Prevent trying to build smallwrite engine for large cases

src/nfagraph/ng.cpp

@@ -75,14 +75,15 @@ using namespace std;
 
 namespace ue2 {
 
-NG::NG(const CompileContext &in_cc, unsigned in_somPrecision)
+NG::NG(const CompileContext &in_cc, size_t num_patterns,
+       unsigned in_somPrecision)
     : maxSomRevHistoryAvailable(in_cc.grey.somMaxRevNfaLength),
       minWidth(depth::infinity()),
       rm(in_cc.grey),
       ssm(in_somPrecision),
       cc(in_cc),
       rose(makeRoseBuilder(rm, ssm, cc, boundary)),
-      smwr(makeSmallWriteBuilder(rm, cc)) {
+      smwr(makeSmallWriteBuilder(num_patterns, rm, cc)) {
 }
 
 NG::~NG() {

src/nfagraph/ng.h

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2015, Intel Corporation
+ * Copyright (c) 2015-2016, Intel Corporation
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are met:
@@ -87,7 +87,8 @@ class SmallWriteBuild;
 
 class NG : boost::noncopyable {
 public:
-    NG(const CompileContext &in_cc, unsigned in_somPrecision);
+    NG(const CompileContext &in_cc, size_t num_patterns,
+       unsigned in_somPrecision);
     ~NG();
 
     /** \brief Consumes a pattern, returns false or throws a CompileError