diff options
Diffstat (limited to 'lv2/atom/atom.ttl')
| -rw-r--r-- | lv2/atom/atom.ttl | 473 |
1 files changed, 58 insertions, 415 deletions
diff --git a/lv2/atom/atom.ttl b/lv2/atom/atom.ttl index dc9fa1e..96e9326 100644 --- a/lv2/atom/atom.ttl +++ b/lv2/atom/atom.ttl @@ -14,121 +14,44 @@ <util.h> , <forge.h> , <atom.meta.ttl> ; - lv2:documentation """ - -<p>An #Atom is a simple generic data container for holding any type of Plain -Old Data (POD). An #Atom can contain simple primitive types like integers, -floating point numbers, and strings; as well as structured data like lists and -dictionary-like <q>Objects</q>. Since Atoms are POD, they can be easily copied -(e.g. using <code>memcpy</code>) anywhere and are suitable for use in real-time -code.</p> - -<p>Every atom starts with an LV2_Atom header, followed by the contents. This -allows code to process atoms without requiring special code for every type of -data. For example, plugins that mutually understand a type can be used -together in a host that does not understand that type, because the host is only -required to copy atoms, not interpret their contents. Similarly, plugins (such -as routers, delays, or data structures) can meaningfully process atoms of a -type unknown to them.</p> - -<p>Atoms should be used anywhere values of various types must be stored or -transmitted. The port type #AtomPort can be used to transmit atoms via ports. -An #AtomPort that contains an #Sequence can be used for sample accurate event -communication, such as MIDI, and replaces the earlier event extension.</p> - -<h3>Serialisation</h3> - -<p>Each Atom type defines a binary format for use at runtime, but also a -serialisation that is natural to express in Turtle format. Thus, this -specification defines a powerful real-time appropriate data model, as well as a -portable way to serialise any data in that model. This is particularly useful -for inter-process communication, saving/restoring state, and describing values -in plugin data files.</p> - -<h3>Custom Atom Types</h3> - -<p>While it is possible to define new Atom types for any binary format, the -standard types defined here are powerful enough to describe almost anything. -Implementations SHOULD build structures out of the types provided here, rather -than define new binary formats (e.g. use #Tuple or #Object rather than -a new C <code>struct</code> type). Current implementations have support for -serialising all standard types, so new binary formats are an implementation -burden which harms interoperabilty. In particular, plugins SHOULD NOT expect -UI communication or state saving with custom Atom types to work. In general, -new Atom types should only be defined where absolutely necessary due to -performance reasons and serialisation is not a concern.</p> -""" . + rdfs:label "LV2 Atom" ; + rdfs:comment "A generic value container and several data types." . atom:cType a rdf:Property , owl:DatatypeProperty , owl:FunctionalProperty ; rdfs:label "C type" ; + rdfs:comment "The C type that describes the binary representation of an Atom type." ; rdfs:domain rdfs:Class ; - rdfs:range lv2:Symbol ; - rdfs:comment "The identifier for a C type describing the binary representation of an Atom of this type." . + rdfs:range lv2:Symbol . atom:Atom a rdfs:Class ; rdfs:label "Atom" ; - atom:cType "LV2_Atom" ; - lv2:documentation """ -<p>Abstract base class for all atoms. An LV2_Atom has a 32-bit -<code>size</code> and <code>type</code> followed by a body of <code>size</code> -bytes. Atoms MUST be 64-bit aligned.</p> - -<p>All concrete Atom types (subclasses of this class) MUST define a precise -binary layout for their body.</p> - -<p>The <code>type</code> field is the URI of an Atom type mapped to an integer. -Implementations SHOULD gracefully pass through, or ignore, atoms with unknown -types.