Patrick Steinhardt 522cc87fdc utf8: fix truncated string lengths in utf8_strnwidth() ...

The `utf8_strnwidth()` function accepts an optional string length as
input parameter. This parameter can either be set to `-1`, in which case
we call `strlen()` on the input. Or it can be set to a positive integer
that indicates a precomputed length, which callers typically compute by
calling `strlen()` at some point themselves.

The input parameter is an `int` though, whereas `strlen()` returns a
`size_t`. This can lead to implementation-defined behaviour though when
the `size_t` cannot be represented by the `int`. In the general case
though this leads to wrap-around and thus to negative string sizes,
which is sure enough to not lead to well-defined behaviour.

Fix this by accepting a `size_t` instead of an `int` as string length.
While this takes away the ability of callers to simply pass in `-1` as
string length, it really is trivial enough to convert them to instead
pass in `strlen()` instead.

Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

2022-12-09 14:26:21 +09:00

9.4 KiB

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