Niels Lohmann a1e91474a8 Split the write-buffer helpers and write indentation directly ...

Follow-up to @gregmarr's review: put_chars() was doing four unrelated jobs, so
give the two that can be made safe their own entry points.

- put_literal(): takes the literal by reference and deduces the length from the
  array bound, so the 27 hand-counted lengths at the call sites can no longer
  drift from the literals they describe. A literal is checked at compile time to
  fit the buffer, so this path needs no write-through branch.

- put_buffer(): takes the fixed-size buffer itself rather than a bare pointer,
  so the length can be checked against the buffer's own bound.

- put_indent(): memsets the indentation into the write buffer, filling and
  flushing it as needed. This removes indent_string entirely, and with it both
  bugs of #5186: the indentation string was grown by doubling, which is not
  enough when indent_step more than doubles it (a heap over-read - dump(2000)
  read 2000 bytes out of a 1024-byte string), and the grown part was filled with
  a space instead of the configured indent_char. next_indent() keeps that PR's
  assertion against the unsigned indentation accumulation wrapping on deep
  nesting.

put_chars() keeps the two cases that are genuinely a pointer and a count: the
run-length copies out of the string being escaped, and to_chars() output.

Tests cover an indent_step wider than the write buffer, a non-space indentation
character past the old growth point, and nesting whose accumulated indentation
spans several buffer-fulls. All three fail against develop.

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

2026-08-19 22:43:17 +02:00

..

nlohmann

Split the write-buffer helpers and write indentation directly

2026-08-19 22:43:17 +02:00