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author | David Robillard <d@drobilla.net> | 2011-11-21 01:36:00 +0000 |
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committer | David Robillard <d@drobilla.net> | 2011-11-21 01:36:00 +0000 |
commit | eb43c8896480114b224755e824fae2e2f7485256 (patch) | |
tree | 26e91bd8dc6421d2296a33991e90f7dcb546b079 /lv2/ns/ext/uri-map/uri-map.h | |
parent | df79255ccef7fb5d091e9d4e52f3c46545b53282 (diff) | |
download | lv2-eb43c8896480114b224755e824fae2e2f7485256.tar.xz |
Move ns to lv2/ns so repository top level can be used as an include dir directly.
Diffstat (limited to 'lv2/ns/ext/uri-map/uri-map.h')
-rw-r--r-- | lv2/ns/ext/uri-map/uri-map.h | 92 |
1 files changed, 92 insertions, 0 deletions
diff --git a/lv2/ns/ext/uri-map/uri-map.h b/lv2/ns/ext/uri-map/uri-map.h new file mode 100644 index 0000000..6767cd1 --- /dev/null +++ b/lv2/ns/ext/uri-map/uri-map.h @@ -0,0 +1,92 @@ +/* + 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 */ |