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Optimize small lists

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The value pointers of lists with 1 or 2 elements are now stored in the
list value itself. In particular, this makes the "concatMap (x: if
cond then [(f x)] else [])" idiom cheaper.
This commit is contained in:
Eelco Dolstra 2015-07-23 22:05:09 +02:00
parent 14be783676
commit b83801f8b3
11 changed files with 157 additions and 121 deletions
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8
src/nix-env/nix-env.cc
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@ -1127,13 +1127,13 @@ static void opQuery(Globals & globals, Strings opFlags, Strings opArgs)
attrs2["type"] = "bool";
attrs2["value"] = v->boolean ? "true" : "false";
xml.writeEmptyElement("meta", attrs2);
} else if (v->type == tList) {
} else if (v->isList()) {
attrs2["type"] = "strings";
XMLOpenElement m(xml, "meta", attrs2);
for (unsigned int j = 0; j < v->list.length; ++j) {
if (v->list.elems[j]->type != tString) continue;
for (unsigned int j = 0; j < v->listSize(); ++j) {
if (v->listElems()[j]->type != tString) continue;
XMLAttrs attrs3;
attrs3["value"] = v->list.elems[j]->string.s;
attrs3["value"] = v->listElems()[j]->string.s;
xml.writeEmptyElement("string", attrs3);
}
}