/[svn]/linuxsampler/trunk/src/scriptvm/common.h
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Contents of /linuxsampler/trunk/src/scriptvm/common.h

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Revision 3292 - (show annotations) (download) (as text)
Sat Jun 24 13:43:09 2017 UTC (3 years, 4 months ago) by schoenebeck
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File size: 50433 byte(s)
- Just minor API cleanup.

1 /*
2 * Copyright (c) 2014-2017 Christian Schoenebeck
3 *
4 * http://www.linuxsampler.org
5 *
6 * This file is part of LinuxSampler and released under the same terms.
7 * See README file for details.
8 */
9
10 // This header defines data types shared between the VM core implementation
11 // (inside the current source directory) and other parts of the sampler
12 // (located at other source directories). It also acts as public API of the
13 // Real-Time script engine for other applications.
14
15 #ifndef LS_INSTR_SCRIPT_PARSER_COMMON_H
16 #define LS_INSTR_SCRIPT_PARSER_COMMON_H
17
18 #include "../common/global.h"
19 #include <vector>
20 #include <map>
21 #include <stddef.h> // offsetof()
22
23 namespace LinuxSampler {
24
25 /**
26 * Identifies the type of a noteworthy issue identified by the script
27 * parser. That's either a parser error or parser warning.
28 */
29 enum ParserIssueType_t {
30 PARSER_ERROR, ///< Script parser encountered an error, the script cannot be executed.
31 PARSER_WARNING ///< Script parser encountered a warning, the script may be executed if desired, but the script may not necessarily behave as originally intended by the script author.
32 };
33
34 /** @brief Expression's data type.
35 *
36 * Identifies to which data type an expression within a script evaluates to.
37 * This can for example reflect the data type of script function arguments,
38 * script function return values, but also the resulting data type of some
39 * mathematical formula within a script.
40 */
41 enum ExprType_t {
42 EMPTY_EXPR, ///< i.e. on invalid expressions or i.e. a function call that does not return a result value (the built-in wait() or message() functions for instance)
43 INT_EXPR, ///< integer (scalar) expression
44 INT_ARR_EXPR, ///< integer array expression
45 STRING_EXPR, ///< string expression
46 STRING_ARR_EXPR, ///< string array expression
47 };
48
49 /** @brief Result flags of a script statement or script function call.
50 *
51 * A set of bit flags which provide informations about the success or
52 * failure of a statement within a script. That's also especially used for
53 * providing informations about success / failure of a call to a built-in
54 * script function. The virtual machine evaluates these flags during runtime
55 * to decide whether it should i.e. stop or suspend execution of a script.
56 *
57 * Since these are bit flags, these constants are bitwise combined.
58 */
59 enum StmtFlags_t {
60 STMT_SUCCESS = 0, ///< Function / statement was executed successfully, no error occurred.
61 STMT_ABORT_SIGNALLED = 1, ///< VM should stop the current callback execution (usually because of an error, but might also be without an error reason, i.e. when the built-in script function exit() was called).
62 STMT_SUSPEND_SIGNALLED = (1<<1), ///< VM supended execution, either because the script called the built-in wait() script function or because the script consumed too much execution time and was forced by the VM to be suspended for some time
63 STMT_ERROR_OCCURRED = (1<<2), ///< VM stopped execution due to some script runtime error that occurred
64 };
65
66 /** @brief Virtual machine execution status.
67 *
68 * A set of bit flags which reflect the current overall execution status of
69 * the virtual machine concerning a certain script execution instance.
70 *
71 * Since these are bit flags, these constants are bitwise combined.
72 */
73 enum VMExecStatus_t {
74 VM_EXEC_NOT_RUNNING = 0, ///< Script is currently not executed by the VM.
75 VM_EXEC_RUNNING = 1, ///< The VM is currently executing the script.
76 VM_EXEC_SUSPENDED = (1<<1), ///< Script is currently suspended by the VM, either because the script called the built-in wait() script function or because the script consumed too much execution time and was forced by the VM to be suspended for some time.
77 VM_EXEC_ERROR = (1<<2), ///< A runtime error occurred while executing the script (i.e. a call to some built-in script function failed).
78 };
79
80 /** @brief Script event handler type.
81 *
82 * Identifies one of the possible event handler callback types defined by
83 * the NKSP script language.
84 */
85 enum VMEventHandlerType_t {
86 VM_EVENT_HANDLER_INIT, ///< Initilization event handler, that is script's "on init ... end on" code block.
87 VM_EVENT_HANDLER_NOTE, ///< Note event handler, that is script's "on note ... end on" code block.
88 VM_EVENT_HANDLER_RELEASE, ///< Release event handler, that is script's "on release ... end on" code block.
89 VM_EVENT_HANDLER_CONTROLLER, ///< Controller event handler, that is script's "on controller ... end on" code block.
90 };
91
92 // just symbol prototyping
93 class VMIntExpr;
94 class VMStringExpr;
95 class VMIntArrayExpr;
96 class VMStringArrayExpr;
97
98 /** @brief Virtual machine expression
99 *
100 * This is the abstract base class for all expressions of scripts.
101 * Deriving classes must implement the abstract method exprType().
102 *
103 * An expression within a script is translated into one instance of this
104 * class. It allows a high level access for the virtual machine to evaluate
105 * and handle expressions appropriately during execution. Expressions are
106 * for example all kinds of formulas, function calls, statements or a
107 * combination of them. Most of them evaluate to some kind of value, which
108 * might be further processed as part of encompassing expressions to outer
109 * expression results and so forth.
