From d6b87aa26ef482a8952437f7472b81a2240f01fd Mon Sep 17 00:00:00 2001 From: David Robillard Date: Mon, 21 Jan 2008 15:14:53 +0000 Subject: Work on generic LV2 events. git-svn-id: http://svn.drobilla.net/lad/ingen@1090 a436a847-0d15-0410-975c-d299462d15a1 --- src/common/lv2ext/lv2_event.h | 178 ++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 178 insertions(+) create mode 100644 src/common/lv2ext/lv2_event.h (limited to 'src/common/lv2ext/lv2_event.h') diff --git a/src/common/lv2ext/lv2_event.h b/src/common/lv2ext/lv2_event.h new file mode 100644 index 00000000..266ba180 --- /dev/null +++ b/src/common/lv2ext/lv2_event.h @@ -0,0 +1,178 @@ +/* lv2_events.h - C header file for the LV2 events extension. + * + * Copyright (C) 2006-2007 Lars Luthman + * Copyright (C) 2008 Dave Robillard + * + * This header 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 header 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 header; if not, write to the Free Software Foundation, + * Inc., 59 Temple Place, Suite 330, Boston, MA 01222-1307 USA + */ + +#ifndef LV2_EVENTS_H +#define LV2_EVENTS_H + +#include + +/** @file + * This header defines the code portion of the LV2 events extension with URI + * (preferred prefix 'lv2ev'). + * + * This extension is a generic transport mechanism for time stamped events + * of any type (e.g. MIDI, OSC, ramps, etc). Each port can transport mixed + * events of any type; the type of events is defined by a URI (in some other + * extension) which is mapped to an integer by the host for performance + * reasons. + */ + + +/** The PPQN (pulses per quarter note) of tempo-based LV2 event time stamps. + * Equal to (2^5 * 3^4 * 5 * 7 * 11 * 13 * 17 * 19), which is evenly divisuble + * by all integers from 1 through 22 inclusive. */ +static const uint32_t LV2_EVENT_PPQN = 4190266080; + + + +/** Opaque host data passed to LV2_Event_Feature. + */ +typedef void* LV2_Event_Callback_Data; + + + +/** The data part of the LV2_Feature for the LV2 events extension. + * + * The host MUST pass an LV2_Feature struct to the plugin's instantiate + * method with URI set to "http://lv2plug.in/ns/ext/events" and data + * set to an instance of this struct. + * + * The plugin MUST pass callback_data to any invocation of the functions + * defined in this struct. Otherwise, callback_data is opaque and the + * plugin MUST NOT interpret its value in any way. + */ +typedef struct { + + /** Get the numeric version of an event type from the host. + * + * The returned value is 0 if there is no type by that URI. + * The returned value correlates to the type field of LV2_Event, and is + * guaranteed never to change over the course of the plugin's + * instantiation, unless the returned value is 0 (i.e. new event types + * can be added, but existing ones can never be changed/removed). + */ + uint16_t (*uri_to_event_type)(LV2_Event_Callback_Data callback_data, + char const* uri); + + LV2_Event_Callback_Data callback_data; + +} LV2_Event_Feature; + + + +/** An LV2 event. + * + * LV2 events are generic time-stamped containers for any type of event. + * The type field defines the format of a given event's contents. + * + * This struct defined the header of an LV2 event. An LV2 event is a single + * chunk of POD (plain old data), usually contained in a flat buffer + * (see LV2_EventBuffer below). Unless a required feature says otherwise, + * hosts may assume a deep copy of an LV2 event can be created safely + * using a simple: + * + * memcpy(ev_copy, ev, sizeof(LV2_Event) + ev->size); (or equivalent) + */ +typedef struct { + + /** The frames portion of timestamp. The units used here can optionally be + * set for a port (with the lv2ev:timeUnits property), otherwise this + * is audio frames, corresponding to the sample_count parameter of the + * LV2 run method (e.g. frame 0 is the first frame for that call to run). + */ + uint32_t frames; + + /** The sub-frames portion of timestamp. The units used here can + * optionally be set for a port (with the lv2ev:timeUnits property), + * otherwise this is 1/(2^32) of an audio frame. + */ + uint32_t subframes; + + /** The type of this event, where this numeric value refers to some URI + * defining an event type. The LV2_Event_Feature passed from the host + * provides a function to map URIs to event types for this field. + * The type 0 is a special nil value, meaning the event has no type and + * should be ignored or passed through without interpretation. + * Plugins MUST gracefully ignore or pass through any events of a type + * which the plugin does not recognize. + */ + uint16_t type; + + /** The size of the data portion of this event in bytes, which immediately + * follows. The header size (12 bytes) is not included in this value. + */ + uint16_t size; + + /* size bytes of data follow here */ + +} LV2_Event; + + + +/** A buffer of LV2 events. + * + * Like events (which this contains) an event buffer is a single chunk of POD: + * the entire buffer (including contents) can be copied with a single memcpy. + * The first contained event begins sizeof(LV2_EventBuffer) bytes after + * the start of this struct. + * + * After this header, the buffer contains an event header (defined by struct + * LV2_Event), followed by that event's contents (padded to 64 bits), followed by + * another header, etc: + * + * | | | | | | | + * | | | | | | | | | | | | | | | | | | | | | | | | | + * |FRAMES |SUBFRMS|TYP|LEN|DATA..DATA..PAD|FRAMES | ... + */ +typedef struct { + + /** The number of events in this buffer. + * INPUT PORTS: The host must set this field to the number of events + * contained in the data buffer before calling run(). + * The plugin must not change this field. + * OUTPUT PORTS: The plugin must set this field to the number of events it + * has written to the buffer before returning from run(). + * Any initial value should be ignored by the plugin. + */ + uint32_t event_count; + + /** The size of the data buffer in bytes. + * This is set by the host and must not be changed by the plugin. + * The host is allowed to change this between run() calls. + */ + uint32_t capacity; + + /** The size of the initial portion of the data buffer containing data. + * INPUT PORTS: The host must set this field to the number of bytes used + * by all events it has written to the buffer (including headers) + * before calling the plugin's run(). + * The plugin must not change this field. + * OUTPUT PORTS: The plugin must set this field to the number of bytes + * used by all events it has written to the buffer (including headers) + * before returning from run(). + * Any initial value should be ignored by the plugin. + */ + uint32_t size; + +} LV2_Event_Buffer; + + +#endif // LV2_EVENTS_H + -- cgit v1.2.1