Chris@366: /* ladspa.h
Chris@366: 
Chris@366:    Linux Audio Developer's Simple Plugin API Version 1.1[LGPL].
Chris@366:    Copyright (C) 2000-2002 Richard W.E. Furse, Paul Barton-Davis,
Chris@366:    Stefan Westerfeld.
Chris@366:    
Chris@366:    This library is free software; you can redistribute it and/or
Chris@366:    modify it under the terms of the GNU Lesser General Public License
Chris@366:    as published by the Free Software Foundation; either version 2.1 of
Chris@366:    the License, or (at your option) any later version.
Chris@366:    
Chris@366:    This library is distributed in the hope that it will be useful, but
Chris@366:    WITHOUT ANY WARRANTY; without even the implied warranty of
Chris@366:    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Chris@366:    Lesser General Public License for more details.
Chris@366:    
Chris@366:    You should have received a copy of the GNU Lesser General Public
Chris@366:    License along with this library; if not, write to the Free Software
Chris@366:    Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307
Chris@366:    USA. */
Chris@366: 
Chris@366: #ifndef LADSPA_INCLUDED
Chris@366: #define LADSPA_INCLUDED
Chris@366: 
Chris@366: #define LADSPA_VERSION "1.1"
Chris@366: #define LADSPA_VERSION_MAJOR 1
Chris@366: #define LADSPA_VERSION_MINOR 1
Chris@366: 
Chris@366: #ifdef __cplusplus
Chris@366: extern "C" {
Chris@366: #endif
Chris@366: 
Chris@366: /*****************************************************************************/
Chris@366: 
Chris@366: /* Overview: 
Chris@366: 
Chris@366:    There is a large number of synthesis packages in use or development
Chris@366:    on the Linux platform at this time. This API (`The Linux Audio
Chris@366:    Developer's Simple Plugin API') attempts to give programmers the
Chris@366:    ability to write simple `plugin' audio processors in C/C++ and link
Chris@366:    them dynamically (`plug') into a range of these packages (`hosts').
Chris@366:    It should be possible for any host and any plugin to communicate
Chris@366:    completely through this interface.
Chris@366: 
Chris@366:    This API is deliberately short and simple. To achieve compatibility
Chris@366:    with a range of promising Linux sound synthesis packages it
Chris@366:    attempts to find the `greatest common divisor' in their logical
Chris@366:    behaviour. Having said this, certain limiting decisions are
Chris@366:    implicit, notably the use of a fixed type (LADSPA_Data) for all
Chris@366:    data transfer and absence of a parameterised `initialisation'
Chris@366:    phase. See below for the LADSPA_Data typedef.
Chris@366: 
Chris@366:    Plugins are expected to distinguish between control and audio
Chris@366:    data. Plugins have `ports' that are inputs or outputs for audio or
Chris@366:    control data and each plugin is `run' for a `block' corresponding
Chris@366:    to a short time interval measured in samples. Audio data is
Chris@366:    communicated using arrays of LADSPA_Data, allowing a block of audio
Chris@366:    to be processed by the plugin in a single pass. Control data is
Chris@366:    communicated using single LADSPA_Data values. Control data has a
Chris@366:    single value at the start of a call to the `run()' or `run_adding()'
Chris@366:    function, and may be considered to remain this value for its
Chris@366:    duration. The plugin may assume that all its input and output ports
Chris@366:    have been connected to the relevant data location (see the
Chris@366:    `connect_port()' function below) before it is asked to run.
Chris@366: 
Chris@366:    Plugins will reside in shared object files suitable for dynamic
Chris@366:    linking by dlopen() and family. The file will provide a number of
Chris@366:    `plugin types' that can be used to instantiate actual plugins
Chris@366:    (sometimes known as `plugin instances') that can be connected
Chris@366:    together to perform tasks.
Chris@366: 
Chris@366:    This API contains very limited error-handling. */
Chris@366: 
Chris@366: /*****************************************************************************/
Chris@366: 
Chris@366: /* Fundamental data type passed in and out of plugin. This data type
Chris@366:    is used to communicate audio samples and control values. It is
Chris@366:    assumed that the plugin will work sensibly given any numeric input
Chris@366:    value although it may have a preferred range (see hints below). 
