/* LV2 - An audio plugin interface specification. Copyright 2006-2012 Steve Harris, David Robillard. Based on LADSPA, Copyright 2000-2002 Richard W.E. Furse, Paul Barton-Davis, Stefan Westerfeld. Permission to use, copy, modify, and/or distribute this software for any purpose with or without fee is hereby granted, provided that the above copyright notice and this permission notice appear in all copies. THIS SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. */ /** @file lv2.h API for the LV2 specification . Revision: 6.1 */ #ifndef LV2_H_INCLUDED #define LV2_H_INCLUDED #include #ifdef __cplusplus extern "C" { #endif /** Plugin Instance Handle. This is a handle for one particular instance of a plugin. It is valid to compare to NULL (or 0 for C++) but otherwise the host MUST NOT attempt to interpret it. */ typedef void * LV2_Handle; /** Feature. Features allow hosts to make additional functionality available to plugins without requiring modification to the LV2 API. Extensions may define new features and specify the @ref URI and @ref data to be used if necessary. Some features, such as lv2:isLive, do not require the host to pass data. */ typedef struct _LV2_Feature { /** A globally unique, case-sensitive identifier (URI) for this feature. This MUST be a valid URI string as defined by RFC 3986. */ const char * URI; /** Pointer to arbitrary data. The format of this data is defined by the extension which describes the feature with the given @ref URI. */ void * data; } LV2_Feature; /** Plugin Descriptor. This structure provides the core functions necessary to instantiate and use a plugin. */ typedef struct _LV2_Descriptor { /** A globally unique, case-sensitive identifier for this plugin. This MUST be a valid URI string as defined by RFC 3986. All plugins with the same URI MUST be compatible to some degree, see http://lv2plug.in/ns/lv2core for details. */ const char * URI; /** Instantiate the plugin. Note that instance initialisation should generally occur in activate() rather than here. If a host calls instantiate(), it MUST call cleanup() at some point in the future. @param descriptor Descriptor of the plugin to instantiate. @param sample_rate Sample rate, in Hz, for the new plugin instance. @param bundle_path Path to the LV2 bundle which contains this plugin binary. It MUST include the trailing directory separator (e.g. '/') so that simply appending a filename will yield the path to that file in the bundle. @param features A NULL terminated array of LV2_Feature structs which represent the features the host supports. Plugins may refuse to instantiate if required features are not found here. However, hosts MUST NOT use this as a discovery mechanism: instead, use the RDF data to determine which features are required and do not attempt to instantiate unsupported plugins at all. This parameter MUST NOT be NULL, i.e. a host that supports no features MUST pass a single element array containing NULL. @return A handle for the new plugin instance, or NULL if instantiation has failed. */ LV2_Handle (*instantiate)(const struct _LV2_Descriptor * descriptor, double sample_rate, const char * bundle_path, const LV2_Feature *const * features); /** Connect a port on a plugin instance to a memory location. Plugin writers should be aware that the host may elect to use the same buffer for more than one port and even use the same buffer for both input and output (see lv2:inPlaceBroken in lv2.ttl). If the plugin has the feature lv2:hardRTCapable then there are various things that the plugin MUST NOT do within the connect_port() function; see lv2core.ttl for details. connect_port() MUST be called at least once for each port before run() is called, unless that port is lv2:connectionOptional. The plugin must pay careful attention to the block size passed to run() since the block allocated may only just be large enough to contain the data, and is not guaranteed to remain constant between run() calls. connect_port() may be called more than once for a plugin instance to allow the host to change the buffers that the plugin is reading or writing. These calls may be made before or after activate() or deactivate() calls. @param instance Plugin instance containing the port. @param port Index of the port to connect. The host MUST NOT try to connect a port index that is not defined in the plugin's RDF data. If it does, the plugin's behaviour is undefined (a crash is likely). @param data_location Pointer to data of the type defined by the port type in the plugin's RDF data (e.g. an array of float for an lv2:AudioPort). This pointer must be stored by the plugin instance and used to read/write data when run() is called. Data present at the time of the connect_port() call MUST NOT be considered meaningful. */ void (*connect_port)(LV2_Handle instance, uint32_t port, void * data_location); /** Initialise a plugin instance and activate it for use. This is separated from instantiate() to aid real-time support and so that hosts can reinitialise a plugin instance by calling deactivate() and then activate(). In this case the plugin instance MUST