</p> - -<p>All atoms are POD by definition except references, which as a special case -have <code>type = 0</code>. An Atom MUST NOT contain a Reference. It is safe -to copy any non-reference Atom with a simple <code>memcpy</code>, even if the -implementation does not understand <code>type</code>. Though this extension -reserves the type 0 for references, the details of reference handling are -currently unspecified. A future revision of this extension, or a different -extension, may define how to use non-POD data and references. Implementations -MUST NOT send references to another implementation unless the receiver is -explicitly known to support references (e.g. by supporting a feature).</p> - -<p>The atom with both <code>type</code> <em>and</em> <code>size</code> 0 is -<q>null</q>, which is not considered a Reference.</p> -""" . + rdfs:comment "Abstract base class for all atoms." ; + atom:cType "LV2_Atom" . atom:Chunk a rdfs:Class , rdfs:Datatype ; rdfs:subClassOf atom:Atom ; - rdfs:label "Chunk of memory" ; - owl:onDatatype xsd:base64Binary ; - lv2:documentation """ -<p>A chunk of memory with undefined contents. This type is used to indicate a -certain amount of space is available. For example, output ports with a -variably sized type are connected to a Chunk so the plugin knows the size of -the buffer available for writing.</p> - -<p>The use of a Chunk should be constrained to a local scope, since -interpreting it is impossible without context. However, if serialised to RDF, -a Chunk may be represented directly as an xsd:base64Binary string, e.g.:</p> - -<pre class="turtle-code"> -[] eg:someChunk "vu/erQ=="^^xsd:base64Binary . -</pre> -""" . + rdfs:label "Chunk" ; + rdfs:comment "A chunk of memory with undefined contents." ; + owl:onDatatype xsd:base64Binary . atom:Number a rdfs:Class ; rdfs:subClassOf atom:Atom ; - rdfs:label "Number" . + rdfs:label "Number" ; + rdfs:comment "Base class for numeric types." . atom:Int a rdfs:Class , rdfs:Datatype ; rdfs:subClassOf atom:Number ; - rdfs:label "Signed 32-bit integer" ; + rdfs:label "Int" ; + rdfs:comment "A native `int32_t`." ; atom:cType "LV2_Atom_Int" ; owl:onDatatype xsd:int . @@ -136,7 +59,8 @@ atom:Long a rdfs:Class , rdfs:Datatype ; rdfs:subClassOf atom:Number ; - rdfs:label "Signed 64-bit integer" ; + rdfs:label "Long" ; + rdfs:comment "A native `int64_t`." ; atom:cType "LV2_Atom_Long" ; owl:onDatatype xsd:long . @@ -144,7 +68,8 @@ atom:Float a rdfs:Class , rdfs:Datatype ; rdfs:subClassOf atom:Number ; - rdfs:label "32-bit floating point number" ; + rdfs:label "Float" ; + rdfs:comment "A native `float`." ; atom:cType "LV2_Atom_Float" ; owl:onDatatype xsd:float . @@ -152,7 +77,8 @@ atom:Double a rdfs:Class , rdfs:Datatype ; rdfs:subClassOf atom:Number ; - rdfs:label "64-bit floating point number" ; + rdfs:label "Double" ; + rdfs:comment "A native `double`." ; atom:cType "LV2_Atom_Double" ; owl:onDatatype xsd:double . @@ -160,289 +86,99 @@ atom:Bool a rdfs:Class , rdfs:Datatype ; rdfs:subClassOf atom:Atom ; - rdfs:label "Boolean" ; + rdfs:label "Bool" ; + rdfs:comment "An atom:Int where 0 is false and any other value is true." ; atom:cType "LV2_Atom_Bool" ; - owl:onDatatype xsd:boolean ; - rdfs:comment "An Int where 0 is false and any other value is true." . + owl:onDatatype xsd:boolean . atom:String a rdfs:Class , rdfs:Datatype ; rdfs:subClassOf atom:Atom ; rdfs:label "String" ; + rdfs:comment "A UTF-8 string." ; atom:cType "LV2_Atom_String" ; - owl:onDatatype xsd:string ; - lv2:documentation """ -<p>A UTF-8 encoded string.</p> - -<p>The body of an LV2_Atom_String is a C string in UTF-8 encoding, i.e. an -array of bytes (<code>uint8_t</code>) terminated with a NULL byte -(<code>'\\0'</code>).