From 86333d9103e5a7a55909eb4a81d9cd28e043ca35 Mon Sep 17 00:00:00 2001
From: Guenter Obiltschnig <guenter.obiltschnig@appinf.com>
Date: Fri, 17 Feb 2017 20:18:57 +0100
Subject: [PATCH] one more fix for #1597: check for empty streams in
 Compress::addEntry() so this also works with non-seekable output streams

---
 Zip/src/Compress.cpp | 22 +++++++++++++++++++++-
 1 file changed, 21 insertions(+), 1 deletion(-)

diff --git a/Zip/src/Compress.cpp b/Zip/src/Compress.cpp
index f37a7b80e..51e644045 100644
--- a/Zip/src/Compress.cpp
+++ b/Zip/src/Compress.cpp
@@ -57,9 +57,14 @@ void Compress::addEntry(std::istream& in, const Poco::DateTime& lastModifiedAt,
 	{
 		std::string ext = Poco::toLower(fileName.getExtension());
 		if (_storeExtensions.find(ext) != _storeExtensions.end())
+		{
 			cm = ZipCommon::CM_STORE;
+			cl = ZipCommon::CL_NORMAL;
+		}
 		else
+		{
 			cm = ZipCommon::CM_DEFLATE;
+		}
 	}
 
 	std::string fn = ZipUtil::validZipEntryFileName(fileName);
@@ -67,12 +72,27 @@ void Compress::addEntry(std::istream& in, const Poco::DateTime& lastModifiedAt,
 	if (!in.good())
 		throw ZipException("Invalid input stream");
 
+	// Check if stream is empty.
+	// In this case, we have to set compression to STORE, otherwise
+	// extraction will fail with various tools.
+	const int eof = std::char_traits<char>::eof();
+	int firstChar = in.get();
+	if (firstChar == eof)
+	{
+		cm = ZipCommon::CM_STORE;
+		cl = ZipCommon::CL_NORMAL;
+	}
+
 	std::streamoff localHeaderOffset = _offset;
 	ZipLocalFileHeader hdr(fileName, lastModifiedAt, cm, cl, _forceZip64);
 	hdr.setStartPos(localHeaderOffset);
 
 	ZipOutputStream zipOut(_out, hdr, _seekableOut);
-	Poco::StreamCopier::copyStream(in, zipOut);
+	if (firstChar != eof)
+	{
+		zipOut.put(static_cast<char>(firstChar));
+		Poco::StreamCopier::copyStream(in, zipOut);
+	}
 	Poco::UInt64 extraDataSize;
 	zipOut.close(extraDataSize);
 	_offset = hdr.getEndPos();