Niels Lohmann 0299efb761 Escape characters below 0x60 from a table straight into the write buffer ...

When the bulk scanner in dump_escaped_impl() stops at a control
character, a quote or a backslash, that byte used to go through the
UTF-8 decoder and a switch that wrote the escape byte by byte into
string_buffer, which was then copied into write_buffer at the next run.

A byte below 0x60 at a character boundary is a complete code point, so
it now skips the decoder: its escape sequence comes from a 96-entry
table of 8-byte rows (sequence padded with zeros, length in the last
byte), and all 8 bytes are copied straight into write_buffer with one
room check. The check sits inside the existing character-boundary
block, so it runs once per scanner stop and not once per byte; testing
every byte cost about 6% on twitter.json with ensure_ascii.

The switch in the decoder's accept branch lost its cases for
characters below 0x60, which can no longer reach it.

Output is byte-identical. The string-buffer boundary tests now use
\u-escaped non-ASCII characters, since simple escapes no longer reach
string_buffer, and a new test case checks every ASCII character at
every position against a reference escaper.

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

2026-10-14 09:16:40 +02:00

..

binary_writer.hpp

Stop the BON8 writer overflowing the stack on deep values (#5806)

2026-10-11 08:24:35 +02:00

error_handler.hpp

Add an error_handler parameter for UTF-8 to the binary readers and writers (#5746)

2026-10-04 12:13:49 +02:00

output_adapters.hpp

Fix lint debt: enum-macro NOLINTs, doctest as SYSTEM, no-op analyzer (#5737)

2026-10-01 07:37:47 +02:00

serializer.hpp

Escape characters below 0x60 from a table straight into the write buffer

2026-10-14 09:16:40 +02:00