reset all state information dependent on the history of the plugin instance except for any data locations provided by connect_port(). If there is nothing for activate() to do then this field may be NULL. When present, hosts MUST call this function once before run() is called for the first time. This call SHOULD be made as close to the run() call as possible and indicates to real-time plugins that they are now live, however plugins MUST NOT rely on a prompt call to run() after activate(). The host MUST NOT call activate() again until deactivate() has been called first. If a host calls activate(), it MUST call deactivate() at some point in the future. Note that connect_port() may be called before or after activate(). */ void (*activate)(LV2_Handle instance); /** Run a plugin instance for a block. Note that if an activate() function exists then it must be called before run(). If deactivate() is called for a plugin instance then run() may not be called until activate() has been called again. If the plugin has the feature lv2:hardRTCapable then there are various things that the plugin MUST NOT do within the run() function (see lv2core.ttl for details). As a special case, when @c sample_count == 0, the plugin should update any output ports that represent a single instant in time (e.g. control ports, but not audio ports). This is particularly useful for latent plugins, which should update their latency output port so hosts can pre-roll plugins to compute latency. Plugins MUST NOT crash when @c sample_count == 0. @param instance Instance to be run. @param sample_count The block size (in samples) for which the plugin instance must run. */ void (*run)(LV2_Handle instance, uint32_t sample_count); /** Deactivate a plugin instance (counterpart to activate()). Hosts MUST deactivate all activated instances after they have been run() for the last time. This call SHOULD be made as close to the last run() call as possible and indicates to real-time plugins that they are no longer live, however plugins MUST NOT rely on prompt deactivation. If there is nothing for deactivate() to do then this field may be NULL Deactivation is not similar to pausing since the plugin instance will be reinitialised by activate(). However, deactivate() itself MUST NOT fully reset plugin state. For example, the host may deactivate a plugin, then store its state (using some extension to do so). Hosts MUST NOT call deactivate() unless activate() was previously called. Note that connect_port() may be called before or after deactivate(). */ void (*deactivate)(LV2_Handle instance); /** Clean up a plugin instance (counterpart to instantiate()). Once an instance of a plugin has been finished with it must be deleted using this function. The instance handle passed ceases to be valid after this call. If activate() was called for a plugin instance then a corresponding call to deactivate() MUST be made before cleanup() is called. Hosts MUST NOT call cleanup() unless instantiate() was previously called. */ void (*cleanup)(LV2_Handle instance); /** Return additional plugin data defined by some extenion. A typical use of this facility is to return a struct containing function pointers to extend the LV2_Descriptor API. The actual type and meaning of the returned object MUST be specified precisely by the extension. This function MUST return NULL for any unsupported URI. If a plugin does not support any extension data, this field may be NULL. The host is never responsible for freeing the returned value. */ const void * (*extension_data)(const char * uri); } LV2_Descriptor; /** Put this (LV2_SYMBOL_EXPORT) before any functions that are to be loaded by the host as a symbol from the dynamic library. */ #ifdef _WIN32 # define LV2_SYMBOL_EXPORT __declspec(dllexport) #else # define LV2_SYMBOL_EXPORT #endif /** Prototype for plugin accessor function. Plugins are discovered by hosts using RDF data (not by loading libraries). See http://lv2plug.in for details on the discovery process, though most hosts should use an existing library to implement this functionality. A plugin library MUST include a function called "lv2_descriptor" with this prototype. This function MUST have C-style linkage (if you are using C++ this is taken care of by the 'extern "C"' clause at the top of this file). When it is time to load a plugin (designated by its URI), the host loads the plugin's library, gets the lv2_descriptor() function from it, and uses this function to find the LV2_Descriptor for the desired plugin. Plugins are accessed by index using values from 0 upwards. This function MUST return NULL for out of range indices, so the host can enumerate plugins by increasing @c index until NULL is returned. Note that @c index has no meaning, hosts MUST NOT depend on it remaining consistent between loads of the plugin library. */ LV2_SYMBOL_EXPORT const LV2_Descriptor * lv2_descriptor(uint32_t index); /** Type of the lv2_descriptor() function in a plugin library. */ typedef const LV2_Descriptor * (*LV2_Descriptor_Function)(uint32_t index); #ifdef __cplusplus } #endif #endif /* LV2_H_INCLUDED */