Issue #230: preserve the compression method when getting a compressed…

src/SharpCompress/Archives/Zip/ZipArchiveEntry.cs

@@ -14,7 +14,15 @@ internal ZipArchiveEntry(ZipArchive archive, SeekableZipFilePart part)
 
         public virtual Stream OpenEntryStream()
         {
-            return Parts.Single().GetCompressedStream();
+            var filePart = Parts.Single() as ZipFilePart;
+            var compressionMethod = filePart.Header.CompressionMethod;
+            var stream = filePart.GetCompressedStream();
+            if (filePart.Header.CompressionMethod != compressionMethod)
+            {
+                filePart.Header.CompressionMethod = compressionMethod;
+            }
+
+            return stream; 
         }
 
         #region IArchiveEntry Members

tests/SharpCompress.Test/Zip/ZipArchiveTests.cs

@@ -324,6 +324,24 @@ public void Zip_Deflate_WinzipAES_Read()
             VerifyFiles();
         }
 
+        [Fact]
+        public void Zip_Deflate_WinzipAES_MultiOpenEntryStream()
+        {
+            ResetScratch();
+            using (var reader = ZipArchive.Open(Path.Combine(TEST_ARCHIVES_PATH, "Zip.deflate.WinzipAES2.zip"), new ReaderOptions()
+            {
+                Password = "test"
+            }))
+            {
+                foreach (var entry in reader.Entries.Where(x => !x.IsDirectory))
+                {
+                    var stream = entry.OpenEntryStream();
+                    Assert.NotNull(stream);
+                    var ex = Record.Exception(() => stream = entry.OpenEntryStream());
+                    Assert.Null(ex);
+                }
+            }
+        }
 
         [Fact]
         public void Zip_BZip2_Pkware_Read()