110 */
111 class VMExpr {
112 public:
113 /**
114 * Identifies the data type to which the result of this expression
115 * evaluates to. This abstract method must be implemented by deriving
116 * classes.
117 */
118 virtual ExprType_t exprType() const = 0;
119
120 /**
121 * In case this expression is an integer expression, then this method
122 * returns a casted pointer to that VMIntExpr object. It returns NULL
123 * if this expression is not an integer expression.
124 *
125 * @b Note: type casting performed by this method is strict! That means
126 * if this expression is i.e. actually a string expression like "12",
127 * calling asInt() will @b not cast that numerical string expression to
128 * an integer expression 12 for you, instead this method will simply
129 * return NULL!
130 *
131 * @see exprType()
132 */
133 VMIntExpr* asInt() const;
134
135 /**
136 * In case this expression is a string expression, then this method
137 * returns a casted pointer to that VMStringExpr object. It returns NULL
138 * if this expression is not a string expression.
139 *
140 * @b Note: type casting performed by this method is strict! That means
141 * if this expression is i.e. actually an integer expression like 120,
142 * calling asString() will @b not cast that integer expression to a
143 * string expression "120" for you, instead this method will simply
144 * return NULL!
145 *
146 * @see exprType()
147 */
148 VMStringExpr* asString() const;
149
150 /**
151 * In case this expression is an integer array expression, then this
152 * method returns a casted pointer to that VMIntArrayExpr object. It
153 * returns NULL if this expression is not an integer array expression.
154 *
155 * @b Note: type casting performed by this method is strict! That means
156 * if this expression is i.e. an integer expression or a string
157 * expression, calling asIntArray() will @b not cast those scalar
158 * expressions to an array expression for you, instead this method will
159 * simply return NULL!
160 *
161 * @b Note: this method is currently, and in contrast to its other
162 * counter parts, declared as virtual method. Some deriving classes are
163 * currently using this to override this default implementation in order
164 * to implement an "evaluate now as integer array" behavior. This has
165 * efficiency reasons, however this also currently makes this part of
166 * the API less clean and should thus be addressed in future with
167 * appropriate changes to the API.
168 *
169 * @see exprType()
170 */
171 virtual VMIntArrayExpr* asIntArray() const;
172
173 /**
174 * Returns true in case this expression can be considered to be a
175 * constant expression. A constant expression will retain the same
176 * value throughout the entire life time of a script and the
177 * expression's constant value may be evaluated already at script
178 * parse time, which may result in performance benefits during script
179 * runtime.
180 *
181 * @b NOTE: A constant expression is per se always also non modifyable.
182 * But a non modifyable expression may not necessarily be a constant
183 * expression!
184 *
185 * @see isModifyable()
186 */
187 virtual bool isConstExpr() const = 0;
188
189 /**
190 * Returns true in case this expression is allowed to be modified.
191 * If this method returns @c false then this expression must be handled
192 * as read-only expression, which means that assigning a new value to it
193 * is either not possible or not allowed.
194 *
195 * @b NOTE: A constant expression is per se always also non modifyable.
196 * But a non modifyable expression may not necessarily be a constant
197 * expression!
198 *
199 * @see isConstExpr()
200 */
201 bool isModifyable() const;
202 };
203
204 /** @brief Virtual machine integer expression
205 *
206 * This is the abstract base class for all expressions inside scripts which
207 * evaluate to an integer (scalar) value. Deriving classes implement the
208 * abstract method evalInt() to return the actual integer result value of
209 * the expression.
210 */
211 class VMIntExpr : virtual public VMExpr {
212 public:
213 /**
214 * Returns the result of this expression as integer (scalar) value.
215 * This abstract method must be implemented by deriving classes.
216 */
217 virtual int evalInt() = 0;
218
219 /**
220 * Returns always INT_EXPR for instances of this class.
221 */
222 ExprType_t exprType() const OVERRIDE { return INT_EXPR; }
223 };
224
225 /** @brief Virtual machine string expression
226 *
227 * This is the abstract base class for all expressions inside scripts which
228 * evaluate to a string value. Deriving classes implement the abstract
229 * method evalStr() to return the actual string result value of the
230 * expression.
231 */
232 class VMStringExpr : virtual public VMExpr {
233 public:
234 /**
235 * Returns the result of this expression as string value. This abstract
236 * method must be implemented by deriving classes.
237 */
238 virtual String evalStr() = 0;
239
240 /**
241 * Returns always STRING_EXPR for instances of this class.
242 */
243 ExprType_t exprType() const OVERRIDE { return STRING_EXPR; }
244 };
245
246 /** @brief Virtual Machine Array Value Expression
247 *
248 * This is the abstract base class for all expressions inside scripts which
249 * evaluate to some kind of array value. Deriving classes implement the
250 * abstract method arraySize() to return the amount of elements within the
251 * array.
252 */
253 class VMArrayExpr : virtual public VMExpr {
254 public:
255 /**
256 * Returns amount of elements in this array. This abstract method must
257 * be implemented by deriving classes.
258 */
259 virtual int arraySize() const = 0;
260 };
261
262 /** @brief Virtual Machine Integer Array Expression
263 *
264 * This is the abstract base class for all expressions inside scripts which
265 * evaluate to an array of integer values. Deriving classes implement the
266 * abstract methods arraySize(), evalIntElement() and assignIntElement() to
267 * access the individual integer array values.
