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authorDavid Robillard <d@drobilla.net>2016-09-17 20:27:41 -0400
committerDavid Robillard <d@drobilla.net>2016-09-18 10:16:49 -0400
commit0ba0e4e27fe8be4bed1b041de12c3917d2f0b53e (patch)
treee8efdc82dbc99a3bbe34c5d6d958c896c68754aa /plugins
parent3c9dbc63d82b40df08041d7b0cc070fae53efe8f (diff)
downloadlv2-0ba0e4e27fe8be4bed1b041de12c3917d2f0b53e.tar.xz
Simplify property handling with state map utility
Diffstat (limited to 'plugins')
-rw-r--r--plugins/eg-params.lv2/params.c354
-rw-r--r--plugins/eg-params.lv2/state_map.h110
2 files changed, 237 insertions, 227 deletions
diff --git a/plugins/eg-params.lv2/params.c b/plugins/eg-params.lv2/params.c
index b36e1be..3df6652 100644
--- a/plugins/eg-params.lv2/params.c
+++ b/plugins/eg-params.lv2/params.c
@@ -33,10 +33,13 @@
#include "lv2/lv2plug.in/ns/lv2core/lv2.h"
#include "lv2/lv2plug.in/ns/lv2core/lv2_util.h"
+#include "state_map.h"
+
#define MAX_STRING 1024
#define EG_PARAMS_URI "http://lv2plug.in/plugins/eg-params"
-#define EG_PARAMS__float EG_PARAMS_URI "#float"
+
+#define N_PROPS 9
typedef struct {
LV2_URID plugin;
@@ -44,14 +47,6 @@ typedef struct {
LV2_URID atom_Sequence;
LV2_URID atom_URID;
LV2_URID atom_eventTransfer;
- LV2_URID eg_int;
- LV2_URID eg_long;
- LV2_URID eg_float;
- LV2_URID eg_double;
- LV2_URID eg_bool;
- LV2_URID eg_string;
- LV2_URID eg_path;
- LV2_URID eg_lfo;
LV2_URID eg_spring;
LV2_URID midi_Event;
LV2_URID patch_Get;
@@ -86,14 +81,6 @@ map_uris(LV2_URID_Map* map, URIs* uris)
uris->atom_Sequence = map->map(map->handle, LV2_ATOM__Sequence);
uris->atom_URID = map->map(map->handle, LV2_ATOM__URID);
uris->atom_eventTransfer = map->map(map->handle, LV2_ATOM__eventTransfer);
- uris->eg_int = map->map(map->handle, EG_PARAMS_URI "#int");
- uris->eg_long = map->map(map->handle, EG_PARAMS_URI "#long");
- uris->eg_float = map->map(map->handle, EG_PARAMS_URI "#float");
- uris->eg_double = map->map(map->handle, EG_PARAMS_URI "#double");
- uris->eg_bool = map->map(map->handle, EG_PARAMS_URI "#bool");
- uris->eg_string = map->map(map->handle, EG_PARAMS_URI "#string");
- uris->eg_path = map->map(map->handle, EG_PARAMS_URI "#path");
- uris->eg_lfo = map->map(map->handle, EG_PARAMS_URI "#lfo");
uris->eg_spring = map->map(map->handle, EG_PARAMS_URI "#spring");
uris->midi_Event = map->map(map->handle, LV2_MIDI__MidiEvent);
uris->patch_Get = map->map(map->handle, LV2_PATCH__Get);
@@ -127,10 +114,11 @@ typedef struct {
URIs uris;
// Plugin state
- State state;
+ StateMapItem props[N_PROPS];
+ State state;
- float spring;
- float lfo;
+ // Buffer for making strings from URIDs if unmap is not provided
+ char urid_buf[12];
} Params;
static void
@@ -151,11 +139,6 @@ connect_port(LV2_Handle instance,
}
}
-#define INIT_PARAM(atype, param) { \
- (param)->atom.type = (atype); \
- (param)->atom.size = sizeof((param)->body); \
-}
-
static LV2_Handle
instantiate(const LV2_Descriptor* descriptor,
double rate,
@@ -186,18 +169,20 @@ instantiate(const LV2_Descriptor* descriptor,
map_uris(self->map, &self->uris);
lv2_atom_forge_init(&self->forge, self->map);
- // Initialize state
- INIT_PARAM(self->forge.Int, &self->state.aint);
- INIT_PARAM(self->forge.Long, &self->state.along);
- INIT_PARAM(self->forge.Float, &self->state.afloat);
