/usr/include/lv2dynparam1/lv2dynparam/lv2dynparam.h is in liblv2dynparam1-dev 2-5.
This file is owned by root:root, with mode 0o644.
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/*****************************************************************************
*
* This work is in public domain.
*
* This file 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.
*
* If you have questions, contact Nedko Arnaudov <nedko@arnaudov.name> or
* ask in #lad channel, FreeNode IRC network.
*
*****************************************************************************/
/**
* @file lv2dynparam.h
* @brief LV2 dynparam extension definition
*
* @par Purpose
*
* The purpose of this extension is to allow plugin parameters appear
* and disappear as response of existing parameter changes (i.e. number
* of voices) or executing commands (i.e. "add new voice"). It also
* allows grouping of parameters and groups. Groups can be used for
* things like ADSR abstraction, i.e. group of 4 float parameters.
*
* @par Architectural overview
*
* Plugin notifies host for changes through callbacks. During
* initialization, plugin notifies host about initial groups,
* parameters and commands through same callbacks used for later
* notification. There are callbacks to notify host for group,
* parameter and command disappears.
*
* Groups are containers of other groups, parameters and
* commands. Parameters and groups have URIs. Parameter URIs are
* used to describe type of parameter (i.e. boolean, integer,
* string, etc.). Parameters are as simple as possible. There is one
* predefined Group URI for "generic group" type, i.e. container
* that is just that - a container of other groups, parameters and
* commands. Other group types are just hints and ones that are
* unknown to host, can be looked as generic ones. Only generic
* groups can contain groups. Groups of other types can contain only
* parameters. There is always one, root group. Name of the root
* groop is expected to match name of the plugin.
*
* Groups, parameters and commands, have "name" containing short
* human readble description of object purpose.
*
* Parameter ports, are bidirectional. Parameters have values, and
* some of them (depending of type) - range. Data storage for
* current, min and max values is in plugin memory. Host gets
* pointers to that memory and accesses the data in type specific
* way.
*
* When plugin decides to change parameter value or range (as
* response to command execution or other parameter value change), it
* notifies host through callback.
*
* When host decides to change parameter value or execute command (as
* resoponse to user action, i.e. knob rotation/button press, or some
* kind of automation), it calls plugin callback. In case of
* parameter, it first changes the value in the plugin data storage
* for particular parameter. Host ensures that values being set are
* within current range (if range is defined for particular port
* type).
*
* Apart from initialization (host_attach), plugin may call host
* callbacks only as response to command execution or parameter
* change notification (from host).
*
* Host serializes calls to plugin dynparam callbacks and the
* run/connect_port lv2 callbacks. Thus plugin does not need to take
* special measures for thread safety. in callbacks called by host.
*
* Plugin can assume that host will never call dynamic parameter
* functions when lv2 plugin callbacks (like run and connect_port) are
* being called. I.e. calls are serialized, no need for locks in
* plugin. Plugin must not suspend execution (sleep/lock) while being
* called by host. If it needs to sleep to implement action requested
* by host, like allocation of data for new voice, the allocation
* should be done in background thread and when ready, transfered to
* the realtime code. During initialization (host_attach) plugin is
* allowed to sleep. Thus conventional memory allocation is allowed
* in host_attach.
*
* @par Intialization sequence
*
* -# Host discovers whether plugin supports the extension by
* inspecting the RDF Turtle file.
* -# Host calls lv2 extension_data callback, plugin returns pointer
* to struct lv2dynparam_plugin_callbacks containing pointers to
* several funtions, including host_attach.
* -# For each instantiated plugin supporting this extension, host
* calls host_attach function with parameters:
* - a LV2_Handle, plugin instance handle
* - pointer to struct lv2dynparam_host_callbacks, containing
* pointers to several functions, to be called by plugin.
* - instance host context, opaque pointer
* -# During initialization (host_attach), initial groups and
* parameters appear and host callbacks are called by plugin.
