1 files changed, 12 insertions, 11 deletions
diff --git a/libgo/go/compress/gzip/gzip.go b/libgo/go/compress/gzip/gzip.go
index c702c493c11..aafb442a667 100644
--- a/libgo/go/compress/gzip/gzip.go
+++ b/libgo/go/compress/gzip/gzip.go
@@ -10,6 +10,7 @@ import (
 	"fmt"
 	"hash/crc32"
 	"io"
+	"time"
 )
 
 // These constants are copied from the flate package, so that code that imports
@@ -19,6 +20,7 @@ const (
 	BestSpeed          = flate.BestSpeed
 	BestCompression    = flate.BestCompression
 	DefaultCompression = flate.DefaultCompression
+	HuffmanOnly        = flate.HuffmanOnly
 )
 
 // A Writer is an io.WriteCloser.
@@ -52,11 +54,11 @@ func NewWriter(w io.Writer) *Writer {
 // NewWriterLevel is like NewWriter but specifies the compression level instead
 // of assuming DefaultCompression.
 //
-// The compression level can be DefaultCompression, NoCompression, or any
-// integer value between BestSpeed and BestCompression inclusive. The error
-// returned will be nil if the level is valid.
+// The compression level can be DefaultCompression, NoCompression, HuffmanOnly
+// or any integer value between BestSpeed and BestCompression inclusive.
+// The error returned will be nil if the level is valid.
 func NewWriterLevel(w io.Writer, level int) (*Writer, error) {
-	if level < DefaultCompression || level > BestCompression {
+	if level < HuffmanOnly || level > BestCompression {
 		return nil, fmt.Errorf("gzip: invalid compression level: %d", level)
 	}
 	z := new(Writer)
@@ -142,10 +144,7 @@ func (z *Writer) Write(p []byte) (int, error) {
 	// Write the GZIP header lazily.
 	if !z.wroteHeader {
 		z.wroteHeader = true
-		z.buf[0] = gzipID1
-		z.buf[1] = gzipID2
-		z.buf[2] = gzipDeflate
-		z.buf[3] = 0
+		z.buf = [10]byte{0: gzipID1, 1: gzipID2, 2: gzipDeflate}
 		if z.Extra != nil {
 			z.buf[3] |= 0x04
 		}
@@ -155,13 +154,15 @@ func (z *Writer) Write(p []byte) (int, error) {
 		if z.Comment != "" {
 			z.buf[3] |= 0x10
 		}
-		le.PutUint32(z.buf[4:8], uint32(z.ModTime.Unix()))
+		if z.ModTime.After(time.Unix(0, 0)) {
+			// Section 2.3.1, the zero value for MTIME means that the
+			// modified time is not set.
+			le.PutUint32(z.buf[4:8], uint32(z.ModTime.Unix()))
+		}
 		if z.level == BestCompression {
 			z.buf[8] = 2
 		} else if z.level == BestSpeed {
 			z.buf[8] = 4
-		} else {
-			z.buf[8] = 0
 		}
 		z.buf[9] = z.OS
 		n, z.err = z.w.Write(z.buf[:10])