From f37f4de8496556afaa024e39e2efb433eb1680d4 Mon Sep 17 00:00:00 2001 From: wm4 Date: Wed, 6 Nov 2019 21:36:02 +0100 Subject: stream: turn into a ring buffer, make size configurable In some corner cases (see #6802), it can be beneficial to use a larger stream buffer size. Use this as argument to rewrite everything for no reason. Turn stream.c itself into a ring buffer, with configurable size. The latter would have been easily achievable with minimal changes, and the ring buffer is the hard part. There is no reason to have a ring buffer at all, except possibly if ffmpeg don't fix their awful mp4 demuxer, and some subtle issues with demux_mkv.c wanting to seek back by small offsets (the latter was handled with small stream_peek() calls, which are unneeded now). In addition, this turns small forward seeks into reads (where data is simply skipped). Before this commit, only stream_skip() did this (which also mean that stream_skip() simply calls stream_seek() now). Replace all stream_peek() calls with something else (usually stream_read_peek()). The function was a problem, because it returned a pointer to the internal buffer, which is now a ring buffer with wrapping. The new function just copies the data into a buffer, and in some cases requires callers to dynamically allocate memory. (The most common case, demux_lavf.c, required a separate buffer allocation anyway due to FFmpeg "idiosyncrasies".) This is the bulk of the demuxer_* changes. I'm not happy with this. There still isn't a good reason why there should be a ring buffer, that is complex, and most of the time just wastes half of the available memory. Maybe another rewrite soon. It also contains bugs; you're an alpha tester now. --- demux/demux_libarchive.c | 8 +++++--- 1 file changed, 5 insertions(+), 3 deletions(-) (limited to 'demux/demux_libarchive.c') diff --git a/demux/demux_libarchive.c b/demux/demux_libarchive.c index 3540082179..bb2ca24862 100644 --- a/demux/demux_libarchive.c +++ b/demux/demux_libarchive.c @@ -43,15 +43,17 @@ static int open_file(struct demuxer *demuxer, enum demux_check check) probe_size *= 100; } - bstr probe = stream_peek(demuxer->stream, probe_size); - if (probe.len == 0) + void *probe = ta_alloc_size(NULL, probe_size); + if (!probe) return -1; + int probe_got = stream_read_peek(demuxer->stream, probe, probe_size); struct stream *probe_stream = - stream_memory_open(demuxer->global, probe.start, probe.len); + stream_memory_open(demuxer->global, probe, probe_got); struct mp_archive *mpa = mp_archive_new(mp_null_log, probe_stream, flags); bool ok = !!mpa; free_stream(probe_stream); mp_archive_free(mpa); + ta_free(probe); if (!ok) return -1; -- cgit v1.2.3