src/scriptvm/ScriptVM.cpp

/*
 * Copyright (c) 2014 - 2016 Christian Schoenebeck
 *
 * http://www.linuxsampler.org
 *
 * This file is part of LinuxSampler and released under the same terms.
 * See README file for details.
 */

#include "ScriptVM.h"

#include <string.h>
#include <assert.h>
#include "../common/global_private.h"
#include "tree.h"
#include "CoreVMFunctions.h"
#include "CoreVMDynVars.h"
#include "editor/NkspScanner.h"

#define DEBUG_SCRIPTVM_CORE 0

int InstrScript_parse(LinuxSampler::ParserContext*);

namespace LinuxSampler {

    static void _printIndents(int n) {
        for (int i = 0; i < n; ++i) printf("  ");
        fflush(stdout);
    }

    static int _requiredMaxStackSizeFor(Statement* statement, int depth = 0) {
        if (!statement) return 1;

        switch (statement->statementType()) {
            case STMT_LEAF:
                #if DEBUG_SCRIPTVM_CORE
                _printIndents(depth);
                printf("-> STMT_LEAF\n");
                #endif
                return 1;

            case STMT_LIST: {
                #if DEBUG_SCRIPTVM_CORE
                _printIndents(depth);
                printf("-> STMT_LIST\n");
                #endif
                Statements* stmts = (Statements*) statement;
                int max = 0;
                for (int i = 0; stmts->statement(i); ++i) {
                    int size = _requiredMaxStackSizeFor( stmts->statement(i), depth+1 );
                    if (max < size) max = size;
                }
                return max + 1;
            }

            case STMT_BRANCH: {
                #if DEBUG_SCRIPTVM_CORE
                _printIndents(depth);
                printf("-> STMT_BRANCH\n");
                #endif
                BranchStatement* branchStmt = (BranchStatement*) statement;
                int max = 0;
                for (int i = 0; branchStmt->branch(i); ++i) {
                    int size = _requiredMaxStackSizeFor( branchStmt->branch(i), depth+1 );
                    if (max < size) max = size;
                }
                return max + 1;
            }

            case STMT_LOOP: {
                #if DEBUG_SCRIPTVM_CORE
                _printIndents(depth);
                printf("-> STMT_LOOP\n");
                #endif
                While* whileStmt = (While*) statement;
                if (whileStmt->statements())
                    return _requiredMaxStackSizeFor( whileStmt->statements() ) + 1;
                else
                    return 1;
            }
        }

        return 1; // actually just to avoid compiler warning
    }

    static int _requiredMaxStackSizeFor(EventHandlers* handlers) {
        int max = 1;
        for (int i = 0; i < handlers->size(); ++i) {
            int size = _requiredMaxStackSizeFor(handlers->eventHandler(i));
            if (max < size) max = size;
        }
        return max;
    }

    ScriptVM::ScriptVM() : m_eventHandler(NULL), m_parserContext(NULL) {
        m_fnMessage = new CoreVMFunction_message;
        m_fnExit = new CoreVMFunction_exit;
        m_fnWait = new CoreVMFunction_wait(this);
        m_fnAbs = new CoreVMFunction_abs;
        m_fnRandom = new CoreVMFunction_random;
        m_fnNumElements = new CoreVMFunction_num_elements;
        m_fnInc = new CoreVMFunction_inc;
        m_fnDec = new CoreVMFunction_dec;
        m_varRealTimer = new CoreVMDynVar_NKSP_REAL_TIMER;
        m_varPerfTimer = new CoreVMDynVar_NKSP_PERF_TIMER;
        m_fnShLeft = new CoreVMFunction_sh_left;
        m_fnShRight = new CoreVMFunction_sh_right;
    }

    ScriptVM::~ScriptVM() {
        delete m_fnMessage;
        delete m_fnExit;
        delete m_fnWait;
        delete m_fnAbs;
        delete m_fnRandom;
        delete m_fnNumElements;
        delete m_fnInc;
        delete m_fnDec;
        delete m_fnShLeft;
        delete m_fnShRight;
        delete m_varRealTimer;
        delete m_varPerfTimer;
    }

    VMParserContext* ScriptVM::loadScript(const String& s) {
        std::istringstream iss(s);
        return loadScript(&iss);
    }
    
