Spacer engine for HORN logic

The algorithms implemented in the engine are described in the following papers

Anvesh Komuravelli, Nikolaj Bjørner, Arie Gurfinkel, Kenneth L. McMillan:
Compositional Verification of Procedural Programs using Horn Clauses over Integers and Arrays. FMCAD 2015: 89-96

Nikolaj Bjørner, Arie Gurfinkel:
Property Directed Polyhedral Abstraction. VMCAI 2015: 263-281

Anvesh Komuravelli, Arie Gurfinkel, Sagar Chaki:
SMT-Based Model Checking for Recursive Programs. CAV 2014: 17-34

src/muz/spacer/spacer_marshal.cpp

@@ -0,0 +1,55 @@
+/*++
+Copyright (c) 2017 Arie Gurfinkel
+Module Name:
+
+   spacer_marshal.cpp
+
+Abstract:
+
+   marshaling and unmarshaling of expressions
+
+   --*/
+#include "spacer_marshal.h"
+
+#include <sstream>
+#include "cmd_context.h"
+#include "smt2parser.h"
+#include "vector.h"
+#include "ast_smt_pp.h"
+#include "ast_pp.h"
+
+namespace spacer {
+std::ostream &marshal(std::ostream &os, expr_ref e, ast_manager &m)
+{
+    ast_smt_pp pp(m);
+    pp.display_smt2(os, e);
+    return os;
+}
+
+std::string marshal(expr_ref e, ast_manager &m)
+{
+    std::stringstream ss;
+    marshal(ss, e, m);
+    return ss.str();
+}
+
+
+expr_ref unmarshal(std::istream &is, ast_manager &m)
+{
+    cmd_context ctx(false, &m);
+    ctx.set_ignore_check(true);
+    if (!parse_smt2_commands(ctx, is)) { return expr_ref(0, m); }
+
+    ptr_vector<expr>::const_iterator it  = ctx.begin_assertions();
+    ptr_vector<expr>::const_iterator end = ctx.end_assertions();
+    if (it == end) { return expr_ref(m.mk_true(), m); }
+    unsigned size = static_cast<unsigned>(end - it);
+    return expr_ref(m.mk_and(size, it), m);
+}
+
+expr_ref unmarshal(std::string s, ast_manager &m)
+{
+    std::istringstream is(s);
+    return unmarshal(is, m);
+}
+}