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 just not copying the data in a temporary buffer at all.
Instead just use the %.*s to bound the number of characters output.
Signed-off-by: Andreas Rheinhardt <andreas.rheinha...@outlook.com>
---
libavformat/dump.c | 4 +---
1 file changed, 1 insertion(+), 3 deletions(-)
diff --git a/libavformat/dump.c b/libavformat/dump.c
index e3f0056c20..cafcef36c6 100644
--- a/libavformat/dump.c
+++ b/libavformat/dump.c
@@ -145,10 +145,8 @@ static void dump_metadata(void *ctx, const AVDictionary
*m, const char *indent)
av_log(ctx, AV_LOG_INFO,
"%s %-16s: ", indent, tag->key);
while (*p) {
- char tmp[256];
size_t len = strcspn(p, "\x8\xa\xb\xc\xd");
- av_strlcpy(tmp, p, FFMIN(sizeof(tmp), len+1));
- av_log(ctx, AV_LOG_INFO, "%s", tmp);
+ av_log(ctx, AV_LOG_INFO, "%.*s", (int)(FFMIN(255, len)),
p);
p += len;
if (*p == 0xd) av_log(ctx, AV_LOG_INFO, " ");
if (*p == 0xa) av_log(ctx, AV_LOG_INFO, "\n%s %-16s: ",
indent, "");
--
2.34.1
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