/*
Copyright (C) 1996-1997 Id Software, Inc.

This program is free software; you can redistribute it and/or
modify it under the terms of the GNU General Public License
as published by the Free Software Foundation; either version 2
of the License, or (at your option) any later version.

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, write to the Free Software
Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.

   $Id: pr_exec.c 845 2009-02-05 00:39:07Z Ivanhoe $
*/

#include "qwsvdef.h"


typedef struct prstack_s
{
	int s;
	dfunction_t *f;
} prstack_t;

#define	MAX_STACK_DEPTH 32
prstack_t	pr_stack[MAX_STACK_DEPTH];
int			pr_depth;

#define	LOCALSTACK_SIZE 2048
int			localstack[LOCALSTACK_SIZE];
int			localstack_used;


qbool		pr_trace;
dfunction_t	*pr_xfunction;
int			pr_xstatement;


int			pr_argc;

char *pr_opnames[] =
    {
        "DONE",

        "MUL_F",
        "MUL_V",
        "MUL_FV",
        "MUL_VF",

        "DIV",

        "ADD_F",
        "ADD_V",

        "SUB_F",
        "SUB_V",

        "EQ_F",
        "EQ_V",
        "EQ_S",
        "EQ_E",
        "EQ_FNC",

        "NE_F",
        "NE_V",
        "NE_S",
        "NE_E",
        "NE_FNC",

        "LE",
        "GE",
        "LT",
        "GT",

        "INDIRECT",
        "INDIRECT",
        "INDIRECT",
        "INDIRECT",
        "INDIRECT",
        "INDIRECT",

        "ADDRESS",

        "STORE_F",
        "STORE_V",
        "STORE_S",
        "STORE_ENT",
        "STORE_FLD",
        "STORE_FNC",

        "STOREP_F",
        "STOREP_V",
        "STOREP_S",
        "STOREP_ENT",
        "STOREP_FLD",
        "STOREP_FNC",

        "RETURN",

        "NOT_F",
        "NOT_V",
        "NOT_S",
        "NOT_ENT",
        "NOT_FNC",

        "IF",
        "IFNOT",

        "CALL0",
        "CALL1",
        "CALL2",
        "CALL3",
        "CALL4",
        "CALL5",
        "CALL6",
        "CALL7",
        "CALL8",

        "STATE",

        "GOTO",

        "AND",
        "OR",

        "BITAND",
        "BITOR"
    };

char *PR_GlobalString (int ofs);
char *PR_GlobalStringNoContents (int ofs);


//=============================================================================

/*
=================
PR_PrintStatement
=================
*/
void PR_PrintStatement (dstatement_t *s)
{
	int i;

	if ( (unsigned)s->op < sizeof(pr_opnames)/sizeof(pr_opnames[0]))
	{

		Con_Printf ("%s ",  pr_opnames[s->op]);

		i = strlen(pr_opnames[s->op]);
		for ( ; i<10 ; i++)
			Con_Printf (" ");
	}

	if (s->op == OP_IF || s->op == OP_IFNOT)
		Con_Printf ("%sbranch %i",PR_GlobalString(s->a),s->b);
	else if (s->op == OP_GOTO)
	{
		Con_Printf ("branch %i",s->a);
	}
	else if ( (unsigned)(s->op - OP_STORE_F) < 6)
	{
		Con_Printf ("%s",PR_GlobalString(s->a));
		Con_Printf ("%s", PR_GlobalStringNoContents(s->b));
	}
	else
	{
		if (s->a)
			Con_Printf ("%s",PR_GlobalString(s->a));
		if (s->b)
			Con_Printf ("%s",PR_GlobalString(s->b));
		if (s->c)
			Con_Printf ("%s", PR_GlobalStringNoContents(s->c));
	}
	Con_Printf ("\n");
}

/*
============
PR_StackTrace
============
*/
void PR_StackTrace (void)
{
	dfunction_t *f;
	int i;

	if (pr_depth == 0)
	{
		Con_Printf ("<NO STACK>\n");
		return;
	}

	pr_stack[pr_depth].f = pr_xfunction;
	for (i=pr_depth ; i>=0 ; i--)
	{
		f = pr_stack[i].f;

		if (!f)
			Con_Printf ("<NO FUNCTION>\n");
		else
			Con_Printf ("%12s : %s\n", PR_GetString(f->s_file), PR_GetString(f->s_name));
	}
}


