sourcemod/public/sourcepawn/sp_vm_api.h

/**
 * vim: set ts=4 :
 * =============================================================================
 * SourcePawn
 * Copyright (C) 2004-2008 AlliedModders LLC.  All rights reserved.
 * =============================================================================
 *
 * This program is free software; you can redistribute it and/or modify it under
 * the terms of the GNU General Public License, version 3.0, as published by the
 * Free Software Foundation.
 * 
 * This program is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
 * FOR A PARTICULAR PURPOSE.  See the GNU General Public License for more
 * details.
 *
 * You should have received a copy of the GNU General Public License along with
 * this program.  If not, see <http://www.gnu.org/licenses/>.
 *
 * As a special exception, AlliedModders LLC gives you permission to link the
 * code of this program (as well as its derivative works) to "Half-Life 2," the
 * "Source Engine," the "SourcePawn JIT," and any Game MODs that run on software
 * by the Valve Corporation.  You must obey the GNU General Public License in
 * all respects for all other code used.  Additionally, AlliedModders LLC grants
 * this exception to all derivative works.  AlliedModders LLC defines further
 * exceptions, found in LICENSE.txt (as of this writing, version JULY-31-2007),
 * or <http://www.sourcemod.net/license.php>.
 *
 * Version: $Id$
 */

#ifndef _INCLUDE_SOURCEPAWN_VM_API_H_
#define _INCLUDE_SOURCEPAWN_VM_API_H_

/**
 * @file sp_vm_api.h
 * @brief Contains all of the object structures used in the SourcePawn API.
 */

#include <stdio.h>
#include "sp_vm_types.h"

/** SourcePawn Engine API Version */
#define SOURCEPAWN_ENGINE_API_VERSION	3

/** SourcePawn VM API Version */
#define SOURCEPAWN_VM_API_VERSION		6

#if !defined SOURCEMOD_BUILD
#define SOURCEMOD_BUILD
#endif

#if defined SOURCEMOD_BUILD
namespace SourceMod
{
	struct IdentityToken_t;
};
#endif

namespace SourcePawn
{
	class IVirtualMachine;

	/* Parameter flags */
	#define SM_PARAM_COPYBACK		(1<<0)		/**< Copy an array/reference back after call */

	/* String parameter flags (separate from parameter flags) */
	#define SM_PARAM_STRING_UTF8	(1<<0)		/**< String should be UTF-8 handled */
	#define SM_PARAM_STRING_COPY	(1<<1)		/**< String should be copied into the plugin */
	#define SM_PARAM_STRING_BINARY	(1<<2)		/**< String should be handled as binary data */

#if defined SOURCEMOD_BUILD
	/**
	 * @brief Pseudo-NULL reference types.
	 */
	enum SP_NULL_TYPE
	{
		SP_NULL_VECTOR = 0,		/**< Float[3] reference */
		SP_NULL_STRING = 1,		/**< const String[1] reference */
	};
#endif

	/**
	 * @brief Represents what a function needs to implement in order to be callable.
	 */
	class ICallable
	{
	public:
		/**
		 * @brief Pushes a cell onto the current call.
		 *
		 * @param cell		Parameter value to push.
		 * @return			Error code, if any.
		 */
		virtual int PushCell(cell_t cell) =0;

		/**
		 * @brief Pushes a cell by reference onto the current call.
		 * NOTE: On Execute, the pointer passed will be modified if copyback is enabled.
		 * NOTE: By reference parameters are cached and thus are not read until execution.
		 *		 This means you cannot push a pointer, change it, and push it again and expect
		 *       two different values to come out.
		 *
		 * @param cell		Address containing parameter value to push.
		 * @param flags		Copy-back flags.
		 * @return			Error code, if any.
		 */
		virtual int PushCellByRef(cell_t *cell, int flags=SM_PARAM_COPYBACK) =0;

		/**
		 * @brief Pushes a float onto the current call.
		 *
		 * @param number	Parameter value to push.
		 * @return			Error code, if any.
		 */
		virtual int PushFloat(float number) =0;

