1 /* ladspa.h 2 3 Linux Audio Developer's Simple Plugin API Version 1.1[LGPL]. 4 Copyright (C) 2000-2002 Richard W.E. Furse, Paul Barton-Davis, 5 Stefan Westerfeld. 6 7 This library is free software; you can redistribute it and/or 8 modify it under the terms of the GNU Lesser General Public License 9 as published by the Free Software Foundation; either version 2.1 of 10 the License, or (at your option) any later version. 11 12 This library is distributed in the hope that it will be useful, but 13 WITHOUT ANY WARRANTY; without even the implied warranty of 14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 15 Lesser General Public License for more details. 16 17 You should have received a copy of the GNU Lesser General Public 18 License along with this library; if not, write to the Free Software 19 Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 20 USA. */ 21 22 #ifndef LADSPA_INCLUDED 23 #define LADSPA_INCLUDED 24 25 #define LADSPA_VERSION "1.1" 26 #define LADSPA_VERSION_MAJOR 1 27 #define LADSPA_VERSION_MINOR 1 28 29 #ifdef __cplusplus 30 extern "C" { 31 #endif 32 33 /*****************************************************************************/ 34 35 /* Overview: 36 37 There is a large number of synthesis packages in use or development 38 on the Linux platform at this time. This API (`The Linux Audio 39 Developer's Simple Plugin API') attempts to give programmers the 40 ability to write simple `plugin' audio processors in C/C++ and link 41 them dynamically (`plug') into a range of these packages (`hosts'). 42 It should be possible for any host and any plugin to communicate 43 completely through this interface. 44 45 This API is deliberately short and simple. To achieve compatibility 46 with a range of promising Linux sound synthesis packages it 47 attempts to find the `greatest common divisor' in their logical 48 behaviour. Having said this, certain limiting decisions are 49 implicit, notably the use of a fixed type (LADSPA_Data) for all 50 data transfer and absence of a parameterised `initialisation' 51 phase. See below for the LADSPA_Data typedef. 52 53 Plugins are expected to distinguish between control and audio 54 data. Plugins have `ports' that are inputs or outputs for audio or 55 control data and each plugin is `run' for a `block' corresponding 56 to a short time interval measured in samples. Audio data is 57 communicated using arrays of LADSPA_Data, allowing a block of audio 58 to be processed by the plugin in a single pass. Control data is 59 communicated using single LADSPA_Data values. Control data has a 60 single value at the start of a call to the `run()' or `run_adding()' 61 function, and may be considered to remain this value for its 62 duration. The plugin may assume that all its input and output ports 63 have been connected to the relevant data location (see the 64 `connect_port()' function below) before it is asked to run. 65 66 Plugins will reside in shared object files suitable for dynamic 67 linking by dlopen() and family. The file will provide a number of 68 `plugin types' that can be used to instantiate actual plugins 69 (sometimes known as `plugin instances') that can be connected 70 together to perform tasks. 71 72 This API contains very limited error-handling. */ 73 74 /*****************************************************************************/ 75 76 /* Fundamental data type passed in and out of plugin. This data type 77 is used to communicate audio samples and control values. It is 78 assumed that the plugin will work sensibly given any numeric input 79 value although it may have a preferred range (see hints below). 