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Allow reading future data without read-commit

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This is in preparation for de-click, fade-out. A disk-reader
can keep going, reading buffered data (if any) without changing the
read-index.
This commit is contained in:
Robin Gareus 2019-02-07 01:30:43 +01:00
parent 243412d930
commit 3c96ba1de6
Signed by: rgareus
GPG Key ID: A090BCE02CF57F04
1 changed files with 12 additions and 3 deletions
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15
libs/pbd/pbd/playback_buffer.h
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@ -111,7 +111,7 @@ public:
}
/* read-thead */
guint read (T *dest, guint cnt, bool commit = true);
guint read (T *dest, guint cnt, bool commit = true, guint offset = 0);
/* write-thead */
guint write (T const * src, guint cnt);
@ -254,7 +254,7 @@ PlaybackBuffer<T>::write_zero (guint cnt)
}
template<class T> /*LIBPBD_API*/ guint
PlaybackBuffer<T>::read (T *dest, guint cnt, bool commit)
PlaybackBuffer<T>::read (T *dest, guint cnt, bool commit, guint offset)
{
Glib::Threads::Mutex::Lock lm (_reset_lock, Glib::Threads::TRY_LOCK);
if (!lm.locked ()) {
@ -265,7 +265,16 @@ PlaybackBuffer<T>::read (T *dest, guint cnt, bool commit)
guint r = g_atomic_int_get (&read_idx);
const guint w = g_atomic_int_get (&write_idx);
const guint free_cnt = (w > r) ? (w - r) : ((w - r + size) & size_mask);
guint free_cnt = (w > r) ? (w - r) : ((w - r + size) & size_mask);
if (!commit && offset > 0) {
if (offset > free_cnt) {
return 0;
}
free_cnt -= offset;
r = (r + offset) & size_mask;
}
const guint to_read = cnt > free_cnt ? free_cnt : cnt;
const guint cnt2 = r + to_read;