dmime: Parse MIDI headers.

dlls/dmime/Makefile.in

@@ -10,6 +10,7 @@ SOURCES = \
 	graph.c \
 	lyricstrack.c \
 	markertrack.c \
+	midi.c \
 	paramcontroltrack.c \
 	performance.c \
 	segment.c \

dlls/dmime/dmime_private.h

@@ -48,6 +48,7 @@
  * Interfaces
  */
 typedef struct IDirectMusicAudioPathImpl IDirectMusicAudioPathImpl;
+struct midi_parser;
 
 /*****************************************************************************
  * ClassFactory
@@ -69,6 +70,12 @@ extern HRESULT create_dmtempotrack(REFIID riid, void **ret_iface);
 extern HRESULT create_dmtimesigtrack(REFIID riid, void **ret_iface);
 extern HRESULT create_dmwavetrack(REFIID riid, void **ret_iface);
 
+/* Create a new MIDI file parser. Note the stream might still be modified even
+ * when this function fails. */
+extern HRESULT midi_parser_new(IStream *stream, struct midi_parser **out_parser);
+extern HRESULT midi_parser_next_track(struct midi_parser *parser, IDirectMusicTrack **out_track, MUSIC_TIME *out_length);
+extern void midi_parser_destroy(struct midi_parser *parser);
+
 extern void set_audiopath_perf_pointer(IDirectMusicAudioPath*,IDirectMusicPerformance8*);
 extern void set_audiopath_dsound_buffer(IDirectMusicAudioPath*,IDirectSoundBuffer*);
 extern void set_audiopath_primary_dsound_buffer(IDirectMusicAudioPath*,IDirectSoundBuffer*);

dlls/dmime/midi.c

+/*
+ * Copyright (C) 2024 Yuxuan Shui for CodeWeavers
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA
+ */
+
+#include "dmime_private.h"
+#include "winternl.h"
+
+WINE_DEFAULT_DEBUG_CHANNEL(dmime);
+
+#ifdef WORDS_BIGENDIAN
+#define GET_BE_WORD(x) (x)
+#define GET_BE_DWORD(x) (x)
+#else
+#define GET_BE_WORD(x) RtlUshortByteSwap(x)
+#define GET_BE_DWORD(x) RtlUlongByteSwap(x)
+#endif
+
+struct midi_parser
+{
+    IStream *stream;
+};
+
+HRESULT midi_parser_next_track(struct midi_parser *parser, IDirectMusicTrack **out_track, MUSIC_TIME *out_length)
+{
+    TRACE("(%p, %p, %p): stub\n", parser, out_track, out_length);
+    return S_FALSE;
+}
+
+HRESULT midi_parser_new(IStream *stream, struct midi_parser **out_parser)
+{
+    LARGE_INTEGER offset;
+    DWORD length;
+    HRESULT hr;
+    WORD format, number_of_tracks, division;
+    struct midi_parser *parser;
+
+    *out_parser = NULL;
+
+    /* Skip over the 'MThd' magic number. */
+    offset.QuadPart = 4;
+    if (FAILED(hr = IStream_Seek(stream, offset, STREAM_SEEK_SET, NULL))) return hr;
+
+    if (FAILED(hr = IStream_Read(stream, &length, sizeof(length), NULL))) return hr;
+    length = GET_BE_DWORD(length);
+    if (length != 6)
+    {
+        WARN("Invalid MIDI header length %lu\n", length);
+        return DMUS_E_UNSUPPORTED_STREAM;
+    }
+
+    if (FAILED(hr = IStream_Read(stream, &format, sizeof(format), NULL))) return hr;
+    format = GET_BE_WORD(format);
+    if (format > 2)
+    {
+        WARN("Invalid MIDI format %u\n", format);
+        return DMUS_E_UNSUPPORTED_STREAM;
+    }
+    if (format == 2)
+    {
+        FIXME("MIDI format 2 not implemented yet\n");
+        return DMUS_E_UNSUPPORTED_STREAM;
+    }
+
+    if (FAILED(hr = IStream_Read(stream, &number_of_tracks, sizeof(number_of_tracks), NULL)))
+        return hr;
+
+    number_of_tracks = GET_BE_WORD(number_of_tracks);
+    if (FAILED(hr = IStream_Read(stream, &division, sizeof(division), NULL))) return hr;
+    division = GET_BE_WORD(division);
+    if (division & 0x8000)
+    {
+        WARN("SMPTE time division not implemented yet\n");
+        return DMUS_E_UNSUPPORTED_STREAM;
+    }
+
+    TRACE("MIDI format %u, %u tracks, division %u\n", format, number_of_tracks, division);
+
+    parser = calloc(1, sizeof(struct midi_parser));
+    if (!parser) return E_OUTOFMEMORY;
+    parser->stream = stream;
+    IStream_AddRef(stream);
+    *out_parser = parser;
+
+    return hr;
+}
+
+void midi_parser_destroy(struct midi_parser *parser)
+{
+    IStream_Release(parser->stream);
+    free(parser);
+}

dlls/dmime/segment.c

@@ -791,7 +791,10 @@ static inline struct segment *impl_from_IPersistStream(IPersistStream *iface)
 static HRESULT WINAPI segment_persist_stream_Load(IPersistStream *iface, IStream *stream)
 {
     struct segment *This = impl_from_IPersistStream(iface);
+    IDirectMusicTrack *track;
+    MUSIC_TIME length;
     struct chunk_entry chunk = {0};
+    struct midi_parser *midi_parser;
     HRESULT hr;
 
     TRACE("(%p, %p): Loading\n", This, stream);
@@ -807,7 +810,18 @@ static HRESULT WINAPI segment_persist_stream_Load(IPersistStream *iface, IStream
             break;
 
         case mmioFOURCC('M','T','h','d'):
-            FIXME("MIDI file loading not supported\n");
+            hr = midi_parser_new(stream, &midi_parser);
+            if (FAILED(hr)) break;
+            This->header.mtLength = 0;
+            while ((hr = midi_parser_next_track(midi_parser, &track, &length)) == S_OK)
+            {
+                hr = segment_append_track(This, track, 1, 0);
+                IDirectMusicTrack_Release(track);
+                if (FAILED(hr)) break;
+                if (length > This->header.mtLength)
+                    This->header.mtLength = length;
+            }
+            midi_parser_destroy(midi_parser);
             break;
 
         case MAKE_IDTYPE(FOURCC_RIFF, mmioFOURCC('W','A','V','E')):