- INIT_PARAM(self->forge.Double, &self->state.adouble);
- INIT_PARAM(self->forge.Bool, &self->state.abool);
- INIT_PARAM(self->forge.Float, &self->state.spring);
- INIT_PARAM(self->forge.Float, &self->state.lfo);
- self->state.astring.type = self->forge.String;
- self->state.astring.size = 0;
- self->state.apath.type = self->forge.Path;
- self->state.apath.size = 0;
+ // Initialise state dictionary
+ State* state = &self->state;
+ state_map_init(
+ self->props, self->map, self->map->handle,
+ EG_PARAMS_URI "#int", STATE_MAP_INIT(Int, &state->aint),
+ EG_PARAMS_URI "#long", STATE_MAP_INIT(Long, &state->along),
+ EG_PARAMS_URI "#float", STATE_MAP_INIT(Float, &state->afloat),
+ EG_PARAMS_URI "#double", STATE_MAP_INIT(Double, &state->adouble),
+ EG_PARAMS_URI "#bool", STATE_MAP_INIT(Bool, &state->abool),
+ EG_PARAMS_URI "#string", STATE_MAP_INIT(String, &state->astring),
+ EG_PARAMS_URI "#path", STATE_MAP_INIT(Path, &state->apath),
+ EG_PARAMS_URI "#lfo", STATE_MAP_INIT(Float, &state->lfo),
+ EG_PARAMS_URI "#spring", STATE_MAP_INIT(Float, &state->spring),
+ NULL);
return (LV2_Handle)self;
}
@@ -208,29 +193,33 @@ cleanup(LV2_Handle instance)
free(instance);
}
+/** Helper function to unmap a URID if possible. */
+static const char*
+unmap(Params* self, LV2_URID urid)
+{
+ if (self->unmap) {
+ return self->unmap->unmap(self->unmap->handle, urid);
+ } else {
+ snprintf(self->urid_buf, sizeof(self->urid_buf), "%u", urid);
+ return self->urid_buf;
+ }
+}
+
static LV2_State_Status
-check_param(Params* self,
- LV2_URID key,
- LV2_URID required_key,
- LV2_URID type,
- LV2_URID required_type)
+check_type(Params* self,
+ LV2_URID key,
+ LV2_URID type,
+ LV2_URID required_type)
{
- if (key == required_key) {
- if (type == required_type) {
- return LV2_STATE_SUCCESS;
- } else if (self->unmap) {
- lv2_log_trace(
- &self->log, "Bad type <%s> for <%s> (needs <%s>)\n",
- self->unmap->unmap(self->unmap->handle, type),
- self->unmap->unmap(self->unmap->handle, key),
- self->unmap->unmap(self->unmap->handle, required_type));
- } else {
- lv2_log_trace(&self->log, "Bad type for parameter %d\n", key);
- }
+ if (type != required_type) {
+ lv2_log_trace(
+ &self->log, "Bad type <%s> for <%s> (needs <%s>)\n",
+ unmap(self, type),
+ unmap(self, key),
+ unmap(self, required_type));
return LV2_STATE_ERR_BAD_TYPE;
}
-
- return LV2_STATE_ERR_NO_PROPERTY;
+ return LV2_STATE_SUCCESS;
}
static LV2_State_Status
@@ -241,105 +230,35 @@ set_parameter(Params* self,
const void* body,
bool from_state)
{
- const URIs* uris = &self->uris;
- const LV2_Atom_Forge* forge = &self->forge;
- LV2_State_Status st = LV2_STATE_SUCCESS;
-
- if (!(st = check_param(self, key, uris->eg_int, type, forge->Int))) {
- self->state.aint.body = *(const int32_t*)body;
- lv2_log_trace(&self->log, "Set int %d\n", self->state.aint.body);
- } else if (!(st = check_param(self, key, uris->eg_long, type, forge->Long))) {
- self->state.along.body = *(const int64_t*)body;
- lv2_log_trace(&self->log, "Set long %ld\n", self->state.along.body);
- } else if (!(st = check_param(self, key, uris->eg_float, type, forge->Float))) {
- self->state.afloat.body = *(const float*)body;
- lv2_log_trace(&self->log, "Set float %f\n", self->state.afloat.body);
- } else if (!(st = check_param(self, key, uris->eg_double, type, forge->Double))) {
