--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/DPF-Prymula-audioplugins/dpf/distrho/src/lv2/state.h	Mon Oct 16 21:53:34 2023 +0200
@@ -0,0 +1,389 @@
+/*
+  Copyright 2010-2016 David Robillard <http://drobilla.net>
+  Copyright 2010 Leonard Ritter <paniq@paniq.org>
+
+  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.
+*/
+
+/**
+   @defgroup state State
+   @ingroup lv2
+
+   An interface for LV2 plugins to save and restore state, see
+   <http://lv2plug.in/ns/ext/state> for details.
+
+   @{
+*/
+
+#ifndef LV2_STATE_H
+#define LV2_STATE_H
+
+#include "lv2.h"
+
+#include <stdbool.h>
+#include <stddef.h>
+#include <stdint.h>
+
+#define LV2_STATE_URI    "http://lv2plug.in/ns/ext/state"  ///< http://lv2plug.in/ns/ext/state
+#define LV2_STATE_PREFIX LV2_STATE_URI "#"                 ///< http://lv2plug.in/ns/ext/state#
+
+#define LV2_STATE__State             LV2_STATE_PREFIX "State"              ///< http://lv2plug.in/ns/ext/state#State
+#define LV2_STATE__interface         LV2_STATE_PREFIX "interface"          ///< http://lv2plug.in/ns/ext/state#interface
+#define LV2_STATE__loadDefaultState  LV2_STATE_PREFIX "loadDefaultState"   ///< http://lv2plug.in/ns/ext/state#loadDefaultState
+#define LV2_STATE__freePath          LV2_STATE_PREFIX "freePath"           ///< http://lv2plug.in/ns/ext/state#freePath
+#define LV2_STATE__makePath          LV2_STATE_PREFIX "makePath"           ///< http://lv2plug.in/ns/ext/state#makePath
+#define LV2_STATE__mapPath           LV2_STATE_PREFIX "mapPath"            ///< http://lv2plug.in/ns/ext/state#mapPath
+#define LV2_STATE__state             LV2_STATE_PREFIX "state"              ///< http://lv2plug.in/ns/ext/state#state
+#define LV2_STATE__threadSafeRestore LV2_STATE_PREFIX "threadSafeRestore"  ///< http://lv2plug.in/ns/ext/state#threadSafeRestore
+#define LV2_STATE__StateChanged      LV2_STATE_PREFIX "StateChanged"       ///< http://lv2plug.in/ns/ext/state#StateChanged
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+typedef void* LV2_State_Handle;            ///< Opaque handle for state save/restore
+typedef void* LV2_State_Free_Path_Handle;  ///< Opaque handle for state:freePath feature
+typedef void* LV2_State_Map_Path_Handle;   ///< Opaque handle for state:mapPath feature
+typedef void* LV2_State_Make_Path_Handle;  ///< Opaque handle for state:makePath feature
+
+/**
+   Flags describing value characteristics.
+
+   These flags are used along with the value's type URI to determine how to
+   (de-)serialise the value data, or whether it is even possible to do so.
+*/
+typedef enum {
+	/**
+	   Plain Old Data.
+
+	   Values with this flag contain no pointers or references to other areas
+	   of memory.  It is safe to copy POD values with a simple memcpy and store
+	   them for the duration of the process.  A POD value is not necessarily
+	   safe to trasmit between processes or machines (for example, filenames
+	   are POD), see LV2_STATE_IS_PORTABLE for details.
+
+	   Implementations MUST NOT attempt to copy or serialise a non-POD value if
+	   they do not understand its type (and thus know how to correctly do so).
+	*/
+	LV2_STATE_IS_POD = 1,
+
+	/**
+	   Portable (architecture independent) data.
+
+	   Values with this flag are in a format that is usable on any
+	   architecture.  A portable value saved on one machine can be restored on
+	   another machine regardless of architecture.  The format of portable
+	   values MUST NOT depend on architecture-specific properties like
+	   endianness or alignment.  Portable values MUST NOT contain filenames.
+	*/
+	LV2_STATE_IS_PORTABLE = 1 << 1,
+
+	/**
+	   Native data.