		/**
		 * @brief Pushes a float onto the current call by reference.
		 * NOTE: On Execute, the pointer passed will be modified if copyback is enabled.
		 * NOTE: By reference parameters are cached and thus are not read until execution.
		 *		 This means you cannot push a pointer, change it, and push it again and expect
		 *       two different values to come out.
		 *
		 * @param number	Parameter value to push.
		 & @param flags		Copy-back flags.
		 * @return			Error code, if any.
		 */
		virtual int PushFloatByRef(float *number, int flags=SM_PARAM_COPYBACK) =0;

		/**
		 * @brief Pushes an array of cells onto the current call. 
		 *
		 * On Execute, the pointer passed will be modified if non-NULL and copy-back
		 * is enabled.  
		 *
		 * By reference parameters are cached and thus are not read until execution.
		 * This means you cannot push a pointer, change it, and push it again and expect
		 * two different values to come out.
		 *
		 * @param inarray	Array to copy, NULL if no initial array should be copied.
		 * @param cells		Number of cells to allocate and optionally read from the input array.
		 * @param flags		Whether or not changes should be copied back to the input array.
		 * @return			Error code, if any.
		 */
		virtual int PushArray(cell_t *inarray, unsigned int cells, int flags=0) =0;

		/**
		 * @brief Pushes a string onto the current call.
		 *
		 * @param string	String to push.
		 * @return			Error code, if any.
		 */
		virtual int PushString(const char *string) =0;

		/**
		 * @brief Pushes a string or string buffer.
		 * 
		 * NOTE: On Execute, the pointer passed will be modified if copy-back is enabled.
		 *
		 * @param buffer	Pointer to string buffer.
		 * @param length	Length of buffer.
		 * @param sz_flags	String flags.  In copy mode, the string will be copied 
		 *					according to the handling (ascii, utf-8, binary, etc).
		 * @param cp_flags	Copy-back flags.
		 * @return			Error code, if any.
		 */
		virtual int PushStringEx(char *buffer, size_t length, int sz_flags, int cp_flags) =0;

		/**
		 * @brief Cancels a function call that is being pushed but not yet executed.
		 * This can be used be reset for CallFunction() use.
		 */
		virtual void Cancel() =0;
	};


	/**
	 * @brief Encapsulates a function call in a plugin.
	 *
	 * NOTE: Function calls must be atomic to one execution context.
	 * NOTE: This object should not be deleted.  It lives for the lifetime of the plugin.
	 */
	class IPluginFunction : public ICallable
	{
	public:
		/**
		 * @brief Executes the forward, resets the pushed parameter list, and performs any copybacks.
		 *
		 * @param result		Pointer to store return value in.
		 * @return				Error code, if any.
		 */
		virtual int Execute(cell_t *result) =0;

		/**
		 * @brief Executes the function with the given parameter array.
		 * Parameters are read in forward order (i.e. index 0 is parameter #1)
		 * NOTE: You will get an error if you attempt to use CallFunction() with
		 * previously pushed parameters.
		 *
		 * @param params		Array of cell parameters.
		 * @param num_params	Number of parameters to push.
		 * @param result		Pointer to store result of function on return.
		 * @return				SourcePawn error code (if any).
		 */
		virtual int CallFunction(const cell_t *params, unsigned int num_params, cell_t *result) =0;

		/**
		 * @brief Returns which plugin this function belongs to.
		 *
		 * @return				IPluginContext pointer to parent plugin.
		 */
		virtual IPluginContext *GetParentContext() =0;

		/**
		 * @brief Returns whether the parent plugin is paused.
		 *
		 * @return				True if runnable, false otherwise.
		 */
		virtual bool IsRunnable() =0;

		/**
		 * @brief Returns the function ID of this function.
		 * 
		 * Note: This was added in API version 4.
		 *
		 * @return				Function id.
		 */
		virtual funcid_t GetFunctionID() =0;
	};


	/**
	 * @brief Interface to managing a debug context at runtime.
	 */
	class IPluginDebugInfo
	{
	public:
		/**
		 * @brief Given a code pointer, finds the file it is associated with.
		 * 
		 * @param addr		Code address offset.
		 * @param filename	Pointer to store filename pointer in.
		 */
		virtual int LookupFile(ucell_t addr, const char **filename) =0;