80 81 For audio it is generally assumed that 1.0f is the `0dB' reference 82 amplitude and is a `normal' signal level. */ 83 84 typedef float LADSPA_Data; 85 86 /*****************************************************************************/ 87 88 /* Special Plugin Properties: 89 90 Optional features of the plugin type are encapsulated in the 91 LADSPA_Properties type. This is assembled by ORing individual 92 properties together. */ 93 94 typedef int LADSPA_Properties; 95 96 /* Property LADSPA_PROPERTY_REALTIME indicates that the plugin has a 97 real-time dependency (e.g. listens to a MIDI device) and so its 98 output must not be cached or subject to significant latency. */ 99 #define LADSPA_PROPERTY_REALTIME 0x1 100 101 /* Property LADSPA_PROPERTY_INPLACE_BROKEN indicates that the plugin 102 may cease to work correctly if the host elects to use the same data 103 location for both input and output (see connect_port()). This 104 should be avoided as enabling this flag makes it impossible for 105 hosts to use the plugin to process audio `in-place.' */ 106 #define LADSPA_PROPERTY_INPLACE_BROKEN 0x2 107 108 /* Property LADSPA_PROPERTY_HARD_RT_CAPABLE indicates that the plugin 109 is capable of running not only in a conventional host but also in a 110 `hard real-time' environment. To qualify for this the plugin must 111 satisfy all of the following: 112 113 (1) The plugin must not use malloc(), free() or other heap memory 114 management within its run() or run_adding() functions. All new 115 memory used in run() must be managed via the stack. These 116 restrictions only apply to the run() function. 117 118 (2) The plugin will not attempt to make use of any library 119 functions with the exceptions of functions in the ANSI standard C 120 and C maths libraries, which the host is expected to provide. 121 122 (3) The plugin will not access files, devices, pipes, sockets, IPC 123 or any other mechanism that might result in process or thread 124 blocking. 125 126 (4) The plugin will take an amount of time to execute a run() or 127 run_adding() call approximately of form (A+B*SampleCount) where A 128 and B depend on the machine and host in use. This amount of time 129 may not depend on input signals or plugin state. The host is left 130 the responsibility to perform timings to estimate upper bounds for 131 A and B. */ 132 #define LADSPA_PROPERTY_HARD_RT_CAPABLE 0x4 133 134 #define LADSPA_IS_REALTIME(x) ((x) & LADSPA_PROPERTY_REALTIME) 135 #define LADSPA_IS_INPLACE_BROKEN(x) ((x) & LADSPA_PROPERTY_INPLACE_BROKEN) 136 #define LADSPA_IS_HARD_RT_CAPABLE(x) ((x) & LADSPA_PROPERTY_HARD_RT_CAPABLE) 137 138 /*****************************************************************************/ 139 140 /* Plugin Ports: 141 142 Plugins have `ports' that are inputs or outputs for audio or 143 data. Ports can communicate arrays of LADSPA_Data (for audio 144 inputs/outputs) or single LADSPA_Data values (for control 145 input/outputs). This information is encapsulated in the 146 LADSPA_PortDescriptor type which is assembled by ORing individual 147 properties together. 148 149 Note that a port must be an input or an output port but not both 150 and that a port must be a control or audio port but not both. */ 151 152 typedef int LADSPA_PortDescriptor; 153 154 /* Property LADSPA_PORT_INPUT indicates that the port is an input. */ 155 #define LADSPA_PORT_INPUT 0x1 156 157 /* Property LADSPA_PORT_OUTPUT indicates that the port is an output. */ 158 #define LADSPA_PORT_OUTPUT 0x2 159 160 /* Property LADSPA_PORT_CONTROL indicates that the port is a control 161 port. */ 162 #define LADSPA_PORT_CONTROL 0x4 163 164 /* Property LADSPA_PORT_AUDIO indicates that the port is a audio 165 port. */ 166 #define LADSPA_PORT_AUDIO 0x8 167 168 #define LADSPA_IS_PORT_INPUT(x) ((x) & LADSPA_PORT_INPUT) 169 #define LADSPA_IS_PORT_OUTPUT(x) ((x) & LADSPA_PORT_OUTPUT) 170 #define LADSPA_IS_PORT_CONTROL(x) ((x) & LADSPA_PORT_CONTROL) 171 #define LADSPA_IS_PORT_AUDIO(x) ((x) & LADSPA_PORT_AUDIO) 172 173 /*****************************************************************************/ 174 175 /* Plugin Port Range Hints: 176 177 The host may wish to provide a representation of data entering or 178 leaving a plugin (e.g. to generate a GUI automatically). To make 179 this more meaningful, the plugin should provide `hints' to the host 180 describing the usual values taken by the data. 181 182 Note that these are only hints. The host may ignore them and the 183 plugin must not assume that data supplied to it is meaningful. If 184 the plugin receives invalid input data it is expected to continue 185 to run without failure and, where possible, produce a sensible 186 output (e.g. a high-pass filter given a negative cutoff frequency 187 might switch to an all-pass mode). 