/**

 * 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: $Id$

 */

#include <string.h>

#include <stdarg.h>

#include <assert.h>

#include <limits.h>

#include "sp_vm_api.h"

#include "sp_vm_basecontext.h"

#include "sp_vm_engine.h"

#include "x86/jit_x86.h"

using namespace SourcePawn;

#define CELLBOUNDMAX	(INT_MAX/sizeof(cell_t))

#define STACKMARGIN		((cell_t)(16*sizeof(cell_t)))

BaseContext::BaseContext(BaseRuntime *pRuntime)

{

	m_pRuntime = pRuntime;

	m_InExec = false;

	m_CustomMsg = false;

	/* Initialize the null references */

	uint32_t index;

	if (FindPubvarByName("NULL_VECTOR", &index) == SP_ERROR_NONE)

	{

		sp_pubvar_t *pubvar;

		GetPubvarByIndex(index, &pubvar);

		m_pNullVec = pubvar->offs;

	}

	else

	{

		m_pNullVec = NULL;

	}

	if (FindPubvarByName("NULL_STRING", &index) == SP_ERROR_NONE)

	{

		sp_pubvar_t *pubvar;

		GetPubvarByIndex(index, &pubvar);

		m_pNullString = pubvar->offs;

	}

	else

	{

		m_pNullString = NULL;

	}

}

BaseContext::~BaseContext()

{

}

IVirtualMachine *BaseContext::GetVirtualMachine()

{

	return NULL;

}

sp_context_t *BaseContext::GetContext()

{

	return &m_ctx;

}

bool BaseContext::IsDebugging()

{

	return m_pRuntime->IsDebugging();

}

int BaseContext::SetDebugBreak(void *newpfn, void *oldpfn)

{

	return SP_ERROR_ABORTED;

}

IPluginDebugInfo *BaseContext::GetDebugInfo()

{

	return NULL;

}

int BaseContext::Execute(uint32_t code_addr, cell_t *result)

{

	return SP_ERROR_ABORTED;

}

void BaseContext::SetErrorMessage(const char *msg, va_list ap)

{

	m_CustomMsg = true;

	vsnprintf(m_MsgCache, sizeof(m_MsgCache), msg, ap);

}

void BaseContext::_SetErrorMessage(const char *msg, ...)

{

	va_list ap;

	va_start(ap, msg);

	SetErrorMessage(msg, ap);

	va_end(ap);

}

cell_t BaseContext::ThrowNativeErrorEx(int error, const char *msg, ...)

{

	if (!m_InExec)

	{

		return 0;

	}

	m_ctx.n_err = error;

	if (msg)

	{

		va_list ap;

		va_start(ap, msg);

		SetErrorMessage(msg, ap);

		va_end(ap);

	}

	return 0;

}

cell_t BaseContext::ThrowNativeError(const char *msg, ...)

{

	if (!m_InExec)

	{

		return 0;

	}

	m_ctx.n_err = SP_ERROR_NATIVE;

	if (msg)

	{

		va_list ap;

		va_start(ap, msg);

		SetErrorMessage(msg, ap);

		va_end(ap);

	}

	return 0;

}

int BaseContext::HeapAlloc(unsigned int cells, cell_t *local_addr, cell_t **phys_addr)

{

	cell_t *addr;

	ucell_t realmem;

#if 0

	if (cells > CELLBOUNDMAX)

	{

		return SP_ERROR_ARAM;

	}

#else

	assert(cells < CELLBOUNDMAX);

#endif

	realmem = cells * sizeof(cell_t);

	/**

	 * Check if the space between the heap and stack is sufficient.

	 */

	if ((cell_t)(m_ctx.sp - m_ctx.hp - realmem) < STACKMARGIN)

	{

		return SP_ERROR_HEAPLOW;

	}

	addr = (cell_t *)(m_pPlugin->memory + m_ctx.hp);

	/* store size of allocation in cells */

	*addr = (cell_t)cells;

	addr++;

	m_ctx.hp += sizeof(cell_t);

	*local_addr = m_ctx.hp;

	if (phys_addr)

	{

		*phys_addr = addr;

	}

	m_ctx.hp += realmem;

	return SP_ERROR_NONE;

}

int BaseContext::HeapPop(cell_t local_addr)

{

	cell_t cellcount;

	cell_t *addr;

	/* check the bounds of this address */

	local_addr -= sizeof(cell_t);

	if (local_addr < (cell_t)m_pPlugin->data_size || local_addr >= m_ctx.sp)

	{

		return SP_ERROR_INVALID_ADDRESS;

	}

	addr = (cell_t *)(m_pPlugin->memory + local_addr);

	cellcount = (*addr) * sizeof(cell_t);

	/* check if this memory count looks valid */

	if ((signed)(m_ctx.hp - cellcount - sizeof(cell_t)) != local_addr)

	{

		return SP_ERROR_INVALID_ADDRESS;

	}

	m_ctx.hp = local_addr;

	return SP_ERROR_NONE;