		/**
		 * @brief Given a code pointer, finds the function it is associated with.
		 *
		 * @param addr		Code address offset.
		 * @param name		Pointer to store function name pointer in.
		 */
		virtual int LookupFunction(ucell_t addr, const char **name) =0;

		/**
		 * @brief Given a code pointer, finds the line it is associated with.
		 *
		 * @param addr		Code address offset.
		 * @param line		Pointer to store line number in.
		 */
		virtual int LookupLine(ucell_t addr, uint32_t *line) =0;
	};

	/**
	 * @brief Interface to managing a context at runtime.
	 */
	class IPluginContext
	{
	public:
		/** Virtual destructor */
		virtual ~IPluginContext() { };
	public:
		/** 
		 * @brief Returns the parent IVirtualMachine.
		 *
		 * @return				Parent virtual machine pointer.
		 */
		virtual IVirtualMachine *GetVirtualMachine() =0;

		/**
		 * @brief Returns the child sp_context_t structure.
		 *
		 * @return				Child sp_context_t structure.
		 */
		virtual sp_context_t *GetContext() =0;

		/**
		 * @brief Returns true if the plugin is in debug mode.
		 *
		 * @return				True if in debug mode, false otherwise.
		 */
		virtual bool IsDebugging() =0;

		/**
		 * @brief Installs a debug break and returns the old one, if any.
		 * This will fail if the plugin is not debugging.
		 *
		 * @param newpfn		New function pointer.
		 * @param oldpfn		Pointer to retrieve old function pointer.
		 */
		virtual int SetDebugBreak(SPVM_DEBUGBREAK newpfn, SPVM_DEBUGBREAK *oldpfn) =0;

		/**
		 * @brief Returns debug info.
		 *
		 * @return				IPluginDebugInfo, or NULL if no debug info found.
		 */
		virtual IPluginDebugInfo *GetDebugInfo() =0;

		/**
		 * @brief Allocates memory on the secondary stack of a plugin.
		 * Note that although called a heap, it is in fact a stack.
		 * 
		 * @param cells			Number of cells to allocate.
		 * @param local_addr	Will be filled with data offset to heap.
		 * @param phys_addr		Physical address to heap memory.
		 */
		virtual int HeapAlloc(unsigned int cells, cell_t *local_addr, cell_t **phys_addr) =0;

		/**
		 * @brief Pops a heap address off the heap stack.  Use this to free memory allocated with
		 *  SP_HeapAlloc().  
		 * Note that in SourcePawn, the heap is in fact a bottom-up stack.  Deallocations
		 *  with this native should be performed in precisely the REVERSE order.
		 *
		 * @param local_addr	Local address to free.
 		 */
		virtual int HeapPop(cell_t local_addr) =0;

		/**
		 * @brief Releases a heap address using a different method than SP_HeapPop().
		 * This allows you to release in any order.  However, if you allocate N 
		 *  objects, release only some of them, then begin allocating again, 
		 *  you cannot go back and starting freeing the originals.  
		 * In other words, for each chain of allocations, if you start deallocating,
		 *  then allocating more in a chain, you must only deallocate from the current 
		 *  allocation chain.  This is basically HeapPop() except on a larger scale.
		 *
		 * @param local_addr	Local address to free.
 		 */
		virtual int HeapRelease(cell_t local_addr) =0;

		/**
		 * @brief Finds a native by name.
		 *
		 * @param name			Name of native.
		 * @param index			Optionally filled with native index number.
		 */
		virtual int FindNativeByName(const char *name, uint32_t *index) =0;

		/**
		 * @brief Gets native info by index.
		 *
		 * @param index			Index number of native.
		 * @param native		Optionally filled with pointer to native structure.
		 */
		virtual int GetNativeByIndex(uint32_t index, sp_native_t **native) =0;

		/**
		 * @brief Gets the number of natives.
		 * 
		 * @return				Filled with the number of natives.
		 */
		virtual uint32_t GetNativesNum() =0;

		/**
		 * @brief Finds a public function by name.
		 *
		 * @param name			Name of public
		 * @param index			Optionally filled with public index number.
		 */
		virtual int FindPublicByName(const char *name, uint32_t *index) =0;