    VMParserContext* ScriptVM::loadScript(std::istream* is) {
        ParserContext* context = new ParserContext(this);
        //printf("parserCtx=0x%lx\n", (uint64_t)context);

        context->registerBuiltInConstIntVariables( builtInConstIntVariables() );
        context->registerBuiltInIntVariables( builtInIntVariables() );
        context->registerBuiltInIntArrayVariables( builtInIntArrayVariables() );
        context->registerBuiltInDynVariables( builtInDynamicVariables() );

        context->createScanner(is);

        InstrScript_parse(context);
        dmsg(2,("Allocating %ld bytes of global int VM memory.\n", long(context->globalIntVarCount * sizeof(int))));
        dmsg(2,("Allocating %d of global VM string variables.\n", context->globalStrVarCount));
        if (!context->globalIntMemory)
            context->globalIntMemory = new ArrayList<int>();
        if (!context->globalStrMemory)
            context->globalStrMemory = new ArrayList<String>();
        context->globalIntMemory->resize(context->globalIntVarCount);
        memset(&((*context->globalIntMemory)[0]), 0, context->globalIntVarCount * sizeof(int));
        
        context->globalStrMemory->resize(context->globalStrVarCount);

        context->destroyScanner();

        return context;
    }

    void ScriptVM::dumpParsedScript(VMParserContext* context) {
        ParserContext* ctx = dynamic_cast<ParserContext*>(context);
        if (!ctx) {
            std::cerr << "No VM context. So nothing to dump.\n";
            return;
        }
        if (!ctx->handlers) {
            std::cerr << "No event handlers defined in script. So nothing to dump.\n";
            return;
        }
        if (!ctx->globalIntMemory) {
            std::cerr << "Internal error: no global memory assigend to script VM.\n";
            return;
        }
        ctx->handlers->dump();
    }

    VMExecContext* ScriptVM::createExecContext(VMParserContext* parserContext) {
        ParserContext* parserCtx = dynamic_cast<ParserContext*>(parserContext);
        ExecContext* execCtx = new ExecContext();
        
        if (parserCtx->requiredMaxStackSize < 0) {
             parserCtx->requiredMaxStackSize =
                _requiredMaxStackSizeFor(&*parserCtx->handlers);
        }
        execCtx->stack.resize(parserCtx->requiredMaxStackSize);
        dmsg(2,("Created VM exec context with %ld bytes VM stack size.\n",
                long(parserCtx->requiredMaxStackSize * sizeof(ExecContext::StackFrame))));
        //printf("execCtx=0x%lx\n", (uint64_t)execCtx);
        const int polySize = parserCtx->polyphonicIntVarCount;
        execCtx->polyphonicIntMemory.resize(polySize);
        memset(&execCtx->polyphonicIntMemory[0], 0, polySize * sizeof(int));

        dmsg(2,("Allocated %ld bytes polyphonic memory.\n", long(polySize * sizeof(int))));
        return execCtx;
    }

    std::vector<VMSourceToken> ScriptVM::syntaxHighlighting(const String& s) {
        std::istringstream iss(s);
        return syntaxHighlighting(&iss);
    }

    std::vector<VMSourceToken> ScriptVM::syntaxHighlighting(std::istream* is) {
        NkspScanner scanner(is);
        std::vector<SourceToken> tokens = scanner.tokens();
        std::vector<VMSourceToken> result;
        result.resize(tokens.size());
        for (int i = 0; i < tokens.size(); ++i) {
            SourceToken* st = new SourceToken;
            *st = tokens[i];
            result[i] = VMSourceToken(st);
        }
        return result;
    }

    VMFunction* ScriptVM::functionByName(const String& name) {
        if (name == "message") return m_fnMessage;
        else if (name == "exit") return m_fnExit;
        else if (name == "wait") return m_fnWait;
        else if (name == "abs") return m_fnAbs;
        else if (name == "random") return m_fnRandom;
        else if (name == "num_elements") return m_fnNumElements;
        else if (name == "inc") return m_fnInc;
        else if (name == "dec") return m_fnDec;
        else if (name == "sh_left") return m_fnShLeft;
        else if (name == "sh_right") return m_fnShRight;
        return NULL;
    }