}

int BaseContext::HeapRelease(cell_t local_addr)

{

	if (local_addr < (cell_t)m_pPlugin->data_size)

	{

		return SP_ERROR_INVALID_ADDRESS;

	}

	m_ctx.hp = local_addr - sizeof(cell_t);

	return SP_ERROR_NONE;

}

int BaseContext::FindNativeByName(const char *name, uint32_t *index)

{

	return m_pRuntime->FindNativeByName(name, index);

}

int BaseContext::GetNativeByIndex(uint32_t index, sp_native_t **native)

{

	return m_pRuntime->GetNativeByIndex(index, native);

}

uint32_t BaseContext::GetNativesNum()

{

	return m_pRuntime->GetNativesNum();

}

int BaseContext::FindPublicByName(const char *name, uint32_t *index)

{

	return m_pRuntime->FindPublicByName(name, index);

}

int BaseContext::GetPublicByIndex(uint32_t index, sp_public_t **pblic)

{

	return m_pRuntime->GetPublicByIndex(index, pblic);

}

uint32_t BaseContext::GetPublicsNum()

{

	return m_pRuntime->GetPublicsNum();

}

int BaseContext::GetPubvarByIndex(uint32_t index, sp_pubvar_t **pubvar)

{

	return m_pRuntime->GetPubvarByIndex(index, pubvar);

}

int BaseContext::FindPubvarByName(const char *name, uint32_t *index)

{

	return m_pRuntime->FindPublicByName(name, index);

}

int BaseContext::GetPubvarAddrs(uint32_t index, cell_t *local_addr, cell_t **phys_addr)

{

	return m_pRuntime->GetPubvarAddrs(index, local_addr, phys_addr);

}

uint32_t BaseContext::GetPubVarsNum()

{

	return m_pRuntime->GetPubVarsNum();

}

int BaseContext::BindNatives(const sp_nativeinfo_t *natives, unsigned int num, int overwrite)

{

	return SP_ERROR_ABORTED;

}

int BaseContext::BindNative(const sp_nativeinfo_t *native)

{

	return SP_ERROR_ABORTED;

}

int BaseContext::BindNativeToIndex(uint32_t index, SPVM_NATIVE_FUNC func)

{

	return SP_ERROR_ABORTED;

}

int BaseContext::BindNativeToAny(SPVM_NATIVE_FUNC native)

{

	return SP_ERROR_ABORTED;

}

int BaseContext::LocalToPhysAddr(cell_t local_addr, cell_t **phys_addr)

{

	if (((local_addr >= m_ctx.hp) && (local_addr < m_ctx.sp)) 

		|| (local_addr < 0) || ((ucell_t)local_addr >= m_pPlugin->mem_size))

	{

		return SP_ERROR_INVALID_ADDRESS;

	}

	if (phys_addr)

	{

		*phys_addr = (cell_t *)(m_pPlugin->memory + local_addr);

	}

	return SP_ERROR_NONE;

}

int BaseContext::PushCell(cell_t value)

{

	return SP_ERROR_ABORTED;

}

int BaseContext::PushCellsFromArray(cell_t array[], unsigned int numcells)

{

	return SP_ERROR_ABORTED;

}

int BaseContext::PushCellArray(cell_t *local_addr, cell_t **phys_addr, cell_t array[], unsigned int numcells)

{

	return SP_ERROR_ABORTED;

}

int BaseContext::LocalToString(cell_t local_addr, char **addr)

{

	if (((local_addr >= m_ctx.hp) && (local_addr < m_ctx.sp))

		|| (local_addr < 0) || ((ucell_t)local_addr >= m_pPlugin->mem_size))

	{

		return SP_ERROR_INVALID_ADDRESS;

	}

	*addr = (char *)(m_pPlugin->memory + local_addr);

	return SP_ERROR_NONE;

}

int BaseContext::PushString(cell_t *local_addr, char **phys_addr, const char *string)

{

	return SP_ERROR_ABORTED;

}

int BaseContext::StringToLocal(cell_t local_addr, size_t bytes, const char *source)

{

	char *dest;

	size_t len;

	if (((local_addr >= m_ctx.hp) && (local_addr < m_ctx.sp))

		|| (local_addr < 0) || ((ucell_t)local_addr >= m_pPlugin->mem_size))

	{

		return SP_ERROR_INVALID_ADDRESS;

	}

	if (bytes == 0)

	{

		return SP_ERROR_NONE;

	}

	len = strlen(source);

	dest = (char *)(m_pPlugin->memory + local_addr);

	if (len >= bytes)

	{

		len = bytes - 1;

	}

	memmove(dest, source, len);

	dest[len] = '\0';

	return SP_ERROR_NONE;

}

inline int __CheckValidChar(char *c)

{

	int count;

	int bytecount = 0;

	for (count=1; (*c & 0xC0) == 0x80; count++)

	{

		c--;

	}

	switch (*c & 0xF0)

	{

	case 0xC0:

	case 0xD0:

		{

			bytecount = 2;

			break;