</p> - -<p>This type is for free-form strings, but SHOULD NOT be used for typed data or -text in any language. Use atom:Literal unless translating the string does not -make sense and the string has no meaningful datatype.</p> -""" . + owl:onDatatype xsd:string . atom:Literal a rdfs:Class ; rdfs:subClassOf atom:Atom ; - rdfs:label "String Literal" ; - atom:cType "LV2_Atom_Literal" ; - lv2:documentation """ -<p>A UTF-8 encoded string literal, with an optional datatype or language.</p> - -<p>This type is compatible with rdfs:Literal and is capable of expressing a -string in any language or a value of any type. A Literal has a -<code>datatype</code> and <code>lang</code> followed by string data in UTF-8 -encoding. The length of the string data in bytes is <code>size - -sizeof(LV2_Atom_Literal)</code>, including the terminating NULL character. The -<code>lang</code> field SHOULD be a URI of the form -<http://lexvo.org/id/iso639-3/LANG> or -<http://lexvo.org/id/iso639-1/LANG> where LANG is a 3-character ISO 693-3 -language code, or a 2-character ISO 693-1 language code, respectively.</p> - -<p>A Literal may have a <code>datatype</code> OR a <code>lang</code>, but never -both.</p> - -<p>For example, a Literal can be "Hello" in English:</p> -<pre class="c-code"> -void set_to_hello_in_english(LV2_Atom_Literal* lit) { - lit->atom.type = map(expand("atom:Literal")); - lit->atom.size = 14; - lit->body.datatype = 0; - lit->body.lang = map("http://lexvo.org/id/iso639-1/en"); - memcpy(LV2_ATOM_CONTENTS(LV2_Atom_Literal, lit), - "Hello", - sizeof("Hello")); // Assumes enough space -} -</pre> - -<p>or a Turtle string:</p> -<pre class="c-code"> -void set_to_turtle_string(LV2_Atom_Literal* lit, const char* ttl) { - lit->atom.type = map(expand("atom:Literal")); - lit->atom.size = 64; - lit->body.datatype = map("http://www.w3.org/2008/turtle#turtle"); - lit->body.lang = 0; - memcpy(LV2_ATOM_CONTENTS(LV2_Atom_Literal, lit), - ttl, - strlen(ttl) + 1); // Assumes enough space -} -</pre> -""" . + rdfs:label "Literal" ; + rdfs:comment "A UTF-8 string literal with optional datatype or language." ; + atom:cType "LV2_Atom_Literal" . atom:Path a rdfs:Class , rdfs:Datatype ; rdfs:subClassOf atom:URI ; owl:onDatatype atom:URI ; - rdfs:label "File path string" ; - lv2:documentation """ -<p>A local file path.</p> - -<p>A Path is a URI reference with only a path component: no scheme, authority, -query, or fragment. In particular, paths to files in the same bundle may be -cleanly written in Turtle files as a relative URI. However, implementations -may assume any binary Path (e.g. in an event payload) is a valid file path -which can passed to system functions like fopen() directly, without any -character encoding or escape expansion required.</p> - -<p>Any implemenation that creates a Path atom to transmit to another is -responsible for ensuring it is valid. A Path SHOULD always be absolute, unless -there is some mechanism in place that defines a base path. Since this is not -the case for plugin instances, effectively any Path sent to or received from a -plugin instance MUST be absolute.</p> -""" . + rdfs:label "Path" ; + rdfs:comment "A local file path." . atom:URI a rdfs:Class , rdfs:Datatype ; rdfs:subClassOf atom:String ; owl:onDatatype xsd:anyURI ; - rdfs:label "URI string" ; - lv2:documentation """ -<p>A URI string. This is useful when a URI is needed but mapping is -inappropriate, for example with temporary or relative URIs. Since the ability -to distinguish URIs from plain strings is often necessary, URIs MUST NOT be -transmitted as atom:String.</p> - -<p>This is not strictly a URI, since UTF-8 is allowed. Escaping and related -issues are the host's responsibility.</p> -""" . + rdfs:label "URI" ; + rdfs:comment "A URI string." . atom:URID a rdfs:Class ; rdfs:subClassOf atom:Atom ; - rdfs:label "Integer URID" ; - atom:cType "LV2_Atom_URID" ; - lv2:documentation """ -<p>An unsigned 32-bit integer mapped from a URI (e.g. with LV2_URID_Map).