268 */
269 class VMIntArrayExpr : virtual public VMArrayExpr {
270 public:
271 /**
272 * Returns the (scalar) integer value of the array element given by
273 * element index @a i.
274 *
275 * @param i - array element index (must be between 0 .. arraySize() - 1)
276 */
277 virtual int evalIntElement(uint i) = 0;
278
279 /**
280 * Changes the current value of an element (given by array element
281 * index @a i) of this integer array.
282 *
283 * @param i - array element index (must be between 0 .. arraySize() - 1)
284 * @param value - new integer scalar value to be assigned to that array element
285 */
286 virtual void assignIntElement(uint i, int value) = 0;
287
288 /**
289 * Returns always INT_ARR_EXPR for instances of this class.
290 */
291 ExprType_t exprType() const OVERRIDE { return INT_ARR_EXPR; }
292 };
293
294 /** @brief Arguments (parameters) for being passed to a built-in script function.
295 *
296 * An argument or a set of arguments passed to a script function are
297 * translated by the parser to an instance of this class. This abstract
298 * interface class is used by implementations of built-in functions to
299 * obtain the individual function argument values being passed to them at
300 * runtime.
301 */
302 class VMFnArgs {
303 public:
304 /**
305 * Returns the amount of arguments going to be passed to the script
306 * function.
307 */
308 virtual int argsCount() const = 0;
309
310 /**
311 * Returns the respective argument (requested by argument index @a i) of
312 * this set of arguments. This method is called by implementations of
313 * built-in script functions to obtain the value of each function
314 * argument passed to the function at runtime.
315 *
316 * @param i - function argument index (indexed from left to right)
317 */
318 virtual VMExpr* arg(int i) = 0;
319 };
320
321 /** @brief Result value returned from a call to a built-in script function.
322 *
323 * Implementations of built-in script functions return an instance of this
324 * object to let the virtual machine obtain the result value of the function
325 * call, which might then be further processed by the virtual machine
326 * according to the script. It also provides informations about the success
327 * or failure of the function call.
328 */
329 class VMFnResult {
330 public:
331 /**
332 * Returns the result value of the function call, represented by a high
333 * level expression object.
334 */
335 virtual VMExpr* resultValue() = 0;
336
337 /**
338 * Provides detailed informations of the success / failure of the
339 * function call. The virtual machine is evaluating the flags returned
340 * here to decide whether it must abort or suspend execution of the
341 * script at this point.
342 */
343 virtual StmtFlags_t resultFlags() { return STMT_SUCCESS; }
344 };
345
346 /** @brief Virtual machine built-in function.
347 *
348 * Abstract base class for built-in script functions, defining the interface
349 * for all built-in script function implementations. All built-in script
350 * functions are deriving from this abstract interface class in order to
351 * provide their functionality to the virtual machine with this unified
352 * interface.
353 *
354 * The methods of this interface class provide two purposes:
355 *
356 * 1. When a script is loaded, the script parser uses the methods of this
357 * interface to check whether the script author was calling the
358 * respective built-in script function in a correct way. For example
359 * the parser checks whether the required amount of parameters were
360 * passed to the function and whether the data types passed match the
361 * data types expected by the function. If not, loading the script will
362 * be aborted with a parser error, describing to the user (i.e. script
363 * author) the precise misusage of the respective function.
364 * 2. After the script was loaded successfully and the script is executed,
365 * the virtual machine calls the exec() method of the respective built-in
366 * function to provide the actual functionality of the built-in function
367 * call.
368 */
369 class VMFunction {
370 public:
371 /**
372 * Script data type of the function's return value. If the function does
373 * not return any value (void), then it returns EMPTY_EXPR here.
374 */
375 virtual ExprType_t returnType() = 0;
376
377 /**
378 * Minimum amount of function arguments this function accepts. If a
379 * script is calling this function with less arguments, the script
380 * parser will throw a parser error.
381 */
382 virtual int minRequiredArgs() const = 0;
383
384 /**
385 * Maximum amount of function arguments this functions accepts. If a
386 * script is calling this function with more arguments, the script
387 * parser will throw a parser error.
388 */
389 virtual int maxAllowedArgs() const = 0;
390
391 /**
392 * Script data type of the function's @c iArg 'th function argument.
393 * The information provided here is less strong than acceptsArgType().
394 * The parser will compare argument data types provided in scripts by
395 * calling acceptsArgType(). The return value of argType() is used by the
396 * parser instead to show an appropriate parser error which data type
397 * this function usually expects as "default" data type. Reason: a
398 * function may accept multiple data types for a certain function
399 * argument and would automatically cast the passed argument value in
400 * that case to the type it actually needs.
401 *
402 * @param iArg - index of the function argument in question
403 * (must be between 0 .. maxAllowedArgs() - 1)
404 */
405 virtual ExprType_t argType(int iArg) const = 0;
406
407 /**
408 * This method is called by the parser to check whether arguments
409 * passed in scripts to this function are accepted by this function. If
410 * a script calls this function with an argument's data type not
411 * accepted by this function, the parser will throw a parser error. On
412 * such errors the data type returned by argType() will be used to
413 * assemble an appropriate error message regarding the precise misusage
414 * of the built-in function.
415 *
416 * @param iArg - index of the function argument in question
417 * (must be between 0 .. maxAllowedArgs() - 1)
418 * @param type - script data type used for this function argument by
419 * currently parsed script
420 * @return true if the given data type would be accepted for the
421 * respective function argument by the function
422 */
423 virtual bool acceptsArgType(int iArg, ExprType_t type) const = 0;
424
425 /**
426 * This method is called by the parser to check whether some arguments
427 * (and if yes which ones) passed to this script function will be
428 * modified by this script function. Most script functions simply use
429 * their arguments as inputs, that is they only read the argument's
430 * values. However some script function may also use passed
431 * argument(s) as output variables. In this case the function
432 * implementation must return @c true for the respective argument
433 * index here.