*
* @par Parameter types
* - float, with range
* - 32-bit 2's complement signed int, with range
* - midi note, value stored as byte, with range
* - string
* - filename
* - boolean, value stored as byte, non-zero means TRUE, zero means FALSE
*
* @par Notes:
* - if function fails, variables where output parameters are normally
* stored remain unmodified.
* - If host callback, called by plugin, fails - plugin should try the
* operation later.
*/
#ifndef LV2DYNPARAM_H__31DEB371_3874_44A0_A9F2_AAFB0360D8C5__INCLUDED
#define LV2DYNPARAM_H__31DEB371_3874_44A0_A9F2_AAFB0360D8C5__INCLUDED
#ifdef __cplusplus
extern "C" {
#endif
#if 0
} /* Adjust editor indent */
#endif
/** base URI to be used for composing real URIs (internal use only) */
#define LV2DYNPARAM_BASE_URI "http://home.gna.org/lv2dynparam/v1"
/** URI of the LV2 extension defined in this file */
#define LV2DYNPARAM_URI LV2DYNPARAM_BASE_URI
/** max size of name and type_uri buffers, including terminating zero char */
#define LV2DYNPARAM_MAX_STRING_SIZE 1024
/** handle identifying parameter, supplied by plugin */
typedef void * lv2dynparam_parameter_handle;
/** handle identifying group, supplied by plugin */
typedef void * lv2dynparam_group_handle;
/** handle identifying command, supplied by plugin */
typedef void * lv2dynparam_command_handle;
/**
* Structure containing set of hints.
*/
struct lv2dynparam_hints
{
unsigned char count; /**< Number of hints in the set. Size of @c names and @c values arrays. */
char ** names; /**< Hint names. Array of hint names with size @c count. */
char ** values; /**< Hint values. Array of hint values with size @c count. Element can be NULL if hint has no value. */
};
/**
* Structure containing poitners to functions called by
* plugin and implemented by host.
*/
struct lv2dynparam_host_callbacks
{
/**
* This function is called by plugin to notify host about new
* group.
*
* @param instance_host_context Host instance context, as supplied
* during initialization (host_attach).
* @param parent_group_host_context Host context of parent
* group. For the root group, parent context is NULL.
* @param group Plugin context for the group
* @param hints_ptr Pointer to structure representing hints set
* associated with appearing group.
* @param group_host_context Pointer to variable where host context
* for the new group will be stored.
*
* @return Success status
* @retval Non-zero - success
* @retval Zero - error, try later
*/
unsigned char (*group_appear)(
void * instance_host_context,
void * parent_group_host_context,
lv2dynparam_group_handle group,
const struct lv2dynparam_hints * hints_ptr,
void ** group_host_context);
/**
* This function is called by plugin to notify host about group
* removal.
*
* @param instance_host_context Host instance context, as supplied
* during initialization (host_attach).
* @param group_host_context Host context of the group
*
* @return Success status
* @retval Non-zero - success
* @retval Zero - error, try later
*/
unsigned char (*group_disappear)(
void * instance_host_context,
void * group_host_context);
/**
* This function is called by plugin to notify host about new
* parameter.
*
* @param instance_host_context Host instance context, as supplied
* during initialization (host_attach).
* @param group_host_context Host context of parent group.
* @param parameter Plugin context for the parameter
* @param hints_ptr Pointer to structure representing hints set
* associated with appearing parameter.
* @param parameter_host_context Pointer to variable where host
* context for the new parameter will be stored.
*
* @return Success status
* @retval Non-zero - success
* @retval Zero - error, try later
*/
unsigned char (*parameter_appear)(
void * instance_host_context,
void * group_host_context,
lv2dynparam_parameter_handle parameter,
const struct lv2dynparam_hints * hints_ptr,
void ** parameter_host_context);
/**
* This function is called by plugin to notify host about parameter
* removal.