/*
============
PR_Profile_f

============
*/
void PR_Profile_f (void)
{
	dfunction_t	*f, *best;
	int max;
	int num;
	int i;

	if (sv.state != ss_active)
		return;	

	num = 0;
	do
	{
		max = 0;
		best = NULL;
		for (i=0 ; i<progs->numfunctions ; i++)
		{
			f = &pr_functions[i];
			if (f->profile > max)
			{
				max = f->profile;
				best = f;
			}
		}
		if (best)
		{
			if (num < 10)
				Con_Printf ("%7i %s\n", best->profile, PR_GetString(best->s_name));
			num++;
			best->profile = 0;
		}
	}
	while (best);
}


/*
============
PR_RunError

Aborts the currently executing function
============
*/
void PR_RunError (char *error, ...)
{
	va_list argptr;
	char string[1024];

	va_start (argptr,error);
	vsnprintf (string, sizeof(string), error, argptr);
	va_end (argptr);


	sv_error = true;

	PR_PrintStatement (pr_statements + pr_xstatement);
	PR_StackTrace ();
	Con_Printf ("%s\n", string);

	pr_depth = 0; // dump the stack so SV_Error can shutdown functions

	SV_Error ("Program error");
}

/*
====================
PR_EnterFunction

Returns the new program statement counter
====================
*/
int PR_EnterFunction (dfunction_t *f)
{
	int i, j, c, o;

	pr_stack[pr_depth].s = pr_xstatement;
	pr_stack[pr_depth].f = pr_xfunction;
	pr_depth++;
	if (pr_depth >= MAX_STACK_DEPTH)
		PR_RunError ("stack overflow");

	// save off any locals that the new function steps on
	c = f->locals;
	if (localstack_used + c > LOCALSTACK_SIZE)
		PR_RunError ("PR_ExecuteProgram: locals stack overflow\n");

	for (i=0 ; i < c ; i++)
		localstack[localstack_used+i] = ((int *)pr_globals)[f->parm_start + i];
	localstack_used += c;

	// copy parameters
	o = f->parm_start;
	for (i=0 ; i<f->numparms ; i++)
	{
		for (j=0 ; j<f->parm_size[i] ; j++)
		{
			((int *)pr_globals)[o] = ((int *)pr_globals)[OFS_PARM0+i*3+j];
			o++;
		}
	}

	pr_xfunction = f;
	return f->first_statement - 1; // offset the s++
}

/*
====================
PR_LeaveFunction
====================
*/
int PR_LeaveFunction (void)
{
	int i, c;

	if (pr_depth <= 0)
		SV_Error ("prog stack underflow");

	// restore locals from the stack
	c = pr_xfunction->locals;
	localstack_used -= c;
	if (localstack_used < 0)
		PR_RunError ("PR_ExecuteProgram: locals stack underflow\n");

	for (i=0 ; i < c ; i++)
		((int *)pr_globals)[pr_xfunction->parm_start + i] = localstack[localstack_used+i];

	// up stack
	pr_depth--;
	pr_xfunction = pr_stack[pr_depth].f;
	return pr_stack[pr_depth].s;
}

/*
============================================================================
PR_ExecuteProgram

The interpretation main loop
============================================================================
*/
void PR_ExecuteProgram (func_t fnum)
{
	eval_t *a = NULL, *b = NULL, *c = NULL;
	int s;
	dstatement_t *st = NULL;
	dfunction_t *f, *newf;
	int runaway;
	int i;
	edict_t *ed;
	int exitdepth;
	eval_t *ptr;

	if (!fnum || fnum >= progs->numfunctions)
	{
		if (pr_global_struct->self)
			ED_Print (PROG_TO_EDICT(pr_global_struct->self));
		SV_Error ("PR_ExecuteProgram: NULL function");
	}

	f = &pr_functions[fnum];

	runaway = 100000;
	pr_trace = false;

