ng_extparam: split up work and do per-comp reduce

This change breaks extparam processing up into:

 - propagateExtendedParams: propagates min_length, min_offset and
   max_offset into the reports on the graph
 - reduceExtendedParams: runs graph reductions based on extparams

Then, we apply the reduce pass to the whole graph, and later as well to
each component after calc_components.

src/nfagraph/ng_extparam.h

@@ -34,15 +34,30 @@
 #ifndef NG_EXTPARAM_H
 #define NG_EXTPARAM_H
 
+#include "som/som.h"
+
 namespace ue2 {
 
-struct CompileContext;
 class ExpressionInfo;
 class NGHolder;
 class ReportManager;
 
-void handleExtendedParams(ReportManager &rm, NGHolder &g, ExpressionInfo &expr,
-                          const CompileContext &cc);
+/**
+ * \brief Propagate extended parameter information to vertex reports. Will
+ * throw CompileError if this expression's extended parameters are not
+ * satisfiable.
+ *
+ * This will also remove extended parameter constraints that are guaranteed to
+ * be satisfied from ExpressionInfo.
+ */
+void propagateExtendedParams(NGHolder &g, ExpressionInfo &expr,
+                             ReportManager &rm);
+
+/**
+ * \brief Perform graph reductions (if possible) to do with extended parameter
+ * constraints on reports.
+ */
+void reduceExtendedParams(NGHolder &g, ReportManager &rm, som_type som);
 
 } // namespace ue2