Chris@366: 
Chris@366:    For audio it is generally assumed that 1.0f is the `0dB' reference
Chris@366:    amplitude and is a `normal' signal level. */
Chris@366: 
Chris@366: typedef float LADSPA_Data;
Chris@366: 
Chris@366: /*****************************************************************************/
Chris@366: 
Chris@366: /* Special Plugin Properties: 
Chris@366:  
Chris@366:    Optional features of the plugin type are encapsulated in the
Chris@366:    LADSPA_Properties type. This is assembled by ORing individual
Chris@366:    properties together. */
Chris@366: 
Chris@366: typedef int LADSPA_Properties;
Chris@366: 
Chris@366: /* Property LADSPA_PROPERTY_REALTIME indicates that the plugin has a
Chris@366:    real-time dependency (e.g. listens to a MIDI device) and so its
Chris@366:    output must not be cached or subject to significant latency. */
Chris@366: #define LADSPA_PROPERTY_REALTIME        0x1
Chris@366: 
Chris@366: /* Property LADSPA_PROPERTY_INPLACE_BROKEN indicates that the plugin
Chris@366:    may cease to work correctly if the host elects to use the same data
Chris@366:    location for both input and output (see connect_port()). This
Chris@366:    should be avoided as enabling this flag makes it impossible for
Chris@366:    hosts to use the plugin to process audio `in-place.' */
Chris@366: #define LADSPA_PROPERTY_INPLACE_BROKEN  0x2
Chris@366: 
Chris@366: /* Property LADSPA_PROPERTY_HARD_RT_CAPABLE indicates that the plugin
Chris@366:    is capable of running not only in a conventional host but also in a
Chris@366:    `hard real-time' environment. To qualify for this the plugin must
Chris@366:    satisfy all of the following:
Chris@366: 
Chris@366:    (1) The plugin must not use malloc(), free() or other heap memory
Chris@366:    management within its run() or run_adding() functions. All new
Chris@366:    memory used in run() must be managed via the stack. These
Chris@366:    restrictions only apply to the run() function.
Chris@366: 
Chris@366:    (2) The plugin will not attempt to make use of any library
Chris@366:    functions with the exceptions of functions in the ANSI standard C
Chris@366:    and C maths libraries, which the host is expected to provide.
Chris@366: 
Chris@366:    (3) The plugin will not access files, devices, pipes, sockets, IPC
Chris@366:    or any other mechanism that might result in process or thread
Chris@366:    blocking.
Chris@366:       
Chris@366:    (4) The plugin will take an amount of time to execute a run() or
Chris@366:    run_adding() call approximately of form (A+B*SampleCount) where A
Chris@366:    and B depend on the machine and host in use. This amount of time
Chris@366:    may not depend on input signals or plugin state. The host is left
Chris@366:    the responsibility to perform timings to estimate upper bounds for
Chris@366:    A and B. */
Chris@366: #define LADSPA_PROPERTY_HARD_RT_CAPABLE 0x4
Chris@366: 
Chris@366: #define LADSPA_IS_REALTIME(x)        ((x) & LADSPA_PROPERTY_REALTIME)
Chris@366: #define LADSPA_IS_INPLACE_BROKEN(x)  ((x) & LADSPA_PROPERTY_INPLACE_BROKEN)
Chris@366: #define LADSPA_IS_HARD_RT_CAPABLE(x) ((x) & LADSPA_PROPERTY_HARD_RT_CAPABLE)
Chris@366: 
Chris@366: /*****************************************************************************/
Chris@366: 
Chris@366: /* Plugin Ports: 
Chris@366: 
Chris@366:    Plugins have `ports' that are inputs or outputs for audio or
Chris@366:    data. Ports can communicate arrays of LADSPA_Data (for audio
Chris@366:    inputs/outputs) or single LADSPA_Data values (for control
Chris@366:    input/outputs). This information is encapsulated in the
Chris@366:    LADSPA_PortDescriptor type which is assembled by ORing individual
Chris@366:    properties together.