	// make a stack frame
	exitdepth = pr_depth;

	s = PR_EnterFunction (f);

	while (1)
	{
		s++; // next statement

		st = &pr_statements[s];
		a = (eval_t *)&pr_globals[st->a];
		b = (eval_t *)&pr_globals[st->b];
		c = (eval_t *)&pr_globals[st->c];

		if (--runaway == 0)
			PR_RunError ("runaway loop error");

		pr_xfunction->profile++;
		pr_xstatement = s;

		if (pr_trace)
			PR_PrintStatement (st);

		switch (st->op)
		{
		case OP_ADD_F:
			c->_float = a->_float + b->_float;
			break;
		case OP_ADD_V:
			c->vector[0] = a->vector[0] + b->vector[0];
			c->vector[1] = a->vector[1] + b->vector[1];
			c->vector[2] = a->vector[2] + b->vector[2];
			break;

		case OP_SUB_F:
			c->_float = a->_float - b->_float;
			break;
		case OP_SUB_V:
			c->vector[0] = a->vector[0] - b->vector[0];
			c->vector[1] = a->vector[1] - b->vector[1];
			c->vector[2] = a->vector[2] - b->vector[2];
			break;

		case OP_MUL_F:
			c->_float = a->_float * b->_float;
			break;
		case OP_MUL_V:
			c->_float = a->vector[0]*b->vector[0]
			            + a->vector[1]*b->vector[1]
			            + a->vector[2]*b->vector[2];
			break;
		case OP_MUL_FV:
			c->vector[0] = a->_float * b->vector[0];
			c->vector[1] = a->_float * b->vector[1];
			c->vector[2] = a->_float * b->vector[2];
			break;
		case OP_MUL_VF:
			c->vector[0] = b->_float * a->vector[0];
			c->vector[1] = b->_float * a->vector[1];
			c->vector[2] = b->_float * a->vector[2];
			break;

		case OP_DIV_F:
			c->_float = a->_float / b->_float;
			break;

		case OP_BITAND:
			c->_float = (int)a->_float & (int)b->_float;
			break;

		case OP_BITOR:
			c->_float = (int)a->_float | (int)b->_float;
			break;


		case OP_GE:
			c->_float = a->_float >= b->_float;
			break;
		case OP_LE:
			c->_float = a->_float <= b->_float;
			break;
		case OP_GT:
			c->_float = a->_float > b->_float;
			break;
		case OP_LT:
			c->_float = a->_float < b->_float;
			break;
		case OP_AND:
			c->_float = a->_float && b->_float;
			break;
		case OP_OR:
			c->_float = a->_float || b->_float;
			break;

		case OP_NOT_F:
			c->_float = !a->_float;
			break;
		case OP_NOT_V:
			c->_float = !a->vector[0] && !a->vector[1] && !a->vector[2];
			break;
		case OP_NOT_S:
			c->_float = !a->string || !*PR_GetString(a->string);
			break;
		case OP_NOT_FNC:
			c->_float = !a->function;
			break;
		case OP_NOT_ENT:
			c->_float = (PROG_TO_EDICT(a->edict) == sv.edicts);
			break;

		case OP_EQ_F:
			c->_float = a->_float == b->_float;
			break;
		case OP_EQ_V:
			c->_float = (a->vector[0] == b->vector[0]) &&
			            (a->vector[1] == b->vector[1]) &&
			            (a->vector[2] == b->vector[2]);
			break;
		case OP_EQ_S:
			c->_float = !strcmp(PR_GetString(a->string), PR_GetString(b->string));
			break;
		case OP_EQ_E:
			c->_float = a->_int == b->_int;
			break;
		case OP_EQ_FNC:
			c->_float = a->function == b->function;
			break;


		case OP_NE_F:
			c->_float = a->_float != b->_float;
			break;
		case OP_NE_V:
			c->_float = (a->vector[0] != b->vector[0]) ||
			            (a->vector[1] != b->vector[1]) ||
			            (a->vector[2] != b->vector[2]);
			break;
		case OP_NE_S:
			c->_float = strcmp(PR_GetString(a->string), PR_GetString(b->string));
			break;
		case OP_NE_E:
			c->_float = a->_int != b->_int;
			break;
		case OP_NE_FNC:
			c->_float = a->function != b->function;
			break;

