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diff --git a/src/control.h b/src/control.h
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+// Copyright 2007-2022 David Robillard <d@drobilla.net>
+// SPDX-License-Identifier: ISC
+
+#ifndef JALV_CONTROL_H
+#define JALV_CONTROL_H
+
+#include "attributes.h"
+#include "nodes.h"
+
+#include <lilv/lilv.h>
+#include <lv2/atom/forge.h>
+#include <lv2/urid/urid.h>
+
+#include <stdbool.h>
+#include <stddef.h>
+#include <stdint.h>
+
+// Support for plugin controls (control port or event-based)
+JALV_BEGIN_DECLS
+
+/// Type of plugin control
+typedef enum {
+  PORT,    ///< Control port
+  PROPERTY ///< Property (set via atom message)
+} ControlType;
+
+// "Interesting" value in a control's value range
+typedef struct {
+  float value;
+  char* label;
+} ScalePoint;
+
+/// Plugin control
+typedef struct {
+  ControlType type; ///< Type of control
+  union {
+    LV2_URID property; ///< Iff type == PROPERTY
+    uint32_t index;    ///< Iff type == PORT
+  } id;
+  LilvNode*   node;           ///< Port or property
+  LilvNode*   symbol;         ///< Symbol
+  LilvNode*   label;          ///< Human readable label
+  LilvNode*   group;          ///< Port/control group, or NULL
+  void*       widget;         ///< Control Widget
+  size_t      n_points;       ///< Number of scale points
+  ScalePoint* points;         ///< Scale points
+  LV2_URID    value_type;     ///< Type of control value
+  LilvNode*   min;            ///< Minimum value
+  LilvNode*   max;            ///< Maximum value
+  LilvNode*   def;            ///< Default value
+  bool        is_toggle;      ///< Boolean (0 and 1 only)
+  bool        is_integer;     ///< Integer values only
+  bool        is_enumeration; ///< Point values only
+  bool        is_logarithmic; ///< Logarithmic scale
+  bool        is_writable;    ///< Writable (input)
+  bool        is_readable;    ///< Readable (output)
+} ControlID;
+
+/// Set of plugin controls
+typedef struct {
+  size_t      n_controls;
+  ControlID** controls;
+} Controls;
+
+/// Create a new ID for a control port
+ControlID*
+new_port_control(LilvWorld*            world,
+                 const LilvPlugin*     plugin,
+                 const LilvPort*       port,
+                 uint32_t              port_index,
+                 float                 sample_rate,
+                 const JalvNodes*      nodes,
+                 const LV2_Atom_Forge* forge);
+
+/// Create a new ID for a property-based parameter
+ControlID*
+new_property_control(LilvWorld*            world,
+                     const LilvNode*       property,
+                     const JalvNodes*      nodes,
+                     LV2_URID_Map*         map,
+                     const LV2_Atom_Forge* forge);
+
+/// Free a control allocated with new_port_control() or new_property_control()
+void
+free_control(ControlID* control);
+
+/// Add a control to the given controls set, reallocating as necessary
+void
+add_control(Controls* controls, ControlID* control);
+
+/// Return a pointer to the control for the given property, or null
+ControlID*
+get_property_control(const Controls* controls, LV2_URID property);
+
+JALV_END_DECLS
+
+#endif // JALV_CONTROL_H