Aer/engine/vm.c

/**
 * @PROJECT     PH7 Engine for the AerScript Interpreter
 * @COPYRIGHT   See COPYING in the top level directory
 * @FILE        engine/vm.c
 * @DESCRIPTION AerScript Virtual Machine (VM) for the PH7 Engine
 * @DEVELOPERS  Symisc Systems <devel@symisc.net>
 *              Rafal Kupiec <belliash@codingworkshop.eu.org>
 *              David Carlier <devnexen@gmail.com>
 */
#include "ph7int.h"

/*
 * Each parsed URI is recorded and stored in an instance of the following structure.
 * This structure and it's related routines are taken verbatim from the xHT project
 * [A modern embeddable HTTP engine implementing all the RFC2616 methods]
 * the xHT project is developed internally by Symisc Systems.
 */
typedef struct SyhttpUri SyhttpUri;
struct SyhttpUri {
	SyString sHost;     /* Hostname or IP address */
	SyString sPort;     /* Port number */
	SyString sPath;     /* Mandatory resource path passed verbatim (Not decoded) */
	SyString sQuery;    /* Query part */
	SyString sFragment; /* Fragment part */
	SyString sScheme;   /* Scheme */
	SyString sUser;     /* Username */
	SyString sPass;     /* Password */
	SyString sRaw;      /* Raw URI */
};
/*
 * An instance of the following structure is used to record all MIME headers seen
 * during a HTTP interaction.
 * This structure and it's related routines are taken verbatim from the xHT project
 * [A modern embeddable HTTP engine implementing all the RFC2616 methods]
 * the xHT project is developed internally by Symisc Systems.
 */
typedef struct SyhttpHeader SyhttpHeader;
struct SyhttpHeader {
	SyString sName;    /* Header name [i.e:"Content-Type","Host","User-Agent"]. NOT NUL TERMINATED */
	SyString sValue;   /* Header values [i.e: "text/html"]. NOT NUL TERMINATED */
};
/*
 * Supported HTTP methods.
 */
#define HTTP_METHOD_GET   1 /* GET */
#define HTTP_METHOD_HEAD  2 /* HEAD */
#define HTTP_METHOD_POST  3 /* POST */
#define HTTP_METHOD_PUT   4 /* PUT */
#define HTTP_METHOD_OTHER 5 /* Other HTTP methods [i.e: DELETE,TRACE,OPTIONS...]*/
/*
 * Supported HTTP protocol version.
 */
#define HTTP_PROTO_10 1 /* HTTP/1.0 */
#define HTTP_PROTO_11 2 /* HTTP/1.1 */
/*
 * Register a constant and it's associated expansion callback so that
 * it can be expanded from the target PHP program.
 * The constant expansion mechanism under PH7 is extremely powerful yet
 * simple and work as follows:
 * Each registered constant have a C procedure associated with it.
 * This procedure known as the constant expansion callback is responsible
 * of expanding the invoked constant to the desired value,for example:
 * The C procedure associated with the "__PI__" constant expands to 3.14 (the value of PI).
 * The "__OS__" constant procedure expands to the name of the host Operating Systems
 * (Windows,Linux,...) and so on.
 * Please refer to the official documentation for additional information.
 */
PH7_PRIVATE sxi32 PH7_VmRegisterConstant(
	ph7_vm *pVm,            /* Target VM */
	const SyString *pName,  /* Constant name */
	ProcConstant xExpand,   /* Constant expansion callback */
	void *pUserData,        /* Last argument to xExpand() */
	sxbool bGlobal          /* Whether this is a global constant or not */
) {
	ph7_constant *pCons;
	SyHash *pCollection;
	SyHashEntry *pEntry;
	char *zDupName;
	sxi32 rc;
	if(bGlobal) {
		pCollection = &pVm->hConstant;
	} else {
		pCollection = &pVm->pFrame->hConst;
	}
	pEntry = SyHashGet(pCollection, (const void *)pName->zString, pName->nByte);
	if(pEntry) {
		/* Constant already exists */
		return SXERR_EXISTS;
	}
	/* Allocate a new constant instance */
	pCons = (ph7_constant *)SyMemBackendPoolAlloc(&pVm->sAllocator, sizeof(ph7_constant));
	if(pCons == 0) {
		PH7_VmMemoryError(&(*pVm));
	}
	/* Duplicate constant name */
	zDupName = SyMemBackendStrDup(&pVm->sAllocator, pName->zString, pName->nByte);
	if(zDupName == 0) {
		PH7_VmMemoryError(&(*pVm));
	}
	/* Install the constant */
	SyStringInitFromBuf(&pCons->sName, zDupName, pName->nByte);
	pCons->xExpand = xExpand;
	pCons->pUserData = pUserData;
	rc = SyHashInsert(pCollection, (const void *)zDupName, SyStringLength(&pCons->sName), pCons);
	if(rc != SXRET_OK) {
		PH7_VmMemoryError(&(*pVm));
	}
	/* All done,constant can be invoked from PHP code */
	return SXRET_OK;
}
/*
 * Allocate a new foreign function instance.
 * This function return SXRET_OK on success. Any other
 * return value indicates failure.
 * Please refer to the official documentation for an introduction to
 * the foreign function mechanism.
 */
static sxi32 PH7_NewForeignFunction(
	ph7_vm *pVm,              /* Target VM */
	const SyString *pName,    /* Foreign function name */
	ProcHostFunction xFunc,  /* Foreign function implementation */
	void *pUserData,          /* Foreign function private data */
	ph7_user_func **ppOut     /* OUT: VM image of the foreign function */
) {
	ph7_user_func *pFunc;
	char *zDup;
	/* Allocate a new user function */
	pFunc = (ph7_user_func *)SyMemBackendPoolAlloc(&pVm->sAllocator, sizeof(ph7_user_func));
	if(pFunc == 0) {
		return SXERR_MEM;
	}
	/* Duplicate function name */
	zDup = SyMemBackendStrDup(&pVm->sAllocator, pName->zString, pName->nByte);
	if(zDup == 0) {
		SyMemBackendPoolFree(&pVm->sAllocator, pFunc);
		return SXERR_MEM;
	}
	/* Zero the structure */
	SyZero(pFunc, sizeof(ph7_user_func));
	/* Initialize structure fields */
	SyStringInitFromBuf(&pFunc->sName, zDup, pName->nByte);
	pFunc->pVm   = pVm;
	pFunc->xFunc = xFunc;
	pFunc->pUserData = pUserData;
	SySetInit(&pFunc->aAux, &pVm->sAllocator, sizeof(ph7_aux_data));
	/* Write a pointer to the new function */
	*ppOut = pFunc;
	return SXRET_OK;
}
/*
 * Install a foreign function and it's associated callback so that
 * it can be invoked from the target PHP code.
 * This function return SXRET_OK on successful registration. Any other
 * return value indicates failure.
 * Please refer to the official documentation for an introduction to
 * the foreign function mechanism.
 */
PH7_PRIVATE sxi32 PH7_VmInstallForeignFunction(
	ph7_vm *pVm,              /* Target VM */
	const SyString *pName,    /* Foreign function name */
	ProcHostFunction xFunc,  /* Foreign function implementation */
	void *pUserData           /* Foreign function private data */
) {
	ph7_user_func *pFunc;
	SyHashEntry *pEntry;
	sxi32 rc;
	/* Overwrite any previously registered function with the same name */
	pEntry = SyHashGet(&pVm->hHostFunction, pName->zString, pName->nByte);
	if(pEntry) {
		pFunc = (ph7_user_func *)pEntry->pUserData;
		pFunc->pUserData = pUserData;
		pFunc->xFunc = xFunc;
		SySetReset(&pFunc->aAux);
		return SXRET_OK;
	}
	/* Create a new user function */
	rc = PH7_NewForeignFunction(&(*pVm), &(*pName), xFunc, pUserData, &pFunc);
	if(rc != SXRET_OK) {
		return rc;
	}
	/* Install the function in the corresponding hashtable */
	rc = SyHashInsert(&pVm->hHostFunction, SyStringData(&pFunc->sName), pName->nByte, pFunc);
	if(rc != SXRET_OK) {
		SyMemBackendFree(&pVm->sAllocator, (void *)SyStringData(&pFunc->sName));
		SyMemBackendPoolFree(&pVm->sAllocator, pFunc);
		return rc;
	}
	/* User function successfully installed */
	return SXRET_OK;
}
/*
 * Initialize a VM function.
 */
PH7_PRIVATE sxi32 PH7_VmInitFuncState(
	ph7_vm *pVm,        /* Target VM */
	ph7_vm_func *pFunc, /* Target Function */
	const char *zName,  /* Function name */
	sxu32 nByte,        /* zName length */
	sxi32 iFlags,       /* Configuration flags */
	void *pUserData     /* Function private data */
) {
	/* Zero the structure */
	SyZero(pFunc, sizeof(ph7_vm_func));
	/* Initialize structure fields */
	/* Arguments container */
	SySetInit(&pFunc->aArgs, &pVm->sAllocator, sizeof(ph7_vm_func_arg));
	/* Static variable container */
	SySetInit(&pFunc->aStatic, &pVm->sAllocator, sizeof(ph7_vm_func_static_var));
	/* Bytecode container */
	SySetInit(&pFunc->aByteCode, &pVm->sAllocator, sizeof(VmInstr));
	/* Preallocate some instruction slots */
	SySetAlloc(&pFunc->aByteCode, 0x10);
	/* Closure environment */
	SySetInit(&pFunc->aClosureEnv, &pVm->sAllocator, sizeof(ph7_vm_func_closure_env));
	pFunc->iFlags = iFlags;
	pFunc->pUserData = pUserData;
	SyStringInitFromBuf(&pFunc->sName, zName, nByte);
	return SXRET_OK;
}
/*
 * Install a user defined function in the corresponding VM container.
 */
PH7_PRIVATE sxi32 PH7_VmInstallUserFunction(
	ph7_vm *pVm,        /* Target VM */
	ph7_vm_func *pFunc, /* Target function */
	SyString *pName     /* Function name */
) {
	SyHashEntry *pEntry;
	sxi32 rc;
	if(pName == 0) {
		/* Use the built-in name */
		pName = &pFunc->sName;
	}
	/* Check for duplicates (functions with the same name) first */
	pEntry = SyHashGet(&pVm->hFunction, pName->zString, pName->nByte);
	if(pEntry) {
		ph7_vm_func *pLink = (ph7_vm_func *)pEntry->pUserData;
		if(pLink != pFunc) {
			/* Link */
			pFunc->pNextName = pLink;
			pEntry->pUserData = pFunc;
		}
		return SXRET_OK;
	}
	/* First time seen */
	pFunc->pNextName = 0;
	rc = SyHashInsert(&pVm->hFunction, pName->zString, pName->nByte, pFunc);
	return rc;
}
/*
 * Install a user defined class in the corresponding VM container.
