Merge pull request #400 from MattKotsenas/feature/avoid-exception-in-readerfactory

Avoid throwing NotSupportedException in ReaderFactory hot path

src/SharpCompress/Common/Zip/StreamingZipHeaderFactory.cs

@@ -49,6 +49,7 @@ namespace SharpCompress.Common.Zip
                 _lastEntryHeader = null;
                 uint headerBytes = reader.ReadUInt32();
                 header = ReadHeader(headerBytes, reader);
+                if (header == null) { yield break; }
 
                 //entry could be zero bytes so we need to know that.
                 if (header.ZipHeaderType == ZipHeaderType.LocalEntry)

src/SharpCompress/Common/Zip/ZipHeaderFactory.cs

@@ -91,7 +91,7 @@ namespace SharpCompress.Common.Zip
                         return entry;
                     }
                 default:
-                    throw new NotSupportedException("Unknown header: " + headerBytes);
+                    return null;
             }
         }