    std::map<String,VMIntRelPtr*> ScriptVM::builtInIntVariables() {
        return std::map<String,VMIntRelPtr*>();
    }

    std::map<String,VMInt8Array*> ScriptVM::builtInIntArrayVariables() {
        return std::map<String,VMInt8Array*>();
    }

    std::map<String,VMDynVar*> ScriptVM::builtInDynamicVariables() {
        std::map<String,VMDynVar*> m;

        m["$NKSP_PERF_TIMER"] = m_varPerfTimer;
        m["$NKSP_REAL_TIMER"] = m_varRealTimer;
        m["$KSP_TIMER"] = m_varRealTimer;

        return m;
    }

    std::map<String,int> ScriptVM::builtInConstIntVariables() {
        std::map<String,int> m;

        m["$NI_CB_TYPE_INIT"] = VM_EVENT_HANDLER_INIT;
        m["$NI_CB_TYPE_NOTE"] = VM_EVENT_HANDLER_NOTE;
        m["$NI_CB_TYPE_RELEASE"] = VM_EVENT_HANDLER_RELEASE;
        m["$NI_CB_TYPE_CONTROLLER"] = VM_EVENT_HANDLER_CONTROLLER;

        return m;
    }

    VMEventHandler* ScriptVM::currentVMEventHandler() {
        return m_eventHandler;
    }

    VMParserContext* ScriptVM::currentVMParserContext() {
        return m_parserContext;
    }

    VMExecContext* ScriptVM::currentVMExecContext() {
        if (!m_parserContext) return NULL;
        return m_parserContext->execContext;
    }

    VMExecStatus_t ScriptVM::exec(VMParserContext* parserContext, VMExecContext* execContex, VMEventHandler* handler) {
        m_parserContext = dynamic_cast<ParserContext*>(parserContext);
        if (!m_parserContext) {
            std::cerr << "No VM parser context provided. Did you load a script?.\n";
            return VMExecStatus_t(VM_EXEC_NOT_RUNNING | VM_EXEC_ERROR);
        }

        // a ParserContext object is always tied to exactly one ScriptVM object
        assert(m_parserContext->functionProvider == this);

        ExecContext* ctx = dynamic_cast<ExecContext*>(execContex);
        if (!ctx) {
            std::cerr << "Invalid VM exec context.\n";
            return VMExecStatus_t(VM_EXEC_NOT_RUNNING | VM_EXEC_ERROR);
        }
        EventHandler* h = dynamic_cast<EventHandler*>(handler);
        if (!h) return VM_EXEC_NOT_RUNNING;
        m_eventHandler = handler;

        m_parserContext->execContext = ctx;

        ctx->status = VM_EXEC_RUNNING;
        StmtFlags_t flags = STMT_SUCCESS;

        int& frameIdx = ctx->stackFrame;
        if (frameIdx < 0) { // start condition ...
            frameIdx = -1;
            ctx->pushStack(h);
        }

        while (flags == STMT_SUCCESS && frameIdx >= 0) {
            if (frameIdx >= ctx->stack.size()) { // should never happen, otherwise it's a bug ...
                std::cerr << "CRITICAL: VM stack overflow! (" << frameIdx << ")\n";
                flags = StmtFlags_t(STMT_ABORT_SIGNALLED | STMT_ERROR_OCCURRED);
                break;
            }

            ExecContext::StackFrame& frame = ctx->stack[frameIdx];
            switch (frame.statement->statementType()) {
                case STMT_LEAF: {
                    #if DEBUG_SCRIPTVM_CORE
                    _printIndents(frameIdx);
                    printf("-> STMT_LEAF\n");
                    #endif
                    LeafStatement* leaf = (LeafStatement*) frame.statement;
                    flags = leaf->exec();
                    ctx->popStack();
                    break;
                }

                case STMT_LIST: {
                    #if DEBUG_SCRIPTVM_CORE
                    _printIndents(frameIdx);
                    printf("-> STMT_LIST subidx=%d\n", frame.subindex);
                    #endif
                    Statements* stmts = (Statements*) frame.statement;
                    if (stmts->statement(frame.subindex)) {
                        ctx->pushStack(
                            stmts->statement(frame.subindex++)
                        );
                    } else {
                        #if DEBUG_SCRIPTVM_CORE
                        _printIndents(frameIdx);
                        printf("[END OF LIST] subidx=%d\n", frame.subindex);
                        #endif
                        ctx->popStack();
                    }
                    break;
                }