- self->state.adouble.body = *(const double*)body;
- lv2_log_trace(&self->log, "Set double %f\n", self->state.adouble.body);
- } else if (!(st = check_param(self, key, uris->eg_bool, type, forge->Bool))) {
- self->state.abool.body = *(const int32_t*)body;
- lv2_log_trace(&self->log, "Set bool %d\n", self->state.abool.body);
- } else if (!(st = check_param(self, key, uris->eg_string, type, forge->String))) {
- if (size <= MAX_STRING) {
- memcpy(self->state.string, body, size);
- self->state.astring.size = size;
- lv2_log_trace(&self->log, "Set string %s\n", self->state.string);
- } else {
- lv2_log_error(&self->log, "Insufficient space for string\n");
- return LV2_STATE_ERR_NO_SPACE;
- }
- } else if (!(st = check_param(self, key, uris->eg_path, type, forge->Path))) {
- if (size <= MAX_STRING) {
- memcpy(self->state.path, body, size);
- self->state.apath.size = size;
- lv2_log_trace(&self->log, "Set path %s\n", self->state.path);
- } else {
- lv2_log_error(&self->log, "Insufficient space for path\n");
- return LV2_STATE_ERR_NO_SPACE;
- }
- } else if (!(st = check_param(self, key, uris->eg_spring, type, forge->Float))) {
- self->spring = *(const float*)body;
- lv2_log_trace(&self->log, "Set spring %f\n", *(const float*)body);
- } else if (key == uris->eg_lfo) {
- if (!from_state) {
- st = LV2_STATE_ERR_UNKNOWN;
- lv2_log_error(&self->log, "Attempt to set non-writable LFO\n");
- } else {
- self->state.lfo.body = *(const float*)body;
- lv2_log_trace(&self->log, "Set LFO %f\n", self->state.lfo.body);
- }
- } else if (self->unmap) {
- st = LV2_STATE_ERR_NO_PROPERTY;
- lv2_log_trace(&self->log, "Unknown parameter <%s>\n",
- self->unmap->unmap(self->unmap->handle, key));
- } else {
- st = LV2_STATE_ERR_NO_PROPERTY;
- lv2_log_trace(&self->log, "Unknown parameter %d\n", key);
+ // Look up property in state dictionary
+ const StateMapItem* entry = state_map_find(self->props, N_PROPS, key);
+ if (!entry) {
+ lv2_log_trace(&self->log, "Unknown parameter <%s>\n", unmap(self, key));
+ return LV2_STATE_ERR_NO_PROPERTY;
}
- return st;
+ // Ensure given type matches property's type
+ if (check_type(self, key, type, entry->value->type)) {
+ return LV2_STATE_ERR_BAD_TYPE;
+ }
+
+ // Set property value in state dictionary
+ lv2_log_trace(&self->log, "Set <%s>\n", entry->uri);
+ memcpy(entry->value + 1, body, size);
+ entry->value->size = size;
+ return LV2_STATE_SUCCESS;
}
static const LV2_Atom*
get_parameter(Params* self, LV2_URID key)
{
- const URIs* uris = &self->uris;
-
- if (key == uris->eg_int) {
- lv2_log_trace(&self->log, "Get int %d\n", self->state.aint.body);
- return &self->state.aint.atom;
- } else if (key == uris->eg_long) {
- lv2_log_trace(&self->log, "Get long %ld\n", self->state.along.body);
- return &self->state.along.atom;
- } else if (key == uris->eg_float) {
- lv2_log_trace(&self->log, "Get float %f\n", self->state.afloat.body);
- return &self->state.afloat.atom;
- } else if (key == uris->eg_double) {
- lv2_log_trace(&self->log, "Get double %f\n", self->state.adouble.body);
- return &self->state.adouble.atom;
- } else if (key == uris->eg_bool) {
- lv2_log_trace(&self->log, "Get bool %d\n", self->state.abool.body);
- return &self->state.abool.atom;
- } else if (key == uris->eg_string) {
- lv2_log_trace(&self->log, "Get string %s\n", self->state.string);