		/**
		 * @brief Gets public function info by index.
		 * 
		 * @param index			Public function index number.
		 * @param publicptr		Optionally filled with pointer to public structure.
		 */
		virtual int GetPublicByIndex(uint32_t index, sp_public_t **publicptr) =0;

		/**
		 * @brief Gets the number of public functions.
		 *
		 * @return				Filled with the number of public functions.
		 */
		virtual uint32_t GetPublicsNum() =0;

		/**
		 * @brief Gets public variable info by index.
		 * 
		 * @param index			Public variable index number.
		 * @param pubvar		Optionally filled with pointer to pubvar structure.
		 */
		virtual int GetPubvarByIndex(uint32_t index, sp_pubvar_t **pubvar) =0;

		/**
		 * @brief Finds a public variable by name.
		 *
		 * @param name			Name of pubvar
		 * @param index			Optionally filled with pubvar index number.
		 */
		virtual int FindPubvarByName(const char *name, uint32_t *index) =0;

		/**
		 * @brief Gets the addresses of a public variable.
		 * 
		 * @param index			Index of public variable.
		 * @param local_addr		Address to store local address in.
		 * @param phys_addr		Address to store physically relocated in.
		 */
		virtual int GetPubvarAddrs(uint32_t index, cell_t *local_addr, cell_t **phys_addr) =0;

		/**
		 * @brief Returns the number of public variables.
		 *
		 * @return				Number of public variables.
		 */
		virtual uint32_t GetPubVarsNum() =0;

		/**
		 * @brief Round-about method of converting a plugin reference to a physical address
		 *
		 * @param local_addr	Local address in plugin.
		 * @param phys_addr		Optionally filled with relocated physical address.
		 */
		virtual int LocalToPhysAddr(cell_t local_addr, cell_t **phys_addr) =0;

		/**
		 * @brief Converts a local address to a physical string.
		 *
		 * @param local_addr	Local address in plugin.
		 * @param addr			Destination output pointer.
		 */
		virtual int LocalToString(cell_t local_addr, char **addr) =0;

		/**
		 * @brief Converts a physical string to a local address.
		 *
		 * @param local_addr	Local address in plugin.
		 * @param bytes			Number of chars to write, including NULL terminator.
		 * @param source		Source string to copy.
		 */
		virtual int StringToLocal(cell_t local_addr, size_t bytes, const char *source) =0;

		/**
		 * @brief Converts a physical UTF-8 string to a local address.
		 * This function is the same as the ANSI version, except it will copy the maximum number of characters possible 
		 *  without accidentally chopping a multi-byte character.
		 *
		 * @param local_addr		Local address in plugin.
		 * @param maxbytes		Number of bytes to write, including NULL terminator.
		 * @param source			Source string to copy.
		 * @param wrtnbytes		Optionally set to the number of actual bytes written.
		 */
		virtual int StringToLocalUTF8(cell_t local_addr, 
									  size_t maxbytes, 
									  const char *source, 
									  size_t *wrtnbytes) =0;

		/**
		 * @brief Pushes a cell onto the stack.  Increases the parameter count by one.
		 *
		 * @param value			Cell value.
		 */
		virtual int PushCell(cell_t value) =0;

		/** 
		 * @brief Pushes an array of cells onto the stack.  Increases the parameter count by one.
		 * If the function returns an error it will fail entirely, releasing anything allocated in the process.
		 * Note that this does not release the heap, so you should release it after
		 *  calling Execute().
		 *
		 * @param local_addr	Filled with local address to release.
		 * @param phys_addr		Optionally filled with physical address of new array.
		 * @param array			Cell array to copy.
		 * @param numcells		Number of cells in the array to copy.
		 */
		virtual int PushCellArray(cell_t *local_addr, cell_t **phys_addr, cell_t array[], unsigned int numcells) =0;

		/**
		 * @brief Pushes a string onto the stack (by reference) and increases the parameter count by one.
		 * Note that this does not release the heap, so you should release it after
		 *  calling Execute().
		 *
		 * @param local_addr	Filled with local address to release.
		 * @param phys_addr		Optionally filled with physical address of new array.
		 * @param string		Source string to push.
		 */
		virtual int PushString(cell_t *local_addr, char **phys_addr, const char *string) =0;

