2 files changed, 22 insertions, 0 deletions
diff --git a/common/idstringlist.cc b/common/idstringlist.cc
index 9900f92a..6f6f8cd0 100644
--- a/common/idstringlist.cc
+++ b/common/idstringlist.cc
@@ -58,4 +58,23 @@ std::string IdStringList::str(const Context *ctx) const
     return s;
 }
 
+IdStringList IdStringList::concat(IdStringList a, IdStringList b)
+{
+    IdStringList result(a.size() + b.size());
+    for (size_t i = 0; i < a.size(); i++)
+        result.ids[i] = a[i];
+    for (size_t i = 0; i < b.size(); i++)
+        result.ids[a.size() + i] = b[i];
+    return result;
+}
+
+IdStringList IdStringList::slice(size_t s, size_t e) const
+{
+    NPNR_ASSERT(e >= s);
+    IdStringList result(e - s);
+    for (size_t i = 0; i < result.size(); i++)
+        result.ids[i] = ids[s + i];
+    return result;
+}
+
 NEXTPNR_NAMESPACE_END
diff --git a/common/idstringlist.h b/common/idstringlist.h
index 6a6a554d..24a46731 100644
--- a/common/idstringlist.h
+++ b/common/idstringlist.h
@@ -64,6 +64,9 @@ struct IdStringList
         }
         return false;
     }
+
+    static IdStringList concat(IdStringList a, IdStringList b);
+    IdStringList slice(size_t s, size_t e) const;
 };
 
 NEXTPNR_NAMESPACE_END