Niels Lohmann 78460d239b Materialize scalars directly and keep the stack of small subtrees local ...

basic_json_view::materialize() (and get<BasicJsonType>()) always set up the
SAX handler that parse() uses and a std::vector for the open containers,
sized from the document's deepest nesting. For a scalar, which is most of what
is materialized one value at a time, neither is needed: the value is made
directly (the same constructors the handler ends up calling). For arrays and
objects the stack of open containers is now a local array for the first 16
levels, and the vector is only used for deeper documents.

Materializing five scalars of a small document, Apple M1: 3.6 K -> 0.9 K instructions
  Linux x86-64 Ir (500 rounds), GCC 13 / Clang 18: 2.96 M -> 2.37 M / 2.90 M -> 2.29 M

Belongs to the PR "json_view: read-side speedups".

Signed-off-by: Niels Lohmann <mail@nlohmann.me>

2026-10-22 09:30:22 +02:00

..

nlohmann

Materialize scalars directly and keep the stack of small subtrees local

2026-10-22 09:30:22 +02:00