</p> -""" . + rdfs:label "URID" ; + rdfs:comment "An unsigned 32-bit integer ID for a URI." ; + atom:cType "LV2_Atom_URID" . atom:Vector a rdfs:Class ; rdfs:subClassOf atom:Atom ; rdfs:label "Vector" ; - atom:cType "LV2_Atom_Vector" ; - lv2:documentation """ -<p>A homogeneous series of atom bodies with equivalent type and size.</p> - -<p>An LV2_Atom_Vector is a 32-bit <code>child_size</code> and -<code>child_type</code> followed by <code>size / child_size</code> atom -bodies.</p> - -<p>For example, an atom:Vector containing 42 elements of type atom:Float:</p> -<pre class="c-code"> -struct VectorOf42Floats { - uint32_t size; // sizeof(LV2_Atom_Vector_Body) + (42 * sizeof(float); - uint32_t type; // map(expand("atom:Vector")) - uint32_t child_size; // sizeof(float) - uint32_t child_type; // map(expand("atom:Float")) - float elems[42]; -}; -</pre> - -<p>Note that it is possible to construct a valid Atom for each element -of the vector, even by an implementation which does not understand -<code>child_type</code>.</p> - -<p>If serialised to RDF, a Vector SHOULD have the form:</p> - -<pre class="turtle-code"> -eg:someVector - a atom:Vector ; - atom:childType atom:Int ; - rdf:value ( - "1"^^xsd:int - "2"^^xsd:int - "3"^^xsd:int - "4"^^xsd:int - ) . -</pre> -""" . + rdfs:comment "A homogeneous sequence of atom bodies with equivalent type and size." ; + atom:cType "LV2_Atom_Vector" . atom:Tuple a rdfs:Class ; rdfs:subClassOf atom:Atom ; rdfs:label "Tuple" ; - lv2:documentation """ -<p>A series of Atoms with varying <code>type</code> and <code>size</code>.</p> - -<p>The body of a Tuple is simply a series of complete atoms, each aligned to -64 bits.</p> - -<p>If serialised to RDF, a Tuple SHOULD have the form:</p> - -<pre class="turtle-code"> -eg:someVector - a atom:Tuple ; - rdf:value ( - "1"^^xsd:int - "3.5"^^xsd:float - "etc" - ) . -</pre> - -""" . + rdfs:comment "A sequence of atoms with varying type and size." . atom:Property a rdfs:Class ; rdfs:subClassOf atom:Atom ; rdfs:label "Property" ; - atom:cType "LV2_Atom_Property" ; - lv2:documentation """ -<p>A property of an atom:Object. An LV2_Atom_Property has a URID -<code>key</code> and <code>context</code>, and an Atom <code>value</code>. -This corresponds to an RDF Property, where the <q>key</q> is the <q>predicate</q> -and the <q>value</q> is the object.</p> - -<p>The <code>context</code> field can be used to specify a different context -for each property, where this is useful. Otherwise, it may be 0.</p> - -<p>Properties generally only exist as part of an atom:Object. Accordingly, -they will typically be represented directly as properties in RDF (see -atom:Object). If this is not possible, they may be expressed as partial -reified statements, e.g.:</p> - -<pre class="turtle-code"> -eg:someProperty - rdf:predicate eg:theKey ; - rdf:object eg:theValue . -</pre> -""" . + rdfs:comment "A property of an atom:Object." ; + atom:cType "LV2_Atom_Property" . atom:Object a rdfs:Class ; rdfs:subClassOf atom:Atom ; rdfs:label "Object" ; - atom:cType "LV2_Atom_Object" ; - lv2:documentation """ -<p>An <q>Object</q> is an atom with a set of properties. This corresponds to -an RDF Resource, and can be thought of as a dictionary with URID keys.</p> - -<p>An LV2_Atom_Object body has a uint32_t <code>id</code> and -<code>type</code>, followed by a series of atom:Property bodies -(LV2_Atom_Property_Body). The LV2_Atom_Object_Body::otype field is equivalent -to a property with key rdf:type, but is included in the structure to allow for -fast dispatching.</p> - -<p>Code SHOULD check for objects using lv2_atom_forge_is_object() or -lv2_atom_forge_is_blank() if a forge is available, rather than checking the -atom type directly. This will correctly handle the deprecated atom:Resource -and atom:Blank types.