libgo: Merge to master revision 19184.

The next revision, 19185, renames several runtime files, and
will be handled in a separate change.

From-SVN: r211328

7 files changed, 42 insertions, 12 deletions

diff --git a/libgo/go/compress/bzip2/bzip2_test.go b/libgo/go/compress/bzip2/bzip2_test.go
index ada1f9a..cd647e5 100644
--- a/libgo/go/compress/bzip2/bzip2_test.go
+++ b/libgo/go/compress/bzip2/bzip2_test.go
@@ -14,7 +14,7 @@ import (
 )
 
 func TestBitReader(t *testing.T) {
-	buf := bytes.NewBuffer([]byte{0xaa})
+	buf := bytes.NewReader([]byte{0xaa})
 	br := newBitReader(buf)
 	if n := br.ReadBits(1); n != 1 {
 		t.Errorf("read 1 wrong")
@@ -31,7 +31,7 @@ func TestBitReader(t *testing.T) {
 }
 
 func TestBitReaderLarge(t *testing.T) {
-	buf := bytes.NewBuffer([]byte{0x12, 0x34, 0x56, 0x78})
+	buf := bytes.NewReader([]byte{0x12, 0x34, 0x56, 0x78})
 	br := newBitReader(buf)
 	if n := br.ReadBits(32); n != 0x12345678 {
 		t.Errorf("got: %x want: %x", n, 0x12345678)
@@ -43,7 +43,7 @@ func readerFromHex(s string) io.Reader {
 	if err != nil {
 		panic("readerFromHex: bad input")
 	}
-	return bytes.NewBuffer(data)
+	return bytes.NewReader(data)
 }
 
 func decompressHex(s string) (out []byte, err error) {
@@ -191,7 +191,7 @@ func benchmarkDecode(b *testing.B, testfile int) {
 	}
 	b.SetBytes(int64(len(compressed)))
 	for i := 0; i < b.N; i++ {
-		r := bytes.NewBuffer(compressed)
+		r := bytes.NewReader(compressed)
 		io.Copy(ioutil.Discard, NewReader(r))
 	}
 }
@@ -201,7 +201,7 @@ func BenchmarkDecodeTwain(b *testing.B)  { benchmarkDecode(b, twain) }
 
 func TestBufferOverrun(t *testing.T) {
 	// Tests https://code.google.com/p/go/issues/detail?id=5747.
-	buffer := bytes.NewBuffer([]byte(bufferOverrunBase64))
+	buffer := bytes.NewReader([]byte(bufferOverrunBase64))
 	decoder := base64.NewDecoder(base64.StdEncoding, buffer)
 	decompressor := NewReader(decoder)
 	// This shouldn't panic.
diff --git a/libgo/go/compress/bzip2/huffman.go b/libgo/go/compress/bzip2/huffman.go
index 8f6b0c9..75a6223 100644
--- a/libgo/go/compress/bzip2/huffman.go
+++ b/libgo/go/compress/bzip2/huffman.go
@@ -190,7 +190,37 @@ func buildHuffmanNode(t *huffmanTree, codes []huffmanCode, level uint32) (nodeIn
 	right := codes[firstRightIndex:]
 
 	if len(left) == 0 || len(right) == 0 {
-		return 0, StructuralError("superfluous level in Huffman tree")
+		// There is a superfluous level in the Huffman tree indicating
+		// a bug in the encoder. However, this bug has been observed in
+		// the wild so we handle it.
+
+		// If this function was called recursively then we know that
+		// len(codes) >= 2 because, otherwise, we would have hit the
+		// "leaf node" case, below, and not recursed.
+		//
+		// However, for the initial call it's possible that len(codes)
+		// is zero or one. Both cases are invalid because a zero length
+		// tree cannot encode anything and a length-1 tree can only
+		// encode EOF and so is superfluous. We reject both.
+		if len(codes) < 2 {
+			return 0, StructuralError("empty Huffman tree")
+		}
+
+		// In this case the recursion doesn't always reduce the length
+		// of codes so we need to ensure termination via another
+		// mechanism.
+		if level == 31 {
+			// Since len(codes) >= 2 the only way that the values
+			// can match at all 32 bits is if they are equal, which
+			// is invalid. This ensures that we never enter
+			// infinite recursion.
+			return 0, StructuralError("equal symbols in Huffman tree")
+		}
+
+		if len(left) == 0 {
+			return buildHuffmanNode(t, right, level+1)
+		}
+		return buildHuffmanNode(t, left, level+1)
 	}
 
