json/include/nlohmann/detail/input at 284ef38125d869e6fed7e505b697d29333694bc7 - json

amorfo77/json

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Niels Lohmann 284ef38125 Do not convert floats that cannot overflow in accept()

accept() only has to find out whether a float token is finite: json_sax_acceptor
ignores the value, and the parser rejects only a float that overflows. A
float whose digits fit into 19 digits and whose decimal exponent is at most
max_exponent10 - 19 is below 10^max_exponent10 and cannot overflow, so the
lexer, told by accept() that the value is not needed, skips the conversion
for those. A token that may overflow, with more digits, or in another float
format is converted as before, so 1e309 and its neighbours are rejected as
they were (the new test compares accept() with parse() on tokens around the
limit).

json::accept(): canada.json Ir -8.6 % (GCC) / -10.9 % (Clang), 124-byte
object -3.2 %; cycles on the M1 (release benchmarks, LTO): canada -7.8 %,
floats.json -9.0 %. The check tests the accept() flag first, so the parser
that needs the value pays one load and branch: SaxParse canada +0.35 % Ir
(GCC and Clang), DOM canada +0.4 %.

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

2026-10-22 09:28:05 +02:00

binary_reader.hpp

Build arrays of the DOM parser in one exact-size allocation

2026-10-22 09:27:51 +02:00

input_adapters.hpp

Read FILE* input with std::fgetc under MemorySanitizer (#5874 )

2026-10-21 10:22:50 +02:00

json_sax.hpp

Trim the work the DOM parser does per container and per member

2026-10-22 09:28:00 +02:00

lexer.hpp

Do not convert floats that cannot overflow in accept()