diff options
| -rw-r--r-- | src/libexpr/primops.cc | 22 |
1 files changed, 15 insertions, 7 deletions
diff --git a/src/libexpr/primops.cc b/src/libexpr/primops.cc index aea2a34354bc..9b4751970167 100644 --- a/src/libexpr/primops.cc +++ b/src/libexpr/primops.cc @@ -1651,22 +1651,30 @@ static void prim_concatMap(EvalState & state, const Pos & pos, Value * * args, V { state.forceFunction(*args[0], pos); state.forceList(*args[1], pos); - auto len = args[1]->listSize(); + auto nrLists = args[1]->listSize(); - Value vList; - state.mkList(vList, len); + Value lists[nrLists]; + size_t len = 0; - for (unsigned int n = 0; n < len; ++n) { + for (unsigned int n = 0; n < nrLists; ++n) { Value * vElem = args[1]->listElems()[n]; state.forceValue(*vElem); - state.callFunction(*args[0], *vElem, *(vList.listElems()[n] = state.allocValue()), pos); + state.callFunction(*args[0], *vElem, lists[n], pos); + state.forceList(lists[n], pos); + len += lists[n].listSize(); } - state.concatLists(v, len, vList.listElems(), pos); + state.mkList(v, len); + auto out = v.listElems(); + for (unsigned int n = 0, pos = 0; n < nrLists; ++n) { + auto l = lists[n].listSize(); + if (l) + memcpy(out + pos, lists[n].listElems(), l * sizeof(Value *)); + pos += l; + } } - /************************************************************* * Integer arithmetic *************************************************************/ |