*
* @param instance_host_context Host instance context, as supplied
* during initialization (host_attach).
* @param parameter_host_context Host context of the parameter
*
* @return Success status
* @retval Non-zero - success
* @retval Zero - error, try later
*/
unsigned char (*parameter_disappear)(
void * instance_host_context,
void * parameter_host_context);
/**
* This function is called by plugin to notify host about parameter
* value or range change.
*
* @param instance_host_context Host instance context, as supplied
* during initialization (host_attach).
* @param parameter_host_context Host context of the parameter
*
* @return Success status
* @retval Non-zero - success
* @retval Zero - error, try later
*/
unsigned char (*parameter_change)(
void * instance_host_context,
void * parameter_host_context);
/**
* This function is called by plugin to notify host about new commmand.
*
* @param instance_host_context Host instance context, as supplied
* during initialization (host_attach).
* @param group_host_context Host context of parent group.
* @param command Plugin context for the command
* @param hints_ptr Pointer to structure representing hints set
* associated with appearing command.
* @param command_host_context Pointer to variable where host
* context for the new command will be stored.
*
* @return Success status
* @retval Non-zero - success
* @retval Zero - error, try later
*/
unsigned char (*command_appear)(
void * instance_host_context,
void * group_host_context,
lv2dynparam_command_handle command,
const struct lv2dynparam_hints * hints_ptr,
void ** command_host_context);
/**
* This function is called by plugin to notify host about command
* removal.
*
* @param instance_host_context Host instance context, as supplied
* during initialization (host_attach).
* @param command_host_context Host context of the command
*
* @return Success status
* @retval Non-zero - success
* @retval Zero - error, try later
*/
unsigned char (*command_disappear)(
void * instance_host_context,
void * command_host_context);
};
/**
* Structure containing poitners to functions called by
* host and implemented by plugin.
* Pointer to this struct is returned by LV2 extension_data plugin callback
*/
struct lv2dynparam_plugin_callbacks
{
/**
* This callback is called by host during initialization.
* Plugin is allowed to suspend execution (sleep/lock).
* Thus conventional memory allocation is allowed.
*
* @param instance Handle of instantiated LV2 plugin
* @param host_callbacks Pointer to struncture containing pointer to
* functions implemented by host, to be called by plugin.
* @param instance_host_context Context to be supplied as parameter
* to callbacks implemented by host and called by plugin.
*
* @return Success status
* @retval Non-zero - success
* @retval Zero - error
*/
unsigned char (*host_attach)(
LV2_Handle instance,
struct lv2dynparam_host_callbacks * host_callbacks,
void * instance_host_context);
/**
* This function is called by host to retrieve name of group
* Plugin implementation must not suspend execution (sleep/lock).
*
* @param group Group handle, as supplied by plugin
* @param buffer Pointer to buffer with size of
* LV2DYNPARAM_MAX_STRING_SIZE bytes, where ASCIIZ string containing
* name of the group will be stored.
*/
void (*group_get_name)(
lv2dynparam_group_handle group,
char * buffer);
/**
* This function is called by host to retrieve type URI of parameter
* Plugin implementation must not suspend execution (sleep/lock).
*
* @param parameter Parameter handle, as supplied by plugin
* @param buffer Pointer to buffer with size of
* LV2DYNPARAM_MAX_STRING_SIZE bytes, where ASCIIZ string containing
* type URI of the parameter will be stored.
*/
void (*parameter_get_type_uri)(
lv2dynparam_parameter_handle parameter,
char * buffer);
/**
* This function is called by host to retrieve name of parameter
* Plugin implementation must not suspend execution (sleep/lock).
*
* @param parameter Parameter handle, as supplied by plugin
* @param buffer Pointer to buffer with size of
* LV2DYNPARAM_MAX_STRING_SIZE bytes, where ASCIIZ string containing
* name of the parameter will be stored.
