Adds gzstream stream, exposes to swig (#2314)

* Move RDBoostStreams to RDStreams

* RDBoostStreams->RDStreams

* RDBoostStreams->RDStreams

* Wrap SWIG (with Java test)

* Fix missing declaration

* Use the file that already exists

* Revert to original version

* Revert to CXSMiles version

* Update boost version

* Remove redundant code

* Add zlib

* check for win32

* FileParsers now builds static on windows

Code/RDStreams/CMakeLists.txt

@@ -0,0 +1,17 @@
+find_package(Boost 1.56.0 COMPONENTS system iostreams REQUIRED)
+set (link_iostreams ${Boost_LIBRARIES})
+if (NOT Boost_USE_STATIC_LIBS)
+   add_definitions("-DBOOST_IOSTREAMS_DYN_LINK")
+endif()
+
+if (WIN32)
+  find_package(Boost 1.58.0 COMPONENTS zlib REQUIRED)
+  set(zlib_lib Boost::zlib)
+endif()
+
+add_definitions(-DRDKIT_RDSTREAMS_BUILD)
+rdkit_library(RDStreams streams.cpp
+              LINK_LIBRARIES ${Boost_LIBRARIES} ${link_iostreams} ${zlib_lib}
+              DEST RDStreams)
+
+

Code/RDStreams/streams.cpp

@@ -0,0 +1,11 @@
+#include "streams.h"
+
+namespace RDKit
+{
+gzstream::gzstream(const std::string &fname) :
+    boost::iostreams::filtering_istream(),
+    is(fname.c_str(), std::ios_base::binary) {
+  push(boost::iostreams::gzip_decompressor());
+  push(is);
+}
+}

Code/RDStreams/streams.h

@@ -0,0 +1,16 @@
+//
+#include <RDGeneral/export.h>
+#include <boost/iostreams/device/file.hpp>
+#include <boost/iostreams/filtering_stream.hpp>
+#include <boost/iostreams/filter/gzip.hpp>
+
+namespace RDKit
+{
+// gzstream from a file
+class RDKIT_RDSTREAMS_EXPORT gzstream : public boost::iostreams::filtering_istream
+{
+  std::ifstream is;
+public:
+  gzstream(const std::string &fname);
+};
+}