Chris@366: 
Chris@366:    Note that a port must be an input or an output port but not both
Chris@366:    and that a port must be a control or audio port but not both. */
Chris@366: 
Chris@366: typedef int LADSPA_PortDescriptor;
Chris@366: 
Chris@366: /* Property LADSPA_PORT_INPUT indicates that the port is an input. */
Chris@366: #define LADSPA_PORT_INPUT   0x1
Chris@366: 
Chris@366: /* Property LADSPA_PORT_OUTPUT indicates that the port is an output. */
Chris@366: #define LADSPA_PORT_OUTPUT  0x2
Chris@366: 
Chris@366: /* Property LADSPA_PORT_CONTROL indicates that the port is a control
Chris@366:    port. */
Chris@366: #define LADSPA_PORT_CONTROL 0x4
Chris@366: 
Chris@366: /* Property LADSPA_PORT_AUDIO indicates that the port is a audio
Chris@366:    port. */
Chris@366: #define LADSPA_PORT_AUDIO   0x8
Chris@366: 
Chris@366: #define LADSPA_IS_PORT_INPUT(x)   ((x) & LADSPA_PORT_INPUT)
Chris@366: #define LADSPA_IS_PORT_OUTPUT(x)  ((x) & LADSPA_PORT_OUTPUT)
Chris@366: #define LADSPA_IS_PORT_CONTROL(x) ((x) & LADSPA_PORT_CONTROL)
Chris@366: #define LADSPA_IS_PORT_AUDIO(x)   ((x) & LADSPA_PORT_AUDIO)
Chris@366: 
Chris@366: /*****************************************************************************/
Chris@366: 
Chris@366: /* Plugin Port Range Hints: 
Chris@366: 
Chris@366:    The host may wish to provide a representation of data entering or
Chris@366:    leaving a plugin (e.g. to generate a GUI automatically). To make
Chris@366:    this more meaningful, the plugin should provide `hints' to the host
Chris@366:    describing the usual values taken by the data.
Chris@366:    
Chris@366:    Note that these are only hints. The host may ignore them and the
Chris@366:    plugin must not assume that data supplied to it is meaningful. If
Chris@366:    the plugin receives invalid input data it is expected to continue
Chris@366:    to run without failure and, where possible, produce a sensible
Chris@366:    output (e.g. a high-pass filter given a negative cutoff frequency
Chris@366:    might switch to an all-pass mode).
Chris@366:     
Chris@366:    Hints are meaningful for all input and output ports but hints for
Chris@366:    input control ports are expected to be particularly useful.
Chris@366:    
Chris@366:    More hint information is encapsulated in the
Chris@366:    LADSPA_PortRangeHintDescriptor type which is assembled by ORing
Chris@366:    individual hint types together. Hints may require further
Chris@366:    LowerBound and UpperBound information.
Chris@366: 
Chris@366:    All the hint information for a particular port is aggregated in the
Chris@366:    LADSPA_PortRangeHint structure. */
Chris@366: 
Chris@366: typedef int LADSPA_PortRangeHintDescriptor;
Chris@366: 
Chris@366: /* Hint LADSPA_HINT_BOUNDED_BELOW indicates that the LowerBound field
Chris@366:    of the LADSPA_PortRangeHint should be considered meaningful. The
Chris@366:    value in this field should be considered the (inclusive) lower
Chris@366:    bound of the valid range. If LADSPA_HINT_SAMPLE_RATE is also
Chris@366:    specified then the value of LowerBound should be multiplied by the
Chris@366:    sample rate. */
Chris@366: #define LADSPA_HINT_BOUNDED_BELOW   0x1
Chris@366: 
Chris@366: /* Hint LADSPA_HINT_BOUNDED_ABOVE indicates that the UpperBound field
Chris@366:    of the LADSPA_PortRangeHint should be considered meaningful. The
Chris@366:    value in this field should be considered the (inclusive) upper
Chris@366:    bound of the valid range. If LADSPA_HINT_SAMPLE_RATE is also
Chris@366:    specified then the value of UpperBound should be multiplied by the
Chris@366:    sample rate. */
Chris@366: #define LADSPA_HINT_BOUNDED_ABOVE   0x2
Chris@366: 
Chris@366: /* Hint LADSPA_HINT_TOGGLED indicates that the data item should be
Chris@366:    considered a Boolean toggle. Data less than or equal to zero should
Chris@366:    be considered `off' or `false,' and data above zero should be
Chris@366:    considered `on' or `true.' LADSPA_HINT_TOGGLED may not be used in
