fixed GH #2661: Poco::Zip::ZipArchive cannot load new tomcat.zip file

Zip/doc/ZipUserGuide.page

@@ -152,6 +152,7 @@ To decompress single files you must first parse a Zip file, and then decompress
     ZipArchive arch(inp);
     ZipArchive::FileHeaders::const_iterator it = arch.findHeader("data/hello.txt");
     poco_assert (it != arch.headerEnd());
+    inp.clear();
     ZipInputStream zipin(inp, it->second);
     std::ostringstream out(std::ios::binary);
     Poco::StreamCopier::copyStream(zipin, out);

Zip/include/Poco/Zip/ZipUtil.h

@@ -54,6 +54,9 @@ public:
 	static void sync(std::istream& in);
 		/// Searches the next valid header in the input stream, stops right before it
 
+	static void syncDataDescriptor(std::istream& in, bool force64);
+		/// Searches the next data descriptor
+
 	static void verifyZipEntryFileName(const std::string& zipPath);
 		/// Verifies that the name of the ZipEntry is a valid path
 

Zip/src/SkipCallback.cpp

@@ -37,7 +37,7 @@ bool SkipCallback::handleZipEntry(std::istream& zipStream, const ZipLocalFileHea
 	if (!hdr.searchCRCAndSizesAfterData())
 		zipStream.seekg(hdr.getCompressedSize(), std::ios_base::cur);
 	else
-		ZipUtil::sync(zipStream);
+		ZipUtil::syncDataDescriptor(zipStream, hdr.needsZip64());
 	if (!zipStream.good()) throw Poco::IOException("Failed to seek on input stream");
 	return true;
 }

Zip/src/ZipFileInfo.cpp

@@ -126,8 +126,7 @@ void ZipFileInfo::parse(std::istream& inp, bool assumeHeaderRead)
 				ptr += 2;
 				if (id == ZipCommon::ZIP64_EXTRA_ID)
 				{
-					poco_assert(size >= 8);
+					if (size >= 8 && getUncompressedSizeFromHeader() == ZipCommon::ZIP64_MAGIC)
-					if (getUncompressedSizeFromHeader() == ZipCommon::ZIP64_MAGIC)
 					{
 						setUncompressedSize(ZipUtil::get64BitValue(ptr, 0));
 						size -= 8;

Zip/src/ZipUtil.cpp

@@ -161,6 +161,70 @@ void ZipUtil::sync(std::istream& in)
 }
 
 
+void ZipUtil::syncDataDescriptor(std::istream & in, bool force64)
+{
+	std::streampos start = in.tellg();
+	const int eof = std::char_traits<char>::eof();
+
+	int c = in.get();
+	do
+	{
+		while (c != eof && c != ZipDataInfo::HEADER[0]) { c = in.get(); }
+
+		if (c == eof) return;
+
+		bool match = true;
+		for (int i = 1; i < 4 && match; i++)
+		{
+			c = in.get();
+			if (c != ZipDataInfo::HEADER[i]) match = false;
+		}
+
+		if (match)
+		{
+			std::streampos end = in.tellg();
+
+			if (force64)
+			{
+				ZipDataInfo64 nfo(in, true);
+				if (nfo.isValid())
+				{
+					if (end - start == nfo.getCompressedSize() + 4)
+					{
+						in.seekg(-static_cast<int>(ZipDataInfo64::getFullHeaderSize()), std::ios::cur);
+						if (!in.good()) throw Poco::IOException("Failed to seek on input stream");
+						break;
+					}
+					else
+					{
+						in.seekg(-static_cast<int>(ZipDataInfo64::getFullHeaderSize()) + 4, std::ios::cur);
+						if (!in.good()) throw Poco::IOException("Failed to seek on input stream");
+					}
+				}
+			}
+			else
+			{
+				ZipDataInfo nfo(in, true);
+				if (nfo.isValid())
+				{
+					if (end - start == nfo.getCompressedSize() + 4)
+					{
+						in.seekg(-static_cast<int>(ZipDataInfo::getFullHeaderSize()), std::ios::cur);
+						if (!in.good()) throw Poco::IOException("Failed to seek on input stream");
+						break;
+					}
+					else
+					{
+						in.seekg(-static_cast<int>(ZipDataInfo::getFullHeaderSize()) + 4, std::ios::cur);
+						if (!in.good()) throw Poco::IOException("Failed to seek on input stream");
+					}
+				}
+			}
+		}
+	} while (c != eof);
+}
+
+
 void ZipUtil::verifyZipEntryFileName(const std::string& fn)
 {
 	if (fn.find("\\") != std::string::npos)