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diff --git a/ns/ext/uri-map/uri-map.h b/ns/ext/uri-map/uri-map.h
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+/*
+  Copyright 2008-2011 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.
+*/
+
+/**
+   @file
+   C header for the LV2 URI Map extension <http://lv2plug.in/ns/ext/uri-map>.
+ 
+   This extension defines a simple mechanism for plugins to map URIs to
+   integers, usually for performance reasons (e.g. processing events typed by
+   URIs in real time). The expected use case is for plugins to map URIs to
+   integers for things they 'understand' at instantiation time, and store those
+   values for use in the audio thread without doing any string comparison.
+   This allows the extensibility of RDF with the performance of integers (or
+   centrally defined enumerations).
+*/
+
+#ifndef LV2_URI_MAP_H
+#define LV2_URI_MAP_H
+
+#define LV2_URI_MAP_URI "http://lv2plug.in/ns/ext/uri-map"
+
+#include <stdint.h>
+
+/**
+   Opaque pointer to host data.
+*/
+typedef void* LV2_URI_Map_Callback_Data;
+
+/**
+   URI Map Feature.
+ 
+   To support this feature the host must pass an LV2_Feature struct to the
+   plugin's instantiate method with URI "http://lv2plug.in/ns/ext/uri-map"
+   and data pointed to an instance of this struct.
+*/
+typedef struct {
+
+	/**
+	   Opaque pointer to host data.
+	 
+	   The plugin MUST pass this to any call to functions in this struct.
+	   Otherwise, it must not be interpreted in any way.
+	*/
+	LV2_URI_Map_Callback_Data callback_data;
+
+	/**
+	   Get the numeric ID of a URI from the host.
+	 
+	   @param callback_data Must be the callback_data member of this struct.
+	   @param map The 'context' of this URI. Certain extensions may define a
+	   URI that must be passed here with certain restrictions on the return
+	   value (e.g. limited range). This value may be NULL if the plugin needs
+	   an ID for a URI in general. Extensions SHOULD NOT define a context
+	   unless there is a specific need to do so, e.g. to restrict the range of
+	   the returned value.
+	   @param uri The URI to be mapped to an integer ID.
+	 
+	   This function is referentially transparent; any number of calls with the
+	   same arguments is guaranteed to return the same value over the life of a
+	   plugin instance (though the same URI may return different values with a
+	   different map parameter). However, this function is not necessarily very
+	   fast: plugins SHOULD cache any IDs they might need in performance
+	   critical situations.
+	   
+	   The return value 0 is reserved and indicates that an ID for that URI
+	   could not be created for whatever reason. Extensions MAY define more
+	   precisely what this means in a certain context, but in general plugins
+	   SHOULD handle this situation as gracefully as possible. However, hosts
+	   SHOULD NOT return 0 from this function in non-exceptional circumstances
+	   (e.g. the URI map SHOULD be dynamic). Hosts that statically support only
+	   a fixed set of URIs should not expect plugins to function correctly.
+	*/
+	uint32_t (*uri_to_id)(LV2_URI_Map_Callback_Data callback_data,
+	                      const char*               map,
+	                      const char*               uri);
+
+} LV2_URI_Map_Feature;
+
+#endif /* LV2_URI_MAP_H */