188 189 Hints are meaningful for all input and output ports but hints for 190 input control ports are expected to be particularly useful. 191 192 More hint information is encapsulated in the 193 LADSPA_PortRangeHintDescriptor type which is assembled by ORing 194 individual hint types together. Hints may require further 195 LowerBound and UpperBound information. 196 197 All the hint information for a particular port is aggregated in the 198 LADSPA_PortRangeHint structure. */ 199 200 typedef int LADSPA_PortRangeHintDescriptor; 201 202 /* Hint LADSPA_HINT_BOUNDED_BELOW indicates that the LowerBound field 203 of the LADSPA_PortRangeHint should be considered meaningful. The 204 value in this field should be considered the (inclusive) lower 205 bound of the valid range. If LADSPA_HINT_SAMPLE_RATE is also 206 specified then the value of LowerBound should be multiplied by the 207 sample rate. */ 208 #define LADSPA_HINT_BOUNDED_BELOW 0x1 209 210 /* Hint LADSPA_HINT_BOUNDED_ABOVE indicates that the UpperBound field 211 of the LADSPA_PortRangeHint should be considered meaningful. The 212 value in this field should be considered the (inclusive) upper 213 bound of the valid range. If LADSPA_HINT_SAMPLE_RATE is also 214 specified then the value of UpperBound should be multiplied by the 215 sample rate. */ 216 #define LADSPA_HINT_BOUNDED_ABOVE 0x2 217 218 /* Hint LADSPA_HINT_TOGGLED indicates that the data item should be 219 considered a Boolean toggle. Data less than or equal to zero should 220 be considered `off' or `false,' and data above zero should be 221 considered `on' or `true.' LADSPA_HINT_TOGGLED may not be used in 222 conjunction with any other hint except LADSPA_HINT_DEFAULT_0 or 223 LADSPA_HINT_DEFAULT_1. */ 224 #define LADSPA_HINT_TOGGLED 0x4 225 226 /* Hint LADSPA_HINT_SAMPLE_RATE indicates that any bounds specified 227 should be interpreted as multiples of the sample rate. For 228 instance, a frequency range from 0Hz to the Nyquist frequency (half 229 the sample rate) could be requested by this hint in conjunction 230 with LowerBound = 0 and UpperBound = 0.5. Hosts that support bounds 231 at all must support this hint to retain meaning. */ 232 #define LADSPA_HINT_SAMPLE_RATE 0x8 233 234 /* Hint LADSPA_HINT_LOGARITHMIC indicates that it is likely that the 235 user will find it more intuitive to view values using a logarithmic 236 scale. This is particularly useful for frequencies and gains. */ 237 #define LADSPA_HINT_LOGARITHMIC 0x10 238 239 /* Hint LADSPA_HINT_INTEGER indicates that a user interface would 240 probably wish to provide a stepped control taking only integer 241 values. Any bounds set should be slightly wider than the actual 242 integer range required to avoid floating point rounding errors. For 243 instance, the integer set {0,1,2,3} might be described as [-0.1, 244 3.1]. */ 245 #define LADSPA_HINT_INTEGER 0x20 246 247 /* The various LADSPA_HINT_HAS_DEFAULT_* hints indicate a `normal' 248 value for the port that is sensible as a default. For instance, 249 this value is suitable for use as an initial value in a user 250 interface or as a value the host might assign to a control port 251 when the user has not provided one. Defaults are encoded using a 252 mask so only one default may be specified for a port. Some of the 253 hints make use of lower and upper bounds, in which case the 254 relevant bound or bounds must be available and 255 LADSPA_HINT_SAMPLE_RATE must be applied as usual. The resulting 256 default