Enable Snappy compression for NodeStore backends.

* Configured via config.cfg

Builds/VisualStudio2013/RippleD.vcxproj.filters

@@ -1740,6 +1740,9 @@
     <ClCompile Include="..\..\src\snappy\snappy.unity.cpp">
       <Filter>[0] Libraries\snappy</Filter>
     </ClCompile>
+    <ClCompile Include="..\..\src\ripple\common\tests\cross_offer.test.cpp">
+      <Filter>[1] Ripple\common\tests</Filter>
+    </ClCompile>
   </ItemGroup>
   <ItemGroup>
     <ClInclude Include="..\..\src\ripple_basics\containers\RangeSet.h">

src/ripple_core/nodestore/backend/LevelDBFactory.cpp

@@ -71,6 +71,14 @@ public:
             options.max_open_files = keyValues["open_files"].getIntValue();
         }
 
+        if (! keyValues["compression"].isEmpty ())
+        {
+            if (keyValues["compression"].getIntValue () == 0)
+            {
+                options.compression = leveldb::kNoCompression;
+            }
+        }
+
         leveldb::DB* db = nullptr;
         leveldb::Status status = leveldb::DB::Open (options, m_name, &db);
         if (!status.ok () || !db)

src/ripple_core/nodestore/backend/RocksDBFactory.cpp

@@ -155,6 +155,14 @@ public:
                 options.max_background_flushes = highThreads;
         }
 
+        if (! keyValues["compression"].isEmpty ())
+        {
+            if (keyValues["compression"].getIntValue () == 0)
+            {
+                options.compression = rocksdb::kNoCompression;
+            }
+        }
+
         rocksdb::DB* db = nullptr;
         rocksdb::Status status = rocksdb::DB::Open (options, m_name, &db);
         if (!status.ok () || !db)

src/ripple_leveldb/ripple_leveldb.h

@@ -20,6 +20,7 @@
 #ifndef RIPPLE_LEVELDB_H_INCLUDED
 #define RIPPLE_LEVELDB_H_INCLUDED
 
+#define SNAPPY
 #include "leveldb/cache.h"
 #include "leveldb/filter_policy.h"
 #include "leveldb/db.h"