434 *
435 * @param iArg - index of the function argument in question
436 * (must be between 0 .. maxAllowedArgs() - 1)
437 */
438 virtual bool modifiesArg(int iArg) const = 0;
439
440 /**
441 * Implements the actual function execution. This exec() method is
442 * called by the VM whenever this function implementation shall be
443 * executed at script runtime. This method blocks until the function
444 * call completed.
445 *
446 * @param args - function arguments for executing this built-in function
447 * @returns function's return value (if any) and general status
448 * informations (i.e. whether the function call caused a
449 * runtime error)
450 */
451 virtual VMFnResult* exec(VMFnArgs* args) = 0;
452
453 /**
454 * Convenience method for function implementations to show warning
455 * messages during actual execution of the built-in function.
456 *
457 * @param txt - runtime warning text to be shown to user
458 */
459 void wrnMsg(const String& txt);
460
461 /**
462 * Convenience method for function implementations to show error
463 * messages during actual execution of the built-in function.
464 *
465 * @param txt - runtime error text to be shown to user
466 */
467 void errMsg(const String& txt);
468 };
469
470 /** @brief Virtual machine relative pointer.
471 *
472 * POD base of VMIntRelPtr and VMInt8RelPtr structures. Not intended to be
473 * used directly. Use VMIntRelPtr or VMInt8RelPtr instead.
474 *
475 * @see VMIntRelPtr, VMInt8RelPtr
476 */
477 struct VMRelPtr {
478 void** base; ///< Base pointer.
479 int offset; ///< Offset (in bytes) relative to base pointer.
480 bool readonly; ///< Whether the pointed data may be modified or just be read.
481 };
482
483 /** @brief Pointer to built-in VM integer variable (of C/C++ type int).
484 *
485 * Used for defining built-in 32 bit integer script variables.
486 *
487 * @b CAUTION: You may only use this class for pointing to C/C++ variables
488 * of type "int" (which on most systems is 32 bit in size). If the C/C++ int
489 * variable you want to reference is only 8 bit in size, then you @b must
490 * use VMInt8RelPtr instead!
491 *
492 * For efficiency reasons the actual native C/C++ int variable is referenced
493 * by two components here. The actual native int C/C++ variable in memory
494 * is dereferenced at VM run-time by taking the @c base pointer dereference
495 * and adding @c offset bytes. This has the advantage that for a large
496 * number of built-in int variables, only one (or few) base pointer need
497 * to be re-assigned before running a script, instead of updating each
498 * built-in variable each time before a script is executed.
499 *
500 * Refer to DECLARE_VMINT() for example code.
501 *
502 * @see VMInt8RelPtr, DECLARE_VMINT()
503 */
504 struct VMIntRelPtr : VMRelPtr {
505 VMIntRelPtr() {
506 base = NULL;
507 offset = 0;
508 readonly = false;
509 }
510 VMIntRelPtr(const VMRelPtr& data) {
511 base = data.base;
512 offset = data.offset;
513 readonly = false;
514 }
515 virtual int evalInt() { return *(int*)&(*(uint8_t**)base)[offset]; }
516 virtual void assign(int i) { *(int*)&(*(uint8_t**)base)[offset] = i; }
517 };
518
519 /** @brief Pointer to built-in VM integer variable (of C/C++ type int8_t).
520 *
521 * Used for defining built-in 8 bit integer script variables.
522 *
523 * @b CAUTION: You may only use this class for pointing to C/C++ variables
524 * of type "int8_t" (8 bit integer). If the C/C++ int variable you want to
525 * reference is an "int" type (which is 32 bit on most systems), then you
526 * @b must use VMIntRelPtr instead!
527 *
528 * For efficiency reasons the actual native C/C++ int variable is referenced
529 * by two components here. The actual native int C/C++ variable in memory
530 * is dereferenced at VM run-time by taking the @c base pointer dereference
531 * and adding @c offset bytes. This has the advantage that for a large
532 * number of built-in int variables, only one (or few) base pointer need
533 * to be re-assigned before running a script, instead of updating each
534 * built-in variable each time before a script is executed.
535 *
536 * Refer to DECLARE_VMINT() for example code.