must be rounded if LADSPA_HINT_INTEGER is present. Default 257 values were introduced in LADSPA v1.1. */ 258 #define LADSPA_HINT_DEFAULT_MASK 0x3C0 259 260 /* This default values indicates that no default is provided. */ 261 #define LADSPA_HINT_DEFAULT_NONE 0x0 262 263 /* This default hint indicates that the suggested lower bound for the 264 port should be used. */ 265 #define LADSPA_HINT_DEFAULT_MINIMUM 0x40 266 267 /* This default hint indicates that a low value between the suggested 268 lower and upper bounds should be chosen. For ports with 269 LADSPA_HINT_LOGARITHMIC, this should be exp(log(lower) * 0.75 + 270 log(upper) * 0.25). Otherwise, this should be (lower * 0.75 + upper 271 * 0.25). */ 272 #define LADSPA_HINT_DEFAULT_LOW 0x80 273 274 /* This default hint indicates that a middle value between the 275 suggested lower and upper bounds should be chosen. For ports with 276 LADSPA_HINT_LOGARITHMIC, this should be exp(log(lower) * 0.5 + 277 log(upper) * 0.5). Otherwise, this should be (lower * 0.5 + upper * 278 0.5). */ 279 #define LADSPA_HINT_DEFAULT_MIDDLE 0xC0 280 281 /* This default hint indicates that a high value between the suggested 282 lower and upper bounds should be chosen. For ports with 283 LADSPA_HINT_LOGARITHMIC, this should be exp(log(lower) * 0.25 + 284 log(upper) * 0.75). Otherwise, this should be (lower * 0.25 + upper 285 * 0.75). */ 286 #define LADSPA_HINT_DEFAULT_HIGH 0x100 287 288 /* This default hint indicates that the suggested upper bound for the 289 port should be used. */ 290 #define LADSPA_HINT_DEFAULT_MAXIMUM 0x140 291 292 /* This default hint indicates that the number 0 should be used. Note 293 that this default may be used in conjunction with 294 LADSPA_HINT_TOGGLED. */ 295 #define LADSPA_HINT_DEFAULT_0 0x200 296 297 /* This default hint indicates that the number 1 should be used. Note 298 that this default may be used in conjunction with 299 LADSPA_HINT_TOGGLED. */ 300 #define LADSPA_HINT_DEFAULT_1 0x240 301 302 /* This default hint indicates that the number 100 should be used. */ 303 #define LADSPA_HINT_DEFAULT_100 0x280 304 305 /* This default hint indicates that the Hz frequency of `concert A' 306 should be used. This will be 440 unless the host uses an unusual 307 tuning convention, in which case it may be within a few Hz. */ 308 #define LADSPA_HINT_DEFAULT_440 0x2C0 309 310 #define LADSPA_IS_HINT_BOUNDED_BELOW(x) ((x) & LADSPA_HINT_BOUNDED_BELOW) 311 #define LADSPA_IS_HINT_BOUNDED_ABOVE(x) ((x) & LADSPA_HINT_BOUNDED_ABOVE) 312 #define LADSPA_IS_HINT_TOGGLED(x) ((x) & LADSPA_HINT_TOGGLED) 313 #define LADSPA_IS_HINT_SAMPLE_RATE(x) ((x) & LADSPA_HINT_SAMPLE_RATE) 314 #define LADSPA_IS_HINT_LOGARITHMIC(x) ((x) & LADSPA_HINT_LOGARITHMIC) 315 #define LADSPA_IS_HINT_INTEGER(x) ((x) & LADSPA_HINT_INTEGER) 316 317 #define LADSPA_IS_HINT_HAS_DEFAULT(x) ((x) & LADSPA_HINT_DEFAULT_MASK) 318 #define LADSPA_IS_HINT_DEFAULT_MINIMUM(x) (((x) & LADSPA_HINT_DEFAULT_MASK) \ 319 == LADSPA_HINT_DEFAULT_MINIMUM) 320 #define LADSPA_IS_HINT_DEFAULT_LOW(x) (((x) & LADSPA_HINT_DEFAULT_MASK) \ 321 == LADSPA_HINT_DEFAULT_LOW) 322 #define LADSPA_IS_HINT_DEFAULT_MIDDLE(x) (((x) & LADSPA_HINT_DEFAULT_MASK) \ 323 == LADSPA_HINT_DEFAULT_MIDDLE) 324 #define LADSPA_IS_HINT_DEFAULT_HIGH(x) (((x) & LADSPA_HINT_DEFAULT_MASK) \ 325 == LADSPA_HINT_DEFAULT_HIGH) 326 #define LADSPA_IS_HINT_DEFAULT_MAXIMUM(x) (((x) & LADSPA_HINT_DEFAULT_MASK) \ 327 == LADSPA_HINT_DEFAULT_MAXIMUM) 328 #define LADSPA_IS_HINT_DEFAULT_0(x) (((x) & LADSPA_HINT_DEFAULT_MASK) \ 329 == LADSPA_HINT_DEFAULT_0) 330 #define LADSPA_IS_HINT_DEFAULT_1(x) (((x) & LADSPA_HINT_DEFAULT_MASK) \ 331 == LADSPA_HINT_DEFAULT_1) 332 #define LADSPA_IS_HINT_DEFAULT_100(x) (((x) & LADSPA_HINT_DEFAULT_MASK) \ 333 == LADSPA_HINT_DEFAULT_100) 334 #define LADSPA_IS_HINT_DEFAULT_440(x) (((x) & LADSPA_HINT_DEFAULT_MASK) \ 335 == LADSPA_HINT_DEFAULT_440) 336 337 typedef struct _LADSPA_PortRangeHint { 338 339 /* Hints about the port. */ 340 