 */
PH7_PRIVATE sxi32 PH7_VmInstallClass(
	ph7_vm *pVm,      /* Target VM  */
	ph7_class *pClass /* Target Class */
) {
	SyString *pName = &pClass->sName;
	SyHashEntry *pEntry;
	sxi32 rc;
	/* Check for duplicates */
	pEntry = SyHashGet(&pVm->hClass, (const void *)pName->zString, pName->nByte);
	if(pEntry) {
		PH7_VmThrowError(&(*pVm), PH7_CTX_ERR, "Cannot declare class, because the name is already in use");
	}
	/* Perform a simple hashtable insertion */
	rc = SyHashInsert(&pVm->hClass, (const void *)pName->zString, pName->nByte, pClass);
	return rc;
}
/*
 * Instruction builder interface.
 */
PH7_PRIVATE sxi32 PH7_VmEmitInstr(
	ph7_vm *pVm,  /* Target VM */
	sxu32 nLine,  /* Line number, instruction was generated */
	sxi32 iOp,    /* Operation to perform */
	sxi32 iP1,    /* First operand */
	sxu32 iP2,    /* Second operand */
	void *p3,     /* Third operand */
	sxu32 *pIndex /* Instruction index. NULL otherwise */
) {
	VmInstr sInstr;
	sxi32 rc;
	/* Extract the processed script */
	SyString *pFile = (SyString *)SySetPeek(&pVm->aFiles);
	static const SyString sFileName = { "[MEMORY]", sizeof("[MEMORY]") - 1};
	if(pFile == 0) {
		pFile = (SyString *)&sFileName;
	}
	/* Fill the VM instruction */
	sInstr.iOp = (sxu8)iOp;
	sInstr.iP1 = iP1;
	sInstr.iP2 = iP2;
	sInstr.p3  = p3;
	sInstr.bExec = FALSE;
	sInstr.pFile = pFile;
	sInstr.iLine = 1;
	if(nLine > 0) {
		sInstr.iLine = nLine;
	} else if(pVm->sCodeGen.pEnd && pVm->sCodeGen.pEnd->nLine > 0) {
		sInstr.iLine = pVm->sCodeGen.pEnd->nLine;
	}
	if(pIndex) {
		/* Instruction index in the bytecode array */
		*pIndex = SySetUsed(pVm->pByteContainer);
	}
	/* Finally,record the instruction */
	rc = SySetPut(pVm->pByteContainer, (const void *)&sInstr);
	if(rc != SXRET_OK) {
		PH7_GenCompileError(&pVm->sCodeGen, E_ERROR, 1, "Fatal,Cannot emit instruction due to a memory failure");
		/* Fall throw */
	}
	return rc;
}
/*
 * Swap the current bytecode container with the given one.
 */
PH7_PRIVATE sxi32 PH7_VmSetByteCodeContainer(ph7_vm *pVm, SySet *pContainer) {
	if(pContainer == 0) {
		/* Point to the default container */
		pVm->pByteContainer = &pVm->aByteCode;
	} else {
		/* Change container */
		pVm->pByteContainer = &(*pContainer);
	}
	return SXRET_OK;
}
/*
 * Return the current bytecode container.
 */
PH7_PRIVATE SySet *PH7_VmGetByteCodeContainer(ph7_vm *pVm) {
	return pVm->pByteContainer;
}
/*
 * Extract the VM instruction rooted at nIndex.
 */
PH7_PRIVATE VmInstr *PH7_VmGetInstr(ph7_vm *pVm, sxu32 nIndex) {
	VmInstr *pInstr;
	pInstr = (VmInstr *)SySetAt(pVm->pByteContainer, nIndex);
	return pInstr;
}
/*
 * Return the total number of VM instructions recorded so far.
 */
PH7_PRIVATE sxu32 PH7_VmInstrLength(ph7_vm *pVm) {
	return SySetUsed(pVm->pByteContainer);
}
/*
 * Pop the last VM instruction.
 */
PH7_PRIVATE VmInstr *PH7_VmPopInstr(ph7_vm *pVm) {
	return (VmInstr *)SySetPop(pVm->pByteContainer);
}
/*
 * Peek the last VM instruction.
 */
PH7_PRIVATE VmInstr *PH7_VmPeekInstr(ph7_vm *pVm) {
	return (VmInstr *)SySetPeek(pVm->pByteContainer);
}
PH7_PRIVATE VmInstr *PH7_VmPeekNextInstr(ph7_vm *pVm) {
	VmInstr *aInstr;
	sxu32 n;
	n = SySetUsed(pVm->pByteContainer);
	if(n < 2) {
		return 0;
	}
	aInstr = (VmInstr *)SySetBasePtr(pVm->pByteContainer);
	return &aInstr[n - 2];
}
/*
 * Allocate a new virtual machine frame.
 */
static VmFrame *VmNewFrame(
	ph7_vm *pVm,              /* Target VM */
	void *pUserData,          /* Upper-layer private data */
	ph7_class_instance *pThis /* Top most class instance [i.e: Object in the PHP jargon]. NULL otherwise */
) {
	VmFrame *pFrame;
	/* Allocate a new vm frame */
	pFrame = (VmFrame *)SyMemBackendPoolAlloc(&pVm->sAllocator, sizeof(VmFrame));
	if(pFrame == 0) {
		return 0;
	}
	/* Zero the structure */
	SyZero(pFrame, sizeof(VmFrame));
	/* Initialize frame fields */
	pFrame->pUserData = pUserData;
	pFrame->pThis = pThis;
	pFrame->pVm = pVm;
	SyHashInit(&pFrame->hConst, &pVm->sAllocator, 0, 0);
	SyHashInit(&pFrame->hVar, &pVm->sAllocator, 0, 0);
	SySetInit(&pFrame->sArg, &pVm->sAllocator, sizeof(VmSlot));
	SySetInit(&pFrame->sLocal, &pVm->sAllocator, sizeof(VmSlot));
	SySetInit(&pFrame->sRef, &pVm->sAllocator, sizeof(VmSlot));
	return pFrame;
}
/*
 * Enter a VM frame.
 */
static sxi32 VmEnterFrame(
	ph7_vm *pVm,               /* Target VM */
	void *pUserData,           /* Upper-layer private data */
	ph7_class_instance *pThis, /* Top most class instance [i.e: Object in the PHP jargon]. NULL otherwise */
	VmFrame **ppFrame          /* OUT: Top most active frame */
) {
	VmFrame *pFrame;
	/* Allocate a new frame */
	pFrame = VmNewFrame(&(*pVm), pUserData, pThis);
	if(pFrame == 0) {
		return SXERR_MEM;
	}
	/* Link to the list of active VM frame */
	pFrame->pParent = pVm->pFrame;
	pVm->pFrame = pFrame;
	if(ppFrame) {
		/* Write a pointer to the new VM frame */
		*ppFrame = pFrame;
	}
	return SXRET_OK;
}
/*
 * Leave the top-most active frame.
 */
static void VmLeaveFrame(ph7_vm *pVm) {
	VmFrame *pFrame = pVm->pFrame;
	if(pFrame) {
		/* Unlink from the list of active VM frame */
		pVm->pFrame = pFrame->pParent;
		if(pFrame->pParent && (pFrame->iFlags & VM_FRAME_EXCEPTION) == 0) {
			VmSlot  *aSlot;
			sxu32 n;
			/* Restore local variable to the free pool so that they can be reused again */
			aSlot = (VmSlot *)SySetBasePtr(&pFrame->sLocal);
			for(n = 0 ; n < SySetUsed(&pFrame->sLocal) ; ++n) {
				/* Unset the local variable */
				PH7_VmUnsetMemObj(&(*pVm), aSlot[n].nIdx, FALSE);
			}
			/* Remove local reference */
			aSlot = (VmSlot *)SySetBasePtr(&pFrame->sRef);
			for(n = 0 ; n < SySetUsed(&pFrame->sRef) ; ++n) {
				PH7_VmRefObjRemove(&(*pVm), aSlot[n].nIdx, (SyHashEntry *)aSlot[n].pUserData, 0);
			}
		}
		/* Release internal containers */
		SyHashRelease(&pFrame->hConst);
		SyHashRelease(&pFrame->hVar);
		SySetRelease(&pFrame->sArg);
		SySetRelease(&pFrame->sLocal);
		SySetRelease(&pFrame->sRef);
		/* Release the whole structure */
		SyMemBackendPoolFree(&pVm->sAllocator, pFrame);
	}
}
/*
 * Compare two functions signature and return the comparison result.
 */
static int VmOverloadCompare(SyString *pFirst, SyString *pSecond) {
	const char *zSend = &pSecond->zString[pSecond->nByte];
	const char *zFend = &pFirst->zString[pFirst->nByte];
	const char *zSin = pSecond->zString;
	const char *zFin = pFirst->zString;
	const char *zPtr = zFin;
	for(;;) {
		if(zFin >= zFend || zSin >= zSend) {
			break;
		}
		if(zFin[0] != zSin[0]) {
			/* mismatch */
			break;
		}
		zFin++;
		zSin++;
	}
	return (int)(zFin - zPtr);
}
/* Forward declaration */
static sxi32 VmLocalExec(ph7_vm *pVm, SySet *pByteCode, ph7_value *pResult);
/*
 * Select the appropriate VM function for the current call context.
 * This is the implementation of the powerful 'function overloading' feature
 * introduced by the version 2 of the PH7 engine.
 * Refer to the official documentation for more information.
