add common lib
diff --git a/libasn1common/asn1_namespace.h b/libasn1common/asn1_namespace.h
new file mode 100644
index 0000000..1ae3d7b
--- /dev/null
+++ b/libasn1common/asn1_namespace.h
@@ -0,0 +1,80 @@
+/*
+ * Structures and prototypes related to parameterization
+ */
+#ifndef ASN1_NAMESPACE_H
+#define ASN1_NAMESPACE_H
+
+struct asn1p_ref_s; /* Forward declaration */
+struct asn1p_expr_s; /* Forward declaration */
+struct asn1p_module_s; /* Forward declaration */
+
+typedef struct asn1_namespace_s {
+ struct asn1_namespace_element_s {
+ enum {
+ NAM_SPACE, /* The whole search space (e.g. Module) */
+ NAM_SYMBOL, /* A particular symbol */
+ } selector;
+ union {
+ struct {
+ struct asn1p_module_s *module;
+ int stop_search; /* This module MUST contain the symbol */
+ } space;
+ struct {
+ struct asn1p_ref_s *opt_governor; /* optional */
+ char *identifier;
+ struct asn1p_expr_s *resolution;
+ } symbol;
+ } u;
+ } *elements;
+ size_t elements_count;
+ size_t elements_size;
+} asn1_namespace_t;
+
+/*
+ * Set callback used to initialize standard namespaces.
+ */
+void asn1_namespace_add_standard_namespaces_callback(
+ void (*)(asn1_namespace_t *));
+
+asn1_namespace_t *asn1_namespace_new(void);
+void asn1_namespace_free(asn1_namespace_t *);
+
+asn1_namespace_t *asn1_namespace_clone(const asn1_namespace_t *);
+
+asn1_namespace_t *asn1_namespace_new_from_module(struct asn1p_module_s *mod, int stop_search);
+
+void asn1_namespace_add_module(asn1_namespace_t *,
+ struct asn1p_module_s *module, int stop_search);
+
+void asn1_namespace_add_symbol(asn1_namespace_t *,
+ struct asn1p_ref_s *opt_governor,
+ const char *identifier,
+ struct asn1p_expr_s *resolved_argument);
+
+/*
+ * Human-readable namespace layout.
+ * Returns a reference to a statically allocated string.
+ */
+const char *asn1_namespace_string(const asn1_namespace_t *);
+
+/*
+ * Create a new namespace by cloning (ns1) and adding (ns2) on top.
+ * Destroys (ns2).
+ */
+asn1_namespace_t *asn1_namespace_new_ND(const asn1_namespace_t *ns1,
+ asn1_namespace_t *ns2);
+
+/*
+ * Introduce and destroy namespace around the given code.
+ * This aids memory management around dynamic namespaces.
+ */
+#define WITH_MODULE_NAMESPACE(mod, ns_var, code) \
+ ({ \
+ struct asn1_namespace_s *ns_var = \
+ asn1_namespace_new_from_module(mod, 1); \
+ typeof(code) ret = code; \
+ asn1_namespace_free(ns_var); \
+ ret; \
+ })
+
+#endif /* ASN1_NAMESPACE_H */