537 *
538 * @see VMIntRelPtr, DECLARE_VMINT()
539 */
540 struct VMInt8RelPtr : VMIntRelPtr {
541 VMInt8RelPtr() : VMIntRelPtr() {}
542 VMInt8RelPtr(const VMRelPtr& data) : VMIntRelPtr(data) {}
543 virtual int evalInt() OVERRIDE {
544 return *(uint8_t*)&(*(uint8_t**)base)[offset];
545 }
546 virtual void assign(int i) OVERRIDE {
547 *(uint8_t*)&(*(uint8_t**)base)[offset] = i;
548 }
549 };
550
551 #if HAVE_CXX_EMBEDDED_PRAGMA_DIAGNOSTICS
552 # define COMPILER_DISABLE_OFFSETOF_WARNING \
553 _Pragma("GCC diagnostic push") \
554 _Pragma("GCC diagnostic ignored \"-Winvalid-offsetof\"")
555 # define COMPILER_RESTORE_OFFSETOF_WARNING \
556 _Pragma("GCC diagnostic pop")
557 #else
558 # define COMPILER_DISABLE_OFFSETOF_WARNING
559 # define COMPILER_RESTORE_OFFSETOF_WARNING
560 #endif
561
562 /**
563 * Convenience macro for initializing VMIntRelPtr and VMInt8RelPtr
564 * structures. Usage example:
565 * @code
566 * struct Foo {
567 * uint8_t a; // native representation of a built-in integer script variable
568 * int b; // native representation of another built-in integer script variable
569 * int c; // native representation of another built-in integer script variable
570 * uint8_t d; // native representation of another built-in integer script variable
571 * };
572 *
573 * // initializing the built-in script variables to some values
574 * Foo foo1 = (Foo) { 1, 2000, 3000, 4 };
575 * Foo foo2 = (Foo) { 5, 6000, 7000, 8 };
576 *
577 * Foo* pFoo;
578 *
579 * VMInt8RelPtr varA = DECLARE_VMINT(pFoo, class Foo, a);
580 * VMIntRelPtr varB = DECLARE_VMINT(pFoo, class Foo, b);
581 * VMIntRelPtr varC = DECLARE_VMINT(pFoo, class Foo, c);
582 * VMInt8RelPtr varD = DECLARE_VMINT(pFoo, class Foo, d);
583 *
584 * pFoo = &foo1;
585 * printf("%d\n", varA->evalInt()); // will print 1
586 * printf("%d\n", varB->evalInt()); // will print 2000
587 * printf("%d\n", varC->evalInt()); // will print 3000
588 * printf("%d\n", varD->evalInt()); // will print 4
589 *
590 * // same printf() code, just with pFoo pointer being changed ...
591 *
592 * pFoo = &foo2;
593 * printf("%d\n", varA->evalInt()); // will print 5
594 * printf("%d\n", varB->evalInt()); // will print 6000
595 * printf("%d\n", varC->evalInt()); // will print 7000
596 * printf("%d\n", varD->evalInt()); // will print 8
597 * @endcode
598 * As you can see above, by simply changing one single pointer, you can
599 * remap a huge bunch of built-in integer script variables to completely
600 * different native values/native variables. Which especially reduces code
601 * complexity inside the sampler engines which provide the actual script
602 * functionalities.
603 */
604 #define DECLARE_VMINT(basePtr, T_struct, T_member) ( \
605 /* Disable offsetof warning, trust us, we are cautios. */ \
606 COMPILER_DISABLE_OFFSETOF_WARNING \
607 (VMRelPtr) { \
608 (void**) &basePtr, \
609 offsetof(T_struct, T_member), \
610 false \
611 } \
612 COMPILER_RESTORE_OFFSETOF_WARNING \
613 ) \
614
615 /**
616 * Same as DECLARE_VMINT(), but this one defines the VMIntRelPtr and
617 * VMInt8RelPtr structures to be of read-only type. That means the script
618 * parser will abort any script at parser time if the script is trying to
619 * modify such a read-only built-in variable.
620 *
621 * @b NOTE: this is only intended for built-in read-only variables that
622 * may change during runtime! If your built-in variable's data is rather
623 * already available at parser time and won't change during runtime, then
624 * you should rather register a built-in constant in your VM class instead!
625 *
626 * @see ScriptVM::builtInConstIntVariables()
627 */
628 #define DECLARE_VMINT_READONLY(basePtr, T_struct, T_member) ( \
629 /* Disable offsetof warning, trust us, we are cautios. */ \
630 COMPILER_DISABLE_OFFSETOF_WARNING \
631 (VMRelPtr) { \
632 (void**) &basePtr, \
633 offsetof(T_struct, T_member), \
634 true \
635 } \
636 COMPILER_RESTORE_OFFSETOF_WARNING \
637 ) \
638
639 /** @brief Built-in VM 8 bit integer array variable.
640 *
641 * Used for defining built-in integer array script variables (8 bit per
642 * array element). Currently there is no support for any other kind of array
643 * type. So all integer arrays of scripts use 8 bit data types.
644 */
645 struct VMInt8Array {
646 int8_t* data;
647 int size;
648 bool readonly; ///< Whether the array data may be modified or just be read.
649
650 VMInt8Array() : data(NULL), size(0), readonly(false) {}
651 };
652
653 /** @brief Virtual machine script variable.
654 *
655 * Common interface for all variables accessed in scripts.
656 */
657 class VMVariable : virtual public VMExpr {
658 public:
659 /**
660 * Whether a script may modify the content of this variable by
661 * assigning a new value to it.
662 *
663 * @see isConstExpr(), assign()
664 */
665 virtual bool isAssignable() const = 0;
666
667 /**
668 * In case this variable is assignable, this method will be called to
669 * perform the value assignment to this variable with @a expr
670 * reflecting the new value to be assigned.
671 *
672 * @param expr - new value to be assigned to this variable
673 */
674 virtual void assignExpr(VMExpr* expr) = 0;
675 };
676
677 /** @brief Dynamically executed variable (abstract base class).
678 *
679 * Interface for the implementation of a dynamically generated content of
680 * a built-in script variable. Most built-in variables are simply pointers
681 * to some native location in memory. So when a script reads them, the
682 * memory location is simply read to get the value of the variable. A
683 * dynamic variable however is not simply a memory location. For each access
684 * to a dynamic variable some native code is executed to actually generate
685 * and provide the content (value) of this type of variable.
