Niels Lohmann c8b380769c Index arrays without subtrees directly ...

operator[](idx), at(idx) and back() skipped the elements of an array one
after the other, whatever they were. In an array none of whose elements is
an array or object (numbers, strings, booleans, null) the elements are
adjacent nodes, which the array node's own sizes tell: its subtree has
exactly one node more than it has elements. Such an element is now the
node idx after the array node; any other array is walked as before.

Reading r[i] for every i of an array of 3000 integers:
  Apple M1: 28.8 M instructions, 3.1 ms -> 0.1 M instructions, 4 us
  Linux x86-64 Ir (whole run), GCC 13 / Clang 18: 84.1 M -> 3.1 M / 75.0 M -> 3.0 M
Arrays that contain arrays are unchanged.

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

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

2026-10-22 09:30:12 +02:00

..

conversions

Use standard library helpers where available, with C++11 fallbacks (#5876)

2026-10-21 20:14:59 +02:00

input

Use standard library helpers where available, with C++11 fallbacks (#5876)

2026-10-21 20:14:59 +02:00

iterators

Fix CI failures on develop from the API performance stack (#5860)

2026-10-16 19:16:21 +02:00

meta

Use standard library helpers where available, with C++11 fallbacks (#5876)

2026-10-21 20:14:59 +02:00

output

Use standard library helpers where available, with C++11 fallbacks (#5876)

2026-10-21 20:14:59 +02:00

view

Index arrays without subtrees directly

2026-10-22 09:30:12 +02:00

abi_config.hpp

Add json_document and json_view: node index, parser, and document (#5620)

2026-10-21 10:21:27 +02:00

abi_macros.hpp

Scan strings with SSE2, SSSE3, or NEON (#5853)

2026-10-21 20:00:50 +02:00

bit_ops.hpp

Use standard library helpers where available, with C++11 fallbacks (#5876)

2026-10-21 20:14:59 +02:00

exceptions.hpp

Fix CI failures on develop from the API performance stack (#5860)

2026-10-16 19:16:21 +02:00

hash.hpp

Make std::hash<basic_json> consistent with operator== for numbers (#5772)

2026-10-07 19:18:51 +02:00

json_custom_base_class.hpp

Fix ADL leak of nlohmann::detail through basic_json's default base class (#5238)

2026-07-06 12:47:24 +02:00

json_pointer.hpp

Speed up flatten(), unflatten(), diff() and patch() (#5861)

2026-10-21 21:27:33 +02:00

json_ref.hpp

Copy a pair-shaped array value under JSON_BRACE_INIT_COPY_SEMANTICS (#5701)

2026-10-07 07:39:05 +02:00

macro_scope.hpp

Silence macro-to-enum for the endianness macros (#5881)

2026-10-22 08:40:05 +02:00

macro_unscope.hpp

Use standard library helpers where available, with C++11 fallbacks (#5876)

2026-10-21 20:14:59 +02:00

recursion_depth_limit.hpp

Share one nesting depth limit between all bounded descents (#5637)

2026-09-30 20:06:43 +02:00

string_concat.hpp

Deduplicate basic_json internals; make insert(pos, json&&) move (#5727)

2026-10-04 11:57:41 +02:00

string_escape.hpp

Fix compiler warnings on develop from the API performance stack (#5858)

2026-10-15 22:42:46 +02:00

string_utils.hpp

Make UTF8_ACCEPT/UTF8_REJECT inline variables to avoid TU-local exposure in modules (#5797)

2026-10-09 23:38:42 +02:00

value_t.hpp

Fix silent wrong results for custom number types (#5805)

2026-10-21 08:36:31 +00:00