		/**
		 * @brief Individually pushes each cell of an array of cells onto the stack.  Increases the 
		 *  parameter count by the number of cells pushed.
		 * If the function returns an error it will fail entirely, releasing anything allocated in the process.
		 *
		 * @param array			Array of cells to read from.
		 * @param numcells		Number of cells to read.
		 */
		virtual int PushCellsFromArray(cell_t array[], unsigned int numcells) =0;

		/** 
		 * @brief Binds a list of native names and their function pointers to a context.
		 * If num is 0, the list is read until an entry with a NULL name is reached.
		 * If overwrite is non-zero, already registered natives will be overwritten.
		 * 
		 * @param natives		Array of natives.
		 * @param num			Number of natives in array.
		 * @param overwrite		Toggles overwrite.
		 */
		virtual int BindNatives(const sp_nativeinfo_t *natives, unsigned int num, int overwrite) =0;

		/**
		 * @brief Binds a single native.  Overwrites any existing bind.
		 * If the context does not contain the native that will be binded the function will return
		 *  with a SP_ERROR_NOT_FOUND error.
		 *
		 * @param native		Pointer to native.
		 */
		virtual int BindNative(const sp_nativeinfo_t *native) =0;

		/**
		 * @brief Binds a single native to any non-registered native.
		 *
		 * @param native		Native to bind.
		 */
		virtual int BindNativeToAny(SPVM_NATIVE_FUNC native) =0;

		/**
		 * @brief Executes a function ID located in this context.
		 *
		 * @param code_addr		Address to execute at.
		 * @param result		Pointer to store the return value (required).
		 * @return				Error code (if any) from the VM.
		 */
		virtual int Execute(uint32_t code_addr, cell_t *result) =0;

		/**
		 * @brief Throws a error and halts any current execution.
		 *
		 * @param error		The error number to set.
		 * @param msg		Custom error message format.  NULL to use default.
		 * @param ...		Message format arguments, if any.
		 * @return			0 for convenience.
		 */
		virtual cell_t ThrowNativeErrorEx(int error, const char *msg, ...) =0;

		/**
		 * @brief Throws a generic native error and halts any current execution.
		 *
		 * @param msg		Custom error message format.  NULL to set no message.
		 * @param ...		Message format arguments, if any.
		 * @return			0 for convenience.
		 */
		virtual cell_t ThrowNativeError(const char *msg, ...) =0;

		/**
		 * @brief Returns a function by name.
		 *
		 * @param public_name		Name of the function.
		 * @return					A new IPluginFunction pointer, NULL if not found.
		 */
		virtual IPluginFunction *GetFunctionByName(const char *public_name) =0;

		/**
		 * @brief Returns a function by its id.
		 *
		 * @param func_id			Function ID.
		 * @return					A new IPluginFunction pointer, NULL if not found.
		 */
		virtual IPluginFunction *GetFunctionById(funcid_t func_id) =0;

#if defined SOURCEMOD_BUILD
		/**
		 * @brief Returns the identity token for this context.
		 * Note: This is a helper function for native calls and the Handle System.
		 *
		 * @return			Identity token.
		 */
		virtual SourceMod::IdentityToken_t *GetIdentity() =0;

		/**
		 * @brief Returns a NULL reference based on one of the available NULL
		 * reference types.
		 *
		 * @param type		NULL reference type.
		 * @return			cell_t address to compare to.
		 */
		virtual cell_t *GetNullRef(SP_NULL_TYPE type) =0;

		/**
		 * @brief Converts a local address to a physical string, and allows
		 * for NULL_STRING to be set.
		 *
		 * @param local_addr	Local address in plugin.
		 * @param addr			Destination output pointer.
		 */
		virtual int LocalToStringNULL(cell_t local_addr, char **addr) =0;
#endif

		/**
		 * @brief Binds a single native to a given native index.
		 *
		 * @param index			Index to bind at.
		 * @param native		Native function to bind.
		 */
		virtual int BindNativeToIndex(uint32_t index, SPVM_NATIVE_FUNC native) =0;