686 */
687 class VMDynVar : public VMVariable {
688 public:
689 /**
690 * Returns true in case this dynamic variable can be considered to be a
691 * constant expression. A constant expression will retain the same value
692 * throughout the entire life time of a script and the expression's
693 * constant value may be evaluated already at script parse time, which
694 * may result in performance benefits during script runtime.
695 *
696 * However due to the "dynamic" behavior of dynamic variables, almost
697 * all dynamic variables are probably not constant expressions. That's
698 * why this method returns @c false by default. If you are really sure
699 * that your dynamic variable implementation can be considered a
700 * constant expression then you may override this method and return
701 * @c true instead. Note that when you return @c true here, your
702 * dynamic variable will really just be executed once; and exectly
703 * already when the script is loaded!
704 *
705 * As an example you may implement a "constant" built-in dynamic
706 * variable that checks for a certain operating system feature and
707 * returns the result of that OS feature check as content (value) of
708 * this dynamic variable. Since the respective OS feature might become
709 * available/unavailable after OS updates, software migration, etc. the
710 * OS feature check should at least be performed once each time the
711 * application is launched. And since the OS feature check might take a
712 * certain amount of execution time, it might make sense to only
713 * perform the check if the respective variable name is actually
714 * referenced at all in the script to be loaded. Note that the dynamic
715 * variable will still be evaluated again though if the script is
716 * loaded again. So it is up to you to probably cache the result in the
717 * implementation of your dynamic variable.
718 *
719 * On doubt, please rather consider to use a constant built-in script
720 * variable instead of implementing a "constant" dynamic variable, due
721 * to the runtime overhead a dynamic variable may cause.
722 *
723 * @see isAssignable()
724 */
725 bool isConstExpr() const OVERRIDE { return false; }
726
727 /**
728 * In case this dynamic variable is assignable, the new value (content)
729 * to be assigned to this dynamic variable.
730 *
731 * By default this method does nothing. Override and implement this
732 * method in your subclass in case your dynamic variable allows to
733 * assign a new value by script.
734 *
735 * @param expr - new value to be assigned to this variable
736 */
737 void assignExpr(VMExpr* expr) OVERRIDE {}
738
739 virtual ~VMDynVar() {}
740 };
741
742 /** @brief Dynamically executed variable (of integer data type).
743 *
744 * This is the base class for all built-in integer script variables whose
745 * variable content needs to be provided dynamically by executable native
746 * code on each script variable access.
747 */
748 class VMDynIntVar : virtual public VMDynVar, virtual public VMIntExpr {
749 public:
750 };
751
752 /** @brief Dynamically executed variable (of string data type).
753 *
754 * This is the base class for all built-in string script variables whose
755 * variable content needs to be provided dynamically by executable native
756 * code on each script variable access.
757 */
758 class VMDynStringVar : virtual public VMDynVar, virtual public VMStringExpr {
759 public:
760 };
761
762 /** @brief Dynamically executed variable (of integer array data type).
763 *
764 * This is the base class for all built-in integer array script variables
765 * whose variable content needs to be provided dynamically by executable
766 * native code on each script variable access.
767 */
768 class VMDynIntArrayVar : virtual public VMDynVar, virtual public VMIntArrayExpr {
769 public:
770 };
771
772 /** @brief Provider for built-in script functions and variables.
773 *
774 * Abstract base class defining the high-level interface for all classes
775 * which add and implement built-in script functions and built-in script
776 * variables.
777 */
778 class VMFunctionProvider {
779 public:
780 /**
781 * Returns pointer to the built-in function with the given function
782 * @a name, or NULL if there is no built-in function with that function
783 * name.
784 *
785 * @param name - function name (i.e. "wait" or "message" or "exit", etc.)
786 */
787 virtual VMFunction* functionByName(const String& name) = 0;
788
789 /**
790 * Returns a variable name indexed map of all built-in script variables
791 * which point to native "int" scalar (usually 32 bit) variables.
792 */
793 virtual std::map<String,VMIntRelPtr*> builtInIntVariables() = 0;
794
795 /**
796 * Returns a variable name indexed map of all built-in script integer
797 * array variables with array element type "int8_t" (8 bit).
798 */
799 virtual std::map<String,VMInt8Array*> builtInIntArrayVariables() = 0;
800
801 /**
802 * Returns a variable name indexed map of all built-in constant script
803 * variables, which never change their value at runtime.
804 */
805 virtual std::map<String,int> builtInConstIntVariables() = 0;
806
807 /**
808 * Returns a variable name indexed map of all built-in dynamic variables,
809 * which are not simply data stores, rather each one of them executes
810 * natively to provide or alter the respective script variable data.
811 */
812 virtual std::map<String,VMDynVar*> builtInDynamicVariables() = 0;
813 };
814
815 /** @brief Execution state of a virtual machine.
816 *
817 * An instance of this abstract base class represents exactly one execution
818 * state of a virtual machine. This encompasses most notably the VM
819 * execution stack, and VM polyphonic variables. It does not contain global
820 * variables. Global variables are contained in the VMParserContext object.
821 * You might see a VMExecContext object as one virtual thread of the virtual
822 * machine.
823 *
824 * In contrast to a VMParserContext, a VMExecContext is not tied to a
825 * ScriptVM instance. Thus you can use a VMExecContext with different
826 * ScriptVM instances, however not concurrently at the same time.