Chris@366:    conjunction with any other hint except LADSPA_HINT_DEFAULT_0 or
Chris@366:    LADSPA_HINT_DEFAULT_1. */
Chris@366: #define LADSPA_HINT_TOGGLED         0x4
Chris@366: 
Chris@366: /* Hint LADSPA_HINT_SAMPLE_RATE indicates that any bounds specified
Chris@366:    should be interpreted as multiples of the sample rate. For
Chris@366:    instance, a frequency range from 0Hz to the Nyquist frequency (half
Chris@366:    the sample rate) could be requested by this hint in conjunction
Chris@366:    with LowerBound = 0 and UpperBound = 0.5. Hosts that support bounds
Chris@366:    at all must support this hint to retain meaning. */
Chris@366: #define LADSPA_HINT_SAMPLE_RATE     0x8
Chris@366: 
Chris@366: /* Hint LADSPA_HINT_LOGARITHMIC indicates that it is likely that the
Chris@366:    user will find it more intuitive to view values using a logarithmic
Chris@366:    scale. This is particularly useful for frequencies and gains. */
Chris@366: #define LADSPA_HINT_LOGARITHMIC     0x10
Chris@366: 
Chris@366: /* Hint LADSPA_HINT_INTEGER indicates that a user interface would
Chris@366:    probably wish to provide a stepped control taking only integer
Chris@366:    values. Any bounds set should be slightly wider than the actual
Chris@366:    integer range required to avoid floating point rounding errors. For
Chris@366:    instance, the integer set {0,1,2,3} might be described as [-0.1,
Chris@366:    3.1]. */
Chris@366: #define LADSPA_HINT_INTEGER         0x20
Chris@366: 
Chris@366: /* The various LADSPA_HINT_HAS_DEFAULT_* hints indicate a `normal'
Chris@366:    value for the port that is sensible as a default. For instance,
Chris@366:    this value is suitable for use as an initial value in a user
Chris@366:    interface or as a value the host might assign to a control port
Chris@366:    when the user has not provided one. Defaults are encoded using a
Chris@366:    mask so only one default may be specified for a port. Some of the
Chris@366:    hints make use of lower and upper bounds, in which case the
Chris@366:    relevant bound or bounds must be available and
Chris@366:    LADSPA_HINT_SAMPLE_RATE must be applied as usual. The resulting
Chris@366:    default must be rounded if LADSPA_HINT_INTEGER is present. Default
Chris@366:    values were introduced in LADSPA v1.1. */
Chris@366: #define LADSPA_HINT_DEFAULT_MASK    0x3C0
Chris@366: 
Chris@366: /* This default values indicates that no default is provided. */
Chris@366: #define LADSPA_HINT_DEFAULT_NONE    0x0
Chris@366: 
Chris@366: /* This default hint indicates that the suggested lower bound for the
Chris@366:    port should be used. */
Chris@366: #define LADSPA_HINT_DEFAULT_MINIMUM 0x40
Chris@366: 
Chris@366: /* This default hint indicates that a low value between the suggested
Chris@366:    lower and upper bounds should be chosen. For ports with
Chris@366:    LADSPA_HINT_LOGARITHMIC, this should be exp(log(lower) * 0.75 +
Chris@366:    log(upper) * 0.25). Otherwise, this should be (lower * 0.75 + upper
Chris@366:    * 0.25). */
Chris@366: #define LADSPA_HINT_DEFAULT_LOW     0x80
Chris@366: 
Chris@366: /* This default hint indicates that a middle value between the
Chris@366:    suggested lower and upper bounds should be chosen. For ports with
Chris@366:    LADSPA_HINT_LOGARITHMIC, this should be exp(log(lower) * 0.5 +
Chris@366:    log(upper) * 0.5). Otherwise, this should be (lower * 0.5 + upper *
Chris@366:    0.5). */
Chris@366: #define LADSPA_HINT_DEFAULT_MIDDLE  0xC0
Chris@366: 
Chris@366: /* This default hint indicates that a high value between the suggested
Chris@366:    lower and upper bounds should be chosen. For ports with
Chris@366:    LADSPA_HINT_LOGARITHMIC, this should be exp(log(lower) * 0.25 +
Chris@366:    log(upper) * 0.75). Otherwise, this should be (lower * 0.25 + upper
Chris@366:    * 0.75). */
Chris@366: #define LADSPA_HINT_DEFAULT_HIGH    0x100
Chris@366: 
Chris@366: /* This default hint indicates that the suggested upper bound for the
Chris@366:    port should be used. */