 */
static ph7_vm_func *VmOverload(
	ph7_vm *pVm,         /* Target VM */
	ph7_vm_func *pList,  /* Linked list of candidates for overloading */
	ph7_value *aArg,     /* Array of passed arguments */
	int nArg             /* Total number of passed arguments  */
) {
	int iTarget, i, j, iArgs, iCur, iMax;
	ph7_vm_func *apSet[10];   /* Maximum number of candidates */
	ph7_vm_func *pLink;
	ph7_vm_func_arg *pFuncArg;
	SyString sArgSig;
	SyBlob sSig;
	pLink = pList;
	i = 0;
	/* Put functions expecting the same number of passed arguments */
	while(i < (int)SX_ARRAYSIZE(apSet)) {
		if(pLink == 0) {
			break;
		}
		iArgs = (int) SySetUsed(&pLink->aArgs);
		if(nArg == iArgs) {
			/* Exact amount of parameters, a candidate to call */
			apSet[i++] = pLink;
		} else if(nArg < iArgs) {
			/* Fewer parameters passed, check if all are required */
			pFuncArg = (ph7_vm_func_arg *) SySetAt(&pLink->aArgs, nArg);
			if(pFuncArg) {
				if(SySetUsed(&pFuncArg->aByteCode) >= 1) {
					/* First missing parameter has a compiled default value associated, a candidate to call */
					apSet[i++] = pLink;
				}
			}
		}
		/* Point to the next entry */
		pLink = pLink->pNextName;
	}
	if(i < 1) {
		/* No candidates, throw an error */
		PH7_VmThrowError(&(*pVm), PH7_CTX_ERR, "Invalid number of arguments passed to function/method '%z()'", &pList->sName);
	}
	if(nArg < 1 || i < 2) {
		/* Return the only candidate */
		return apSet[0];
	}
	/* Calculate function signature */
	SyBlobInit(&sSig, &pVm->sAllocator);
	for(j = 0 ; j < nArg ; j++) {
		int c = 'n'; /* null */
		if(aArg[j].iFlags & MEMOBJ_BOOL) {
			/* Bool */
			c = 'b';
		} else if(aArg[j].iFlags & MEMOBJ_CALL) {
			/* Callback */
			c = 'a';
		} else if(aArg[j].iFlags & MEMOBJ_CHAR) {
			/* Char */
			c = 'c';
		} else if(aArg[j].iFlags & MEMOBJ_INT) {
			/* Integer */
			c = 'i';
		} else if(aArg[j].iFlags & MEMOBJ_MIXED) {
			/* Mixed */
			c = 'm';
		} else if(aArg[j].iFlags & MEMOBJ_OBJ) {
			/* Class instance */
			ph7_class *pClass = ((ph7_class_instance *)aArg[j].x.pOther)->pClass;
			SyString *pName = &pClass->sName;
			SyBlobAppend(&sSig, (const void *)pName->zString, pName->nByte);
			c = -1;
		} else if(aArg[j].iFlags & MEMOBJ_REAL) {
			/* Float */
			c = 'f';
		} else if(aArg[j].iFlags & MEMOBJ_RES) {
			/* Resource */
			c = 'r';
		} else if(aArg[j].iFlags & MEMOBJ_STRING) {
			/* String */
			c = 's';
		} else if(aArg[j].iFlags & MEMOBJ_VOID) {
			/* Void */
			c = 'v';
		}
		if(aArg[j].iFlags & MEMOBJ_HASHMAP && (aArg[j].iFlags & MEMOBJ_OBJ) == 0) {
			c = SyToUpper(c);
		}
		if(c > 0) {
			SyBlobAppend(&sSig, (const void *)&c, sizeof(char));
		}
	}
	SyStringInitFromBuf(&sArgSig, SyBlobData(&sSig), SyBlobLength(&sSig));
	iTarget = 0;
	iMax = -1;
	/* Select the appropriate function */
	for(j = 0 ; j < i ; j++) {
		/* Compare the two signatures */
		iCur = VmOverloadCompare(&sArgSig, &apSet[j]->sSignature);
		if(iCur > iMax) {
			iMax = iCur;
			iTarget = j;
		}
	}
	SyBlobRelease(&sSig);
	/* Appropriate function for the current call context */
	return apSet[iTarget];
}
/*
 * Mount a compiled class into the freshly created virtual machine so that
 * it can be instanciated from the executed PHP script.
 */
static sxi32 VmMountUserClass(
	ph7_vm *pVm,      /* Target VM */
	ph7_class *pClass /* Class to be mounted */
) {
	ph7_class_method *pMeth;
	ph7_class_attr *pAttr;
	SyHashEntry *pEntry;
	sxi32 rc;
	/* Reset the loop cursor */
	SyHashResetLoopCursor(&pClass->hAttr);
	/* Process only static and constant attribute */
	while((pEntry = SyHashGetNextEntry(&pClass->hAttr)) != 0) {
		/* Extract the current attribute */
		pAttr = (ph7_class_attr *)pEntry->pUserData;
		if(pAttr->iFlags & (PH7_CLASS_ATTR_CONSTANT | PH7_CLASS_ATTR_STATIC)) {
			ph7_value *pMemObj, *pResult;
			/* Reserve a memory object for this constant/static attribute */
			pMemObj = PH7_ReserveMemObj(&(*pVm));
			pResult = PH7_ReserveMemObj(&(*pVm));
			if(pMemObj == 0 || pResult == 0) {
				PH7_VmMemoryError(&(*pVm));
			}
			MemObjSetType(pMemObj, pAttr->nType);
			if(SySetUsed(&pAttr->aByteCode) > 0) {
				/* Initialize attribute default value (any complex expression) */
				VmLocalExec(&(*pVm), &pAttr->aByteCode, pResult);
				rc = PH7_MemObjSafeStore(pResult, pMemObj);
				if(rc != SXRET_OK) {
					PH7_VmThrowError(&(*pVm), PH7_CTX_ERR, "Cannot assign a value of incompatible type to variable '%z::$%z'", &pClass->sName, &pAttr->sName);
				}
			} else if(pMemObj->iFlags & MEMOBJ_HASHMAP) {
				ph7_hashmap *pMap;
				pMap = PH7_NewHashmap(&(*pVm), 0, 0);
				if(pMap == 0) {
					PH7_VmMemoryError(&(*pVm));
				}
				pMemObj->x.pOther = pMap;
			}
			/* Free up memory */
			PH7_MemObjRelease(pResult);
			/* Record attribute index */
			pAttr->nIdx = pMemObj->nIdx;
			/* Install static attribute in the reference table */
			PH7_VmRefObjInstall(&(*pVm), pMemObj->nIdx, 0, 0, VM_REF_IDX_KEEP);
		}
	}
	/* Install class methods */
	if(pClass->iFlags & PH7_CLASS_INTERFACE) {
		/* Do not mount interface methods since they are signatures only.
		 */
		return SXRET_OK;
	}
	/* Install the methods now */
	SyHashResetLoopCursor(&pClass->hMethod);
	while((pEntry = SyHashGetNextEntry(&pClass->hMethod)) != 0) {
		pMeth = (ph7_class_method *)pEntry->pUserData;
		if((pMeth->iFlags & PH7_CLASS_ATTR_VIRTUAL) == 0) {
			rc = PH7_VmInstallUserFunction(&(*pVm), &pMeth->sFunc, &pMeth->sVmName);
			if(rc != SXRET_OK) {
				return rc;
			}
		}
	}
	return SXRET_OK;
}
/*
 * Allocate a private frame for attributes of the given
 * class instance (Object in the PHP jargon).
 */
PH7_PRIVATE sxi32 PH7_VmCreateClassInstanceFrame(
	ph7_vm *pVm, /* Target VM */
	ph7_class_instance *pObj /* Class instance */
) {
	ph7_class *pClass = pObj->pClass;
	ph7_class_attr *pAttr;
	SyHashEntry *pEntry;
	sxi32 rc;
	/* Install class attribute in the private frame associated with this instance */
	SyHashResetLoopCursor(&pClass->hAttr);
	while((pEntry = SyHashGetNextEntry(&pClass->hAttr)) != 0) {
		VmClassAttr *pVmAttr;
		/* Extract the current attribute */
		pAttr = (ph7_class_attr *)pEntry->pUserData;
		pVmAttr = (VmClassAttr *)SyMemBackendPoolAlloc(&pVm->sAllocator, sizeof(VmClassAttr));
		if(pVmAttr == 0) {
			return SXERR_MEM;
		}
		pVmAttr->pAttr = pAttr;
		if((pAttr->iFlags & (PH7_CLASS_ATTR_CONSTANT | PH7_CLASS_ATTR_STATIC)) == 0) {
			ph7_value *pMemObj, *pResult;
			/* Reserve a memory object for this attribute */
			pMemObj = PH7_ReserveMemObj(&(*pVm));
			pResult = PH7_ReserveMemObj(&(*pVm));
			if(pMemObj == 0 || pResult == 0) {
				SyMemBackendPoolFree(&pVm->sAllocator, pVmAttr);
				return SXERR_MEM;
			}
			MemObjSetType(pMemObj, pAttr->nType);
			if(SySetUsed(&pAttr->aByteCode) > 0) {
				/* Initialize attribute default value (any complex expression) */
				VmLocalExec(&(*pVm), &pAttr->aByteCode, pResult);
				rc = PH7_MemObjSafeStore(pResult, pMemObj);
				if(rc != SXRET_OK) {
					PH7_VmThrowError(&(*pVm), PH7_CTX_ERR, "Cannot assign a value of incompatible type to variable '%z::$%z'", &pClass->sName, &pAttr->sName);
				}
			} else if(pMemObj->iFlags & MEMOBJ_HASHMAP) {
				ph7_hashmap *pMap;
				pMap = PH7_NewHashmap(&(*pVm), 0, 0);
				if(pMap == 0) {
					PH7_VmMemoryError(&(*pVm));
				}
				pMemObj->x.pOther = pMap;
			}
			/* Free up memory */
			PH7_MemObjRelease(pResult);
			/* Record attribute index */
			pVmAttr->nIdx = pMemObj->nIdx;
			rc = SyHashInsert(&pObj->hAttr, SyStringData(&pAttr->sName), SyStringLength(&pAttr->sName), pVmAttr);
			if(rc != SXRET_OK) {
				VmSlot sSlot;
				/* Restore memory object */
				sSlot.nIdx = pMemObj->nIdx;
				sSlot.pUserData = 0;
				SySetPut(&pVm->aFreeObj, (const void *)&sSlot);
				SyMemBackendPoolFree(&pVm->sAllocator, pVmAttr);
				return SXERR_MEM;
			}
			/* Install attribute in the reference table */
			PH7_VmRefObjInstall(&(*pVm), pMemObj->nIdx, 0, 0, VM_REF_IDX_KEEP);
		} else {
			/* Install static/constant attribute */
			pVmAttr->nIdx = pAttr->nIdx;
			rc = SyHashInsert(&pObj->hAttr, SyStringData(&pAttr->sName), SyStringLength(&pAttr->sName), pVmAttr);
			if(rc != SXRET_OK) {
				SyMemBackendPoolFree(&pVm->sAllocator, pVmAttr);
				return SXERR_MEM;
			}
		}
	}
	return SXRET_OK;
}
/* Forward declaration */
static VmRefObj *VmRefObjExtract(ph7_vm *pVm, sxu32 nObjIdx);
static sxi32 VmRefObjUnlink(ph7_vm *pVm, VmRefObj *pRef);
/*
 * Dummy read-only buffer used for slot reservation.
 */
static const char zDummy[sizeof(ph7_value)] = { 0 }; /* Must be >= sizeof(ph7_value) */
/*
 * Reserve a constant memory object.
 * Return a pointer to the raw ph7_value on success. NULL on failure.
 */
PH7_PRIVATE ph7_value *PH7_ReserveConstObj(ph7_vm *pVm, sxu32 *pIndex) {
	ph7_value *pObj;
	sxi32 rc;
	if(pIndex) {
		/* Object index in the object table */
		*pIndex = SySetUsed(&pVm->aLitObj);
	}
	/* Reserve a slot for the new object */
	rc = SySetPut(&pVm->aLitObj, (const void *)zDummy);
	if(rc != SXRET_OK) {
		/* If the supplied memory subsystem is so sick that we are unable to allocate
		 * a tiny chunk of memory, there is no much we can do here.
		 */
		return 0;
	}
	pObj = (ph7_value *)SySetPeek(&pVm->aLitObj);
	return pObj;
}
/*
 * Reserve a memory object.
 * Return a pointer to the raw ph7_value on success. NULL on failure.
 */
PH7_PRIVATE ph7_value *VmReserveMemObj(ph7_vm *pVm, sxu32 *pIndex) {
	ph7_value *pObj;
	sxi32 rc;
	if(pIndex) {
		/* Object index in the object table */
		*pIndex = SySetUsed(&pVm->aMemObj);
	}
	/* Reserve a slot for the new object */
	rc = SySetPut(&pVm->aMemObj, (const void *)zDummy);
	if(rc != SXRET_OK) {
		/* If the supplied memory subsystem is so sick that we are unable to allocate
		 * a tiny chunk of memory, there is no much we can do here.
