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Diffstat (limited to 'ns/lv2core/lv2.h')
| -rw-r--r-- | ns/lv2core/lv2.h | 298 |
1 files changed, 298 insertions, 0 deletions
diff --git a/ns/lv2core/lv2.h b/ns/lv2core/lv2.h new file mode 100644 index 0000000..ce55d45 --- /dev/null +++ b/ns/lv2core/lv2.h @@ -0,0 +1,298 @@ +/* + LV2 - An audio plugin interface specification. + Copyright 2006-2011 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 <http://lv2plug.in/ns/lv2core>. + Revision: 4.1 +*/ + +#ifndef LV2_H_INCLUDED +#define LV2_H_INCLUDED + +#include <stdint.h> + +#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 lv2.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 + lv2.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; + +/** + 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. +*/ +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); + +/** + 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 + +#ifdef __cplusplus +} +#endif + +#endif /* LV2_H_INCLUDED */ |