From d2834dca45a153af8fe557572f0228c693308622 Mon Sep 17 00:00:00 2001
From: Niels Martin Hansen <nielsm@aegisub.org>
Date: Sat, 31 Oct 2009 00:54:42 +0000
Subject: [PATCH] Re-integrate r3740 from the 2.1.8 branch to fix the
 DirectSoundPlayer2 buffer locking bug. Updates #1028.

Originally committed to SVN as r3751.
---
 aegisub/src/audio_player_dsound2.cpp | 85 +++++++++++++++++-----------
 1 file changed, 51 insertions(+), 34 deletions(-)

diff --git a/aegisub/src/audio_player_dsound2.cpp b/aegisub/src/audio_player_dsound2.cpp
index ecfe701e9..a2749ba82 100644
--- a/aegisub/src/audio_player_dsound2.cpp
+++ b/aegisub/src/audio_player_dsound2.cpp
@@ -157,36 +157,35 @@ class DirectSoundPlayer2Thread {
 	// Used to signal state-changes to thread
 	HANDLE
 
-		/// DOCME
-		event_start_playback,
+	/// DOCME
+	event_start_playback,
 
-		/// DOCME
-		event_stop_playback,
+	/// DOCME
+	event_stop_playback,
 
-		/// DOCME
-		event_update_end_time,
+	/// DOCME
+	event_update_end_time,
 
-		/// DOCME
-		event_set_volume,
+	/// DOCME
+	event_set_volume,
 
-		/// DOCME
-		event_kill_self;
+	/// DOCME
+	event_kill_self;
 
 	// Thread communicating back
 	HANDLE
 
-		/// DOCME
-		thread_running,
-
-		/// DOCME
-		is_playing,
-
-		/// DOCME
-		error_happened;
-
+	/// DOCME
+	thread_running,
 
 	/// DOCME
-	wxChar *error_message;
+	is_playing,
+
+	/// DOCME
+	error_happened;
+
+	/// DOCME
+	const wxChar *error_message;
 
 	/// DOCME
 	double volume;
@@ -470,28 +469,46 @@ do_fill_buffer:
 				int bytes_needed = (int)play_cursor - (int)buffer_offset;
 				if (bytes_needed < 0) bytes_needed += (int)bufSize;
 
+				// Requesting zero buffer makes Windows cry, and zero buffer seemed to be
+				// a common request on Windows 7. (Maybe related to the new timer coalescing?)
+				// We'll probably get non-zero bytes requested on the next iteration.
+				if (bytes_needed == 0)
+					break;
+
 				DWORD buf1sz, buf2sz;
 				void *buf1, *buf2;
 
+				assert(buffer_offset < bufSize);
+				assert(bytes_needed <= bufSize);
+
 				HRESULT res = bfr->Lock(buffer_offset, bytes_needed, &buf1, &buf1sz, &buf2, &buf2sz, 0);
-				while (FAILED(res)) // yes, while, so I can break out of it without a goto!
+				switch (res)
 				{
-					if (res == DSERR_BUFFERLOST)
+				case DSERR_BUFFERLOST:
+					// Try to regain the buffer
+					// When the buffer was lost the entire contents was lost too, so we have to start over
+					if (SUCCEEDED(bfr->Restore()) &&
+					    SUCCEEDED(bfr->Lock(0, bufSize, &buf1, &buf1sz, &buf2, &buf2sz, 0)) &&
+					    SUCCEEDED(bfr->Play(0, 0, DSBPLAY_LOOPING)))
 					{
-						// Try to regain the buffer
-						// When the buffer was lost the entire contents was lost too, so we have to start over
-						if (SUCCEEDED(bfr->Restore()) &&
-						    SUCCEEDED(bfr->Lock(0, bufSize, &buf1, &buf1sz, &buf2, &buf2sz, 0)) &&
-						    SUCCEEDED(bfr->Play(0, 0, DSBPLAY_LOOPING)))
-						{
-							wxLogDebug(_T("DirectSoundPlayer2: Lost and restored buffer"));
-							break;
-						}
-
-						REPORT_ERROR("Lost buffer and could not restore it.")
+						wxLogDebug(_T("DirectSoundPlayer2: Lost and restored buffer"));
+						break;
 					}
+					REPORT_ERROR("Lost buffer and could not restore it.")
 
-					REPORT_ERROR("Could not lock buffer for filling.")
+				case DSERR_INVALIDPARAM:
+					REPORT_ERROR("Invalid parameters to IDirectSoundBuffer8::Lock().")
+
+				case DSERR_INVALIDCALL:
+					REPORT_ERROR("Invalid call to IDirectSoundBuffer8::Lock().")
+
+				case DSERR_PRIOLEVELNEEDED:
+					REPORT_ERROR("Incorrect priority level set on DirectSoundBuffer8 object.")
+
+				default:
+					if (FAILED(res))
+						REPORT_ERROR("Could not lock audio buffer, unknown error.")
+					break;
 				}
 
 				DWORD bytes_filled = FillAndUnlockBuffers(buf1, buf1sz, buf2, buf2sz, next_input_frame, bfr.obj);