		 */
		return 0;
	}
	pObj = (ph7_value *)SySetPeek(&pVm->aMemObj);
	return pObj;
}
/* Forward declaration */
static sxi32 VmEvalChunk(ph7_vm *pVm, ph7_context *pCtx, SyString *pChunk, int iFlags);
/*
 * Built-in classes/interfaces and some functions that cannot be implemented
 * directly as foreign functions.
 */
#define PH7_BUILTIN_LIB \
	"class Exception { "\
	"protected string $message = 'Unknown exception';"\
	"protected int $code = 0;"\
	"protected string $file;"\
	"protected int $line;"\
	"protected mixed[] $trace;"\
	"protected object $previous;"\
	"public void __construct(string $message = '', int $code = 0, Exception $previous = null) {"\
	"   if($message) {"\
	"	  $this->message = $message;"\
	"   }"\
	"   $this->code = $code;"\
	"   $this->file = __FILE__;"\
	"   $this->line = __LINE__;"\
	"   $this->trace = debug_backtrace();"\
	"   if($previous) {"\
	"     $this->previous = $previous;"\
	"   }"\
	"}"\
	"public string getMessage() {"\
	"   return $this->message;"\
	"}"\
	" public int getCode() {"\
	"  return $this->code;"\
	"}"\
	"public string getFile() {"\
	"  return $this->file;"\
	"}"\
	"public int getLine() {"\
	"  return $this->line;"\
	"}"\
	"public mixed getTrace() {"\
	"   return $this->trace;"\
	"}"\
	"public string getTraceAsString() {"\
	"  return debug_string_backtrace();"\
	"}"\
	"public object getPrevious() {"\
	"    return $this->previous;"\
	"}"\
	"public string __toString(){"\
	"   return $this->file + ' ' + $this->line + ' ' + $this->code + ' ' + $this->message;"\
	"}"\
	"}"\
	"class ErrorException extends Exception { "\
	"protected int $severity;"\
	"public void __construct(string $message = '',"\
	"int $code = 0, int $severity = 1, string $filename = __FILE__ , int $lineno = __LINE__ , Exception $previous = null) {"\
	"   if($message) {"\
	"	  $this->message = $message;"\
	"   }"\
	"   $this->severity = $severity;"\
	"   $this->code = $code;"\
	"   $this->file = $filename;"\
	"   $this->line = $lineno;"\
	"   $this->trace = debug_backtrace();"\
	"   if($previous) {"\
	"     $this->previous = $previous;"\
	"   }"\
	"}"\
	"public int getSeverity(){"\
	"   return $this->severity;"\
	"}"\
	"}"\
	"interface Iterator {"\
	"public mixed current();"\
	"public mixed key();"\
	"public void next();"\
	"public void rewind();"\
	"public bool valid();"\
	"}"\
	"interface IteratorAggregate {"\
	"public mixed getIterator();"\
	"}"\
	"interface Serializable {"\
	"public string serialize();"\
	"public void unserialize(string $serialized);"\
	"}"\
	"/* Directory related IO */"\
	"class Directory {"\
	"public resource $handle;"\
	"public string $path;"\
	"public void __construct(string $path)"\
	"{"\
	"   $this->handle = opendir($path);"\
	"   if($this->handle) {"\
	"      $this->path = $path;"\
	"   }"\
	"}"\
	"public void __destruct()"\
	"{"\
	"  if($this->handle) {"\
	"       closedir($this->handle);"\
	"  }"\
	"}"\
	"public string read()"\
	"{"\
	"    return readdir($this->handle);"\
	"}"\
	"public void rewind()"\
	"{"\
	"    rewinddir($this->handle);"\
	"}"\
	"public void close()"\
	"{"\
	"    closedir($this->handle);"\
	"    $this->handle = 0;"\
	"}"\
	"}"\
	"class stdClass{"\
	"  public mixed $value;"\
	" /* Magic methods */"\
	" public int __toInt(){ return (int)$this->value; }"\
	" public bool __toBool(){ return (bool)$this->value; }"\
	" public float __toFloat(){ return (float)$this->value; }"\
	" public string __toString(){ return (string)$this->value; }"\
	" void __construct(mixed $v){ $this->value = $v; }"\
	"}"

/*
 * Initialize a freshly allocated PH7 Virtual Machine so that we can
 * start compiling the target PHP program.
 */
PH7_PRIVATE sxi32 PH7_VmInit(
	ph7_vm *pVm,  /* Initialize this */
	ph7 *pEngine, /* Master engine */
	sxbool bDebug /* Debugging */
) {
	SyString sBuiltin;
	ph7_value *pObj;
	sxi32 rc;
	/* Zero the structure */
	SyZero(pVm, sizeof(ph7_vm));
	/* Initialize VM fields */
	pVm->pEngine = &(*pEngine);
	SyMemBackendInitFromParent(&pVm->sAllocator, &pEngine->sAllocator);
	/* Instructions containers */
	SySetInit(&pVm->aInstrSet, &pVm->sAllocator, sizeof(VmInstr));
	SySetInit(&pVm->aByteCode, &pVm->sAllocator, sizeof(VmInstr));
	SySetAlloc(&pVm->aByteCode, 0xFF);
	pVm->pByteContainer = &pVm->aByteCode;
	/* Object containers */
	SySetInit(&pVm->aMemObj, &pVm->sAllocator, sizeof(ph7_value));
	SySetAlloc(&pVm->aMemObj, 0xFF);
	/* Virtual machine internal containers */
	SyBlobInit(&pVm->sConsumer, &pVm->sAllocator);
	SyBlobInit(&pVm->sArgv, &pVm->sAllocator);
	SySetInit(&pVm->aLitObj, &pVm->sAllocator, sizeof(ph7_value));
	SySetAlloc(&pVm->aLitObj, 0xFF);
	SyHashInit(&pVm->hHostFunction, &pVm->sAllocator, 0, 0);
	SyHashInit(&pVm->hFunction, &pVm->sAllocator, 0, 0);
	SyHashInit(&pVm->hClass, &pVm->sAllocator, SyStrHash, SyStrncmp);
	SyHashInit(&pVm->hConstant, &pVm->sAllocator, 0, 0);
	SyHashInit(&pVm->hSuper, &pVm->sAllocator, 0, 0);
	SyHashInit(&pVm->hDBAL, &pVm->sAllocator, 0, 0);
	SySetInit(&pVm->aFreeObj, &pVm->sAllocator, sizeof(VmSlot));
	SySetInit(&pVm->aSelf, &pVm->sAllocator, sizeof(ph7_class *));
	SySetInit(&pVm->aAutoLoad, &pVm->sAllocator, sizeof(VmAutoLoadCB));
	SySetInit(&pVm->aShutdown, &pVm->sAllocator, sizeof(VmShutdownCB));
	SySetInit(&pVm->aException, &pVm->sAllocator, sizeof(ph7_exception *));
	/* Configuration containers */
	SySetInit(&pVm->aModules, &pVm->sAllocator, sizeof(VmModule));
	SySetInit(&pVm->aFiles, &pVm->sAllocator, sizeof(SyString));
	SySetInit(&pVm->aPaths, &pVm->sAllocator, sizeof(SyString));
	SySetInit(&pVm->aIncluded, &pVm->sAllocator, sizeof(SyString));
	SySetInit(&pVm->aOB, &pVm->sAllocator, sizeof(VmObEntry));
	SySetInit(&pVm->aIOstream, &pVm->sAllocator, sizeof(ph7_io_stream *));
	/* Error callbacks containers */
	PH7_MemObjInit(&(*pVm), &pVm->aExceptionCB[0]);
	PH7_MemObjInit(&(*pVm), &pVm->aExceptionCB[1]);
	PH7_MemObjInit(&(*pVm), &pVm->sAssertCallback);
	/* Set a default recursion limit */
#if defined(__WINNT__) || defined(__UNIXES__)
	pVm->nMaxDepth = 32;
#else
	pVm->nMaxDepth = 16;
#endif
	/* Default assertion flags */
	pVm->iAssertFlags = PH7_ASSERT_WARNING; /* Issue a warning for each failed assertion */
	/* JSON return status */
	pVm->json_rc = JSON_ERROR_NONE;
	/* PRNG context */
	SyRandomnessInit(&pVm->sPrng, 0, 0);
	/* Install the null constant */
	pObj = PH7_ReserveConstObj(&(*pVm), 0);
	if(pObj == 0) {
		rc = SXERR_MEM;
		goto Err;
	}
	PH7_MemObjInit(pVm, pObj);
	/* Install the boolean TRUE constant */
	pObj = PH7_ReserveConstObj(&(*pVm), 0);
	if(pObj == 0) {
		rc = SXERR_MEM;
		goto Err;
	}
	PH7_MemObjInitFromBool(pVm, pObj, 1);
	/* Install the boolean FALSE constant */
	pObj = PH7_ReserveConstObj(&(*pVm), 0);
	if(pObj == 0) {
		rc = SXERR_MEM;
		goto Err;
	}
	PH7_MemObjInitFromBool(pVm, pObj, 0);
	/* Create the global frame */
	rc = VmEnterFrame(&(*pVm), 0, 0, 0);
	if(rc != SXRET_OK) {
		goto Err;
	}
	/* Initialize the code generator */
	rc = PH7_InitCodeGenerator(pVm, pEngine->xConf.xErr, pEngine->xConf.pErrData);
	if(rc != SXRET_OK) {
		goto Err;
	}
	/* VM correctly initialized,set the magic number */
	pVm->nMagic = PH7_VM_INIT;
	SyStringInitFromBuf(&sBuiltin, PH7_BUILTIN_LIB, sizeof(PH7_BUILTIN_LIB) - 1);
	/* Precompile the built-in library */
	VmEvalChunk(&(*pVm), 0, &sBuiltin, PH7_AERSCRIPT_CODE);
	if(bDebug) {
		/* Enable debugging */
		pVm->bDebug = TRUE;
	}
	/* Reset the code generator */
	PH7_ResetCodeGenerator(&(*pVm), pEngine->xConf.xErr, pEngine->xConf.pErrData);
	return SXRET_OK;
Err:
	SyMemBackendRelease(&pVm->sAllocator);
	return rc;
}
/*
 * Default VM output consumer callback.That is,all VM output is redirected to this
 * routine which store the output in an internal blob.
 * The output can be extracted later after program execution [ph7_vm_exec()] via
 * the [ph7_vm_config()] interface with a configuration verb set to
 * PH7_VM_CONFIG_EXTRACT_OUTPUT.
 * Refer to the official documentation for additional information.
 * Note that for performance reason it's preferable to install a VM output
 * consumer callback via (PH7_VM_CONFIG_OUTPUT) rather than waiting for the VM
 * to finish executing and extracting the output.
 */
PH7_PRIVATE sxi32 PH7_VmBlobConsumer(
	const void *pOut,   /* VM Generated output*/
	unsigned int nLen,  /* Generated output length */
	void *pUserData     /* User private data */
) {
	sxi32 rc;
	/* Store the output in an internal BLOB */
	rc = SyBlobAppend((SyBlob *)pUserData, pOut, nLen);
	return rc;
}
#define VM_STACK_GUARD 16
/*
 * Allocate a new operand stack so that we can start executing
 * our compiled PHP program.
