From b58ecb11b0f43ae75e60f29c70fae4f981e54ca7 Mon Sep 17 00:00:00 2001
From: Nigel Tao <nigeltao@golang.org>
Date: Thu, 20 Aug 2009 16:03:34 -0700
Subject: [PATCH] Fix inflate.go's decompressing of a fixed Huffman block that
 has length-distance pairs.

The new test data was generated by "gzip shesells.txt", which is
presumably what you (rsc) did before, for the other test cases in
gunzip_test.go.

R=rsc
APPROVED=rsc
DELTA=21  (17 added, 2 deleted, 2 changed)
OCL=33582
CL=33616
---
 src/pkg/compress/flate/inflate.go    |  5 ++---
 src/pkg/compress/gzip/gunzip_test.go | 18 +++++++++++++++++-
 2 files changed, 19 insertions(+), 4 deletions(-)

diff --git a/src/pkg/compress/flate/inflate.go b/src/pkg/compress/flate/inflate.go
index 8719473d91..819528514f 100644
--- a/src/pkg/compress/flate/inflate.go
+++ b/src/pkg/compress/flate/inflate.go
@@ -460,7 +460,7 @@ func (f *inflater) decodeBlock(hl, hd *huffmanDecoder) os.Error {
 					return err;
 				}
 			}
-			dist = int(f.b & 0x1F);
+			dist = int(reverseByte[(f.b & 0x1F) << 3]);
 			f.b >>= 5;
 			f.nb -= 5;
 		} else {
@@ -628,7 +628,6 @@ func makeReader(r io.Reader) Reader {
 // Inflate reads DEFLATE-compressed data from r and writes
 // the uncompressed data to w.
 func (f *inflater) inflater(r io.Reader, w io.Writer) os.Error {
-	var ok bool;	// TODO(rsc): why not := on next line?
 	f.r = makeReader(r);
 	f.w = w;
 	f.woffset = 0;
@@ -643,7 +642,7 @@ func (f *inflater) inflater(r io.Reader, w io.Writer) os.Error {
 
 // NewInflater returns a new ReadCloser that can be used
 // to read the uncompressed version of r.  It is the caller's
-// responsibility to call Close on the ReadClosed when
+// responsibility to call Close on the ReadCloser when
 // finished reading.
 func NewInflater(r io.Reader) io.ReadCloser {
 	var f inflater;
diff --git a/src/pkg/compress/gzip/gunzip_test.go b/src/pkg/compress/gzip/gunzip_test.go
index 49f6e9c919..d881c9875b 100644
--- a/src/pkg/compress/gzip/gunzip_test.go
+++ b/src/pkg/compress/gzip/gunzip_test.go
@@ -8,8 +8,8 @@ import (
 	"bytes";
 	"fmt";
 	"io";
-	"testing";
 	"os";
+	"testing";
 )
 
 type gzipTest struct {
@@ -68,6 +68,22 @@ var gzipTests = []gzipTest {
 		},
 		nil
 	},
+	gzipTest {	// has a fixed huffman block with some length-distance pairs
+		"shesells.txt",
+		"shesells.txt",
+		"she sells seashells by the seashore\n",
+		[]byte {
+			0x1f, 0x8b, 0x08, 0x08, 0x72, 0x66, 0x8b, 0x4a,
+			0x00, 0x03, 0x73, 0x68, 0x65, 0x73, 0x65, 0x6c,
+			0x6c, 0x73, 0x2e, 0x74, 0x78, 0x74, 0x00, 0x2b,
+			0xce, 0x48, 0x55, 0x28, 0x4e, 0xcd, 0xc9, 0x29,
+			0x06, 0x92, 0x89, 0xc5, 0x19, 0x60, 0x56, 0x52,
+			0xa5, 0x42, 0x09, 0x58, 0x18, 0x28, 0x90, 0x5f,
+			0x94, 0xca, 0x05, 0x00, 0x76, 0xb0, 0x3b, 0xeb,
+			0x24, 0x00, 0x00, 0x00,
+		},
+		nil
+	},
 	gzipTest {	// has dynamic huffman blocks
 		"gettysburg",
 		"gettysburg",