Niels Lohmann 02d57db31e Do not compare an edited NaN equal to itself in json_view (#6085) ...

Two views compared equal when the tokens of two floats were equal, and
the same node was equal to itself. An edit writes a NaN as the token
"nan", so a view of it (or of an array holding it) was equal to itself
and to another NaN, while json(NaN) == json(NaN) and view == json are
false. The token shortcut now excludes the edited "nan" token (found by
the missing digit layout), dispatched on the document mode by a tag: a
read-only document cannot hold a NaN, and its walk is unchanged
(instruction count and cycles on canada, citm and twitter within
noise). For editable documents the check costs about 2 % instructions
on canada (cycles within noise). The same-node shortcut is kept for
read-only documents and for editable ones that were never edited; a
document with edits is walked, so comparing it with itself is linear
instead of constant.

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

2026-11-11 22:36:54 +01:00

..

nlohmann

Do not compare an edited NaN equal to itself in json_view (#6085)

2026-11-11 22:36:54 +01:00