- return &self->state.astring;
- } else if (key == uris->eg_path) {
- lv2_log_trace(&self->log, "Get path %s\n", self->state.path);
- return &self->state.apath;
- } else if (key == uris->eg_spring) {
- lv2_log_trace(&self->log, "Get spring %f\n", self->state.spring.body);
- return &self->state.spring.atom;
- } else if (key == uris->eg_lfo) {
- lv2_log_trace(&self->log, "Get LFO %f\n", self->state.lfo.body);
- return &self->state.lfo.atom;
- } else if (self->unmap) {
- lv2_log_trace(&self->log, "Unknown parameter <%s>\n",
- self->unmap->unmap(self->unmap->handle, key));
- } else {
- lv2_log_trace(&self->log, "Unknown parameter %d\n", key);
+ const StateMapItem* entry = state_map_find(self->props, N_PROPS, key);
+ if (entry) {
+ lv2_log_trace(&self->log, "Get <%s>\n", entry->uri);
+ return entry->value;
}
+ lv2_log_trace(&self->log, "Unknown parameter <%s>\n", unmap(self, key));
return NULL;
}
@@ -363,63 +282,48 @@ write_param_to_forge(LV2_State_Handle handle,
}
static void
-store_param(Params* self,
- LV2_State_Status* save_status,
- LV2_State_Store_Function store,
- LV2_State_Handle handle,
- LV2_URID key,
- const LV2_Atom* value)
-{
- const LV2_State_Status st = store(handle,
- key,
- value + 1,
- value->size,
- value->type,
- LV2_STATE_IS_POD | LV2_STATE_IS_PORTABLE);
-
- if (!*save_status) {
- *save_status = st;
- }
-}
-
-static LV2_State_Status
-store_state(Params* self,
- LV2_State_Store_Function store,
- LV2_State_Handle handle,
- uint32_t flags,
- LV2_State_Map_Path* map_path)
+store_prop(Params* self,
+ LV2_State_Map_Path* map_path,
+ LV2_State_Status* save_status,
+ LV2_State_Store_Function store,
+ LV2_State_Handle handle,
+ LV2_URID key,
+ const LV2_Atom* value)
{
- const URIs* uris = &self->uris;
- const State* state = &self->state;
- LV2_State_Status st = LV2_STATE_SUCCESS;
-
- // Store simple properties
- store_param(self, &st, store, handle, uris->eg_int, &state->aint.atom);
- store_param(self, &st, store, handle, uris->eg_long, &state->along.atom);
- store_param(self, &st, store, handle, uris->eg_float, &state->afloat.atom);
- store_param(self, &st, store, handle, uris->eg_double, &state->adouble.atom);
- store_param(self, &st, store, handle, uris->eg_bool, &state->abool.atom);
- store_param(self, &st, store, handle, uris->eg_string, &state->astring);
- store_param(self, &st, store, handle, uris->eg_spring, &state->spring.atom);
- store_param(self, &st, store, handle, uris->eg_lfo, &state->lfo.atom);
-
- if (map_path) {
+ LV2_State_Status st;
+ if (map_path && value->type == self->uris.atom_Path) {
// Map path to abstract path for portable storage
- char* apath = map_path->abstract_path(map_path->handle, state->path);
+ const char* path = (const char*)(value + 1);
+ char* apath = map_path->abstract_path(map_path->handle, path);
st = store(handle,
- self->uris.eg_path,
+ key,
apath,
strlen(apath) + 1,
self->uris.atom_Path,
LV2_STATE_IS_POD | LV2_STATE_IS_PORTABLE);
free(apath);
} else {
- store_param(self, &st, store, handle, uris->eg_path, &state->apath);
+ // Store simple property
+ st = store(handle,
+ key,
+ value + 1,
+ value->size,
+ value->type,
+ LV2_STATE_IS_POD | LV2_STATE_IS_PORTABLE);
}
- return st;
+ if (save_status && !*save_status) {
+ *save_status = st;
+ }
}
+/**
+ State save method.