LADSPA_PortRangeHintDescriptor HintDescriptor; 341 342 /* Meaningful when hint LADSPA_HINT_BOUNDED_BELOW is active. When 343 LADSPA_HINT_SAMPLE_RATE is also active then this value should be 344 multiplied by the relevant sample rate. */ 345 LADSPA_Data LowerBound; 346 347 /* Meaningful when hint LADSPA_HINT_BOUNDED_ABOVE is active. When 348 LADSPA_HINT_SAMPLE_RATE is also active then this value should be 349 multiplied by the relevant sample rate. */ 350 LADSPA_Data UpperBound; 351 352 } LADSPA_PortRangeHint; 353 354 /*****************************************************************************/ 355 356 /* Plugin Handles: 357 358 This plugin handle indicates a particular instance of the plugin 359 concerned. It is valid to compare this to NULL (0 for C++) but 360 otherwise the host should not attempt to interpret it. The plugin 361 may use it to reference internal instance data. */ 362 363 typedef void * LADSPA_Handle; 364 365 /*****************************************************************************/ 366 367 /* Descriptor for a Type of Plugin: 368 369 This structure is used to describe a plugin type. It provides a 370 number of functions to examine the type, instantiate it, link it to 371 buffers and workspaces and to run it. */ 372 373 typedef struct _LADSPA_Descriptor { 374 375 /* This numeric identifier indicates the plugin type 376 uniquely. Plugin programmers may reserve ranges of IDs from a 377 central body to avoid clashes. Hosts may assume that IDs are 378 below 0x1000000. */ 379 unsigned long UniqueID; 380 381 /* This identifier can be used as a unique, case-sensitive 382 identifier for the plugin type within the plugin file. Plugin 383 types should be identified by file and label rather than by index 384 or plugin name, which may be changed in new plugin 385 versions. Labels must not contain white-space characters. */ 386 const char * Label; 387 388 /* This indicates a number of properties of the plugin. */ 389 LADSPA_Properties Properties; 390 391 /* This member points to the null-terminated name of the plugin 392 (e.g. "Sine Oscillator"). */ 393 const char * Name; 394 395 /* This member points to the null-terminated string indicating the 396 maker of the plugin. This can be an empty string but not NULL. */ 397 const char * Maker; 398 399 /* This member points to the null-terminated string indicating any 400 copyright applying to the plugin. If no Copyright applies the 401 string "None" should be used. */ 402 const char * Copyright; 403 404 /* This indicates the number of ports (input AND output) present on 405 the plugin. */ 406 unsigned long PortCount; 407 408 /* This member indicates an array of port descriptors. Valid indices 409 vary from 0 to PortCount-1. */ 410 const LADSPA_PortDescriptor * PortDescriptors; 411 412 /* This member indicates an array of null-terminated strings 413 describing ports (e.g. "Frequency (Hz)"). Valid indices vary from 414 0 to PortCount-1. */ 415 const char * const * PortNames; 416 417 /* This member indicates an array of range hints for each port (see 418 above). Valid indices vary from 0 to PortCount-1. */ 419 const LADSPA_PortRangeHint * PortRangeHints; 420 421 /* This may be used by the plugin developer to pass any custom 422 implementation data into an instantiate call. It must not be used 423 or interpreted by the host. It is expected that most plugin 424 writers will not use this facility as LADSPA_Handle should be 425 used to hold instance data. */ 426 void * ImplementationData; 427 428 /* This member is a function pointer that instantiates a plugin. A 429 handle is returned indicating the new plugin instance. The 430 instantiation function accepts a sample rate as a parameter. The 431 plugin descriptor from which this instantiate function was found 432 must also be passed. This function must return NULL if 433 instantiation fails. 