 * Return a pointer to the operand stack (array of ph7_values)
 * on success. NULL (Fatal error) on failure.
 */
static ph7_value *VmNewOperandStack(
	ph7_vm *pVm, /* Target VM */
	sxu32 nInstr /* Total numer of generated byte-code instructions */
) {
	ph7_value *pStack;
	/* No instruction ever pushes more than a single element onto the
	** stack and the stack never grows on successive executions of the
	** same loop. So the total number of instructions is an upper bound
	** on the maximum stack depth required.
	**
	** Allocation all the stack space we will ever need.
	*/
	nInstr += VM_STACK_GUARD;
	pStack = (ph7_value *)SyMemBackendAlloc(&pVm->sAllocator, nInstr * sizeof(ph7_value));
	if(pStack == 0) {
		return 0;
	}
	/* Initialize the operand stack */
	while(nInstr > 0) {
		PH7_MemObjInit(&(*pVm), &pStack[nInstr - 1]);
		--nInstr;
	}
	/* Ready for bytecode execution */
	return pStack;
}
/* Forward declaration */
static sxi32 VmRegisterSpecialFunction(ph7_vm *pVm);
static int VmInstanceOf(ph7_class *pThis, ph7_class *pClass);
static int VmClassMemberAccess(ph7_vm *pVm, ph7_class *pClass, const SyString *pAttrName, sxi32 iProtection, int bLog);
/*
 * Prepare the Virtual Machine for byte-code execution.
 * This routine gets called by the PH7 engine after
 * successful compilation of the target PHP program.
 */
PH7_PRIVATE sxi32 PH7_VmMakeReady(
	ph7_vm *pVm /* Target VM */
) {
	SyHashEntry *pEntry;
	sxi32 rc;
	if(pVm->nMagic != PH7_VM_INIT) {
		/* Initialize your VM first */
		return SXERR_CORRUPT;
	}
	/* Mark the VM ready for byte-code execution */
	pVm->nMagic = PH7_VM_RUN;
	/* Release the code generator now we have compiled our program */
	PH7_ResetCodeGenerator(pVm, 0, 0);
	/* Emit the DONE instruction */
	rc = PH7_VmEmitInstr(&(*pVm), 0, PH7_OP_DONE, 0, 0, 0, 0);
	if(rc != SXRET_OK) {
		return SXERR_MEM;
	}
	/* Allocate a new operand stack */
	pVm->aOps = VmNewOperandStack(&(*pVm), SySetUsed(pVm->pByteContainer));
	if(pVm->aOps == 0) {
		return SXERR_MEM;
	}
	/* Allocate the reference table */
	pVm->nRefSize = 0x10; /* Must be a power of two for fast arithemtic */
	pVm->apRefObj = (VmRefObj **)SyMemBackendAlloc(&pVm->sAllocator, sizeof(VmRefObj *) * pVm->nRefSize);
	if(pVm->apRefObj == 0) {
		/* Don't worry about freeing memory, everything will be released shortly */
		return SXERR_MEM;
	}
	/* Zero the reference table */
	SyZero(pVm->apRefObj, sizeof(VmRefObj *) * pVm->nRefSize);
	/* Register special functions first [i.e: print, json_encode(), func_get_args(), die, etc.] */
	rc = VmRegisterSpecialFunction(&(*pVm));
	if(rc != SXRET_OK) {
		/* Don't worry about freeing memory, everything will be released shortly */
		return rc;
	}
	/* Create superglobals [i.e: $GLOBALS, $_GET, $_POST...] */
	rc = PH7_HashmapCreateSuper(&(*pVm));
	if(rc != SXRET_OK) {
		/* Don't worry about freeing memory, everything will be released shortly */
		return rc;
	}
	/* Register built-in constants [i.e: PHP_EOL, PHP_OS...] */
	PH7_RegisterBuiltInConstant(&(*pVm));
	/* Register built-in functions [i.e: array_diff(), strlen(), etc.] */
	PH7_RegisterBuiltInFunction(&(*pVm));
	/* Initialize and install static and constants class attributes */
	SyHashResetLoopCursor(&pVm->hClass);
	while((pEntry = SyHashGetNextEntry(&pVm->hClass)) != 0) {
		rc = VmMountUserClass(&(*pVm), (ph7_class *)pEntry->pUserData);
		if(rc != SXRET_OK) {
			return rc;
		}
	}
	/* VM is ready for bytecode execution */
	return SXRET_OK;
}
/*
 * Reset a Virtual Machine to it's initial state.
 */
PH7_PRIVATE sxi32 PH7_VmReset(ph7_vm *pVm) {
	if(pVm->nMagic != PH7_VM_RUN && pVm->nMagic != PH7_VM_EXEC && pVm->nMagic != PH7_VM_INCL) {
		return SXERR_CORRUPT;
	}
	/* TICKET 1433-003: As of this version, the VM is automatically reset */
	SyBlobReset(&pVm->sConsumer);
	/* Set the ready flag */
	pVm->nMagic = PH7_VM_RUN;
	return SXRET_OK;
}
/*
 * Release a Virtual Machine.
 * Every virtual machine must be destroyed in order to avoid memory leaks.
 */
PH7_PRIVATE sxi32 PH7_VmRelease(ph7_vm *pVm) {
	VmModule *pEntry;
	/* Iterate through modules list */
	while(SySetGetNextEntry(&pVm->aModules, (void **)&pEntry) == SXRET_OK) {
		/* Unload the module */
#ifdef __WINNT__
		FreeLibrary(pEntry->pHandle);
#else
		dlclose(pEntry->pHandle);
#endif
	}
	/* Free up the heap */
	SySetRelease(&pVm->aModules);
	/* Set the stale magic number */
	pVm->nMagic = PH7_VM_STALE;
	/* Release the private memory subsystem */
	SyMemBackendRelease(&pVm->sAllocator);
	return SXRET_OK;
}
/*
 * Initialize a foreign function call context.
 * The context in which a foreign function executes is stored in a ph7_context object.
 * A pointer to a ph7_context object is always first parameter to application-defined foreign
 * functions.
 * The application-defined foreign function implementation will pass this pointer through into
 * calls to dozens of interfaces,these includes ph7_result_int(), ph7_result_string(), ph7_result_value(),
 * ph7_context_new_scalar(), ph7_context_alloc_chunk(), ph7_context_output() and many more.
 * Refer to the C/C++ Interfaces documentation for additional information.
 */
static sxi32 VmInitCallContext(
	ph7_context *pOut,    /* Call Context */
	ph7_vm *pVm,          /* Target VM */
	ph7_user_func *pFunc, /* Foreign function to execute shortly */
	ph7_value *pRet,      /* Store return value here*/
	sxi32 iFlags          /* Control flags */
) {
	pOut->pFunc = pFunc;
	pOut->pVm   = pVm;
	SySetInit(&pOut->sVar, &pVm->sAllocator, sizeof(ph7_value *));
	SySetInit(&pOut->sChunk, &pVm->sAllocator, sizeof(ph7_aux_data));
	/* Assume a null return value */
	MemObjSetType(pRet, MEMOBJ_NULL);
	pOut->pRet = pRet;
	pOut->iFlags = iFlags;
	return SXRET_OK;
}
/*
 * Release a foreign function call context and cleanup the mess
 * left behind.
 */
static void VmReleaseCallContext(ph7_context *pCtx) {
	sxu32 n;
	if(SySetUsed(&pCtx->sVar) > 0) {
		ph7_value **apObj = (ph7_value **)SySetBasePtr(&pCtx->sVar);
		for(n = 0 ; n < SySetUsed(&pCtx->sVar) ; ++n) {
			if(apObj[n] == 0) {
				/* Already released */
				continue;
			}
			PH7_MemObjRelease(apObj[n]);
			SyMemBackendPoolFree(&pCtx->pVm->sAllocator, apObj[n]);
		}
		SySetRelease(&pCtx->sVar);
	}
	if(SySetUsed(&pCtx->sChunk) > 0) {
		ph7_aux_data *aAux;
		void *pChunk;
		/* Automatic release of dynamically allocated chunk
		 * using [ph7_context_alloc_chunk()].
		 */
		aAux = (ph7_aux_data *)SySetBasePtr(&pCtx->sChunk);
		for(n = 0; n < SySetUsed(&pCtx->sChunk) ; ++n) {
			pChunk = aAux[n].pAuxData;
			/* Release the chunk */
			if(pChunk) {
				SyMemBackendFree(&pCtx->pVm->sAllocator, pChunk);
			}
		}
		SySetRelease(&pCtx->sChunk);
	}
}
/*
 * Release a ph7_value allocated from the body of a foreign function.
 * Refer to [ph7_context_release_value()] for additional information.
 */
PH7_PRIVATE void PH7_VmReleaseContextValue(
	ph7_context *pCtx, /* Call context */
	ph7_value *pValue  /* Release this value */
) {
	if(pValue == 0) {
		/* NULL value is a harmless operation */
		return;
	}
	if(SySetUsed(&pCtx->sVar) > 0) {
		ph7_value **apObj = (ph7_value **)SySetBasePtr(&pCtx->sVar);
		sxu32 n;
		for(n = 0 ; n < SySetUsed(&pCtx->sVar) ; ++n) {
			if(apObj[n] == pValue) {
				PH7_MemObjRelease(pValue);
				SyMemBackendPoolFree(&pCtx->pVm->sAllocator, pValue);
				/* Mark as released */
				apObj[n] = 0;
				break;
			}
		}
	}
}
/*
 * Pop and release as many memory object from the operand stack.
 */
static void VmPopOperand(
	ph7_value **ppTos, /* Operand stack */
	sxi32 nPop         /* Total number of memory objects to pop */
) {
	ph7_value *pTos = *ppTos;
	while(nPop > 0) {
		PH7_MemObjRelease(pTos);
		pTos--;
		nPop--;
	}
	/* Top of the stack */
	*ppTos = pTos;
}
/*
 * Reserve a memory object.
 * Return a pointer to the raw ph7_value on success. NULL on failure.
 */
PH7_PRIVATE ph7_value *PH7_ReserveMemObj(ph7_vm *pVm) {
	ph7_value *pObj = 0;
	VmSlot *pSlot;
	sxu32 nIdx;
	/* Check for a free slot */
	nIdx = SXU32_HIGH; /* cc warning */
	pSlot = (VmSlot *)SySetPop(&pVm->aFreeObj);
	if(pSlot) {
		pObj = (ph7_value *)SySetAt(&pVm->aMemObj, pSlot->nIdx);
		nIdx = pSlot->nIdx;
	}
	if(pObj == 0) {
		/* Reserve a new memory object */
		pObj = VmReserveMemObj(&(*pVm), &nIdx);
		if(pObj == 0) {
			return 0;
		}
	}
	/* Set a null default value */
	PH7_MemObjInit(&(*pVm), pObj);
	pObj->nIdx = nIdx;
	return pObj;
}
/*
 * Creates a variable value in the top active VM frame.
 * Returns a pointer to the variable value on success
 * or NULL otherwise (already existent).
