Add lv2_features_data() and lv2_features_query()

This adds a new header lv2/lv2plug.in/ns/lv2core/lv2_util.h for utility
functions useful with core LV2.

5 files changed, 115 insertions, 4 deletions

diff --git a/lv2/lv2plug.in/ns/lv2core/lv2_util.h b/lv2/lv2plug.in/ns/lv2core/lv2_util.h
new file mode 100644
index 0000000..038b5a6
--- /dev/null
+++ b/lv2/lv2plug.in/ns/lv2core/lv2_util.h
@@ -0,0 +1,101 @@
+/*
+  Copyright 2016 David Robillard <http://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.
+*/
+
+/**
+   @defgroup util Utilities
+   @ingroup lv2core
+   @{
+*/
+
+#include <string.h>
+
+#include "lv2/lv2plug.in/ns/lv2core/lv2.h"
+
+#ifdef __cplusplus
+extern "C" {
+#else
+#    include <stdbool.h>
+#endif
+
+/**
+   Return the data for a feature in a features array.
+
+   If the feature is not found, NULL is returned.  Note that this function is
+   only useful for features with data, and can not detect features that are
+   present but have NULL data.
+*/
+static inline void*
+lv2_features_data(const LV2_Feature*const* features,
+                  const char* const        uri)
+{
+	for (const LV2_Feature*const* f = features; *f; ++f) {
+		if (!strcmp(uri, (*f)->URI)) {
+			return (*f)->data;
+		}
+	}
+	return NULL;
+}
+
+/**
+   Query a features array.
+
+   This function allows getting several features in one call, and detect
+   missing required features, with the same caveat of lv2_features_data().
+
+   The arguments should be a series of const char* uri, void** data, bool
+   required, terminated by a NULL URI.  The data pointers MUST be initialized
+   to NULL.  For example:
+
+   @code
+   LV2_URID_Log* log = NULL;
+   LV2_URID_Map* map = NULL;
+   const char* missing = lv2_features_query(
+        features,
+        LV2_LOG__log,  &log, false,
+        LV2_URID__map, &map, true,
+        NULL);
+   @endcode
+
+   @return NULL on success, otherwise the URI of this missing feature.
+*/
+static inline const char*
+lv2_features_query(const LV2_Feature* const* features, ...)
+{
+	va_list args;
+	va_start(args, features);
+
+	const char* uri = NULL;
+	while ((uri = va_arg(args, const char*))) {
+		void** data     = va_arg(args, void**);
+		bool   required = va_arg(args, int);
+
+		*data = lv2_features_data(features, uri);
+		if (required && !*data) {
+			return uri;
+		}
+	}
+
+	return NULL;
+}
+
+#ifdef __cplusplus
+}  /* extern "C" */
+#endif
+
+/**
+   @}
+   @}
+*/
diff --git a/lv2/lv2plug.in/ns/lv2core/lv2core.doap.ttl b/lv2/lv2plug.in/ns/lv2core/lv2core.doap.ttl
index 2e74227..3768faf 100644
--- a/lv2/lv2plug.in/ns/lv2core/lv2core.doap.ttl
+++ b/lv2/lv2plug.in/ns/lv2core/lv2core.doap.ttl
@@ -16,6 +16,15 @@
 		<http://drobilla.net/drobilla#me> ;
 	doap:maintainer <http://drobilla.net/drobilla#me> ;
 	doap:release [
+		doap:revision "13.1" ;
+		doap:created "2016-07-30" ;
+		dcs:blame <http://drobilla.net/drobilla#me> ;
+		dcs:changeset [
+			dcs:item [
+				rdfs:label "Add lv2_util.h with lv2_features_data() and lv2_features_query()."
+			]
+		]
+	] , [
 		doap:revision "12.4" ;
 		doap:created "2015-04-07" ;
 		doap:file-release <http://lv2plug.in/spec/lv2-1.12.0.tar.bz2> ;
diff --git a/lv2/lv2plug.in/ns/lv2core/lv2core.ttl b/lv2/lv2plug.in/ns/lv2core/lv2core.ttl
index d08d063..1980f37 100644
--- a/lv2/lv2plug.in/ns/lv2core/lv2core.ttl
+++ b/lv2/lv2plug.in/ns/lv2core/lv2core.ttl
@@ -38,6 +38,7 @@ devices). See <a href="http://www.w3.org/TR/xhtml-basic/#s_xhtmlmodules"
 <http://lv2plug.in/ns/lv2core>
 	a owl:Ontology ;
 	rdfs:seeAlso <lv2.h> ,
+		<lv2_util.h> ,
 		<lv2core.doap.ttl> ,
 		<../meta/meta.ttl> ;
 	lv2:documentation """
diff --git a/lv2/lv2plug.in/ns/lv2core/manifest.ttl b/lv2/lv2plug.in/ns/lv2core/manifest.ttl
index 2995826..916b596 100644
--- a/lv2/lv2plug.in/ns/lv2core/manifest.ttl
+++ b/lv2/lv2plug.in/ns/lv2core/manifest.ttl
@@ -4,6 +4,6 @@
 
 <http://lv2plug.in/ns/lv2core>
 	a lv2:Specification ;
-	lv2:minorVersion 12 ;
-	lv2:microVersion 4 ;
+	lv2:minorVersion 13 ;
+	lv2:microVersion 1 ;
 	rdfs:seeAlso <lv2core.ttl> .
diff --git a/lv2/lv2plug.in/ns/meta/meta.ttl b/lv2/lv2plug.in/ns/meta/meta.ttl
index a3c21fb..4725a50 100644
--- a/lv2/lv2plug.in/ns/meta/meta.ttl
+++ b/lv2/lv2plug.in/ns/meta/meta.ttl
@@ -46,8 +46,8 @@ THIS SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES WITH R
 		meta:kfoltman ,
 		meta:paniq ;
 	doap:release [
-		doap:revision "1.12.1" ;
-		doap:created "2015-10-24" ;
+		doap:revision "1.13.1" ;
+		doap:created "2016-07-31" ;
 		dcs:blame <http://drobilla.net/drobilla#me> ;
 		dcs:changeset [
 			dcs:item [