Claude 2992ca9f08 Stop dump() from heap-allocating its output adapter per call ...

The serializer held its output sink as output_adapter_t<char>
(a std::shared_ptr<output_adapter_protocol<char>>), which dump() and
operator<< built via make_shared -- one heap allocation per call for a
sink that only wraps a reference to the caller's string or stream.

Hold the sink as a non-owning output_adapter_protocol<char>* instead and
construct the concrete adapter on the stack at the call site. The write
path (o->write_characters) is unchanged, so output is byte-for-byte
identical; a compact dump() of a small object drops from 2 heap
allocations to 1 (only the returned string remains), ~3% faster.

Completes the per-call allocation cleanup on this branch, which already
removed the indent_string buffer (both were reported in #5413).

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01L1oJ2ggRHS37zeVe94QTA1
Signed-off-by: Claude <noreply@anthropic.com>

2026-08-31 23:25:06 +02:00

..

nlohmann

Stop dump() from heap-allocating its output adapter per call

2026-08-31 23:25:06 +02:00