Chris@366: #define LADSPA_HINT_DEFAULT_MAXIMUM 0x140
Chris@366: 
Chris@366: /* This default hint indicates that the number 0 should be used. Note
Chris@366:    that this default may be used in conjunction with
Chris@366:    LADSPA_HINT_TOGGLED. */
Chris@366: #define LADSPA_HINT_DEFAULT_0       0x200
Chris@366: 
Chris@366: /* This default hint indicates that the number 1 should be used. Note
Chris@366:    that this default may be used in conjunction with
Chris@366:    LADSPA_HINT_TOGGLED. */
Chris@366: #define LADSPA_HINT_DEFAULT_1       0x240
Chris@366: 
Chris@366: /* This default hint indicates that the number 100 should be used. */
Chris@366: #define LADSPA_HINT_DEFAULT_100     0x280
Chris@366: 
Chris@366: /* This default hint indicates that the Hz frequency of `concert A'
Chris@366:    should be used. This will be 440 unless the host uses an unusual
Chris@366:    tuning convention, in which case it may be within a few Hz. */
Chris@366: #define LADSPA_HINT_DEFAULT_440     0x2C0
Chris@366: 
Chris@366: #define LADSPA_IS_HINT_BOUNDED_BELOW(x)   ((x) & LADSPA_HINT_BOUNDED_BELOW)
Chris@366: #define LADSPA_IS_HINT_BOUNDED_ABOVE(x)   ((x) & LADSPA_HINT_BOUNDED_ABOVE)
Chris@366: #define LADSPA_IS_HINT_TOGGLED(x)         ((x) & LADSPA_HINT_TOGGLED)
Chris@366: #define LADSPA_IS_HINT_SAMPLE_RATE(x)     ((x) & LADSPA_HINT_SAMPLE_RATE)
Chris@366: #define LADSPA_IS_HINT_LOGARITHMIC(x)     ((x) & LADSPA_HINT_LOGARITHMIC)
Chris@366: #define LADSPA_IS_HINT_INTEGER(x)         ((x) & LADSPA_HINT_INTEGER)
Chris@366: 
Chris@366: #define LADSPA_IS_HINT_HAS_DEFAULT(x)     ((x) & LADSPA_HINT_DEFAULT_MASK)
Chris@366: #define LADSPA_IS_HINT_DEFAULT_MINIMUM(x) (((x) & LADSPA_HINT_DEFAULT_MASK)   \
Chris@366:                                            == LADSPA_HINT_DEFAULT_MINIMUM)
Chris@366: #define LADSPA_IS_HINT_DEFAULT_LOW(x)     (((x) & LADSPA_HINT_DEFAULT_MASK)   \
Chris@366:                                            == LADSPA_HINT_DEFAULT_LOW)
Chris@366: #define LADSPA_IS_HINT_DEFAULT_MIDDLE(x)  (((x) & LADSPA_HINT_DEFAULT_MASK)   \
Chris@366:                                            == LADSPA_HINT_DEFAULT_MIDDLE)
Chris@366: #define LADSPA_IS_HINT_DEFAULT_HIGH(x)    (((x) & LADSPA_HINT_DEFAULT_MASK)   \
Chris@366:                                            == LADSPA_HINT_DEFAULT_HIGH)
Chris@366: #define LADSPA_IS_HINT_DEFAULT_MAXIMUM(x) (((x) & LADSPA_HINT_DEFAULT_MASK)   \
Chris@366:                                            == LADSPA_HINT_DEFAULT_MAXIMUM)
Chris@366: #define LADSPA_IS_HINT_DEFAULT_0(x)       (((x) & LADSPA_HINT_DEFAULT_MASK)   \
Chris@366:                                            == LADSPA_HINT_DEFAULT_0)
Chris@366: #define LADSPA_IS_HINT_DEFAULT_1(x)       (((x) & LADSPA_HINT_DEFAULT_MASK)   \
Chris@366:                                            == LADSPA_HINT_DEFAULT_1)
Chris@366: #define LADSPA_IS_HINT_DEFAULT_100(x)     (((x) & LADSPA_HINT_DEFAULT_MASK)   \
Chris@366:                                            == LADSPA_HINT_DEFAULT_100)
Chris@366: #define LADSPA_IS_HINT_DEFAULT_440(x)     (((x) & LADSPA_HINT_DEFAULT_MASK)   \
Chris@366:                                             == LADSPA_HINT_DEFAULT_440)
Chris@366: 
Chris@366: typedef struct _LADSPA_PortRangeHint {
Chris@366: 
Chris@366:   /* Hints about the port. */
Chris@366:   LADSPA_PortRangeHintDescriptor HintDescriptor;
Chris@366: 
Chris@366:   /* Meaningful when hint LADSPA_HINT_BOUNDED_BELOW is active. When
Chris@366:      LADSPA_HINT_SAMPLE_RATE is also active then this value should be
Chris@366:      multiplied by the relevant sample rate. */
Chris@366:   LADSPA_Data LowerBound;
Chris@366: 
Chris@366:   /* Meaningful when hint LADSPA_HINT_BOUNDED_ABOVE is active. When
Chris@366:      LADSPA_HINT_SAMPLE_RATE is also active then this value should be
Chris@366:      multiplied by the relevant sample rate. */
Chris@366:   LADSPA_Data UpperBound;
Chris@366: 
Chris@366: } LADSPA_PortRangeHint;
Chris@366: 
Chris@366: /*****************************************************************************/