+
+ This is used in the usual way when called by the host to save plugin state,
+ but also internally for writing messages in the audio thread by passing a
+ "store" function which actually writes the description to the forge.
+*/
static LV2_State_Status
save(LV2_Handle instance,
LV2_State_Store_Function store,
@@ -431,15 +335,21 @@ save(LV2_Handle instance,
LV2_State_Map_Path* map_path = (LV2_State_Map_Path*)lv2_features_data(
features, LV2_STATE__mapPath);
- return store_state(self, store, handle, flags, map_path);
+ LV2_State_Status st = LV2_STATE_SUCCESS;
+ for (unsigned i = 0; i < N_PROPS; ++i) {
+ StateMapItem* prop = &self->props[i];
+ store_prop(self, map_path, &st, store, handle, prop->urid, prop->value);
+ }
+
+ return st;
}
static void
-retrieve_param(Params* self,
- LV2_State_Status* restore_status,
- LV2_State_Retrieve_Function retrieve,
- LV2_State_Handle handle,
- LV2_URID key)
+retrieve_prop(Params* self,
+ LV2_State_Status* restore_status,
+ LV2_State_Retrieve_Function retrieve,
+ LV2_State_Handle handle,
+ LV2_URID key)
{
// Retrieve value from saved state
size_t vsize;
@@ -457,6 +367,7 @@ retrieve_param(Params* self,
}
}
+/** State restore method. */
static LV2_State_Status
restore(LV2_Handle instance,
LV2_State_Retrieve_Function retrieve,
@@ -467,16 +378,9 @@ restore(LV2_Handle instance,
Params* self = (Params*)instance;
LV2_State_Status st = LV2_STATE_SUCCESS;
- // Retrieve simple properties
- retrieve_param(self, &st, retrieve, handle, self->uris.eg_int);
- retrieve_param(self, &st, retrieve, handle, self->uris.eg_long);
- retrieve_param(self, &st, retrieve, handle, self->uris.eg_float);
- retrieve_param(self, &st, retrieve, handle, self->uris.eg_double);
- retrieve_param(self, &st, retrieve, handle, self->uris.eg_bool);
- retrieve_param(self, &st, retrieve, handle, self->uris.eg_string);
- retrieve_param(self, &st, retrieve, handle, self->uris.eg_path);
- retrieve_param(self, &st, retrieve, handle, self->uris.eg_spring);
- retrieve_param(self, &st, retrieve, handle, self->uris.eg_lfo);
+ for (unsigned i = 0; i < N_PROPS; ++i) {
+ retrieve_prop(self, &st, retrieve, handle, self->props[i].urid);
+ }
return st;
}
@@ -502,7 +406,7 @@ run(LV2_Handle instance, uint32_t sample_count)
(uint8_t*)self->out_port,
out_capacity);
- // Start a sequence in the output port.
