From 96a123200190782c35a3f7349a4ed5118d91823a Mon Sep 17 00:00:00 2001
From: Ivan Mogilko <ikm_spb@yahoo.com>
Date: Sat, 18 Feb 2017 21:12:13 +0300
Subject: [PATCH] Engine: implemented load_midi_pf - something that Allegro 4
 should have

---
 Engine/libsrc/allegro-4.2.2-agspatch/midi.c | 98 +++++++++++++++++++++
 Engine/media/audio/sound.cpp                | 13 ++-
 Solutions/Engine.App/Engine.App.vcproj      |  4 +
 3 files changed, 114 insertions(+), 1 deletion(-)
 create mode 100644 Engine/libsrc/allegro-4.2.2-agspatch/midi.c

diff --git a/Engine/libsrc/allegro-4.2.2-agspatch/midi.c b/Engine/libsrc/allegro-4.2.2-agspatch/midi.c
new file mode 100644
index 0000000000..06337811f2
--- /dev/null
+++ b/Engine/libsrc/allegro-4.2.2-agspatch/midi.c
@@ -0,0 +1,98 @@
+//
+// Unfortunately, as of now Allegro 4 does not have a variant of MIDI
+// constructor that takes PACKFILE stream as parameter. Hence our own
+// version. This should be removed when either Allegro 4 gets patched
+// or we switch to another backend library.
+//
+// Much of the code is plain copied from load_midi Allegro's function.
+//
+
+#include <allegro.h>
+#include <allegro/internal/aintern.h>
+
+/* load_midi_pf:
+ *  Reads a standard MIDI file from the packfile given, returning a MIDI
+ *  structure, or NULL on error.
+ *
+ *  If unsuccessful the offset into the file is unspecified, i.e. you must
+ *  either reset the offset to some known place or close the packfile. The
+ *  packfile is not closed by this function.
+ */
+MIDI *load_midi_pf(PACKFILE *fp)
+{
+   int c;
+   char buf[4];
+   long data;
+   MIDI *midi;
+   int num_tracks;
+   ASSERT(fp);
+
+   midi = _AL_MALLOC(sizeof(MIDI));              /* get some memory */
+   if (!midi)
+      return NULL;
+
+   for (c=0; c<MIDI_TRACKS; c++) {
+      midi->track[c].data = NULL;
+      midi->track[c].len = 0;
+   }
+
+   pack_fread(buf, 4, fp); /* read midi header */
+
+   /* Is the midi inside a .rmi file? */
+   if (memcmp(buf, "RIFF", 4) == 0) { /* check for RIFF header */
+      pack_mgetl(fp);
+
+      while (!pack_feof(fp)) {
+         pack_fread(buf, 4, fp); /* RMID chunk? */
+         if (memcmp(buf, "RMID", 4) == 0) break;
+
+         pack_fseek(fp, pack_igetl(fp)); /* skip to next chunk */
+      }
+
+      if (pack_feof(fp)) goto err;
+
+      pack_mgetl(fp);
+      pack_mgetl(fp);
+      pack_fread(buf, 4, fp); /* read midi header */
+   }
+
+   if (memcmp(buf, "MThd", 4))
+      goto err;
+
+   pack_mgetl(fp);                           /* skip header chunk length */
+
+   data = pack_mgetw(fp);                    /* MIDI file type */
+   if ((data != 0) && (data != 1))
+      goto err;
+
+   num_tracks = pack_mgetw(fp);              /* number of tracks */
+   if ((num_tracks < 1) || (num_tracks > MIDI_TRACKS))
+      goto err;
+
+   data = pack_mgetw(fp);                    /* beat divisions */
+   midi->divisions = ABS(data);
+
+   for (c=0; c<num_tracks; c++) {            /* read each track */
+      pack_fread(buf, 4, fp);                /* read track header */
+      if (memcmp(buf, "MTrk", 4))
+	 goto err;
+
+      data = pack_mgetl(fp);                 /* length of track chunk */
+      midi->track[c].len = data;
+
+      midi->track[c].data = _AL_MALLOC_ATOMIC(data); /* allocate memory */
+      if (!midi->track[c].data)
+	 goto err;
+					     /* finally, read track data */
+      if (pack_fread(midi->track[c].data, data, fp) != data)
+	 goto err;
+   }
+
+   lock_midi(midi);
+   return midi;
+
+   /* oh dear... */
+   err:
+   destroy_midi(midi);
+   return NULL;
+}
diff --git a/Engine/media/audio/sound.cpp b/Engine/media/audio/sound.cpp
index 577e152f5b..59fda8ba22 100644
--- a/Engine/media/audio/sound.cpp
+++ b/Engine/media/audio/sound.cpp
@@ -46,6 +46,12 @@
 #error Either JGMOD_MOD_PLAYER or DUMB_MOD_PLAYER should be defined.
 #endif
 
+extern "C"
+{
+// Load MIDI from PACKFILE stream
+MIDI *load_midi_pf(PACKFILE *pf);
+}
+
 int numSoundChannels = 8;
 
 
@@ -254,7 +260,12 @@ SOUNDCLIP *my_load_midi(const AssetPath &asset_name, int repet)
     if (!thismidi && psp_midi_preload_patches)
         load_midi_patches();
 
-    MIDI* midiPtr = load_midi(asset_name.second);
+    PACKFILE *pf = PackfileFromAsset(asset_name);
+    if (!pf)
+        return NULL;
+
+    MIDI* midiPtr = load_midi_pf(pf);
+    pack_fclose(pf);
 
     if (midiPtr == NULL)
         return NULL;
diff --git a/Solutions/Engine.App/Engine.App.vcproj b/Solutions/Engine.App/Engine.App.vcproj
index 5effadc4b9..8646bbe2bf 100644
--- a/Solutions/Engine.App/Engine.App.vcproj
+++ b/Solutions/Engine.App/Engine.App.vcproj
@@ -2331,6 +2331,10 @@
 					RelativePath="..\..\Engine\libsrc\allegro-4.2.2-agspatch\c\cstretch.c"
 					>
 				</File>
+				<File
+					RelativePath="..\..\Engine\libsrc\allegro-4.2.2-agspatch\midi.c"
+					>
+				</File>
 				<File
 					RelativePath="..\..\Engine\libsrc\allegro-4.2.2-agspatch\win\wkeybd.c"
 					>