Chris@366: 
Chris@366: /* Plugin Handles: 
Chris@366: 
Chris@366:    This plugin handle indicates a particular instance of the plugin
Chris@366:    concerned. It is valid to compare this to NULL (0 for C++) but
Chris@366:    otherwise the host should not attempt to interpret it. The plugin
Chris@366:    may use it to reference internal instance data. */
Chris@366: 
Chris@366: typedef void * LADSPA_Handle;
Chris@366: 
Chris@366: /*****************************************************************************/
Chris@366: 
Chris@366: /* Descriptor for a Type of Plugin: 
Chris@366: 
Chris@366:    This structure is used to describe a plugin type. It provides a
Chris@366:    number of functions to examine the type, instantiate it, link it to
Chris@366:    buffers and workspaces and to run it. */
Chris@366: 
Chris@366: typedef struct _LADSPA_Descriptor { 
Chris@366: 
Chris@366:   /* This numeric identifier indicates the plugin type
Chris@366:      uniquely. Plugin programmers may reserve ranges of IDs from a
Chris@366:      central body to avoid clashes. Hosts may assume that IDs are
Chris@366:      below 0x1000000. */
Chris@366:   unsigned long UniqueID;
Chris@366: 
Chris@366:   /* This identifier can be used as a unique, case-sensitive
Chris@366:      identifier for the plugin type within the plugin file. Plugin
Chris@366:      types should be identified by file and label rather than by index
Chris@366:      or plugin name, which may be changed in new plugin
Chris@366:      versions. Labels must not contain white-space characters. */
Chris@366:   const char * Label;
Chris@366: 
Chris@366:   /* This indicates a number of properties of the plugin. */
Chris@366:   LADSPA_Properties Properties;
Chris@366: 
Chris@366:   /* This member points to the null-terminated name of the plugin
Chris@366:      (e.g. "Sine Oscillator"). */
Chris@366:   const char * Name;
Chris@366: 
Chris@366:   /* This member points to the null-terminated string indicating the
Chris@366:      maker of the plugin. This can be an empty string but not NULL. */
Chris@366:   const char * Maker;
Chris@366: 
Chris@366:   /* This member points to the null-terminated string indicating any
Chris@366:      copyright applying to the plugin. If no Copyright applies the
Chris@366:      string "None" should be used. */
Chris@366:   const char * Copyright;
Chris@366: 
Chris@366:   /* This indicates the number of ports (input AND output) present on
Chris@366:      the plugin. */
Chris@366:   unsigned long PortCount;
Chris@366: 
Chris@366:   /* This member indicates an array of port descriptors. Valid indices
Chris@366:      vary from 0 to PortCount-1. */
Chris@366:   const LADSPA_PortDescriptor * PortDescriptors;
Chris@366: 
Chris@366:   /* This member indicates an array of null-terminated strings
Chris@366:      describing ports (e.g. "Frequency (Hz)"). Valid indices vary from
Chris@366:      0 to PortCount-1. */
Chris@366:   const char * const * PortNames;
Chris@366: 
Chris@366:   /* This member indicates an array of range hints for each port (see
Chris@366:      above). Valid indices vary from 0 to PortCount-1. */
Chris@366:   const LADSPA_PortRangeHint * PortRangeHints;
Chris@366: 
Chris@366:   /* This may be used by the plugin developer to pass any custom
Chris@366:      implementation data into an instantiate call. It must not be used
Chris@366:      or interpreted by the host. It is expected that most plugin
Chris@366:      writers will not use this facility as LADSPA_Handle should be
Chris@366:      used to hold instance data. */
Chris@366:   void * ImplementationData;
Chris@366: 
Chris@366:   /* This member is a function pointer that instantiates a plugin. A
Chris@366:      handle is returned indicating the new plugin instance. The
Chris@366:      instantiation function accepts a sample rate as a parameter. The
Chris@366:      plugin descriptor from which this instantiate function was found
Chris@366:      must also be passed. This function must return NULL if
Chris@366:      instantiation fails. 