</p> - -<p>When serialised to RDF, an Object is represented as a resource, e.g.:</p> - -<pre class="turtle-code"> -eg:someObject - eg:firstPropertyKey "first property value" ; - eg:secondPropertyKey "first loser" ; - eg:andSoOn "and so on" . -</pre> -""" . + rdfs:comment "A collection of properties." ; + atom:cType "LV2_Atom_Object" . atom:Resource a rdfs:Class ; rdfs:subClassOf atom:Object ; rdfs:label "Resource" ; + rdfs:comment "A named collection of properties with a URI." ; owl:deprecated "true"^^xsd:boolean ; - atom:cType "LV2_Atom_Object" ; - lv2:documentation """ -<p>This class is deprecated. Use atom:Object instead.</p> - -<p>An atom:Object where the <code>id</code> field is a URID, i.e. an Object -with a URI.</p> -""" . + atom:cType "LV2_Atom_Object" . atom:Blank a rdfs:Class ; rdfs:subClassOf atom:Object ; rdfs:label "Blank" ; + rdfs:comment "An anonymous collection of properties without a URI." ; owl:deprecated "true"^^xsd:boolean ; - atom:cType "LV2_Atom_Object" ; - lv2:documentation """ -<p>This class is deprecated. Use atom:Object with ID 0 instead.</p> - -<p>An atom:Object where the LV2_Atom_Object::id is a blank node ID (NOT a URI). -The ID of a Blank is valid only within the context the Blank appears in. For -ports this is the context of the associated run() call, i.e. all ports share -the same context so outputs can contain IDs that correspond to IDs of blanks in -the input.</p> -""" . + atom:cType "LV2_Atom_Object" . atom:Sound a rdfs:Class ; rdfs:subClassOf atom:Vector ; rdfs:label "Sound" ; - atom:cType "LV2_Atom_Sound" ; - lv2:documentation """ -<p>An atom:Vector of atom:Float which represents an audio waveform. The format -is the same as the buffer format for lv2:AudioPort (except the size may be -arbitrary). An atom:Sound inherently depends on the sample rate, which is -assumed to be known from context. Because of this, directly serialising an -atom:Sound is probably a bad idea, use a standard format like WAV instead.</p> -""" . + rdfs:comment "A atom:Vector of atom:Float which represents an audio waveform." ; + atom:cType "LV2_Atom_Sound" . atom:frameTime a rdf:Property , @@ -450,9 +186,7 @@ atom:frameTime owl:FunctionalProperty ; rdfs:range xsd:decimal ; rdfs:label "frame time" ; - lv2:documentation """ -<p>Time stamp in audio frames. Typically used for events.</p> -""" . + rdfs:comment "A time stamp in audio frames." . atom:beatTime a rdf:Property , @@ -460,66 +194,26 @@ atom:beatTime owl:FunctionalProperty ; rdfs:range xsd:decimal ; rdfs:label "beat time" ; - lv2:documentation """ -<p>Time stamp in beats. Typically used for events.</p> -""" . + rdfs:comment "A time stamp in beats." . atom:Event a rdfs:Class ; rdfs:label "Event" ; atom:cType "LV2_Atom_Event" ; - lv2:documentation """ -<p>An atom with a time stamp prefix, typically an element of an atom:Sequence. -Note this is not an Atom type.</p> -""" . + rdfs:comment "An atom with a time stamp prefix in a sequence." . atom:Sequence a rdfs:Class ; rdfs:subClassOf atom:Atom ; rdfs:label "Sequence" ; atom:cType "LV2_Atom_Sequence" ; - lv2:documentation """ -<p>A sequence of atom:Event, i.e. a series of time-stamped Atoms.</p> - -<p>LV2_Atom_Sequence_Body.unit describes the time unit for the contained atoms. -If the unit is known from context (e.g. run() stamps are always audio frames), -this field may be zero. Otherwise, it SHOULD be either units:frame or -units:beat, in which case ev.time.frames or ev.time.beats is valid, -respectively.