/* lv2_uri_map.h - C header file for the LV2 URI Map extension. * * Copyright (C) 2008-2009 David Robillard * * This header is free software; you can redistribute it and/or modify it * under the terms of the GNU Lesser General Public License as published * by the Free Software Foundation; either version 2 of the License, or * (at your option) any later version. * * This header is distributed in the hope that it will be useful, but WITHOUT * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or * FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public * License for more details. * * You should have received a copy of the GNU Lesser General Public License * along with this header; if not, write to the Free Software Foundation, * Inc., 59 Temple Place, Suite 330, Boston, MA 01222-1307 USA */ /** @file * C header for the LV2 URI Map extension . * * 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 /** Opaque pointer to host data. */ typedef void* LV2_URI_Map_Callback_Data; /** The data field of the LV2_Feature for this extension. * * 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. * @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 means an ID for that URI could not * be created for whatever reason. Extensions may define more precisely * what this means, but in general plugins should gracefully handle 0 * and consider whatever they wanted the URI for "unsupported". */ 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 */ > 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168