827 *
828 * @see VMParserContext
829 */
830 class VMExecContext {
831 public:
832 virtual ~VMExecContext() {}
833
834 /**
835 * In case the script was suspended for some reason, this method returns
836 * the amount of microseconds before the script shall continue its
837 * execution. Note that the virtual machine itself does never put its
838 * own execution thread(s) to sleep. So the respective class (i.e. sampler
839 * engine) which is using the virtual machine classes here, must take
840 * care by itself about taking time stamps, determining the script
841 * handlers that shall be put aside for the requested amount of
842 * microseconds, indicated by this method by comparing the time stamps in
843 * real-time, and to continue passing the respective handler to
844 * ScriptVM::exec() as soon as its suspension exceeded, etc. Or in other
845 * words: all classes in this directory never have an idea what time it
846 * is.
847 *
848 * You should check the return value of ScriptVM::exec() to determine
849 * whether the script was actually suspended before calling this method
850 * here.
851 *
852 * @see ScriptVM::exec()
853 */
854 virtual int suspensionTimeMicroseconds() const = 0;
855
856 /**
857 * Causes all polyphonic variables to be reset to zero values. A
858 * polyphonic variable is expected to be zero when entering a new event
859 * handler instance. As an exception the values of polyphonic variables
860 * shall only be preserved from an note event handler instance to its
861 * correspending specific release handler instance. So in the latter
862 * case the script author may pass custom data from the note handler to
863 * the release handler, but only for the same specific note!
864 */
865 virtual void resetPolyphonicData() = 0;
866
867 /**
868 * Returns amount of virtual machine instructions which have been
869 * performed the last time when this execution context was executing a
870 * script. So in case you need the overall amount of instructions
871 * instead, then you need to add them by yourself after each
872 * ScriptVM::exec() call.
873 */
874 virtual size_t instructionsPerformed() const = 0;
875
876 /**
877 * Sends a signal to this script execution instance to abort its script
878 * execution as soon as possible. This method is called i.e. when one
879 * script execution instance intends to stop another script execution
880 * instance.
881 */
882 virtual void signalAbort() = 0;
883 };
884
885 /** @brief Script callback for a certain event.
886 *
887 * Represents a script callback for a certain event, i.e.
888 * "on note ... end on" code block.
889 */
890 class VMEventHandler {
891 public:
892 /**
893 * Type of this event handler, which identifies its purpose. For example
894 * for a "on note ... end on" script callback block,
895 * @c VM_EVENT_HANDLER_NOTE would be returned here.
896 */
897 virtual VMEventHandlerType_t eventHandlerType() const = 0;
898
899 /**
900 * Name of the event handler which identifies its purpose. For example
901 * for a "on note ... end on" script callback block, the name "note"
902 * would be returned here.
903 */
904 virtual String eventHandlerName() const = 0;
905
906 /**
907 * Whether or not the event handler makes any use of so called
908 * "polyphonic" variables.
909 */
910 virtual bool isPolyphonic() const = 0;
911 };
912
913 /**
914 * Reflects the precise position and span of a specific code block within
915 * a script. This is currently only used for the locations of commented
916 * code blocks due to preprocessor statements, and for parser errors and
917 * parser warnings.
918 *
919 * @see ParserIssue for code locations of parser errors and parser warnings
920 *
921 * @see VMParserContext::preprocessorComments() for locations of code which
922 * have been filtered out by preprocessor statements
923 */
924 struct CodeBlock {
925 int firstLine; ///< The first line number of this code block within the script (indexed with 1 being the very first line).
926 int lastLine; ///< The last line number of this code block within the script.
927 int firstColumn; ///< The first column of this code block within the script (indexed with 1 being the very first column).
928 int lastColumn; ///< The last column of this code block within the script.
929 };
930
931 /**
932 * Encapsulates a noteworty parser issue. This encompasses the type of the
933 * issue (either a parser error or parser warning), a human readable
934 * explanation text of the error or warning and the location of the
935 * encountered parser issue within the script.
936 *
937 * @see VMSourceToken for processing syntax highlighting instead.
938 */
939 struct ParserIssue : CodeBlock {
940 String txt; ///< Human readable explanation text of the parser issue.
941 ParserIssueType_t type; ///< Whether this issue is either a parser error or just a parser warning.
942
943 /**
944 * Print this issue out to the console (stdio).
945 */
946 inline void dump() {
947 switch (type) {
948 case PARSER_ERROR:
949 printf("[ERROR] line %d, column %d: %s\n", firstLine, firstColumn, txt.c_str());
950 break;
951 case PARSER_WARNING:
952 printf("[Warning] line %d, column %d: %s\n", firstLine, firstColumn, txt.c_str());
953 break;
954 }
955 }
956
957 /**
958 * Returns true if this issue is a parser error. In this case the parsed
959 * script may not be executed!
960 */
961 inline bool isErr() const { return type == PARSER_ERROR; }
962
963 /**
964 * Returns true if this issue is just a parser warning. A parsed script
965 * that only raises warnings may be executed if desired, however the
966 * script may not behave exactly as intended by the script author.
967 */
968 inline bool isWrn() const { return type == PARSER_WARNING; }
969 };
970
971 /**
972 * Convenience function used for converting an ExprType_t constant to a
973 * string, i.e. for generating error message by the parser.
974 */
975 inline String typeStr(const ExprType_t& type) {
976 switch (type) {
977 case EMPTY_EXPR: return "empty";
978 case INT_EXPR: return "integer";
979 case INT_ARR_EXPR: return "integer array";
980 case STRING_EXPR: return "string";
981 case STRING_ARR_EXPR: return "string array";
982 }
983 return "invalid";
984 }
985
986 /** @brief Virtual machine representation of a script.