                case STMT_BRANCH: {
                    #if DEBUG_SCRIPTVM_CORE
                    _printIndents(frameIdx);
                    printf("-> STMT_BRANCH\n");
                    #endif
                    if (frame.subindex < 0) ctx->popStack();
                    else {
                        BranchStatement* branchStmt = (BranchStatement*) frame.statement;
                        frame.subindex = branchStmt->evalBranch();
                        if (frame.subindex >= 0) {
                            ctx->pushStack(
                                branchStmt->branch(frame.subindex)
                            );
                            frame.subindex = -1;
                        } else ctx->popStack();
                    }
                    break;
                }

                case STMT_LOOP: {
                    #if DEBUG_SCRIPTVM_CORE
                    _printIndents(frameIdx);
                    printf("-> STMT_LOOP\n");
                    #endif
                    While* whileStmt = (While*) frame.statement;
                    if (whileStmt->evalLoopStartCondition() && whileStmt->statements()) {
                        ctx->pushStack(
                            whileStmt->statements()
                        );
                    } else ctx->popStack();
                }
            }
        }

        if (flags & STMT_SUSPEND_SIGNALLED) {
            ctx->status = VM_EXEC_SUSPENDED;
        } else {
            ctx->status = VM_EXEC_NOT_RUNNING;
            if (flags & STMT_ERROR_OCCURRED)
                ctx->status = VM_EXEC_ERROR;
            ctx->reset();
        }

        m_eventHandler = NULL;
        m_parserContext->execContext = NULL;
        m_parserContext = NULL;
        return ctx->status;
    }

