avformat/dump: Avoid unnecessary implicit calculation of strlen

av_strlcpy() returns the length of the src string to enable
the caller to check for truncation. It is currently used in
the following way in dump_metadata(): Every metadata value
is searched for \b, \n, \v, \f, \r and then the data up to
the first of these characters found is copied to a small
temporary buffer via av_strlcpy() (but of course not more
than fits into said buffer) and then printed; all characters up
to the character found earlier are then treated as consumed.

But this is bad performance-wise if the while string is big
and contains many of these characters, because av_strlcpy()
will unnecessarily calculate the length of the whole remaining string.
(dump_metadata() actually ignored the return value of av_strlcpy().)

Fix this by not copying the data to a temporary buffer at all.
Instead just use %.*s to bound the number of characters output.

Reviewed-by: Paul B Mahol <[email protected]>
Signed-off-by: Andreas Rheinhardt <[email protected]>

0 files changed, 0 insertions, 0 deletions