := plain[0 : maxio-frag]
+				if len(data) != len(plain) {
+					t.Errorf("%s: want %d bytes, got %d", test, len(plain), len(data))
+					continue
+				}
+
+				if string(data) != string(plain) {
+					t.Errorf("%s: input=%x want %x got %x", test, crypt, plain, data)
+				}
+			}
+		}
+	}
+}
+
+func TestXorReader(t *testing.T) {
+	// Do shorter I/O sizes first; they're easier to debug.
+	for n := 1; n <= 256 && !t.Failed(); n *= 2 {
+		testXorReader(t, n)
+	}
+}
+
+// TODO(rsc): Test handling of writes after write errors.