} // namespace LinuxSampler
1	/*
2	* Copyright (c) 2014 - 2016 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	#include "ScriptVM.h"
11
12	#include <string.h>
13	#include <assert.h>
14	#include "../common/global_private.h"
15	#include "tree.h"
16	#include "CoreVMFunctions.h"
17	#include "CoreVMDynVars.h"
18	#include "editor/NkspScanner.h"
19
20	#define DEBUG_SCRIPTVM_CORE 0
21
22	int InstrScript_parse(LinuxSampler::ParserContext*);
23
24	namespace LinuxSampler {
25
26	static void _printIndents(int n) {
27	for (int i = 0; i < n; ++i) printf(" ");
28	fflush(stdout);
29	}
30
31	static int _requiredMaxStackSizeFor(Statement* statement, int depth = 0) {
32	if (!statement) return 1;
33
34	switch (statement->statementType()) {
35	case STMT_LEAF:
36	#if DEBUG_SCRIPTVM_CORE
37	_printIndents(depth);
38	printf("-> STMT_LEAF\n");
39	#endif
40	return 1;
41
42	case STMT_LIST: {
43	#if DEBUG_SCRIPTVM_CORE
44	_printIndents(depth);
45	printf("-> STMT_LIST\n");
46	#endif
47	Statements* stmts = (Statements*) statement;
48	int max = 0;
49	for (int i = 0; stmts->statement(i); ++i) {
50	int size = _requiredMaxStackSizeFor( stmts->statement(i), depth+1 );
51	if (max < size) max = size;
52	}
53	return max + 1;
54	}
55
56	case STMT_BRANCH: {
57	#if DEBUG_SCRIPTVM_CORE
58	_printIndents(depth);
59	printf("-> STMT_BRANCH\n");
60	#endif
61	BranchStatement* branchStmt = (BranchStatement*) statement;
62	int max = 0;
63	for (int i = 0; branchStmt->branch(i); ++i) {
64	int size = _requiredMaxStackSizeFor( branchStmt->branch(i), depth+1 );
65	if (max < size) max = size;
66	}
67	return max + 1;
68	}
69
70	case STMT_LOOP: {
71	#if DEBUG_SCRIPTVM_CORE
72	_printIndents(depth);
73	printf("-> STMT_LOOP\n");
74	#endif
75	While* whileStmt = (While*) statement;
76	if (whileStmt->statements())
77	return _requiredMaxStackSizeFor( whileStmt->statements() ) + 1;
78	else
79	return 1;
80	}
81	}
82
83	return 1; // actually just to avoid compiler warning
84	}
85
86	static int _requiredMaxStackSizeFor(EventHandlers* handlers) {
87	int max = 1;
88	for (int i = 0; i < handlers->size(); ++i) {
89	int size = _requiredMaxStackSizeFor(handlers->eventHandler(i));
90	if (max < size) max = size;
91	}
92	return max;
93	}
94
95	ScriptVM::ScriptVM() : m_eventHandler(NULL), m_parserContext(NULL) {
96	m_fnMessage = new CoreVMFunction_message;
97	m_fnExit = new CoreVMFunction_exit;
98	m_fnWait = new CoreVMFunction_wait(this);
99	m_fnAbs = new CoreVMFunction_abs;
100	m_fnRandom = new CoreVMFunction_random;
101	m_fnNumElements = new CoreVMFunction_num_elements;
102	m_fnInc = new CoreVMFunction_inc;
103	m_fnDec = new CoreVMFunction_dec;
104	m_varRealTimer = new CoreVMDynVar_NKSP_REAL_TIMER;
105	m_varPerfTimer = new CoreVMDynVar_NKSP_PERF_TIMER;
106	m_fnShLeft = new CoreVMFunction_sh_left;
107	m_fnShRight = new CoreVMFunction_sh_right;
108	}
109
110	ScriptVM::~ScriptVM() {
111	delete m_fnMessage;
112	delete m_fnExit;
113	delete m_fnWait;
114	delete m_fnAbs;
115	delete m_fnRandom;
116	delete m_fnNumElements;
117	delete m_fnInc;
118	delete m_fnDec;
119	delete m_fnShLeft;
120	delete m_fnShRight;
121	delete m_varRealTimer;
122	delete m_varPerfTimer;
123	}
124
125	VMParserContext* ScriptVM::loadScript(const String& s) {
126	std::istringstream iss(s);
127	return loadScript(&iss);
128	}
129
130	VMParserContext* ScriptVM::loadScript(std::istream* is) {
131	ParserContext* context = new ParserContext(this);
132	//printf("parserCtx=0x%lx\n", (uint64_t)context);
133
134	context->registerBuiltInConstIntVariables( builtInConstIntVariables() );
135	context->registerBuiltInIntVariables( builtInIntVariables() );
136	context->registerBuiltInIntArrayVariables( builtInIntArrayVariables() );
137	context->registerBuiltInDynVariables( builtInDynamicVariables() );
138
139	context->createScanner(is);
140
141	InstrScript_parse(context);
142	dmsg(2,("Allocating %ld bytes of global int VM memory.\n", long(context->globalIntVarCount * sizeof(int))));