+
+	   This flag is used by the host to indicate that the saved data is only
+	   going to be used locally in the currently running process (for things
+	   like instance duplication or snapshots), so the plugin should use the
+	   most efficient representation possible and not worry about serialisation
+	   and portability.
+	*/
+	LV2_STATE_IS_NATIVE = 1 << 2
+} LV2_State_Flags;
+
+/** A status code for state functions. */
+typedef enum {
+	LV2_STATE_SUCCESS         = 0,  /**< Completed successfully. */
+	LV2_STATE_ERR_UNKNOWN     = 1,  /**< Unknown error. */
+	LV2_STATE_ERR_BAD_TYPE    = 2,  /**< Failed due to unsupported type. */
+	LV2_STATE_ERR_BAD_FLAGS   = 3,  /**< Failed due to unsupported flags. */
+	LV2_STATE_ERR_NO_FEATURE  = 4,  /**< Failed due to missing features. */
+	LV2_STATE_ERR_NO_PROPERTY = 5,  /**< Failed due to missing property. */
+	LV2_STATE_ERR_NO_SPACE    = 6   /**< Failed due to insufficient space. */
+} LV2_State_Status;
+
+/**
+   A host-provided function to store a property.
+   @param handle Must be the handle passed to LV2_State_Interface.save().
+   @param key The key to store `value` under (URID).
+   @param value Pointer to the value to be stored.
+   @param size The size of `value` in bytes.
+   @param type The type of `value` (URID).
+   @param flags LV2_State_Flags for `value`.
+   @return 0 on success, otherwise a non-zero error code.
+
+   The host passes a callback of this type to LV2_State_Interface.save(). This
+   callback is called repeatedly by the plugin to store all the properties that
+   describe its current state.
+
+   DO NOT INVENT NONSENSE URI SCHEMES FOR THE KEY.  Best is to use keys from
+   existing vocabularies.  If nothing appropriate is available, use http URIs
+   that point to somewhere you can host documents so documentation can be made
+   resolvable (typically a child of the plugin or project URI).  If this is not
+   possible, invent a URN scheme, e.g. urn:myproj:whatever.  The plugin MUST
+   NOT pass an invalid URI key.
+
+   The host MAY fail to store a property for whatever reason, but SHOULD
+   store any property that is LV2_STATE_IS_POD and LV2_STATE_IS_PORTABLE.
+   Implementations SHOULD use the types from the LV2 Atom extension
+   (http://lv2plug.in/ns/ext/atom) wherever possible.  The plugin SHOULD
+   attempt to fall-back and avoid the error if possible.
+
+   Note that `size` MUST be > 0, and `value` MUST point to a valid region of
+   memory `size` bytes long (this is required to make restore unambiguous).
+
+   The plugin MUST NOT attempt to use this function outside of the
+   LV2_State_Interface.restore() context.
+*/
+typedef LV2_State_Status (*LV2_State_Store_Function)(
+	LV2_State_Handle handle,
+	uint32_t         key,
+	const void*      value,
+	size_t           size,
+	uint32_t         type,
+	uint32_t         flags);
+
+/**
+   A host-provided function to retrieve a property.
+   @param handle Must be the handle passed to LV2_State_Interface.restore().
+   @param key The key of the property to retrieve (URID).
+   @param size (Output) If non-NULL, set to the size of the restored value.
+   @param type (Output) If non-NULL, set to the type of the restored value.
+   @param flags (Output) If non-NULL, set to the flags for the restored value.
+   @return A pointer to the restored value (object), or NULL if no value
+   has been stored under `key`.
+
+   A callback of this type is passed by the host to
+   LV2_State_Interface.restore().  This callback is called repeatedly by the
+   plugin to retrieve any properties it requires to restore its state.
+
+   The returned value MUST remain valid until LV2_State_Interface.restore()
+   returns.  The plugin MUST NOT attempt to use this function, or any value
+   returned from it, outside of the LV2_State_Interface.restore() context.
