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Diffstat (limited to 'ext/event.lv2/event.h')
| -rw-r--r-- | ext/event.lv2/event.h | 259 |
1 files changed, 259 insertions, 0 deletions
diff --git a/ext/event.lv2/event.h b/ext/event.lv2/event.h new file mode 100644 index 0000000..7fb189c --- /dev/null +++ b/ext/event.lv2/event.h @@ -0,0 +1,259 @@ +/* lv2_event.h - C header file for the LV2 events extension. + * + * Copyright (C) 2006-2007 Lars Luthman <lars.luthman@gmail.com> + * Copyright (C) 2008-2009 David Robillard <http://drobilla.net> + * + * 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_EVENT_H +#define LV2_EVENT_H + +#define LV2_EVENT_URI "http://lv2plug.in/ns/ext/event" +#define LV2_EVENT_AUDIO_STAMP 0 + +#include <stdint.h> + +/** @file + * C header for the LV2 Event extension <http://lv2plug.in/ns/ext/event>. + * + * 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 and timestamps are defined by a URI + * which is mapped to an integer by the host for performance reasons. + * + * This extension requires the host to support the LV2 URI Map extension. + * Any host which supports this extension MUST guarantee that any call to + * the LV2 URI Map uri_to_id function with the URI of this extension as the + * 'map' argument returns a value within the range of uint16_t. + */ + + +/** The best Pulses Per Quarter Note for tempo-based uint32_t timestmaps. + * Equal to 2^12 * 5 * 7 * 9 * 11 * 13 * 17, which is evenly divisble + * by all integers from 1 through 18 inclusive, and powers of 2 up to 2^12. + */ +static const uint32_t LV2_EVENT_PPQN = 3136573440U; + + +/** An LV2 event (header only). + * + * 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 defines 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, as a number which represents some URI + * defining an event type. This value MUST be some value previously + * returned from a call to the uri_to_id function defined in the LV2 + * URI map extension (see lv2_uri_map.h). + * There are special rules which must be followed depending on the type + * of an event. If the plugin recognizes an event type, the definition + * of that event type will describe how to interpret the event, and + * any required behaviour. Otherwise, if the type is 0, this event is a + * non-POD event and lv2_event_unref MUST be called if the event is + * 'dropped' (see above). Even if the plugin does not understand an event, + * it may pass the event through to an output by simply copying (and NOT + * calling lv2_event_unref). These rules are designed to allow for generic + * event handling plugins and large non-POD events, but with minimal hassle + * on simple plugins that "don't care" about these more advanced features. + */ + 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 (header only). + * + * 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 contents of the event buffer. This may or may not reside in the + * same block of memory as this header, plugins must not assume either. + * The host guarantees this points to at least capacity bytes of allocated + * memory (though only size bytes of that are valid events). + */ + uint8_t* data; + + /** The size of this event header in bytes (including everything). + * + * This is to allow for extending this header in the future without + * breaking binary compatibility. Whenever this header is copied, + * it MUST be done using this field (and NOT the sizeof this struct). + */ + uint16_t header_size; + + /** The type of the time stamps for events in this buffer. + * As a special exception, '0' always means audio frames and subframes + * (1/UINT32_MAX'th of a frame) in the sample rate passed to instantiate. + * INPUTS: The host must set this field to the numeric ID of some URI + * defining the meaning of the frames/subframes fields of contained + * events (obtained by the LV2 URI Map uri_to_id function with the URI + * of this extension as the 'map' argument, see lv2_uri_map.h). + * The host must never pass a plugin a buffer which uses a stamp type + * the plugin does not 'understand'. The value of this field must + * never change, except when connect_port is called on the input + * port, at which time the host MUST have set the stamp_type field to + * the value that will be used for all subsequent run calls. + * OUTPUTS: The plugin may set this to any value that has been returned + * from uri_to_id with the URI of this extension for a 'map' argument. + * When connected to a buffer with connect_port, output ports MUST set + * this field to the type of time stamp they will be writing. On any + * call to connect_port on an event input port, the plugin may change + * this field on any output port, it is the responsibility of the host + * to check if any of these values have changed and act accordingly. + */ + uint16_t stamp_type; + + /** The number of events in this buffer. + * INPUTS: 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. + * OUTPUTS: 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. + * INPUTS: 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. + * OUTPUTS: 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; + + +/** Opaque pointer to host data. */ +typedef void* LV2_Event_Callback_Data; + + +/** The data field of the LV2_Feature for this extension. + * + * To support this feature the host must pass an LV2_Feature struct to the + * plugin's instantiate method with URI "http://lv2plug.in/ns/ext/event" + * and data pointed to an instance of this struct. + */ +typedef struct { + + /** Opaque pointer to host data. + * + * The plugin MUST pass this to any call to functions in this struct. + * Otherwise, it must not be interpreted in any way. + */ + LV2_Event_Callback_Data callback_data; + + /** Take a reference to a non-POD event. + * + * If a plugin receives an event with type 0, it means the event is a + * pointer to some object in memory and not a flat sequence of bytes + * in the buffer. When receiving a non-POD event, the plugin already + * has an implicit reference to the event. If the event is stored AND + * passed to an output, lv2_event_ref MUST be called on that event. + * If the event is only stored OR passed through, this is not necessary + * (as the plugin already has 1 implicit reference). + * + * @param event An event received at an input that will not be copied to + * an output or stored in any way. + * @param context The calling context. (Like event types) this is a mapped + * URI, see lv2_context.h. Simple plugin with just a run() + * method should pass 0 here (the ID of the 'standard' LV2 + * run context). The host guarantees that this function is + * realtime safe iff @a context is realtime safe. + * + * PLUGINS THAT VIOLATE THESE RULES MAY CAUSE CRASHES AND MEMORY LEAKS. + */ + uint32_t (*lv2_event_ref)(LV2_Event_Callback_Data callback_data, + LV2_Event* event); + + /** Drop a reference to a non-POD event. + * + * If a plugin receives an event with type 0, it means the event is a + * pointer to some object in memory and not a flat sequence of bytes + * in the buffer. If the plugin does not pass the event through to + * an output or store it internally somehow, it MUST call this function + * on the event (more information on using non-POD events below). + * + * @param event An event received at an input that will not be copied to + * an output or stored in any way. + * @param context The calling context. (Like event types) this is a mapped + * URI, see lv2_context.h. Simple plugin with just a run() + * method should pass 0 here (the ID of the 'standard' LV2 + * run context). The host guarantees that this function is + * realtime safe iff @a context is realtime safe. + * + * PLUGINS THAT VIOLATE THESE RULES MAY CAUSE CRASHES AND MEMORY LEAKS. + */ + uint32_t (*lv2_event_unref)(LV2_Event_Callback_Data callback_data, + LV2_Event* event); + +} LV2_Event_Feature; + + +#endif /* LV2_EVENT_H */ + |