434 435 Note that instance initialisation should generally occur in 436 activate() rather than here. */ 437 LADSPA_Handle (*instantiate)(const struct _LADSPA_Descriptor * Descriptor, 438 unsigned long SampleRate); 439 440 /* This member is a function pointer that connects a port on an 441 instantiated plugin to a memory location at which a block of data 442 for the port will be read/written. The data location is expected 443 to be an array of LADSPA_Data for audio ports or a single 444 LADSPA_Data value for control ports. Memory issues will be 445 managed by the host. The plugin must read/write the data at these 446 locations every time run() or run_adding() is called and the data 447 present at the time of this connection call should not be 448 considered meaningful. 449 450 connect_port() may be called more than once for a plugin instance 451 to allow the host to change the buffers that the plugin is 452 reading or writing. These calls may be made before or after 453 activate() or deactivate() calls. 454 455 connect_port() must be called at least once for each port before 456 run() or run_adding() is called. When working with blocks of 457 LADSPA_Data the plugin should pay careful attention to the block 458 size passed to the run function as the block allocated may only 459 just be large enough to contain the block of samples. 460 461 Plugin writers should be aware that the host may elect to use the 462 same buffer for more than one port and even use the same buffer 463 for both input and output (see LADSPA_PROPERTY_INPLACE_BROKEN). 464 However, overlapped buffers or use of a single buffer for both 465 audio and control data may result in unexpected behaviour. */ 466 void (*connect_port)(LADSPA_Handle Instance, 467 unsigned long Port, 468 LADSPA_Data * DataLocation); 469 470 /* This member is a function pointer that initialises a plugin 471 instance and activates it for use. This is separated from 472 instantiate() to aid real-time support and so that hosts can 473 reinitialise a plugin instance by calling deactivate() and then 474 activate(). In this case the plugin instance must reset all state 475 information dependent on the history of the plugin instance 476 except for any data locations provided by connect_port() and any 477 gain set by set_run_adding_gain(). If there is nothing for 478 activate() to do then the plugin writer may provide a NULL rather 479 than an empty function. 480 481 When present, hosts must call this function once before run() (or 482 run_adding()) is called for the first time. This call should be 483 made as close to the run() call as possible and indicates to 484 real-time plugins that they are now live. Plugins should not rely 485 on a prompt call to run() after activate(). activate() may not be 486 called again unless deactivate() is called first. Note that 487 connect_port() may be called before or after a call to 488 activate(). */ 489 void (*activate)(LADSPA_Handle Instance); 490 491 /* This method is a function pointer that runs an instance of a 492 plugin for a block. Two parameters are required: the first is a 493 handle to the particular instance to be run and the second 494 indicates the block size (in samples) for which the plugin 495 instance may run. 496 497 Note that if an activate() function exists then it must be called 498 before run() or run_adding(). If deactivate() is called for a 499 plugin instance then the plugin instance may not be reused until 500 activate() has been called again. 501 502 If the plugin has the property LADSPA_PROPERTY_HARD_RT_CAPABLE 503 then there are various things that the plugin should not do 504 within the run() or run_adding() functions (see above). */ 505 void (*run)(LADSPA_Handle Instance, 506 unsigned long SampleCount); 507 508 /* This method is a function pointer that runs an instance of a 509 plugin for a block. This has identical behaviour to run() except 510 in the way data is output from the plugin. When run() is used, 511 values are written directly to the memory areas associated with 512 the output ports. However when run_adding() is called, values 513 must be added to the values already present in the memory 514 areas. Furthermore, output values written must be scaled by the 515 current gain set by set_run_adding_gain() (see below) before 516 addition. 