143	dmsg(2,("Allocating %d of global VM string variables.\n", context->globalStrVarCount));
144	if (!context->globalIntMemory)
145	context->globalIntMemory = new ArrayList<int>();
146	if (!context->globalStrMemory)
147	context->globalStrMemory = new ArrayList<String>();
148	context->globalIntMemory->resize(context->globalIntVarCount);
149	memset(&((context->globalIntMemory)[0]), 0, context->globalIntVarCount sizeof(int));
150
151	context->globalStrMemory->resize(context->globalStrVarCount);
152
153	context->destroyScanner();
154
155	return context;
156	}
157
158	void ScriptVM::dumpParsedScript(VMParserContext* context) {
159	ParserContext* ctx = dynamic_cast<ParserContext*>(context);
160	if (!ctx) {
161	std::cerr << "No VM context. So nothing to dump.\n";
162	return;
163	}
164	if (!ctx->handlers) {
165	std::cerr << "No event handlers defined in script. So nothing to dump.\n";
166	return;
167	}
168	if (!ctx->globalIntMemory) {
169	std::cerr << "Internal error: no global memory assigend to script VM.\n";
170	return;
171	}
172	ctx->handlers->dump();
173	}
174
175	VMExecContext* ScriptVM::createExecContext(VMParserContext* parserContext) {
176	ParserContext* parserCtx = dynamic_cast<ParserContext*>(parserContext);
177	ExecContext* execCtx = new ExecContext();
178
179	if (parserCtx->requiredMaxStackSize < 0) {
180	parserCtx->requiredMaxStackSize =
181	_requiredMaxStackSizeFor(&*parserCtx->handlers);
182	}
183	execCtx->stack.resize(parserCtx->requiredMaxStackSize);
184	dmsg(2,("Created VM exec context with %ld bytes VM stack size.\n",
185	long(parserCtx->requiredMaxStackSize * sizeof(ExecContext::StackFrame))));
186	//printf("execCtx=0x%lx\n", (uint64_t)execCtx);
187	const int polySize = parserCtx->polyphonicIntVarCount;
188	execCtx->polyphonicIntMemory.resize(polySize);
189	memset(&execCtx->polyphonicIntMemory[0], 0, polySize * sizeof(int));
190
191	dmsg(2,("Allocated %ld bytes polyphonic memory.\n", long(polySize * sizeof(int))));
192	return execCtx;
193	}
194
195	std::vector<VMSourceToken> ScriptVM::syntaxHighlighting(const String& s) {
196	std::istringstream iss(s);
197	return syntaxHighlighting(&iss);
198	}
199
200	std::vector<VMSourceToken> ScriptVM::syntaxHighlighting(std::istream* is) {
201	NkspScanner scanner(is);
202	std::vector<SourceToken> tokens = scanner.tokens();
203	std::vector<VMSourceToken> result;
204	result.resize(tokens.size());
205	for (int i = 0; i < tokens.size(); ++i) {
206	SourceToken* st = new SourceToken;
207	*st = tokens[i];
208	result[i] = VMSourceToken(st);
209	}
210	return result;
211	}
212
213	VMFunction* ScriptVM::functionByName(const String& name) {
214	if (name == "message") return m_fnMessage;
215	else if (name == "exit") return m_fnExit;
216	else if (name == "wait") return m_fnWait;
217	else if (name == "abs") return m_fnAbs;
218	else if (name == "random") return m_fnRandom;
219	else if (name == "num_elements") return m_fnNumElements;
220	else if (name == "inc") return m_fnInc;
221	else if (name == "dec") return m_fnDec;
222	else if (name == "sh_left") return m_fnShLeft;
223	else if (name == "sh_right") return m_fnShRight;
224	return NULL;
225	}
226
227	std::map<String,VMIntRelPtr*> ScriptVM::builtInIntVariables() {
228	return std::map<String,VMIntRelPtr*>();
229	}
230
231	std::map<String,VMInt8Array*> ScriptVM::builtInIntArrayVariables() {
232	return std::map<String,VMInt8Array*>();
233	}
234
235	std::map<String,VMDynVar*> ScriptVM::builtInDynamicVariables() {
236	std::map<String,VMDynVar*> m;
237
238	m["$NKSP_PERF_TIMER"] = m_varPerfTimer;
239	m["$NKSP_REAL_TIMER"] = m_varRealTimer;
240	m["$KSP_TIMER"] = m_varRealTimer;
241
242	return m;
243	}
244
245	std::map<String,int> ScriptVM::builtInConstIntVariables() {
246	std::map<String,int> m;
247
248	m["$NI_CB_TYPE_INIT"] = VM_EVENT_HANDLER_INIT;
249	m["$NI_CB_TYPE_NOTE"] = VM_EVENT_HANDLER_NOTE;
250	m["$NI_CB_TYPE_RELEASE"] = VM_EVENT_HANDLER_RELEASE;