+ // Start a sequence in the output port
LV2_Atom_Forge_Frame out_frame;
lv2_atom_forge_sequence_head(&self->forge, &out_frame, 0);
@@ -526,11 +430,12 @@ run(LV2_Handle instance, uint32_t sample_count)
} else if (property->atom.type != uris->atom_URID) {
lv2_log_error(&self->log, "Set property is not a URID\n");
} else {
+ // Set property to the given value
const LV2_URID key = property->body;
set_parameter(self, key, value->size, value->type, value + 1, false);
}
} else if (obj->body.otype == uris->patch_Get) {
- // Get the property and value of the get message
+ // Get the property of the get message
const LV2_Atom_URID* subject = NULL;
const LV2_Atom_URID* property = NULL;
lv2_atom_object_get(obj,
@@ -540,7 +445,7 @@ run(LV2_Handle instance, uint32_t sample_count)
if (!subject_is_plugin(self, subject)) {
lv2_log_error(&self->log, "Get with unknown subject\n");
} else if (!property) {
- // Received a get message, emit our full state (probably to UI)
+ // Get with no property, emit complete state
lv2_atom_forge_frame_time(&self->forge, ev->time.frames);
LV2_Atom_Forge_Frame pframe;
lv2_atom_forge_object(&self->forge, &pframe, 0, uris->patch_Put);
@@ -548,41 +453,36 @@ run(LV2_Handle instance, uint32_t sample_count)
LV2_Atom_Forge_Frame bframe;
lv2_atom_forge_object(&self->forge, &bframe, 0, 0);
- store_state(self, write_param_to_forge, &self->forge, 0, NULL);
+ save(self, write_param_to_forge, &self->forge, 0, NULL);
lv2_atom_forge_pop(&self->forge, &bframe);
lv2_atom_forge_pop(&self->forge, &pframe);
} else if (property->atom.type != uris->atom_URID) {
lv2_log_error(&self->log, "Get property is not a URID\n");
} else {
- // Received a get message, emit single property state (probably to UI)
- const LV2_URID key = property->body;
- const LV2_Atom* atom = get_parameter(self, key);
- if (atom) {
+ // Get for a specific property
+ const LV2_URID key = property->body;
+ const LV2_Atom* value = get_parameter(self, key);
+ if (value) {
lv2_atom_forge_frame_time(&self->forge, ev->time.frames);
- LV2_State_Status st = LV2_STATE_SUCCESS;
LV2_Atom_Forge_Frame frame;
lv2_atom_forge_object(&self->forge, &frame, 0, uris->patch_Set);
lv2_atom_forge_key(&self->forge, uris->patch_property);
lv2_atom_forge_urid(&self->forge, property->body);
- store_param(self, &st, write_param_to_forge, &self->forge,
- uris->patch_value, atom);
+ store_prop(self, NULL, NULL, write_param_to_forge, &self->forge,
+ uris->patch_value, value);
lv2_atom_forge_pop(&self->forge, &frame);
}
}
} else {
- if (self->unmap) {
- lv2_log_trace(&self->log, "Unknown object type <%s>\n",
- self->unmap->unmap(self->unmap->handle, obj->body.otype));
- } else {
- lv2_log_trace(&self->log, "Unknown object type %d\n",
- obj->body.otype);
- }
+ lv2_log_trace(&self->log, "Unknown object type <%s>\n",
+ unmap(self, obj->body.otype));
}
}
- if (self->spring > 0.0f) {
- self->spring = (self->spring >= 0.001) ? self->spring - 0.001 : 0.0;
+ if (self->state.spring.body > 0.0f) {
+ const float spring = self->state.spring.body;
+ self->state.spring.body = (spring >= 0.001) ? spring - 0.001 : 0.0;
lv2_atom_forge_frame_time(&self->forge, 0);
LV2_Atom_Forge_Frame frame;
lv2_atom_forge_object(&self->forge, &frame, 0, uris->patch_Set);
@@ -590,7 +490,7 @@ run(LV2_Handle instance, uint32_t sample_count)
lv2_atom_forge_key(&self->forge, uris->patch_property);
lv2_atom_forge_urid(&self->forge, uris->eg_spring);
lv2_atom_forge_key(&self->forge, uris->patch_value);
- lv2_atom_forge_float(&self->forge, self->spring);
+ lv2_atom_forge_float(&self->forge, self->state.spring.body);
lv2_atom_forge_pop(&self->forge, &frame);
}
diff --git a/plugins/eg-params.lv2/state_map.h b/plugins/eg-params.lv2/state_map.h
new file mode 100644
index 0000000..ccd9ca6
--- /dev/null
+++ b/plugins/eg-params.lv2/state_map.h
@@ -0,0 +1,110 @@
+/*
+ LV2 State Map
+ Copyright 2016 David Robillard <d@drobilla.net>
+
+ 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.