		}

	case 0xE0:

		{

			bytecount = 3;

			break;

		}

	case 0xF0:

		{

			bytecount = 4;

			break;

		}

	}

	if (bytecount != count)

	{

		return count;

	}

	return 0;

}

int BaseContext::StringToLocalUTF8(cell_t local_addr, size_t maxbytes, const char *source, size_t *wrtnbytes)

{

	char *dest;

	size_t len;

	bool needtocheck = false;

	if (((local_addr >= m_ctx.hp) && (local_addr < m_ctx.sp))

		|| (local_addr < 0)

		|| ((ucell_t)local_addr >= m_pPlugin->mem_size))

	{

		return SP_ERROR_INVALID_ADDRESS;

	}

	if (maxbytes == 0)

	{

		return SP_ERROR_NONE;

	}

	len = strlen(source);

	dest = (char *)(m_pPlugin->memory + local_addr);

	if ((size_t)len >= maxbytes)

	{

		len = maxbytes - 1;

		needtocheck = true;

	}

	memmove(dest, source, len);

	if ((dest[len-1] & 1<<7) && needtocheck)

	{

		len -= __CheckValidChar(dest+len-1);

	}

	dest[len] = '\0';

	if (wrtnbytes)

	{

		*wrtnbytes = len;

	}

	return SP_ERROR_NONE;

}

IPluginFunction *BaseContext::GetFunctionById(funcid_t func_id)

{

	return m_pRuntime->GetFunctionById(func_id);

}

IPluginFunction *BaseContext::GetFunctionByName(const char *public_name)

{

	return m_pRuntime->GetFunctionByName(public_name);

}

int BaseContext::LocalToStringNULL(cell_t local_addr, char **addr)

{

	int err;

	if ((err = LocalToString(local_addr, addr)) != SP_ERROR_NONE)

	{

		return err;

	}

	if ((cell_t *)*addr == m_pNullString)

	{

		*addr = NULL;

	}

	return SP_ERROR_NONE;

}

SourceMod::IdentityToken_t *BaseContext::GetIdentity()

{

	return m_pToken;

}

void BaseContext::SetIdentity(SourceMod::IdentityToken_t *token)

{

	m_pToken = token;

}

cell_t *BaseContext::GetNullRef(SP_NULL_TYPE type)

{

	if (type == SP_NULL_VECTOR)

	{

		return m_pNullVec;

	}

	return NULL;

}

bool BaseContext::IsInExec()

{

	return m_InExec;

}

int BaseContext::Execute(IPluginFunction *function, const cell_t *params, unsigned int num_params, cell_t *result)

{

	int ir;

	int serial;

	cell_t *sp;

	funcid_t fnid;

	sp_public_t *pubfunc;

	cell_t _ignore_result;

	fnid = function->GetFunctionID();

	if (fnid & 1)

	{

		unsigned int public_id;

		public_id = fnid >> 1;

		if (m_pRuntime->GetPublicByIndex(public_id, &pubfunc) != SP_ERROR_NONE)

		{

			return SP_ERROR_NOT_FOUND;

		}

	}

	else

	{

		return SP_ERROR_INVALID_ADDRESS;

	}

	if (m_pRuntime->IsPaused())

	{

		return SP_ERROR_NOT_RUNNABLE;

	}

	if (m_ctx.hp + 16*sizeof(cell_t) > (cell_t)(m_ctx.sp - (sizeof(cell_t) * (num_params + 1))))

	{

		return SP_ERROR_STACKLOW;

	}

	if (result == NULL)

	{

		result = &_ignore_result;

	}

	/* We got this far.  It's time to start profiling. */

	if ((m_pPlugin->prof_flags & SP_PROF_CALLBACKS) == SP_PROF_CALLBACKS)

	{

		serial = m_pPlugin->profiler->OnCallbackBegin(this, pubfunc);

	}

	/* Save our previous state. */

	bool save_exec;

	uint32_t save_n_idx;

	cell_t save_sp, save_hp;

	save_sp = m_ctx.sp;

	save_hp = m_ctx.hp;

	save_exec = m_InExec;

	save_n_idx = m_ctx.n_idx;

	/* Push parameters */

	m_ctx.sp -= sizeof(cell_t) * (num_params + 1);

	sp = (cell_t *)(m_pPlugin->memory + m_ctx.sp);

	sp[0] = num_params;

	for (unsigned int i = 0; i < num_params; i++)

	{

		sp[i + 1] = params[i];

	}

	/* Clear internal state */

	m_ctx.n_err = SP_ERROR_NONE;

	m_ctx.n_idx = 0;

	m_MsgCache[0] = '\0';

	m_CustomMsg = false;

	m_InExec = false;

	/* Start the tracer */

	g_engine1.PushTracer(this);

	/* Execute the function */

	ir = g_Jit1.ContextExecute(m_pPlugin, &m_ctx, pubfunc->code_offs, result);

	/* Restore some states, stop tracing */

	m_InExec = save_exec;