</p> - -<p>If serialised to RDF, a Sequence has a similar form to atom:Vector, but for -brevity the elements may be assumed to be atom:Event, e.g.:</p> - -<pre class="turtle-code"> -eg:someSequence - a atom:Sequence ; - rdf:value ( - [ - atom:frameTime 1 ; - rdf:value "901A01"^^midi:MidiEvent - ] [ - atom:frameTime 3 ; - rdf:value "902B02"^^midi:MidiEvent - ] - ) . -</pre> -""" . + rdfs:comment "A sequence of events." . atom:AtomPort a rdfs:Class ; rdfs:subClassOf lv2:Port ; rdfs:label "Atom Port" ; - lv2:documentation """ -<p>A port which contains an atom:Atom. Ports of this type are connected to an -LV2_Atom with a type specified by atom:bufferType.</p> - -<p>Output ports with a variably sized type MUST be initialised by the host -before every run() to an atom:Chunk with size set to the available space. The -plugin reads this size to know how much space is available for writing. In all -cases, the plugin MUST write a complete atom (including header) to outputs. -However, to be robust, hosts SHOULD initialise output ports to a safe sentinel -(e.g. the null Atom) before calling run().</p> -""" . + rdfs:comment "A port which contains an atom:Atom." . atom:bufferType a rdf:Property , @@ -527,78 +221,27 @@ atom:bufferType rdfs:domain atom:AtomPort ; rdfs:range rdfs:Class ; rdfs:label "buffer type" ; - lv2:documentation """ -<p>Indicates that an AtomPort may be connected to a certain Atom type. A port -MAY support several buffer types. The host MUST NOT connect a port to an Atom -with a type not explicitly listed with this property. The value of this -property MUST be a sub-class of atom:Atom. For example, an input port that is -connected directly to an LV2_Atom_Double value is described like so:</p> - -<pre class="turtle-code"> -<plugin> - lv2:port [ - a lv2:InputPort , atom:AtomPort ; - atom:bufferType atom:Double ; - ] . -</pre> - -<p>This property only describes the types a port may be <em>directly</em> -connected to. It says nothing about the expected contents of containers. For -that, use atom:supports.</p> -""" . + rdfs:comment "An atom type that a port may be connected to." . atom:childType a rdf:Property , owl:ObjectProperty ; rdfs:label "child type" ; - rdfs:comment """The type of a container's children.""" . + rdfs:comment "The type of children in a container." . atom:supports a rdf:Property ; rdfs:label "supports" ; - rdfs:range rdfs:Class ; - lv2:documentation """ -<p>Indicates that a particular Atom type is supported.</p> - -<p>This property is defined loosely, it may be used to indicate that anything -<q>supports</q> an Atom type, wherever that may be useful. It applies -<q>recursively</q> where collections are involved.</p> - -<p>In particular, this property can be used to describe which event types are -expected by a port. For example, a port that receives MIDI events is described -like so:</p> - -<pre class="turtle-code"> -<plugin> - lv2:port [ - a lv2:InputPort , atom:AtomPort ; - atom:bufferType atom:Sequence ; - atom:supports midi:MidiEvent ; - ] . -</pre> -""" . + rdfs:comment "A supported atom type." ; + rdfs:range rdfs:Class . atom:eventTransfer a ui:PortProtocol ; rdfs:label "event transfer" ; - lv2:documentation """ -<p>Transfer of individual events in a port buffer. Useful as the -<code>format</code> for a LV2UI_Write_Function.</p> - -<p>This protocol applies to ports which contain events, usually in an -atom:Sequence. The host must transfer each individual event to the recipient. -The format of the received data is an LV2_Atom, there is no timestamp -header.</p> -""" . + rdfs:comment "A port protocol for transferring events." . atom:atomTransfer a ui:PortProtocol ; rdfs:label "atom transfer" ; - lv2:documentation """ -<p>Transfer of the complete atom in a port buffer. Useful as the -<code>format</code> for a LV2UI_Write_Function.</p> - -<p>This protocol applies to atom ports. The host must transfer the complete -atom contained in the port, including header.</p> -""" . + rdfs:comment "A port protocol for transferring atoms." . |