517 518 run_adding() is optional. When it is not provided by a plugin, 519 this function pointer must be set to NULL. When it is provided, 520 the function set_run_adding_gain() must be provided also. */ 521 void (*run_adding)(LADSPA_Handle Instance, 522 unsigned long SampleCount); 523 524 /* This method is a function pointer that sets the output gain for 525 use when run_adding() is called (see above). If this function is 526 never called the gain is assumed to default to 1. Gain 527 information should be retained when activate() or deactivate() 528 are called. 529 530 This function should be provided by the plugin if and only if the 531 run_adding() function is provided. When it is absent this 532 function pointer must be set to NULL. */ 533 void (*set_run_adding_gain)(LADSPA_Handle Instance, 534 LADSPA_Data Gain); 535 536 /* This is the counterpart to activate() (see above). If there is 537 nothing for deactivate() to do then the plugin writer may provide 538 a NULL rather than an empty function. 539 540 Hosts must deactivate all activated units after they have been 541 run() (or run_adding()) for the last time. This call should be 542 made as close to the last run() call as possible and indicates to 543 real-time plugins that they are no longer live. Plugins should 544 not rely on prompt deactivation. Note that connect_port() may be 545 called before or after a call to deactivate(). 546 547 Deactivation is not similar to pausing as the plugin instance 548 will be reinitialised when activate() is called to reuse it. */ 549 void (*deactivate)(LADSPA_Handle Instance); 550 551 /* Once an instance of a plugin has been finished with it can be 552 deleted using the following function. The instance handle passed 553 ceases to be valid after this call. 554 555 If activate() was called for a plugin instance then a 556 corresponding call to deactivate() must be made before cleanup() 557 is called. */ 558 void (*cleanup)(LADSPA_Handle Instance); 559 560 } LADSPA_Descriptor; 561 562 /**********************************************************************/ 563 564 /* Accessing a Plugin: */ 565 566 /* The exact mechanism by which plugins are loaded is host-dependent, 567 however all most hosts will need to know is the name of shared 568 object file containing the plugin types. To allow multiple hosts to 569 share plugin types, hosts may wish to check for environment 570 variable LADSPA_PATH. If present, this should contain a 571 colon-separated path indicating directories that should be searched 572 (in order) when loading plugin types. 573 574 A plugin programmer must include a function called 575 "ladspa_descriptor" with the following function prototype within 576 the shared object file. This function will have C-style linkage (if 577 you are using C++ this is taken care of by the `extern "C"' clause 578 at the top of the file). 579 580 A host will find the plugin shared object file by one means or 581 another, find the ladspa_descriptor() function, call it, and 582 proceed from there. 583 584 Plugin types are accessed by index (not ID) using values from 0 585 upwards. Out of range indexes must result in this function 586 returning NULL, so the plugin count can be determined by checking 587 for the least index that results in NULL being returned. */ 588 589 const LADSPA_Descriptor * ladspa_descriptor(unsigned long Index); 590 591 /* Datatype corresponding to the ladspa_descriptor() function. */ 592 typedef const LADSPA_Descriptor * 593 (*LADSPA_Descriptor_Function)(unsigned long Index); 594 595 /**********************************************************************/ 596 597 #ifdef __cplusplus 598 } 599 #endif 600 601 #endif /* LADSPA_INCLUDED */ 602 603 /* EOF */ 604