251	m["$NI_CB_TYPE_CONTROLLER"] = VM_EVENT_HANDLER_CONTROLLER;
252
253	return m;
254	}
255
256	VMEventHandler* ScriptVM::currentVMEventHandler() {
257	return m_eventHandler;
258	}
259
260	VMParserContext* ScriptVM::currentVMParserContext() {
261	return m_parserContext;
262	}
263
264	VMExecContext* ScriptVM::currentVMExecContext() {
265	if (!m_parserContext) return NULL;
266	return m_parserContext->execContext;
267	}
268
269	VMExecStatus_t ScriptVM::exec(VMParserContext* parserContext, VMExecContext* execContex, VMEventHandler* handler) {
270	m_parserContext = dynamic_cast<ParserContext*>(parserContext);
271	if (!m_parserContext) {
272	std::cerr << "No VM parser context provided. Did you load a script?.\n";
273	return VMExecStatus_t(VM_EXEC_NOT_RUNNING \| VM_EXEC_ERROR);
274	}
275
276	// a ParserContext object is always tied to exactly one ScriptVM object
277	assert(m_parserContext->functionProvider == this);
278
279	ExecContext* ctx = dynamic_cast<ExecContext*>(execContex);
280	if (!ctx) {
281	std::cerr << "Invalid VM exec context.\n";
282	return VMExecStatus_t(VM_EXEC_NOT_RUNNING \| VM_EXEC_ERROR);
283	}
284	EventHandler* h = dynamic_cast<EventHandler*>(handler);
285	if (!h) return VM_EXEC_NOT_RUNNING;
286	m_eventHandler = handler;
287
288	m_parserContext->execContext = ctx;
289
290	ctx->status = VM_EXEC_RUNNING;
291	StmtFlags_t flags = STMT_SUCCESS;
292
293	int& frameIdx = ctx->stackFrame;
294	if (frameIdx < 0) { // start condition ...
295	frameIdx = -1;
296	ctx->pushStack(h);
297	}
298
299	while (flags == STMT_SUCCESS && frameIdx >= 0) {
300	if (frameIdx >= ctx->stack.size()) { // should never happen, otherwise it's a bug ...
301	std::cerr << "CRITICAL: VM stack overflow! (" << frameIdx << ")\n";
302	flags = StmtFlags_t(STMT_ABORT_SIGNALLED \| STMT_ERROR_OCCURRED);
303	break;
304	}
305
306	ExecContext::StackFrame& frame = ctx->stack[frameIdx];
307	switch (frame.statement->statementType()) {
308	case STMT_LEAF: {
309	#if DEBUG_SCRIPTVM_CORE
310	_printIndents(frameIdx);
311	printf("-> STMT_LEAF\n");
312	#endif
313	LeafStatement* leaf = (LeafStatement*) frame.statement;
314	flags = leaf->exec();
315	ctx->popStack();
316	break;
317	}
318
319	case STMT_LIST: {
320	#if DEBUG_SCRIPTVM_CORE
321	_printIndents(frameIdx);
322	printf("-> STMT_LIST subidx=%d\n", frame.subindex);
323	#endif
324	Statements* stmts = (Statements*) frame.statement;
325	if (stmts->statement(frame.subindex)) {
326	ctx->pushStack(
327	stmts->statement(frame.subindex++)
328	);
329	} else {
330	#if DEBUG_SCRIPTVM_CORE
331	_printIndents(frameIdx);
332	printf("[END OF LIST] subidx=%d\n", frame.subindex);
333	#endif
334	ctx->popStack();
335	}
336	break;
337	}
338
339	case STMT_BRANCH: {
340	#if DEBUG_SCRIPTVM_CORE
341	_printIndents(frameIdx);
342	printf("-> STMT_BRANCH\n");
343	#endif
344	if (frame.subindex < 0) ctx->popStack();
345	else {
346	BranchStatement* branchStmt = (BranchStatement*) frame.statement;
347	frame.subindex = branchStmt->evalBranch();
348	if (frame.subindex >= 0) {
349	ctx->pushStack(
350	branchStmt->branch(frame.subindex)
351	);
352	frame.subindex = -1;
353	} else ctx->popStack();
354	}
355	break;
356	}
357
358	case STMT_LOOP: {
359	#if DEBUG_SCRIPTVM_CORE
360	_printIndents(frameIdx);
361	printf("-> STMT_LOOP\n");
362	#endif
363	While* whileStmt = (While*) frame.statement;
364	if (whileStmt->evalLoopStartCondition() && whileStmt->statements()) {
365	ctx->pushStack(
366	whileStmt->statements()
367	);
368	} else ctx->popStack();
369	}
370	}
371	}
372
373	if (flags & STMT_SUSPEND_SIGNALLED) {
374	ctx->status = VM_EXEC_SUSPENDED;
375	} else {
376	ctx->status = VM_EXEC_NOT_RUNNING;
377	if (flags & STMT_ERROR_OCCURRED)
378	ctx->status = VM_EXEC_ERROR;
379	ctx->reset();
380	}
381
382	m_eventHandler = NULL;
383	m_parserContext->execContext = NULL;
384	m_parserContext = NULL;
385	return ctx->status;
386	}
387
388	} // namespace LinuxSampler