		/**
		 * @brief Returns if there is currently an execution in progress.
		 *
		 * @return				True if in exec, false otherwise.
		 */
		virtual bool IsInExec() =0;
	};


	/**
	 * @brief Information about a position in a call stack.
	 */
	struct CallStackInfo
	{
		const char *filename;		/**< NULL if not found */
		unsigned int line;			/**< 0 if not found */
		const char *function;		/**< NULL if not found */
	};

	/**
	 * @brief Retrieves error information from a debug hook.
	 */
	class IContextTrace
	{
	public:
		/**
		 * @brief Returns the integer error code.
		 *
		 * @return			Integer error code.
		 */
		virtual int GetErrorCode() =0;

		/**
		 * @brief Returns a string describing the error.
		 *
		 * @return			Error string.
		 */
		virtual const char *GetErrorString() =0;

		/**
		 * @brief Returns whether debug info is available.
		 *
		 * @return			True if debug info is available, false otherwise.
		 */
		virtual bool DebugInfoAvailable() =0;

		/**
		 * @brief Returns a custom error message.
		 *
		 * @return			A pointer to a custom error message, or NULL otherwise.
		 */
		virtual const char *GetCustomErrorString() =0;

		/**
		 * @brief Returns trace info for a specific point in the backtrace, if any.
		 * The next subsequent call to GetTraceInfo() will return the next item in the call stack.
		 * Calls are retrieved in descending order (i.e. the first item is at the top of the stack/call sequence).
		 *
		 * @param trace		An ErrorTraceInfo buffer to store information (NULL to ignore).
		 * @return			True if successful, false if there are no more traces.
		 */
		virtual bool GetTraceInfo(CallStackInfo *trace) =0;

		/**
		 * @brief Resets the trace to its original position (the call on the top of the stack).
		 */
		virtual void ResetTrace() =0;

		/**
		 * @brief Retrieves the name of the last native called.
		 * Returns NULL if there was no native that caused the error.
		 *
		 * @param index		Optional pointer to store index.
		 * @return			Native name, or NULL if none.
		 */
		virtual const char *GetLastNative(uint32_t *index) =0;
	};


	/**
	 * @brief Provides callbacks for debug information.
	 */
	class IDebugListener
	{
	public:
		virtual void OnContextExecuteError(IPluginContext *ctx, IContextTrace *error) =0;
	};

	/**
	 * @brief Represents a code profiler for plugins.
	 */
	class IProfiler
	{
	public:
		/**
		 * @brief Invoked by the JIT to notify that a native is being started.
		 *
		 * @param pContext			Plugin context.
		 * @param native			Native information.
		 */
		virtual void OnNativeBegin(IPluginContext *pContext, sp_native_t *native) =0;

		/**
		 * @brief Invoked by the JIT to notify that the last native on the stack 
		 * is no longer being executed.
		 */
		virtual void OnNativeEnd() =0;

		/**
		 * @brief Invoked by the JIT to notify that a function call is starting.
		 *
		 * @param pContext			Plugin context.
		 * @param name				Function name, or NULL if not known.
		 * @param code_addr			P-Code address.
		 */
		virtual void OnFunctionBegin(IPluginContext *pContext, const char *name) =0;

		/**
		 * @brief Invoked by the JIT to notify that the last function call has 
		 * concluded.  In the case of an error inside a function, this will not 
		 * be called.  Instead, the VM will call OnCallbackEnd() and the profiler 
		 * stack must be unwound.
		 */
		virtual void OnFunctionEnd() =0;

		/**
		 * @brief Invoked by the VM to notify that a forward/callback is starting.
		 *
		 * @param pContext			Plugin context.
		 * @param pubfunc			Public function information.
		 * @return					Unique number to pass to OnFunctionEnd().
		 */
		virtual int OnCallbackBegin(IPluginContext *pContext, sp_public_t *pubfunc) =0;

		/**
		 * @brief Invoked by the JIT to notify that a callback has ended.  
		 *
		 * As noted in OnFunctionEnd(), this my be called with a misaligned 
		 * profiler stack.  To correct this, the stack should be unwound 
		 * (discarding data as appropriate) to a matching serial number.
		 *
		 * @param serial			Unique number from OnCallbackBegin().
		 */
		virtual void OnCallbackEnd(int serial) =0;
	};

