/[svn]/linuxsampler/trunk/src/hostplugins/lv2/lv2_uri_map.h
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Contents of /linuxsampler/trunk/src/hostplugins/lv2/lv2_uri_map.h

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Revision 2174 - (show annotations) (download) (as text)
Tue Apr 12 15:19:56 2011 UTC (8 years, 9 months ago) by capela
File MIME type: text/x-c++hdr
File size: 3542 byte(s)
* plugin changes:
    - LV2 Persist + Files support (patch by David Robillard)

1 /* lv2_uri_map.h - C header file for the LV2 URI Map extension.
2 *
3 * Copyright (C) 2008-2009 David Robillard <http://drobilla.net>
4 *
5 * This header is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU Lesser General Public License as published
7 * by the Free Software Foundation; either version 2 of the License, or
8 * (at your option) any later version.
9 *
10 * This header is distributed in the hope that it will be useful, but WITHOUT
11 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
12 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public
13 * License for more details.
14 *
15 * You should have received a copy of the GNU Lesser General Public License
16 * along with this header; if not, write to the Free Software Foundation,
17 * Inc., 59 Temple Place, Suite 330, Boston, MA 01222-1307 USA
18 */
19
20 /** @file
21 * C header for the LV2 URI Map extension <http://lv2plug.in/ns/ext/uri-map>.
22 *
23 * This extension defines a simple mechanism for plugins to map URIs to
24 * integers, usually for performance reasons (e.g. processing events
25 * typed by URIs in real time). The expected use case is for plugins to
26 * map URIs to integers for things they 'understand' at instantiation time,
27 * and store those values for use in the audio thread without doing any string
28 * comparison. This allows the extensibility of RDF with the performance of
29 * integers (or centrally defined enumerations).
30 */
31
32 #ifndef LV2_URI_MAP_H
33 #define LV2_URI_MAP_H
34
35 #define LV2_URI_MAP_URI "http://lv2plug.in/ns/ext/uri-map"
36
37 #include <stdint.h>
38
39
40 /** Opaque pointer to host data. */
41 typedef void* LV2_URI_Map_Callback_Data;
42
43
44 /** The data field of the LV2_Feature for this extension.
45 *
46 * To support this feature the host must pass an LV2_Feature struct to the
47 * plugin's instantiate method with URI "http://lv2plug.in/ns/ext/uri-map"
48 * and data pointed to an instance of this struct.
49 */
50 typedef struct {
51
52 /** Opaque pointer to host data.
53 *
54 * The plugin MUST pass this to any call to functions in this struct.
55 * Otherwise, it must not be interpreted in any way.
56 */
57 LV2_URI_Map_Callback_Data callback_data;
58
59 /** Get the numeric ID of a URI from the host.
60 *
61 * @param callback_data Must be the callback_data member of this struct.
62 * @param map The 'context' of this URI. Certain extensions may define a
63 * URI that must be passed here with certain restrictions on the
64 * return value (e.g. limited range). This value may be NULL if
65 * the plugin needs an ID for a URI in general.
66 * @param uri The URI to be mapped to an integer ID.
67 *
68 * This function is referentially transparent - any number of calls with
69 * the same arguments is guaranteed to return the same value over the life
70 * of a plugin instance (though the same URI may return different values
71 * with a different map parameter). However, this function is not
72 * necessarily very fast: plugins should cache any IDs they might need in
73 * performance critical situations.
74 * The return value 0 is reserved and means an ID for that URI could not
75 * be created for whatever reason. Extensions may define more precisely
76 * what this means, but in general plugins should gracefully handle 0
77 * and consider whatever they wanted the URI for "unsupported".
78 */
79 uint32_t (*uri_to_id)(LV2_URI_Map_Callback_Data callback_data,
80 const char* map,
81 const char* uri);
82
83 } LV2_URI_Map_Feature;
84
85
86 #endif /* LV2_URI_MAP_H */
87

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