987 *
988 * An instance of this abstract base class represents a parsed script,
989 * translated into a virtual machine tree. You should first check if there
990 * were any parser errors. If there were any parser errors, you should
991 * refrain from executing the virtual machine. Otherwise if there were no
992 * parser errors (i.e. only warnings), then you might access one of the
993 * script's event handlers by i.e. calling eventHandlerByName() and pass the
994 * respective event handler to the ScriptVM class (or to one of the ScriptVM
995 * descendants) for execution.
996 *
997 * @see VMExecContext, ScriptVM
998 */
999 class VMParserContext {
1000 public:
1001 virtual ~VMParserContext() {}
1002
1003 /**
1004 * Returns all noteworthy issues encountered when the script was parsed.
1005 * These are parser errors and parser warnings.
1006 */
1007 virtual std::vector<ParserIssue> issues() const = 0;
1008
1009 /**
1010 * Same as issues(), but this method only returns parser errors.
1011 */
1012 virtual std::vector<ParserIssue> errors() const = 0;
1013
1014 /**
1015 * Same as issues(), but this method only returns parser warnings.
1016 */
1017 virtual std::vector<ParserIssue> warnings() const = 0;
1018
1019 /**
1020 * Returns all code blocks of the script which were filtered out by the
1021 * preprocessor.
1022 */
1023 virtual std::vector<CodeBlock> preprocessorComments() const = 0;
1024
1025 /**
1026 * Returns the translated virtual machine representation of an event
1027 * handler block (i.e. "on note ... end on" code block) within the
1028 * parsed script. This translated representation of the event handler
1029 * can be executed by the virtual machine.
1030 *
1031 * @param index - index of the event handler within the script
1032 */
1033 virtual VMEventHandler* eventHandler(uint index) = 0;
1034
1035 /**
1036 * Same as eventHandler(), but this method returns the event handler by
1037 * its name. So for a "on note ... end on" code block of the parsed
1038 * script you would pass "note" for argument @a name here.
1039 *
1040 * @param name - name of the event handler (i.e. "init", "note",
1041 * "controller", "release")
1042 */
1043 virtual VMEventHandler* eventHandlerByName(const String& name) = 0;
1044 };
1045
1046 class SourceToken;
1047
1048 /** @brief Recognized token of a script's source code.
1049 *
1050 * Represents one recognized token of a script's source code, for example
1051 * a keyword, variable name, etc. and it provides further informations about
1052 * that particular token, i.e. the precise location (line and column) of the
1053 * token within the original script's source code.
1054 *
1055 * This class is not actually used by the sampler itself. It is rather
1056 * provided for external script editor applications. Primary purpose of
1057 * this class is syntax highlighting for external script editors.
1058 *
1059 * @see ParserIssue for processing compile errors and warnings instead.
1060 */
1061 class VMSourceToken {
1062 public:
1063 VMSourceToken();
1064 VMSourceToken(SourceToken* ct);
1065 VMSourceToken(const VMSourceToken& other);
1066 virtual ~VMSourceToken();
1067
1068 // original text of this token as it is in the script's source code
1069 String text() const;
1070
1071 // position of token in script
1072 int firstLine() const; ///< First line this source token is located at in script source code (indexed with 0 being the very first line). Most source code tokens are not spanning over multiple lines, the only current exception are comments, in the latter case you need to process text() to get the last line and last column for the comment.
1073 int firstColumn() const; ///< First column on the first line this source token is located at in script source code (indexed with 0 being the very first column). To get the length of this token use text().length().
1074
1075 // base types
1076 bool isEOF() const; ///< Returns true in case this source token represents the end of the source code file.
1077 bool isNewLine() const; ///< Returns true in case this source token represents a line feed character (i.e. "\n" on Unix systems).
1078 bool isKeyword() const; ///< Returns true in case this source token represents a language keyword (i.e. "while", "function", "declare", "on", etc.).
1079 bool isVariableName() const; ///< Returns true in case this source token represents a variable name (i.e. "$someIntVariable", "%someArrayVariable", "\@someStringVariable"). @see isIntegerVariable(), isStringVariable(), isArrayVariable() for the precise variable type.
1080 bool isIdentifier() const; ///< Returns true in case this source token represents an identifier, which currently always means a function name.
1081 bool isNumberLiteral() const; ///< Returns true in case this source token represents a number literal (i.e. 123).
1082 bool isStringLiteral() const; ///< Returns true in case this source token represents a string literal (i.e. "Some text").
1083 bool isComment() const; ///< Returns true in case this source token represents a source code comment.
1084 bool isPreprocessor() const; ///< Returns true in case this source token represents a preprocessor statement.
1085 bool isOther() const; ///< Returns true in case this source token represents anything else not covered by the token types mentioned above.
1086
1087 // extended types
1088 bool isIntegerVariable() const; ///< Returns true in case this source token represents an integer variable name (i.e. "$someIntVariable").
1089 bool isStringVariable() const; ///< Returns true in case this source token represents an string variable name (i.e. "\@someStringVariable").
1090 bool isArrayVariable() const; ///< Returns true in case this source token represents an array variable name (i.e. "%someArryVariable").
1091 bool isEventHandlerName() const; ///< Returns true in case this source token represents an event handler name (i.e. "note", "release", "controller").
1092
1093 VMSourceToken& operator=(const VMSourceToken& other);
1094
1095 private:
1096 SourceToken* m_token;
1097 };
1098
1099 } // namespace LinuxSampler
1100
1101 #endif // LS_INSTR_SCRIPT_PARSER_COMMON_H

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