	/**
	 * @brief Contains helper functions used by VMs and the host app
	 */
	class ISourcePawnEngine
	{
	public:
		/**
		 * @brief Loads a named file from a file pointer.  
		 * Note: Using this means the memory will be allocated by the VM.
		 * 
		 * @param fp			File pointer.  May be at any offset.  Not closed on return.
		 * @param err		Optional error code pointer.
		 * @return			A new plugin structure.
		 */	
		virtual sp_plugin_t *LoadFromFilePointer(FILE *fp, int *err) =0;
	
		/**
		 * @brief Loads a file from a base memory address.
		 *	
		 * @param base		Base address of the plugin's memory region.
		 * @param plugin	If NULL, a new plugin pointer is returned.
		 *                  Otherwise, the passed pointer is used.
		 * @param err		Optional error code pointer.
		 * @return			The resulting plugin pointer.
		 */
		virtual sp_plugin_t *LoadFromMemory(void *base, sp_plugin_t *plugin, int *err) =0;

		/**
		 * Frees all of the memory associated with a plugin file.
		 * If allocated using SP_LoadFromMemory, the base and plugin pointer 
		 *  itself are not freed (so this may end up doing nothing).
		 */
		virtual int FreeFromMemory(sp_plugin_t *plugin) =0;

		/**
		 * @brief Allocates large blocks of temporary memory.
		 * 
		 * @param size		Size of memory to allocate.
		 * @return			Pointer to memory, NULL if allocation failed.
		 */
		virtual void *BaseAlloc(size_t size) =0;

		/**
		 * @brief Frees memory allocated with BaseAlloc.
		 *
		 * @param memory	Memory address to free.
		 */
		virtual void BaseFree(void *memory) =0;

		/**
		 * @brief Allocates executable memory.
		 * @deprecated Use AllocPageMemory()
		 *
		 * @param size		Size of memory to allocate.
		 * @return			Pointer to memory, NULL if allocation failed.
		 */
		virtual void *ExecAlloc(size_t size) =0;

		/**
		 * @brief Frees executable memory.
		 * @deprecated Use FreePageMemory()
		 *
		 * @param address	Address to free.
		 */
		virtual void ExecFree(void *address) =0;

		/**
		 * @brief Sets the debug listener.  This should only be called once.
		 * If called successively (using manual chaining), only the last function should
		 * attempt to call back into the same plugin.  Otherwise, globally cached states
		 * can be accidentally overwritten.
		 *
		 * @param listener	Pointer to an IDebugListener.
		 * @return			Old IDebugListener, or NULL if none.
		 */
		virtual IDebugListener *SetDebugListener(IDebugListener *listener) =0;
		
		/**
		 * @brief Returns the number of plugins on the call stack.
		 *
		 * @return			Number of contexts in the call stack.
		 */
		virtual unsigned int GetContextCallCount() =0;

		/**
		 * @brief Returns the engine API version.
		 *
		 * @return			Engine API version.
		 */
		virtual unsigned int GetEngineAPIVersion() =0;

		/**
		 * @brief Allocates executable memory.
		 *
		 * @param size		Size of memory to allocate.
		 * @return			Pointer to memory, NULL if allocation failed.
		 */
		virtual void *AllocatePageMemory(size_t size) =0;
		
		/**
		 * @brief Sets the input memory permissions to read+write.
		 *
		 * @param ptr		Memory block.
		 */
		virtual void SetReadWrite(void *ptr) =0;

		/**
		 * @brief Sets the input memory permissions to read+execute.
		 *
		 * @param ptr		Memory block.
		 */
		virtual void SetReadExecute(void *ptr) =0;

		/**
		 * @brief Frees executable memory.
		 *
		 * @param ptr		Address to free.
		 */
		virtual void FreePageMemory(void *ptr) =0;
	};


	/**
	 * @brief Dummy class for encapsulating private compilation data.
	 */
	class ICompilation
	{
	public:
		/** Virtual destructor */
		virtual ~ICompilation() { };
	};


