pkg: add pkg_comparator_lookup_by_name().

pkg.c

@@ -689,6 +689,29 @@ pkg_get_comparator(pkg_dependency_t *pkgdep)
 	return "???";
 }
 
+/*
+ * pkg_comparator_lookup_by_name(name)
+ *
+ * look up the appropriate comparator bytecode in the comparator set (defined
+ * above, see pkg_comparator_names and pkg_comparator_impls).
+ *
+ * XXX: on error return PKG_ANY or maybe we should return PKG_CMP_SIZE which
+ * is poisoned?
+ */
+pkg_comparator_t
+pkg_comparator_lookup_by_name(const char *name)
+{
+	const pkg_comparator_name_t *i;
+
+	for (i = pkg_comparator_names; i->compare != PKG_CMP_SIZE; i++)
+	{
+		if (!strcmp(i->name, name))
+			return i->compare;
+	}
+
+	return PKG_ANY;
+}
+
 /*
  * pkg_verify_dependency(pkgdep, flags)
  *

pkg.h

@@ -137,6 +137,7 @@ pkg_t *pkg_verify_dependency(pkg_dependency_t *pkgdep, unsigned int flags, unsig
 const char *pkg_get_comparator(pkg_dependency_t *pkgdep);
 int pkg_cflags(pkg_t *root, pkg_fragment_t **list, int maxdepth, unsigned int flags);
 int pkg_libs(pkg_t *root, pkg_fragment_t **list, int maxdepth, unsigned int flags);
+pkg_comparator_t pkg_comparator_lookup_by_name(const char *name);
 
 /* parse.c */
 pkg_t *pkg_new_from_file(const char *path, FILE *f);