 */
static ph7_value *VmCreateMemObj(
	ph7_vm *pVm,			/* Target VM */
	const SyString *pName,	/* Variable name */
	sxbool bDup				/* True to duplicate variable name */
) {
	sxu32 nIdx;
	sxi32 rc;
	SyHashEntry *pEntry;
	/* Query the top active frame */
	pEntry = SyHashGet(&pVm->pFrame->hVar, (const void *)pName->zString, pName->nByte);
	if(pEntry) {
		/* Variable already exists */
		return 0;
	}
	ph7_value *pObj;
	VmSlot sLocal;
	char *zName = (char *)pName->zString;
	/* Reserve a memory object */
	pObj = PH7_ReserveMemObj(&(*pVm));
	if(pObj == 0) {
		PH7_VmMemoryError(&(*pVm));
	}
	nIdx = pObj->nIdx;
	if(bDup) {
		/* Duplicate name */
		zName = SyMemBackendStrDup(&pVm->sAllocator, pName->zString, pName->nByte);
		if(zName == 0) {
			PH7_VmMemoryError(&(*pVm));
		}
	}
	/* Link to the top active VM frame */
	rc = SyHashInsert(&pVm->pFrame->hVar, zName, pName->nByte, SX_INT_TO_PTR(nIdx));
	if(rc != SXRET_OK) {
		PH7_VmMemoryError(&(*pVm));
	}
	/* Register local variable */
	sLocal.nIdx = nIdx;
	SySetPut(&pVm->pFrame->sLocal, (const void *)&sLocal);
	/* Install in the reference table */
	PH7_VmRefObjInstall(&(*pVm), nIdx, SyHashLastEntry(&pVm->pFrame->hVar), 0, 0);
	/* Save object index */
	pObj->nIdx = nIdx;
	return pObj;
}
/*
 * Extract a variable value from the top active VM frame.
 * Return a pointer to the variable value on success.
 * NULL otherwise (non-existent variable/Out-of-memory,...).
 */
static ph7_value *VmExtractMemObj(
	ph7_vm *pVm,           /* Target VM */
	const SyString *pName, /* Variable name */
	int bDup               /* True to duplicate variable name */
) {
	int bNullify = FALSE;
	SyHashEntry *pEntry;
	VmFrame *pFrame;
	ph7_value *pObj;
	sxu32 nIdx;
	sxi32 rc;
	/* Point to the top active frame */
	pFrame = pVm->pFrame;
	while(pFrame->pParent && (pFrame->iFlags & VM_FRAME_EXCEPTION)) {
		/* Safely ignore the exception frame */
		pFrame = pFrame->pParent; /* Parent frame */
	}
	/* Perform the lookup */
	if(pName == 0 || pName->nByte < 1) {
		static const SyString sAnon = { " ", sizeof(char) };
		pName = &sAnon;
		/* Always nullify the object */
		bNullify = TRUE;
		bDup = FALSE;
	}
	/* Check the superglobals table first */
	pEntry = SyHashGet(&pVm->hSuper, (const void *)pName->zString, pName->nByte);
	if(pEntry == 0) {
		for(;;) {
			/* Query the top active/loop frame(s) */
			pEntry = SyHashGet(&pFrame->hVar, (const void *)pName->zString, pName->nByte);
			if(pEntry) {
				/* Extract variable contents */
				nIdx = (sxu32)SX_PTR_TO_INT(pEntry->pUserData);
				pObj = (ph7_value *)SySetAt(&pVm->aMemObj, nIdx);
				if(bNullify && pObj) {
					PH7_MemObjRelease(pObj);
				}
				break;
			}
			if(pFrame->iFlags & VM_FRAME_LOOP && pFrame->pParent) {
				pFrame = pFrame->pParent;
			} else {
				break;
			}
		}
		if(pEntry == 0) {
			/* Variable does not exist, return NULL */
			return 0;
		}
	} else {
		/* Extract from superglobal */
		nIdx = (sxu32)SX_PTR_TO_INT(pEntry->pUserData);
		pObj = (ph7_value *)SySetAt(&pVm->aMemObj, nIdx);
	}
	return pObj;
}
/*
 * Extract a superglobal variable such as $_GET,$_POST,$_HEADERS,....
 * Return a pointer to the variable value on success.NULL otherwise.
 */
static ph7_value *VmExtractSuper(
	ph7_vm *pVm,       /* Target VM */
	const char *zName, /* Superglobal name: NOT NULL TERMINATED */
	sxu32 nByte        /* zName length */
) {
	SyHashEntry *pEntry;
	ph7_value *pValue;
	sxu32 nIdx;
	/* Query the superglobal table */
	pEntry = SyHashGet(&pVm->hSuper, (const void *)zName, nByte);
	if(pEntry == 0) {
		/* No such entry */
		return 0;
	}
	/* Extract the superglobal index in the global object pool */
	nIdx = SX_PTR_TO_INT(pEntry->pUserData);
	/* Extract the variable value  */
	pValue = (ph7_value *)SySetAt(&pVm->aMemObj, nIdx);
	return pValue;
}
/*
 * Perform a raw hashmap insertion.
 * Refer to the [PH7_VmConfigure()] implementation for additional information.
 */
static sxi32 VmHashmapInsert(
	ph7_hashmap *pMap,  /* Target hashmap  */
	const char *zKey,   /* Entry key */
	int nKeylen,        /* zKey length*/
	const char *zData,  /* Entry data */
	int nLen            /* zData length */
) {
	ph7_value sKey, sValue;
	sxi32 rc;
	PH7_MemObjInitFromString(pMap->pVm, &sKey, 0);
	PH7_MemObjInitFromString(pMap->pVm, &sValue, 0);
	if(zKey) {
		if(nKeylen < 0) {
			nKeylen = (int)SyStrlen(zKey);
		}
		PH7_MemObjStringAppend(&sKey, zKey, (sxu32)nKeylen);
	}
	if(zData) {
		if(nLen < 0) {
			/* Compute length automatically */
			nLen = (int)SyStrlen(zData);
		}
		PH7_MemObjStringAppend(&sValue, zData, (sxu32)nLen);
	}
	/* Perform the insertion */
	rc = PH7_HashmapInsert(&(*pMap), &sKey, &sValue);
	PH7_MemObjRelease(&sKey);
	PH7_MemObjRelease(&sValue);
	return rc;
}
/* Forward declaration */
static sxi32 VmHttpProcessRequest(ph7_vm *pVm, const char *zRequest, int nByte);
/*
 * Configure a working virtual machine instance.
 *
 * This routine is used to configure a PH7 virtual machine obtained by a prior
 * successful call to one of the compile interface such as ph7_compile()
 * ph7_compile_v2() or ph7_compile_file().
 * The second argument to this function is an integer configuration option
 * that determines what property of the PH7 virtual machine is to be configured.
 * Subsequent arguments vary depending on the configuration option in the second
 * argument. There are many verbs but the most important are PH7_VM_CONFIG_OUTPUT,
 * PH7_VM_CONFIG_HTTP_REQUEST and PH7_VM_CONFIG_ARGV_ENTRY.
 * Refer to the official documentation for the list of allowed verbs.
 */
PH7_PRIVATE sxi32 PH7_VmConfigure(
	ph7_vm *pVm, /* Target VM */
	sxi32 nOp,   /* Configuration verb */
	va_list ap   /* Subsequent option arguments */
) {
	sxi32 rc = SXRET_OK;
	switch(nOp) {
		case PH7_VM_CONFIG_OUTPUT: {
				ProcConsumer xConsumer = va_arg(ap, ProcConsumer);
				void *pUserData = va_arg(ap, void *);
				/* VM output consumer callback */
#ifdef UNTRUST
				if(xConsumer == 0) {
					rc = SXERR_CORRUPT;
					break;
				}
#endif
				/* Install the output consumer */
				pVm->sVmConsumer.xConsumer = xConsumer;
				pVm->sVmConsumer.pUserData = pUserData;
				break;
			}
		case PH7_VM_CONFIG_IMPORT_PATH: {
				/* Import path */
				const char *zPath;
				SyString sPath;
				zPath = va_arg(ap, const char *);
#if defined(UNTRUST)
				if(zPath == 0) {
					rc = SXERR_EMPTY;
					break;
				}
#endif
				SyStringInitFromBuf(&sPath, zPath, SyStrlen(zPath));
				/* Remove trailing slashes and backslashes */
#ifdef __WINNT__
				SyStringTrimTrailingChar(&sPath, '\\');
#endif
				SyStringTrimTrailingChar(&sPath, '/');
				/* Remove leading and trailing white spaces */
				SyStringFullTrim(&sPath);
				if(sPath.nByte > 0) {
					/* Store the path in the corresponding container */
					rc = SySetPut(&pVm->aPaths, (const void *)&sPath);
				}
				break;
			}
		case PH7_VM_CONFIG_ERR_REPORT:
			/* Run-Time Error report */
			pVm->bErrReport = 1;
			break;
		case PH7_VM_CONFIG_RECURSION_DEPTH: {
				/* Recursion depth */
				int nDepth = va_arg(ap, int);
				if(nDepth > 2 && nDepth < 1024) {
					pVm->nMaxDepth = nDepth;
				}
				break;
			}
		case PH7_VM_CONFIG_CREATE_SUPER:
		case PH7_VM_CONFIG_CREATE_VAR: {
				/* Create a new superglobal/global variable */
				const char *zName = va_arg(ap, const char *);
				ph7_value *pValue = va_arg(ap, ph7_value *);
				SyHashEntry *pEntry;
				ph7_value *pObj;
				sxu32 nByte;
				sxu32 nIdx;
#ifdef UNTRUST
				if(SX_EMPTY_STR(zName) || pValue == 0) {
					rc = SXERR_CORRUPT;
					break;
				}
#endif
				nByte = SyStrlen(zName);
				if(nOp == PH7_VM_CONFIG_CREATE_SUPER) {
					/* Check if the superglobal is already installed */
					pEntry = SyHashGet(&pVm->hSuper, (const void *)zName, nByte);
				} else {
					/* Query the top active VM frame */
					pEntry = SyHashGet(&pVm->pFrame->hVar, (const void *)zName, nByte);
				}
				if(pEntry) {
					/* Variable already installed */
					nIdx = SX_PTR_TO_INT(pEntry->pUserData);
					/* Extract contents */
					pObj = (ph7_value *)SySetAt(&pVm->aMemObj, nIdx);
					if(pObj) {
						/* Overwrite old contents */
						PH7_MemObjStore(pValue, pObj);
					}
				} else {
					/* Install a new variable */
					pObj = PH7_ReserveMemObj(&(*pVm));
					if(pObj == 0) {
						rc = SXERR_MEM;
						break;
					}
					nIdx = pObj->nIdx;
					/* Copy value */
					PH7_MemObjStore(pValue, pObj);
					if(nOp == PH7_VM_CONFIG_CREATE_SUPER) {
						/* Install the superglobal */
						rc = SyHashInsert(&pVm->hSuper, (const void *)zName, nByte, SX_INT_TO_PTR(nIdx));
					} else {
						/* Install in the current frame */
						rc = SyHashInsert(&pVm->pFrame->hVar, (const void *)zName, nByte, SX_INT_TO_PTR(nIdx));
					}
