test-convenience failed (macOS finished first; the failure is
platform-independent) because check_escaped() calls the internal
serializer::dump_escaped() directly and then reads the output stream.
Since dump_escaped() now writes into the serializer's internal write
buffer, the bytes were still buffered and the stream was empty.
Expose flush() under JSON_PRIVATE_UNLESS_TESTED (same visibility as
dump_escaped) and flush in check_escaped() before inspecting the output.
Per-string flushing inside dump_escaped() was rejected on purpose: it
would defeat the buffering that makes object/array-heavy dumps faster.
Library behavior is unchanged (flush()'s body is identical; only its
access label moved).
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01XAYM1qhSA2FDaDcGfPW3fG
Signed-off-by: Niels Lohmann <mail@nlohmann.me>
* Replace snprintf with a branch-free writer for \uXXXX escapes
dump_escaped called std::snprintf(..., "\u%04x", ...) once per escaped
code point in the string serialization hot path. snprintf re-parses
the format string and pulls in locale/printf machinery on every call,
which is far heavier than the fixed 6-/12-byte output warrants. This
is hot for any string containing control characters, and for all
non-ASCII text when ensure_ascii is set.
Replace it with write_u_escape, a small helper that writes the escape
directly into string_buffer via a nibble-to-hex lookup table, mirroring
the existing hand-rolled dump_integer fast path in the same file.
Signed-off-by: Niels Lohmann <mail@nlohmann.me>
* Fix clang-tidy avoid-c-arrays warning in write_u_escape
Use a const char* rather than a char[] lookup table, matching the
existing hex_bytes helper in the same file.
Signed-off-by: Niels Lohmann <mail@nlohmann.me>
* ♻️ adjust write_u_escape signature
Signed-off-by: Niels Lohmann <mail@nlohmann.me>
---------
Signed-off-by: Niels Lohmann <mail@nlohmann.me>
Niels LohmannandClaude Opus 4.8