*/
void (*parameter_get_name)(
lv2dynparam_parameter_handle parameter,
char * buffer);
/**
* This funtion is called by host to retrieve pointer to memory
* where value data for particular parameter is stored.
* Plugin implementation must not suspend execution (sleep/lock).
*
* @param parameter Parameter handle, as supplied by plugin
* @param value_buffer Pointer to variable where pointer to value
* data will be stored.
*/
void (*parameter_get_value)(
lv2dynparam_parameter_handle parameter,
void ** value_buffer);
/**
* This funtion is called by host to retrieve pointer to memory
* where range min and max values data for particular parameter are
* stored. Host calls this function only for parameter with types
* that have range.
* Plugin implementation must not suspend execution (sleep/lock).
*
* @param parameter Parameter handle, as supplied by plugin
* @param value_min_buffer Pointer to variable where pointer to min
* value data will be stored.
* @param value_max_buffer Pointer to variable where pointer to max
* value data will be stored.
*/
void (*parameter_get_range)(
lv2dynparam_parameter_handle parameter,
void ** value_min_buffer,
void ** value_max_buffer);
/**
* This function is called by host to notify plugin about value
* change. For parameters with types that have range, value is
* guaranteed to be with the range. Before calling this function,
* host updates value data storage with the new value.
* Plugin implementation must not suspend execution (sleep/lock).
*
* @param parameter Parameter handle, as supplied by plugin
*
* @return Success status
* @retval Non-zero - success
* @retval Zero - error, try later
*/
unsigned char (*parameter_change)(
lv2dynparam_parameter_handle parameter);
/**
* This function is called by host to retrieve name of command
* Plugin implementation must not suspend execution (sleep/lock).
*
* @param command Command handle, as supplied by plugin
* @param buffer Pointer to buffer with size of
* LV2DYNPARAM_MAX_STRING_SIZE bytes, where ASCIIZ string containing
* name of the command will be stored.
*/
void (*command_get_name)(
lv2dynparam_command_handle command,
char * buffer);
/**
* This function is called by host to execute command defined by
* plugin.
* Plugin implementation must not suspend execution (sleep/lock).
*
* @param command Command handle, as supplied by plugin
*
* @return Success status
* @retval Non-zero - success
* @retval Zero - error, try later
*/
unsigned char (*command_execute)(
lv2dynparam_command_handle command);
};
/** URI for float parameter */
#define LV2DYNPARAM_PARAMETER_TYPE_FLOAT_URI LV2DYNPARAM_BASE_URI "#parameter_float"
/** URI for integer parameter */
#define LV2DYNPARAM_PARAMETER_TYPE_INT_URI LV2DYNPARAM_BASE_URI "#parameter_int"
/** URI for note parameter */
#define LV2DYNPARAM_PARAMETER_TYPE_NOTE_URI LV2DYNPARAM_BASE_URI "#parameter_note"
/** URI for string parameter */
#define LV2DYNPARAM_PARAMETER_TYPE_STRING_URI LV2DYNPARAM_BASE_URI "#parameter_string"
/** URI for filename parameter */
#define LV2DYNPARAM_PARAMETER_TYPE_FILENAME_URI LV2DYNPARAM_BASE_URI "#parameter_filename"
/** URI for boolean parameter */
#define LV2DYNPARAM_PARAMETER_TYPE_BOOLEAN_URI LV2DYNPARAM_BASE_URI "#parameter_boolean"
/** URI for enumeration parameter */
#define LV2DYNPARAM_PARAMETER_TYPE_ENUM_URI LV2DYNPARAM_BASE_URI "#parameter_enum"
#if 0
{ /* Adjust editor indent */
#endif
#ifdef __cplusplus
} /* extern "C" */
#endif
#endif /* #ifndef LV2DYNPARAM_H__31DEB371_3874_44A0_A9F2_AAFB0360D8C5__INCLUDED */
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