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Niels Lohmann
366f3d26e5
* 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>