+*/
+typedef const void* (*LV2_State_Retrieve_Function)(
+	LV2_State_Handle handle,
+	uint32_t         key,
+	size_t*          size,
+	uint32_t*        type,
+	uint32_t*        flags);
+
+/**
+   LV2 Plugin State Interface.
+
+   When the plugin's extension_data is called with argument
+   LV2_STATE__interface, the plugin MUST return an LV2_State_Interface
+   structure, which remains valid for the lifetime of the plugin.
+
+   The host can use the contained function pointers to save and restore the
+   state of a plugin instance at any time, provided the threading restrictions
+   of the functions are met.
+
+   Stored data is only guaranteed to be compatible between instances of plugins
+   with the same URI (i.e. if a change to a plugin would cause a fatal error
+   when restoring state saved by a previous version of that plugin, the plugin
+   URI MUST change just as it must when ports change incompatibly).  Plugin
+   authors should consider this possibility, and always store sensible data
+   with meaningful types to avoid such problems in the future.
+*/
+typedef struct {
+	/**
+	   Save plugin state using a host-provided `store` callback.
+
+	   @param instance The instance handle of the plugin.
+	   @param store The host-provided store callback.
+	   @param handle An opaque pointer to host data which MUST be passed as the
+	   handle parameter to `store` if it is called.
+	   @param flags Flags describing desired properties of this save.  These
+	   flags may be used to determine the most appropriate values to store.
+	   @param features Extensible parameter for passing any additional
+	   features to be used for this save.
+
+	   The plugin is expected to store everything necessary to completely
+	   restore its state later.  Plugins SHOULD store simple POD data whenever
+	   possible, and consider the possibility of state being restored much
+	   later on a different machine.
+
+	   The `handle` pointer and `store` function MUST NOT be used
+	   beyond the scope of save().
+
+	   This function has its own special threading class: it may not be called
+	   concurrently with any "Instantiation" function, but it may be called
+	   concurrently with functions in any other class, unless the definition of
+	   that class prohibits it (for example, it may not be called concurrently
+	   with a "Discovery" function, but it may be called concurrently with an
+	   "Audio" function.  The plugin is responsible for any locking or
+	   lock-free techniques necessary to make this possible.
+
+	   Note that in the simple case where state is only modified by restore(),
+	   there are no synchronization issues since save() is never called
+	   concurrently with restore() (though run() may read it during a save).
+
+	   Plugins that dynamically modify state while running, however, must take
+	   care to do so in such a way that a concurrent call to save() will save a
+	   consistent representation of plugin state for a single instant in time.
+	*/
+	LV2_State_Status (*save)(LV2_Handle                 instance,
+	                         LV2_State_Store_Function   store,
+	                         LV2_State_Handle           handle,
+	                         uint32_t                   flags,
+	                         const LV2_Feature *const * features);
+
+	/**
+	   Restore plugin state using a host-provided `retrieve` callback.
+
+	   @param instance The instance handle of the plugin.
+	   @param retrieve The host-provided retrieve callback.
+	   @param handle An opaque pointer to host data which MUST be passed as the
+	   handle parameter to `retrieve` if it is called.
+	   @param flags Currently unused.
+	   @param features Extensible parameter for passing any additional
+	   features to be used for this restore.
+
+	   The plugin MAY assume a restored value was set by a previous call to
+	   LV2_State_Interface.save() by a plugin with the same URI.
+
+	   The plugin MUST gracefully fall back to a default value when a value can
+	   not be retrieved.  This allows the host to reset the plugin state with
+	   an empty map.
+
+	   The `handle` pointer and `store` function MUST NOT be used
+	   beyond the scope of restore().
+
+	   This function is in the "Instantiation" threading class as defined by
+	   LV2. This means it MUST NOT be called concurrently with any other
+	   function on the same plugin instance.
+	*/
+	LV2_State_Status (*restore)(LV2_Handle                  instance,
+	                            LV2_State_Retrieve_Function retrieve,
+	                            LV2_State_Handle            handle,
+	                            uint32_t                    flags,
+	                            const LV2_Feature *const *  features);
+} LV2_State_Interface;
+
+/**
+   Feature data for state:mapPath (@ref LV2_STATE__mapPath).