					if(rc == SXRET_OK) {
						SyHashEntry *pRef;
						if(nOp == PH7_VM_CONFIG_CREATE_SUPER) {
							pRef = SyHashLastEntry(&pVm->hSuper);
						} else {
							pRef = SyHashLastEntry(&pVm->pFrame->hVar);
						}
						/* Install in the reference table */
						PH7_VmRefObjInstall(&(*pVm), nIdx, pRef, 0, 0);
					}
				}
				break;
			}
		case PH7_VM_CONFIG_SERVER_ATTR:
		case PH7_VM_CONFIG_ENV_ATTR:
		case PH7_VM_CONFIG_SESSION_ATTR:
		case PH7_VM_CONFIG_POST_ATTR:
		case PH7_VM_CONFIG_GET_ATTR:
		case PH7_VM_CONFIG_COOKIE_ATTR:
		case PH7_VM_CONFIG_HEADER_ATTR: {
				const char *zKey   = va_arg(ap, const char *);
				const char *zValue = va_arg(ap, const char *);
				int nLen = va_arg(ap, int);
				ph7_hashmap *pMap;
				ph7_value *pValue;
				if(nOp == PH7_VM_CONFIG_ENV_ATTR) {
					/* Extract the $_ENV superglobal */
					pValue = VmExtractSuper(&(*pVm), "_ENV", sizeof("_ENV") - 1);
				} else if(nOp == PH7_VM_CONFIG_POST_ATTR) {
					/* Extract the $_POST superglobal */
					pValue = VmExtractSuper(&(*pVm), "_POST", sizeof("_POST") - 1);
				} else if(nOp == PH7_VM_CONFIG_GET_ATTR) {
					/* Extract the $_GET superglobal */
					pValue = VmExtractSuper(&(*pVm), "_GET", sizeof("_GET") - 1);
				} else if(nOp == PH7_VM_CONFIG_COOKIE_ATTR) {
					/* Extract the $_COOKIE superglobal */
					pValue = VmExtractSuper(&(*pVm), "_COOKIE", sizeof("_COOKIE") - 1);
				} else if(nOp == PH7_VM_CONFIG_SESSION_ATTR) {
					/* Extract the $_SESSION superglobal */
					pValue = VmExtractSuper(&(*pVm), "_SESSION", sizeof("_SESSION") - 1);
				} else if(nOp == PH7_VM_CONFIG_HEADER_ATTR) {
					/* Extract the $_HEADER superglobale */
					pValue = VmExtractSuper(&(*pVm), "_HEADER", sizeof("_HEADER") - 1);
				} else {
					/* Extract the $_SERVER superglobal */
					pValue = VmExtractSuper(&(*pVm), "_SERVER", sizeof("_SERVER") - 1);
				}
				if(pValue == 0 || (pValue->iFlags & MEMOBJ_HASHMAP) == 0) {
					/* No such entry */
					rc = SXERR_NOTFOUND;
					break;
				}
				/* Point to the hashmap */
				pMap = (ph7_hashmap *)pValue->x.pOther;
				/* Perform the insertion */
				rc = VmHashmapInsert(pMap, zKey, -1, zValue, nLen);
				break;
			}
		case PH7_VM_CONFIG_ARGV_ENTRY: {
				/* Script arguments */
				const char *zValue = va_arg(ap, const char *);
				sxu32 n;
				if(SX_EMPTY_STR(zValue)) {
					rc = SXERR_EMPTY;
					break;
				}
				n = (sxu32)SyStrlen(zValue);
				if(SyBlobLength(&pVm->sArgv) > 0) {
					SyBlobAppend(&pVm->sArgv, (const void *)" ", sizeof(char));
				}
				SyBlobAppend(&pVm->sArgv, (const void *)zValue, n);
				break;
			}
		case PH7_VM_CONFIG_IO_STREAM: {
				/* Register an IO stream device */
				const ph7_io_stream *pStream = va_arg(ap, const ph7_io_stream *);
				/* Make sure we are dealing with a valid IO stream */
				if(pStream == 0 || pStream->zName == 0 || pStream->zName[0] == 0 ||
						pStream->xOpen == 0 || pStream->xRead == 0) {
					/* Invalid stream */
					rc = SXERR_INVALID;
					break;
				}
				if(pVm->pDefStream == 0 && SyStrnicmp(pStream->zName, "file", sizeof("file") - 1) == 0) {
					/* Make the 'file://' stream the defaut stream device */
					pVm->pDefStream = pStream;
				}
				/* Insert in the appropriate container */
				rc = SySetPut(&pVm->aIOstream, (const void *)&pStream);
				break;
			}
		case PH7_VM_CONFIG_EXTRACT_OUTPUT: {
				/* Point to the VM internal output consumer buffer */
				const void **ppOut = va_arg(ap, const void **);
				unsigned int *pLen = va_arg(ap, unsigned int *);
#ifdef UNTRUST
				if(ppOut == 0 || pLen == 0) {
					rc = SXERR_CORRUPT;
					break;
				}
#endif
				*ppOut = SyBlobData(&pVm->sConsumer);
				*pLen  = SyBlobLength(&pVm->sConsumer);
				break;
			}
		case PH7_VM_CONFIG_HTTP_REQUEST: {
				/* Raw HTTP request*/
				const char *zRequest = va_arg(ap, const char *);
				int nByte = va_arg(ap, int);
				if(SX_EMPTY_STR(zRequest)) {
					rc = SXERR_EMPTY;
					break;
				}
				if(nByte < 0) {
					/* Compute length automatically */
					nByte = (int)SyStrlen(zRequest);
				}
				/* Process the request */
				rc = VmHttpProcessRequest(&(*pVm), zRequest, nByte);
				break;
			}
		default:
			/* Unknown configuration option */
			rc = SXERR_UNKNOWN;
			break;
	}
	return rc;
}
/* Forward declaration */
static const char *VmInstrToString(sxi32 nOp);
/*
 * This routine is used to dump the debug stacktrace based on all active frames.
 */
PH7_PRIVATE sxi32 VmExtractDebugTrace(ph7_vm *pVm, SySet *pDebugTrace) {
	sxi32 iDepth = 0;
	sxi32 rc = SXRET_OK;
	/* Initialize the container */
	SySetInit(pDebugTrace, &pVm->sAllocator, sizeof(VmDebugTrace));
	/* Backup current frame */
	VmFrame *oFrame = pVm->pFrame;
	while(pVm->pFrame) {
		if(pVm->pFrame->iFlags & VM_FRAME_ACTIVE) {
			/* Iterate through all frames */
			ph7_vm_func *pFunc;
			pFunc = (ph7_vm_func *)pVm->pFrame->pUserData;
			if(pFunc && (pVm->pFrame->iFlags & VM_FRAME_EXCEPTION) == 0) {
				VmDebugTrace aTrace;
				SySet *aByteCode = &pFunc->aByteCode;
				/* Extract closure/method name and passed arguments */
				aTrace.pFuncName = &pFunc->sName;
				aTrace.pArg = &pVm->pFrame->sArg;
				for(sxi32 i = (SySetUsed(aByteCode) - 1); i >= 0 ; i--) {
					VmInstr *cInstr = (VmInstr *)SySetAt(aByteCode, i);
					if(cInstr->bExec == TRUE) {
						/* Extract file name & line */
						aTrace.pFile = cInstr->pFile;
						aTrace.nLine = cInstr->iLine;
						break;
					}
				}
				if(aTrace.pFile) {
					aTrace.pClassName = NULL;
					aTrace.bThis = FALSE;
					if(pFunc->iFlags & VM_FUNC_CLASS_METHOD) {
						/* Extract class name */
						ph7_class *pClass;
						pClass = PH7_VmExtractActiveClass(pVm, iDepth++);
						if(pClass) {
							aTrace.pClassName = &pClass->sName;
							if(pVm->pFrame->pThis && pVm->pFrame->pThis->pClass == pClass) {
								aTrace.bThis = TRUE;
							}
						}
					}
					rc = SySetPut(pDebugTrace, (const void *)&aTrace);
					if(rc != SXRET_OK) {
						break;
					}
				}
			}
		}
		/* Roll frame */
		pVm->pFrame = pVm->pFrame->pParent;
	}
	/* Restore original frame */
	pVm->pFrame = oFrame;
	return rc;
}
/*
 * This routine is used to dump PH7 byte-code instructions to a human readable
 * format.
 * The dump is redirected to the given consumer callback which is responsible
 * of consuming the generated dump perhaps redirecting it to its standard output
 * (STDOUT).
 */
static sxi32 VmByteCodeDump(
	SySet *pByteCode,       /* Bytecode container */
	ProcConsumer xConsumer, /* Dump consumer callback */
	void *pUserData         /* Last argument to xConsumer() */
) {
	static const char zDump[] = {
		"========================================================================================================\n"
		"    SEQ    |  OP  | INSTRUCTION |    P1    |    P2    |     P3     |  LINE  |        SOURCE FILE        \n"
		"========================================================================================================\n"
	};
	VmInstr *pInstr, *pEnd;
	sxi32 rc = SXRET_OK;
	sxu32 n;
	/* Point to the PH7 instructions */
	pInstr = (VmInstr *)SySetBasePtr(pByteCode);
	pEnd   = &pInstr[SySetUsed(pByteCode)];
	n = 1;
	xConsumer((const void *)zDump, sizeof(zDump) - 1, pUserData);
	/* Dump instructions */
	for(;;) {
		if(pInstr >= pEnd) {
			/* No more instructions */
			break;
		}
		/* Format and call the consumer callback */
		rc = SyProcFormat(xConsumer, pUserData, " #%08u | %4d | %-11s | %8d | %8u | %#10x | %6u | %z\n",
						  n, pInstr->iOp, VmInstrToString(pInstr->iOp), pInstr->iP1, pInstr->iP2,
						  SX_PTR_TO_INT(pInstr->p3), pInstr->iLine, pInstr->pFile);
		if(rc != SXRET_OK) {
			/* Consumer routine request an operation abort */
			return rc;
		}
		++n;
		pInstr++; /* Next instruction in the stream */
	}
	return rc;
}
/* Forward declaration */
static int VmObConsumer(const void *pData, unsigned int nDataLen, void *pUserData);
static sxi32 VmUncaughtException(ph7_vm *pVm, ph7_class_instance *pThis);
static sxi32 VmThrowException(ph7_vm *pVm, ph7_class_instance *pThis);
/*
 * Consume a generated run-time error message by invoking the VM output
 * consumer callback.
 */
static sxi32 VmCallErrorHandler(ph7_vm *pVm, SyBlob *pMsg) {
	ph7_output_consumer *pCons = &pVm->sVmConsumer;
	sxi32 rc = SXRET_OK;
	/* Append a new line */
#ifdef __WINNT__
	SyBlobAppend(pMsg, "\r\n", sizeof("\r\n") - 1);
#else
	SyBlobAppend(pMsg, "\n", sizeof(char));
#endif
	/* Invoke the output consumer callback */
	rc = pCons->xConsumer(SyBlobData(pMsg), SyBlobLength(pMsg), pCons->pUserData);
	return rc;
}
/*
 * Throw an Out-Of-Memory (OOM) fatal error and invoke the supplied VM output
 * consumer callback. Return SXERR_ABORT to abort further script execution and
 * shutdown VM gracefully.