Chris@366: 
Chris@366:      Note that instance initialisation should generally occur in
Chris@366:      activate() rather than here. */
Chris@366:   LADSPA_Handle (*instantiate)(const struct _LADSPA_Descriptor * Descriptor,
Chris@366:                                unsigned long                     SampleRate);
Chris@366: 
Chris@366:   /* This member is a function pointer that connects a port on an
Chris@366:      instantiated plugin to a memory location at which a block of data
Chris@366:      for the port will be read/written. The data location is expected
Chris@366:      to be an array of LADSPA_Data for audio ports or a single
Chris@366:      LADSPA_Data value for control ports. Memory issues will be
Chris@366:      managed by the host. The plugin must read/write the data at these
Chris@366:      locations every time run() or run_adding() is called and the data
Chris@366:      present at the time of this connection call should not be
Chris@366:      considered meaningful.
Chris@366: 
Chris@366:      connect_port() may be called more than once for a plugin instance
Chris@366:      to allow the host to change the buffers that the plugin is
Chris@366:      reading or writing. These calls may be made before or after
Chris@366:      activate() or deactivate() calls.
Chris@366: 
Chris@366:      connect_port() must be called at least once for each port before
Chris@366:      run() or run_adding() is called. When working with blocks of
Chris@366:      LADSPA_Data the plugin should pay careful attention to the block
Chris@366:      size passed to the run function as the block allocated may only
Chris@366:      just be large enough to contain the block of samples.
Chris@366: 
Chris@366:      Plugin writers should be aware that the host may elect to use the
Chris@366:      same buffer for more than one port and even use the same buffer
Chris@366:      for both input and output (see LADSPA_PROPERTY_INPLACE_BROKEN).
Chris@366:      However, overlapped buffers or use of a single buffer for both
Chris@366:      audio and control data may result in unexpected behaviour. */
Chris@366:    void (*connect_port)(LADSPA_Handle Instance,
Chris@366:                         unsigned long Port,
Chris@366:                         LADSPA_Data * DataLocation);
Chris@366: 
Chris@366:   /* This member is a function pointer that initialises a plugin
Chris@366:      instance and activates it for use. This is separated from
Chris@366:      instantiate() to aid real-time support and so that hosts can
Chris@366:      reinitialise a plugin instance by calling deactivate() and then
Chris@366:      activate(). In this case the plugin instance must reset all state
Chris@366:      information dependent on the history of the plugin instance
Chris@366:      except for any data locations provided by connect_port() and any
Chris@366:      gain set by set_run_adding_gain(). If there is nothing for
Chris@366:      activate() to do then the plugin writer may provide a NULL rather
Chris@366:      than an empty function.
Chris@366: 
Chris@366:      When present, hosts must call this function once before run() (or
Chris@366:      run_adding()) is called for the first time. This call should be
Chris@366:      made as close to the run() call as possible and indicates to
Chris@366:      real-time plugins that they are now live. Plugins should not rely
Chris@366:      on a prompt call to run() after activate(). activate() may not be
Chris@366:      called again unless deactivate() is called first. Note that
Chris@366:      connect_port() may be called before or after a call to
Chris@366:      activate(). */
Chris@366:   void (*activate)(LADSPA_Handle Instance);
Chris@366: 
Chris@366:   /* This method is a function pointer that runs an instance of a
Chris@366:      plugin for a block. Two parameters are required: the first is a
Chris@366:      handle to the particular instance to be run and the second
Chris@366:      indicates the block size (in samples) for which the plugin
Chris@366:      instance may run.
Chris@366: 
Chris@366:      Note that if an activate() function exists then it must be called
Chris@366:      before run() or run_adding(). If deactivate() is called for a
Chris@366:      plugin instance then the plugin instance may not be reused until
Chris@366:      activate() has been called again.
Chris@366: 
Chris@366:      If the plugin has the property LADSPA_PROPERTY_HARD_RT_CAPABLE
Chris@366:      then there are various things that the plugin should not do
Chris@366:      within the run() or run_adding() functions (see above). */
Chris@366:   void (*run)(LADSPA_Handle Instance,
Chris@366:               unsigned long SampleCount);
Chris@366: 
Chris@366:   /* This method is a function pointer that runs an instance of a
Chris@366:      plugin for a block. This has identical behaviour to run() except
Chris@366:      in the way data is output from the plugin. When run() is used,
Chris@366:      values are written directly to the memory areas associated with
Chris@366:      the output ports. However when run_adding() is called, values
Chris@366:      must be added to the values already present in the memory
Chris@366:      areas. Furthermore, output values written must be scaled by the
Chris@366:      current gain set by set_run_adding_gain() (see below) before
Chris@366:      addition.