+*/
+typedef struct {
+	/**
+	   Opaque host data.
+	*/
+	LV2_State_Map_Path_Handle handle;
+
+	/**
+	   Map an absolute path to an abstract path for use in plugin state.
+	   @param handle MUST be the `handle` member of this struct.
+	   @param absolute_path The absolute path of a file.
+	   @return An abstract path suitable for use in plugin state.
+
+	   The plugin MUST use this function to map any paths that will be stored
+	   in plugin state.  The returned value is an abstract path which MAY not
+	   be an actual file system path; absolute_path() MUST be used to map
+	   it to an actual path in order to use the file.
+
+	   Plugins MUST NOT make any assumptions about abstract paths except that
+	   they can be mapped back to the absolute path of the "same" file (though
+	   not necessarily the same original path) using absolute_path().
+
+	   This function may only be called within the context of
+	   LV2_State_Interface methods.  The caller must free the returned value
+	   with LV2_State_Free_Path.free_path().
+	*/
+	char* (*abstract_path)(LV2_State_Map_Path_Handle handle,
+	                       const char*               absolute_path);
+
+	/**
+	   Map an abstract path from plugin state to an absolute path.
+	   @param handle MUST be the `handle` member of this struct.
+	   @param abstract_path An abstract path (typically from plugin state).
+	   @return An absolute file system path.
+
+	   The plugin MUST use this function in order to actually open or otherwise
+	   use any paths loaded from plugin state.
+
+	   This function may only be called within the context of
+	   LV2_State_Interface methods.  The caller must free the returned value
+	   with LV2_State_Free_Path.free_path().
+	*/
+	char* (*absolute_path)(LV2_State_Map_Path_Handle handle,
+	                       const char*               abstract_path);
+} LV2_State_Map_Path;
+
+/**
+   Feature data for state:makePath (@ref LV2_STATE__makePath).
+*/
+typedef struct {
+	/**
+	   Opaque host data.
+	*/
+	LV2_State_Make_Path_Handle handle;
+
+	/**
+	   Return a path the plugin may use to create a new file.
+	   @param handle MUST be the `handle` member of this struct.
+	   @param path The path of the new file within a namespace unique to this
+	   plugin instance.
+	   @return The absolute path to use for the new file.
+
+	   This function can be used by plugins to create files and directories,
+	   either at state saving time (if this feature is passed to
+	   LV2_State_Interface.save()) or any time (if this feature is passed to
+	   LV2_Descriptor.instantiate()).
+
+	   The host MUST do whatever is necessary for the plugin to be able to
+	   create a file at the returned path (for example, using fopen()),
+	   including creating any leading directories.
+
+	   If this function is passed to LV2_Descriptor.instantiate(), it may be
+	   called from any non-realtime context.  If it is passed to
+	   LV2_State_Interface.save(), it may only be called within the dynamic
+	   scope of that function call.
+
+	   The caller must free the returned value with
+	   LV2_State_Free_Path.free_path().
+	*/
+	char* (*path)(LV2_State_Make_Path_Handle handle,
+	              const char*                path);
+} LV2_State_Make_Path;
+
+/**
+   Feature data for state:freePath (@ref LV2_STATE__freePath).
+*/
+typedef struct {
+	/**
+	   Opaque host data.
+	*/
+	LV2_State_Free_Path_Handle handle;
+
+	/**
+	   Free a path returned by a state feature.
+
+	   @param handle MUST be the `handle` member of this struct.
+	   @param path The path previously returned by a state feature.
+
+	   This function can be used by plugins to free paths allocated by the host
+	   and returned by state features (LV2_State_Map_Path.abstract_path(),
+	   LV2_State_Map_Path.absolute_path(), and LV2_State_Make_Path.path()).
+	*/
+	void (*free_path)(LV2_State_Free_Path_Handle handle,
+	                  char*                      path);
+} LV2_State_Free_Path;
+
+#ifdef __cplusplus
+} /* extern "C" */
+#endif
+
+#endif /* LV2_STATE_H */
+
+/**
+   @}
+*/