Split jack_host into slv2_simple_jack_host and slv2_host, added MIDI support to slv2_host.

git-svn-id: http://svn.drobilla.net/lad/slv2@251 a436a847-0d15-0410-975c-d299462d15a1

1 files changed, 161 insertions, 0 deletions

diff --git a/examples/hosts/lv2-midifunctions.h b/examples/hosts/lv2-midifunctions.h
new file mode 100644
index 0000000..68691f3
--- /dev/null
+++ b/examples/hosts/lv2-midifunctions.h
@@ -0,0 +1,161 @@
+/****************************************************************************
+    
+    lv2-midifunctions.h - support file for using MIDI in LV2 plugins
+    
+    Copyright (C) 2006  Lars Luthman <lars.luthman@gmail.com>
+    
+    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 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., 59 Temple Place, Suite 330, Boston, MA 01222-1307  USA
+
+****************************************************************************/
+
+#ifndef LV2_MIDIFUNCTIONS
+#define LV2_MIDIFUNCTIONS
+
+#include <string.h>
+
+#include "lv2-miditype.h"
+
+
+/** This structure contains information about a MIDI port buffer, the 
+    current period size, and the position in the MIDI data buffer that
+    we are currently reading from or writing to. It needs to be recreated
+    or at least reinitialised every process() call. */
+typedef struct {
+
+  /** The MIDI port structure that we want to read or write. */
+  LV2_MIDI* midi;
+  
+  /** The number of frames in this process cycle. */
+  uint32_t frame_count;
+  
+  /** The current position in the data buffer. Should be initialised to 0. */
+  uint32_t position;
+
+} LV2_MIDIState;
+
+
+static LV2_MIDI* lv2midi_new(uint32_t capacity)
+{
+	LV2_MIDI* midi = malloc(sizeof(LV2_MIDI));
+
+	midi->event_count = 0;
+	midi->capacity = capacity;
+	midi->size = 0;
+	midi->data = malloc(sizeof(char) * capacity);
+
+	return midi;
+}
+
+
+static void lv2midi_free(LV2_MIDI* midi)
+{
+	free(midi->data);
+	free(midi);
+}
+
+
+static void lv2midi_reset_buffer(LV2_MIDI* midi)
+{
+	midi->event_count = 0;
+	midi->size = 0;
+}
+
+static void lv2midi_reset_state(LV2_MIDIState* state, LV2_MIDI* midi, uint32_t frame_count)
+{
+	state->midi = midi;
+	state->frame_count = frame_count;
+	state->position = 0;
+}
+
+
+/** This function advances the read/write position in @c state to the next 
+    event and returns its timestamp, or the @c frame_count member of @c state
+    is there are no more events. */
+static double lv2midi_increment(LV2_MIDIState* state) {
+
+  if (state->position + sizeof(double) + sizeof(size_t) >= state->midi->size) {
+    state->position = state->midi->size;
+    return state->frame_count;
+  }
+  
+  state->position += sizeof(double);
+  size_t size = *(size_t*)(state->midi->data + state->position);
+  state->position += sizeof(size_t);
+  state->position += size;
+  
+  if (state->position >= state->midi->size)
+    return state->frame_count;
+  
+  return *(double*)(state->midi->data + state->position);
+}
+
+
+/** This function reads one event from the port associated with the @c state
+    parameter and writes its timestamp, size and a pointer to its data bytes
+    into the parameters @c timestamp, @c size and @c data, respectively.
+    It does not advance the read position in the MIDI data buffer, two 
+    subsequent calls to lv2midi_get_event() will read the same event.
+    
+    The function returns the timestamp for the read event, or the @c frame_count
+    member of @c state if there are no more events in the buffer. */
+static double lv2midi_get_event(LV2_MIDIState* state,
+                                double* timestamp, 
+                                uint32_t* size, 
+                                unsigned char** data) {
+  
+  if (state->position >= state->midi->size) {
+    state->position = state->midi->size;
+    *timestamp = state->frame_count;
+    *size = 0;
+    *data = NULL;
+    return *timestamp;
+  }
+  
+  *timestamp = *(double*)(state->midi->data + state->position);
+  *size = *(size_t*)(state->midi->data + state->position + sizeof(double));
+  *data = state->midi->data + state->position + 
+    sizeof(double) + sizeof(size_t);
+  return *timestamp;
+}
+
+
+/** This function writes one MIDI event to the port buffer associated with
+    @c state. It returns 0 when the event was written successfully to the
+    buffer, and -1 when there was not enough room. The read/write position
+    is advanced automatically. */
+static int lv2midi_put_event(LV2_MIDIState* state, 
+                             double timestamp,
+                             uint32_t size,
+                             const unsigned char* data) {
+
+  if (state->midi->capacity - state->midi->size < 
+      sizeof(double) + sizeof(size_t) + size)
+    return -1;
+  
+  *(double*)(state->midi->data + state->midi->size) = timestamp;
+  state->midi->size += sizeof(double);
+  *(size_t*)(state->midi->data + state->midi->size) = size;
+  state->midi->size += sizeof(size_t);
+  memcpy(state->midi->data + state->midi->size, data, size);
+  state->midi->size += size;
+  
+  ++state->midi->event_count;
+  
+  return 0;
+}
+
+
+#endif
+