 	nodeIndex = uint16(t.nextNode)
diff --git a/libgo/go/compress/flate/flate_test.go b/libgo/go/compress/flate/flate_test.go
index 57fea5a..0687663 100644
--- a/libgo/go/compress/flate/flate_test.go
+++ b/libgo/go/compress/flate/flate_test.go
@@ -14,7 +14,7 @@ import (
 )
 
 func TestUncompressedSource(t *testing.T) {
-	decoder := NewReader(bytes.NewBuffer([]byte{0x01, 0x01, 0x00, 0xfe, 0xff, 0x11}))
+	decoder := NewReader(bytes.NewReader([]byte{0x01, 0x01, 0x00, 0xfe, 0xff, 0x11}))
 	output := make([]byte, 1)
 	n, error := decoder.Read(output)
 	if n != 1 || error != nil {
diff --git a/libgo/go/compress/gzip/gunzip_test.go b/libgo/go/compress/gzip/gunzip_test.go
index 572fb58..5615373 100644
--- a/libgo/go/compress/gzip/gunzip_test.go
+++ b/libgo/go/compress/gzip/gunzip_test.go
@@ -284,7 +284,7 @@ var gunzipTests = []gunzipTest{
 func TestDecompressor(t *testing.T) {
 	b := new(bytes.Buffer)
 	for _, tt := range gunzipTests {
-		in := bytes.NewBuffer(tt.gzip)
+		in := bytes.NewReader(tt.gzip)
 		gzip, err := NewReader(in)
 		if err != nil {
 			t.Errorf("%s: NewReader: %s", tt.name, err)
diff --git a/libgo/go/compress/gzip/gzip_test.go b/libgo/go/compress/gzip/gzip_test.go
index 119be2e..09271b2 100644
--- a/libgo/go/compress/gzip/gzip_test.go
+++ b/libgo/go/compress/gzip/gzip_test.go
@@ -85,7 +85,7 @@ func TestRoundTrip(t *testing.T) {
 func TestLatin1(t *testing.T) {
 	latin1 := []byte{0xc4, 'u', 0xdf, 'e', 'r', 'u', 'n', 'g', 0}
 	utf8 := "Äußerung"
-	z := Reader{r: bufio.NewReader(bytes.NewBuffer(latin1))}
+	z := Reader{r: bufio.NewReader(bytes.NewReader(latin1))}
 	s, err := z.readString()
 	if err != nil {
 		t.Fatalf("readString: %v", err)
diff --git a/libgo/go/compress/lzw/reader_test.go b/libgo/go/compress/lzw/reader_test.go
index 6f155b1..9006c91 100644
--- a/libgo/go/compress/lzw/reader_test.go
+++ b/libgo/go/compress/lzw/reader_test.go
@@ -127,7 +127,7 @@ func benchmarkDecoder(b *testing.B, n int) {
 		if len(buf0) > n-i {
 			buf0 = buf0[:n-i]
 		}
-		io.Copy(w, bytes.NewBuffer(buf0))
+		w.Write(buf0)
 	}
 	w.Close()
 	buf1 := compressed.Bytes()
@@ -135,7 +135,7 @@ func benchmarkDecoder(b *testing.B, n int) {
 	runtime.GC()
 	b.StartTimer()
 	for i := 0; i < b.N; i++ {
-		io.Copy(ioutil.Discard, NewReader(bytes.NewBuffer(buf1), LSB, 8))
+		io.Copy(ioutil.Discard, NewReader(bytes.NewReader(buf1), LSB, 8))
 	}
 }
 
diff --git a/libgo/go/compress/zlib/reader_test.go b/libgo/go/compress/zlib/reader_test.go
index 3b02a08..218ccba1 100644
--- a/libgo/go/compress/zlib/reader_test.go
+++ b/libgo/go/compress/zlib/reader_test.go
@@ -102,7 +102,7 @@ var zlibTests = []zlibTest{
 func TestDecompressor(t *testing.T) {
 	b := new(bytes.Buffer)
 	for _, tt := range zlibTests {
-		in := bytes.NewBuffer(tt.compressed)
+		in := bytes.NewReader(tt.compressed)
 		zlib, err := NewReaderDict(in, tt.dict)
 		if err != nil {
 			if err != tt.err {