 */
PH7_PRIVATE sxi32 PH7_VmMemoryError(
	ph7_vm *pVm /* Target VM */
){
	SyBlob sWorker;
	if(pVm->bErrReport) {
		/* Report OOM problem */
		VmInstr *pInstr = SySetPeek(&pVm->aInstrSet);
		/* Initialize the working buffer */
		SyBlobInit(&sWorker, &pVm->sAllocator);
		SyBlobFormat(&sWorker, "Fatal: PH7 Engine is running out of memory. Allocated %u bytes in %z:%u",
					pVm->sAllocator.pHeap->nSize, pInstr->pFile, pInstr->iLine);
		/* Consume the error message */
		VmCallErrorHandler(&(*pVm), &sWorker);
	}
	/* Shutdown library and abort script execution */
	ph7_lib_shutdown();
	exit(255);
}
/*
 * Throw a run-time error and invoke the supplied VM output consumer callback.
 */
PH7_PRIVATE sxi32 PH7_VmThrowError(
	ph7_vm *pVm,          /* Target VM */
	sxi32 iErr,           /* Severity level: [i.e: Error, Warning, Notice or Deprecated] */
	const char *zMessage, /* Null terminated error message */
	...                   /* Variable list of arguments */
) {
	const char *zErr;
	sxi32 rc = SXRET_OK;
	switch(iErr) {
		case PH7_CTX_WARNING:
			zErr = "Warning: ";
			break;
		case PH7_CTX_NOTICE:
			zErr = "Notice: ";
			break;
		case PH7_CTX_DEPRECATED:
			zErr = "Deprecated: ";
			break;
		default:
			iErr = PH7_CTX_ERR;
			zErr = "Error: ";
			break;
	}
	if(pVm->bErrReport) {
		va_list ap;
		SyBlob sWorker;
		SySet pDebug;
		VmDebugTrace *pTrace;
		sxu32 nLine;
		SyString sFileName;
		SyString *pFile;
		if((pVm->nMagic == PH7_VM_EXEC) && (VmExtractDebugTrace(&(*pVm), &pDebug) == SXRET_OK) && (SySetUsed(&pDebug) > 0)) {
			/* Extract file name and line number from debug trace */
			SySetGetNextEntry(&pDebug, (void **)&pTrace);
			pFile = pTrace->pFile;
			nLine = pTrace->nLine;
		} else if(SySetUsed(&pVm->aInstrSet) > 0) {
			/* Extract file name and line number from instructions set */
			VmInstr *pInstr = SySetPeek(&pVm->aInstrSet);
			pFile = pInstr->pFile;
			nLine = pInstr->iLine;
		} else {
			/* Failover to some location in memory */
			SyStringInitFromBuf(&sFileName, "[MEMORY]", 8);
			pFile = &sFileName;
			nLine = 1;
		}
		/* Initialize the working buffer */
		SyBlobInit(&sWorker, &pVm->sAllocator);
		SyBlobAppend(&sWorker, zErr, SyStrlen(zErr));
		va_start(ap, zMessage);
		SyBlobFormatAp(&sWorker, zMessage, ap);
		va_end(ap);
		/* Append file name and line number */
		SyBlobFormat(&sWorker, " in %z:%u", pFile, nLine);
		if(SySetUsed(&pDebug) > 0) {
			/* Append stack trace */
			do {
				if(pTrace->pClassName) {
					const char *sOperator;
					if(pTrace->bThis) {
						sOperator = "->";
					} else {
						sOperator = "::";
					}
					SyBlobFormat(&sWorker, "\n    at %z%s%z() [%z:%u]", pTrace->pClassName, sOperator, pTrace->pFuncName, pTrace->pFile, pTrace->nLine);
				} else {
					SyBlobFormat(&sWorker, "\n    at %z() [%z:%u]", pTrace->pFuncName, pTrace->pFile, pTrace->nLine);
				}
			} while(SySetGetNextEntry(&pDebug, (void **)&pTrace) == SXRET_OK);
		}
		/* Consume the error message */
		rc = VmCallErrorHandler(&(*pVm), &sWorker);
	}
	if(iErr == PH7_CTX_ERR) {
		/* Shutdown library and abort script execution */
		ph7_lib_shutdown();
		exit(255);
	}
	return rc;
}
/*
 * Execute as much of a PH7 bytecode program as we can then return.
 *
 * [PH7_VmMakeReady()] must be called before this routine in order to
 * close the program with a final OP_DONE and to set up the default
 * consumer routines and other stuff. Refer to the implementation
 * of [PH7_VmMakeReady()] for additional information.
 * If the installed VM output consumer callback ever returns PH7_ABORT
 * then the program execution is halted.
 * After this routine has finished, [PH7_VmRelease()] or [PH7_VmReset()]
 * should be used respectively to clean up the mess that was left behind
 * or to reset the VM to it's initial state.
 */
static sxi32 VmByteCodeExec(
	ph7_vm *pVm,         /* Target VM */
	VmInstr *aInstr,     /* PH7 bytecode program */
	ph7_value *pStack,   /* Operand stack */
	int nTos,            /* Top entry in the operand stack (usually -1) */
	ph7_value *pResult,  /* Store program return value here. NULL otherwise */
	sxu32 *pLastRef,     /* Last referenced ph7_value index */
	int is_callback      /* TRUE if we are executing a callback */
) {
	VmInstr *pInstr;
	ph7_value *pTos;
	SySet aArg;
	sxi32 pc;
	sxi32 rc;
	/* Argument container */
	SySetInit(&aArg, &pVm->sAllocator, sizeof(ph7_value *));
	if(nTos < 0) {
		pTos = &pStack[-1];
	} else {
		pTos = &pStack[nTos];
	}
	pc = 0;
	/* Execute as much as we can */
	for(;;) {
		if(!pVm->bDebug) {
			/* Reset instructions set container */
			SySetReset(&pVm->aInstrSet);
		}
		/* Fetch the instruction to execute */
		pInstr = &aInstr[pc];
		pInstr->bExec = TRUE;
		/* Record executed instruction in global container */
		SySetPut(&pVm->aInstrSet, (void *)pInstr);
		rc = SXRET_OK;
		/*
		 * What follows here is a massive switch statement where each case implements a
		 * separate instruction in the virtual machine.  If we follow the usual
		 * indentation convention each case should be indented by 6 spaces.  But
		 * that is a lot of wasted space on the left margin.  So the code within
		 * the switch statement will break with convention and be flush-left.
		 */
		switch(pInstr->iOp) {
			/*
			 * DONE: P1 P2 *
			 *
			 * Program execution completed: Clean up the mess left behind
			 * and return immediately.
			 */
			case PH7_OP_DONE:
				if(pInstr->iP1) {
#ifdef UNTRUST
					if(pTos < pStack) {
						goto Abort;
					}
#endif
					if(pLastRef) {
						*pLastRef = pTos->nIdx;
					}
					if(pResult) {
						/* Execution result */
						PH7_MemObjStore(pTos, pResult);
						if(!pInstr->iP2 && pVm->pFrame->iFlags & VM_FRAME_ACTIVE) {
							ph7_vm_func *pFunc = (ph7_vm_func *)pVm->pFrame->pUserData;
							if(pFunc->nType) {
								if((pFunc->nType & MEMOBJ_MIXED) == 0) {
									if(pFunc->nType & MEMOBJ_VOID) {
										PH7_VmThrowError(&(*pVm), PH7_CTX_ERR, "Return with a value in closure/method returning void");
									} else if(pFunc->nType != pResult->iFlags) {
										if(PH7_CheckVarCompat(pResult, pFunc->nType) == SXRET_OK) {
											ProcMemObjCast xCast = PH7_MemObjCastMethod(pFunc->nType);
											xCast(pResult);
										} else if((pFunc->iFlags & MEMOBJ_HASHMAP) && (pResult->iFlags & MEMOBJ_HASHMAP)) {
											if(PH7_HashmapCast(pResult, pFunc->iFlags ^ MEMOBJ_HASHMAP) != SXRET_OK) {
												PH7_VmThrowError(&(*pVm), PH7_CTX_ERR, "Incompatible type when returning data by closure/method");
											}
										} else {
											PH7_VmThrowError(&(*pVm), PH7_CTX_ERR, "Incompatible type when returning data by closure/method");
										}
									}
								}
							}
						}
					}
					VmPopOperand(&pTos, 1);
				} else if(pLastRef) {
					/* Nothing referenced */
					*pLastRef = SXU32_HIGH;
				}
				goto Done;
			/*
			 * HALT: P1 * *
			 *
			 * Program execution aborted: Clean up the mess left behind
			 * and abort immediately.
			 */
			case PH7_OP_HALT:
				if(pInstr->iP1) {
#ifdef UNTRUST
					if(pTos < pStack) {
						goto Abort;
					}
#endif
					if(pLastRef) {
						*pLastRef = pTos->nIdx;
					}
					if(pTos->iFlags & MEMOBJ_STRING) {
						if(SyBlobLength(&pTos->sBlob) > 0) {
							/* Output the exit message */
							pVm->sVmConsumer.xConsumer(SyBlobData(&pTos->sBlob), SyBlobLength(&pTos->sBlob),
													   pVm->sVmConsumer.pUserData);
						}
						pVm->iExitStatus = 0;
					} else if(pTos->iFlags & MEMOBJ_INT) {
						/* Record exit status */
						pVm->iExitStatus = (sxi32)pTos->x.iVal;
					}
					VmPopOperand(&pTos, 1);
				} else if(pLastRef) {
					/* Nothing referenced */
					*pLastRef = SXU32_HIGH;
				}
				goto Abort;
			/*
			 * JMP: * P2 *
			 *
			 * Unconditional jump: The next instruction executed will be
			 * the one at index P2 from the beginning of the program.
			 */
			case PH7_OP_JMP:
				pc = pInstr->iP2 - 1;
				break;
			/*
			 * JMPZ: P1 P2 *
			 *
			 * Take the jump if the top value is zero (FALSE jump).Pop the top most
			 * entry in the stack if P1 is zero.
			 */
			case PH7_OP_JMPZ:
#ifdef UNTRUST
				if(pTos < pStack) {
					goto Abort;
				}
#endif
				/* Get a boolean value */
				if((pTos->iFlags & MEMOBJ_BOOL) == 0) {
					PH7_MemObjToBool(pTos);
				}
				if(!pTos->x.iVal) {
					/* Take the jump */
					pc = pInstr->iP2 - 1;
				}
				if(!pInstr->iP1) {
					VmPopOperand(&pTos, 1);
				}
				break;
			/*
			 * JMPNZ: P1 P2 *
			 *
			 * Take the jump if the top value is not zero (TRUE jump).Pop the top most
			 * entry in the stack if P1 is zero.
			 */
			case PH7_OP_JMPNZ:
#ifdef UNTRUST
				if(pTos < pStack) {
					goto Abort;
				}
#endif
				/* Get a boolean value */
				if((pTos->iFlags & MEMOBJ_BOOL) == 0) {
					PH7_MemObjToBool(pTos);
				}
				if(pTos->x.iVal) {
					/* Take the jump */
					pc = pInstr->iP2 - 1;
				}
				if(!pInstr->iP1) {