Chris@366: 
Chris@366:      run_adding() is optional. When it is not provided by a plugin,
Chris@366:      this function pointer must be set to NULL. When it is provided,
Chris@366:      the function set_run_adding_gain() must be provided also. */
Chris@366:   void (*run_adding)(LADSPA_Handle Instance,
Chris@366:                      unsigned long SampleCount);
Chris@366: 
Chris@366:   /* This method is a function pointer that sets the output gain for
Chris@366:      use when run_adding() is called (see above). If this function is
Chris@366:      never called the gain is assumed to default to 1. Gain
Chris@366:      information should be retained when activate() or deactivate()
Chris@366:      are called.
Chris@366: 
Chris@366:      This function should be provided by the plugin if and only if the
Chris@366:      run_adding() function is provided. When it is absent this
Chris@366:      function pointer must be set to NULL. */
Chris@366:   void (*set_run_adding_gain)(LADSPA_Handle Instance,
Chris@366:                               LADSPA_Data   Gain);
Chris@366: 
Chris@366:   /* This is the counterpart to activate() (see above). If there is
Chris@366:      nothing for deactivate() to do then the plugin writer may provide
Chris@366:      a NULL rather than an empty function.
Chris@366: 
Chris@366:      Hosts must deactivate all activated units after they have been
Chris@366:      run() (or run_adding()) for the last time. This call should be
Chris@366:      made as close to the last run() call as possible and indicates to
Chris@366:      real-time plugins that they are no longer live. Plugins should
Chris@366:      not rely on prompt deactivation. Note that connect_port() may be
Chris@366:      called before or after a call to deactivate().
Chris@366: 
Chris@366:      Deactivation is not similar to pausing as the plugin instance
Chris@366:      will be reinitialised when activate() is called to reuse it. */
Chris@366:   void (*deactivate)(LADSPA_Handle Instance);
Chris@366: 
Chris@366:   /* Once an instance of a plugin has been finished with it can be
Chris@366:      deleted using the following function. The instance handle passed
Chris@366:      ceases to be valid after this call.
Chris@366:   
Chris@366:      If activate() was called for a plugin instance then a
Chris@366:      corresponding call to deactivate() must be made before cleanup()
Chris@366:      is called. */
Chris@366:   void (*cleanup)(LADSPA_Handle Instance);
Chris@366: 
Chris@366: } LADSPA_Descriptor;
Chris@366: 
Chris@366: /**********************************************************************/
Chris@366: 
Chris@366: /* Accessing a Plugin: */
Chris@366: 
Chris@366: /* The exact mechanism by which plugins are loaded is host-dependent,
Chris@366:    however all most hosts will need to know is the name of shared
Chris@366:    object file containing the plugin types. To allow multiple hosts to
Chris@366:    share plugin types, hosts may wish to check for environment
Chris@366:    variable LADSPA_PATH. If present, this should contain a
Chris@366:    colon-separated path indicating directories that should be searched
Chris@366:    (in order) when loading plugin types.
Chris@366: 
Chris@366:    A plugin programmer must include a function called
Chris@366:    "ladspa_descriptor" with the following function prototype within
Chris@366:    the shared object file. This function will have C-style linkage (if
Chris@366:    you are using C++ this is taken care of by the `extern "C"' clause
Chris@366:    at the top of the file).
Chris@366: 
Chris@366:    A host will find the plugin shared object file by one means or
Chris@366:    another, find the ladspa_descriptor() function, call it, and
Chris@366:    proceed from there.
Chris@366: 
Chris@366:    Plugin types are accessed by index (not ID) using values from 0
Chris@366:    upwards. Out of range indexes must result in this function
Chris@366:    returning NULL, so the plugin count can be determined by checking
Chris@366:    for the least index that results in NULL being returned. */
Chris@366: 
Chris@366: const LADSPA_Descriptor * ladspa_descriptor(unsigned long Index);
Chris@366: 
Chris@366: /* Datatype corresponding to the ladspa_descriptor() function. */
Chris@366: typedef const LADSPA_Descriptor * 
Chris@366: (*LADSPA_Descriptor_Function)(unsigned long Index);
Chris@366: 
Chris@366: /**********************************************************************/
Chris@366: 
Chris@366: #ifdef __cplusplus
Chris@366: }
Chris@366: #endif
Chris@366: 
Chris@366: #endif /* LADSPA_INCLUDED */
Chris@366: 
Chris@366: /* EOF */