	/** 
	 * @brief Outlines the interface a Virtual Machine (JIT) must expose
	 */
	class IVirtualMachine
	{
	public:
		/**
		 * @brief Returns the current API version.
		 */
		virtual unsigned int GetAPIVersion() =0;

		/**
		 * @brief Returns the string name of a VM implementation.
		 */
		virtual const char *GetVMName() =0;

		/**
		 * @brief Begins a new compilation
		 * 
		 * @param plugin	Pointer to a plugin structure.
		 * @return			New compilation pointer.
		 */
		virtual ICompilation *StartCompilation(sp_plugin_t *plugin) =0;

		/**
		 * @brief Sets a compilation option.
		 *
		 * @param co		Pointer to a compilation.
		 * @param key		Option key name.
		 * @param val		Option value string.
		 * @return			True if option could be set, false otherwise.
		 */
		virtual bool SetCompilationOption(ICompilation *co, const char *key, const char *val) =0;

		/**
		 * @brief Finalizes a compilation into a new sp_context_t.
		 * Note: This will free the ICompilation pointer.
		 *
		 * @param co		Compilation pointer.
		 * @param err		Filled with error code on exit.
		 * @return			New plugin context.
		 */
		virtual sp_context_t *CompileToContext(ICompilation *co, int *err) =0;

		/**
		 * @brief Aborts a compilation and frees the ICompilation pointer.
		 *
		 * @param co		Compilation pointer.
		 */
		virtual void AbortCompilation(ICompilation *co) =0;

		/**
		 * @brief Frees any internal variable usage on a context.
		 *
		 * @param ctx		Context structure pointer.
		 */
		virtual void FreeContext(sp_context_t *ctx) =0;

		/**
		 * @brief Calls the "execute" function on a context.
		 *
		 * @param ctx		Executes a function in a context.
		 * @param code_addr	Index into the code section.
		 * @param result	Pointer to store result into.
		 * @return			Error code (if any).
		 */
		virtual int ContextExecute(sp_context_t *ctx, uint32_t code_addr, cell_t *result) =0;

		/**
		 * @brief Given a context and a code address, returns the index of the function.
		 * 
		 * @param ctx		Context to search.
		 * @param code_addr	Index into the code section.
		 * @param result	Pointer to store result into.
		 * @return			True if code index is valid, false otherwise.
		 */
		virtual bool FunctionLookup(const sp_context_t *ctx, uint32_t code_addr, unsigned int *result) =0;

		/**
		 * @brief Returns the number of functions defined in the context.
		 *
		 * @param ctx		Context to search.
		 * @return			Number of functions.
		 */
		virtual unsigned int FunctionCount(const sp_context_t *ctx) =0;

		/**
		 * @brief Returns a version string.
		 *
		 * @return			Versioning string.
		 */
		virtual const char *GetVersionString() =0;

		/**
		 * @brief Returns a string describing optimizations.
		 *
		 * @return			String describing CPU specific optimizations.
		 */
		virtual const char *GetCPUOptimizations() =0;

		/**
		 * @brief Given a context and a p-code address, returns the index of the function.
		 * 
		 * @param ctx		Context to search.
		 * @param code_addr	Index into the p-code section.
		 * @param result	Pointer to store result into.
		 * @return			True if code index is valid, false otherwise.
		 */
		virtual bool FunctionPLookup(const sp_context_t *ctx, uint32_t code_addr, unsigned int *result) =0;

		/**
		 * @brief Creates a fake native and binds it to a general callback function.
		 *
		 * @param callback	Callback function to bind the native to.
		 * @param pData		Private data to pass to the callback when the native is invoked.
		 * @return			A new fake native function as a wrapper around the callback.
		 */
		virtual SPVM_NATIVE_FUNC CreateFakeNative(SPVM_FAKENATIVE_FUNC callback, void *pData) =0;

		/**
		 * @brief Destroys a fake native function wrapper.  
		 *
		 * @param func		Pointer to the fake native created by CreateFakeNative.
		 */
		virtual void DestroyFakeNative(SPVM_NATIVE_FUNC func) =0;
	};
};

#endif //_INCLUDE_SOURCEPAWN_VM_API_H_