+*/
+
+#include <stdlib.h>
+
+/** Entry in an array that serves as a dictionary of properties. */
+typedef struct {
+ const char* uri;
+ LV2_URID urid;
+ LV2_Atom* value;
+} StateMapItem;
+
+/** Comparator for StateMapItems sorted by URID. */
+static int
+state_map_cmp(const void* a, const void* b)
+{
+ const StateMapItem* ka = (const StateMapItem*)a;
+ const StateMapItem* kb = (const StateMapItem*)b;
+ if (ka->urid < kb->urid) {
+ return -1;
+ } else if (kb->urid < ka->urid) {
+ return 1;
+ }
+ return 0;
+}
+
+/** Helper macro for terse state map initialisation. */
+#define STATE_MAP_INIT(type, ptr) \
+ (LV2_ATOM__ ## type), \
+ (sizeof(*ptr) - sizeof(LV2_Atom)), \
+ (ptr)
+
+/**
+ Initialise a state map.
+
+ The variable parameters list must be NULL terminated, and is a sequence of
+ const char* uri, const char* type, uint32_t size, LV2_Atom* value. The
+ value must point to a valid atom that resides elsewhere, the state map is
+ only an index and does not contain actual state values. The macro
+ STATE_MAP_INIT can be used to make simpler code when state is composed of
+ standard atom types, for example:
+
+ struct Plugin {
+ LV2_URID_Map* map;
+ StateMapItem props[3];
+ // ...
+ };
+
+ state_map_init(
+ self->props, self->map, self->map->handle,
+ PLUG_URI "#gain", STATE_MAP_INIT(Float, &state->gain),
+ PLUG_URI "#offset", STATE_MAP_INIT(Int, &state->offset),
+ PLUG_URI "#file", STATE_MAP_INIT(Path, &state->file),
+ NULL);
+*/
+static void
+state_map_init(StateMapItem dict[],
+ LV2_URID_Map* map,
+ LV2_URID_Map_Handle* handle,
+ /* const char* uri, const char* type, uint32_t size, LV2_Atom* value */ ...)
+{
+ // Set dict entries from parameters
+ unsigned i = 0;
+ va_list args;
+ va_start(args, handle);
+ for (const char* uri; (uri = va_arg(args, const char*)); ++i) {
+ const char* type = va_arg(args, const char*);
+ const uint32_t size = va_arg(args, uint32_t);
+ LV2_Atom* const value = va_arg(args, LV2_Atom*);
+ dict[i].uri = uri;
+ dict[i].urid = map->map(map->handle, uri);
+ dict[i].value = value;
+ dict[i].value->size = size;
+ dict[i].value->type = map->map(map->handle, type);
+ }
+ va_end(args);
+
+ // Sort for fast lookup by URID by state_map_find()
+ qsort(dict, i, sizeof(StateMapItem), state_map_cmp);
+}
+
+/**
+ Retrieve an item from a state map by URID.
+
+ This takes O(lg(n)) time, and is useful for implementing generic property
+ access with little code, for example to respond to patch:Get messages for a
+ specific property.
+*/
+static StateMapItem*
+state_map_find(StateMapItem dict[], uint32_t n_entries, LV2_URID urid)
+{
+ const StateMapItem key = { NULL, urid, NULL };
+ return (StateMapItem*)bsearch(
+ &key, dict, n_entries, sizeof(StateMapItem), state_map_cmp);
+}
+