			//==================
		case OP_STORE_F:
		case OP_STORE_ENT:
		case OP_STORE_FLD:		// integers
		case OP_STORE_S:
		case OP_STORE_FNC:		// pointers
			b->_int = a->_int;
			break;
		case OP_STORE_V:
			b->vector[0] = a->vector[0];
			b->vector[1] = a->vector[1];
			b->vector[2] = a->vector[2];
			break;

		case OP_STOREP_F:
		case OP_STOREP_ENT:
		case OP_STOREP_FLD:		// integers
		case OP_STOREP_S:
		case OP_STOREP_FNC:		// pointers
			ptr = (eval_t *)((byte *)sv.edicts + b->_int);
			ptr->_int = a->_int;
			break;
		case OP_STOREP_V:
			ptr = (eval_t *)((byte *)sv.edicts + b->_int);
			ptr->vector[0] = a->vector[0];
			ptr->vector[1] = a->vector[1];
			ptr->vector[2] = a->vector[2];
			break;

		case OP_ADDRESS:
			ed = PROG_TO_EDICT(a->edict);
#ifdef PARANOID
			NUM_FOR_EDICT(ed);		// make sure it's in range
#endif
			if (ed == (edict_t *)sv.edicts && sv.state == ss_active)
				PR_RunError ("assignment to world entity");
			c->_int = (byte *)((int *)&ed->v + b->_int) - (byte *)sv.edicts;
			break;

		case OP_LOAD_F:
		case OP_LOAD_FLD:
		case OP_LOAD_ENT:
		case OP_LOAD_S:
		case OP_LOAD_FNC:
			ed = PROG_TO_EDICT(a->edict);
#ifdef PARANOID
			NUM_FOR_EDICT(ed);		// make sure it's in range
#endif
			//need for checking 'cmd mmode player N', if N >= 0x10000000 =(signed)=> negative
			if (b->_int >= 0)
			{
				a = (eval_t *)((int *)&ed->v + b->_int);
				c->_int = a->_int;
			}
			else
				c->_int = 0;
			break;

		case OP_LOAD_V:
			ed = PROG_TO_EDICT(a->edict);
#ifdef PARANOID
			NUM_FOR_EDICT(ed);		// make sure it's in range
#endif
			a = (eval_t *)((int *)&ed->v + b->_int);
			c->vector[0] = a->vector[0];
			c->vector[1] = a->vector[1];
			c->vector[2] = a->vector[2];
			break;

			//==================

		case OP_IFNOT:
			if (!a->_int)
				s += st->b - 1;	// offset the s++
			break;

		case OP_IF:
			if (a->_int)
				s += st->b - 1;	// offset the s++
			break;

		case OP_GOTO:
			s += st->a - 1;	// offset the s++
			break;

		case OP_CALL0:
		case OP_CALL1:
		case OP_CALL2:
		case OP_CALL3:
		case OP_CALL4:
		case OP_CALL5:
		case OP_CALL6:
		case OP_CALL7:
		case OP_CALL8:
			pr_argc = st->op - OP_CALL0;
			if (!a->function)
				PR_RunError ("NULL function");

			newf = &pr_functions[a->function];

			if (newf->first_statement < 0)
			{	// negative statements are built in functions
				i = -newf->first_statement;
				if (i >= pr_numbuiltins)
					PR_RunError ("Bad builtin call number");
				pr_builtins[i] ();
				break;
			}

			s = PR_EnterFunction (newf);

			break;

		case OP_DONE:
		case OP_RETURN:
			pr_globals[OFS_RETURN] = pr_globals[st->a];
			pr_globals[OFS_RETURN+1] = pr_globals[st->a+1];
			pr_globals[OFS_RETURN+2] = pr_globals[st->a+2];

			s = PR_LeaveFunction ();
			if (pr_depth == exitdepth)
				return;		// all done
			break;

		case OP_STATE:
			ed = PROG_TO_EDICT(pr_global_struct->self);
			ed->v.nextthink = pr_global_struct->time + 0.1;
			if (a->_float != ed->v.frame)
			{
				ed->v.frame = a->_float;
			}
			ed->v.think = b->function;
			break;

		default:
			PR_RunError ("Bad opcode %i", st->op);
		}
	}

}

/*----------------------*/

char *pr_newstrtbl[MAX_PRSTR];
char *pr_strtbl[MAX_PRSTR];
int num_prstr;

char *PR_GetString(int num)
{
	if (num < 0)
	{
		//Con_DPrintf("GET:%d == %s\n", num, pr_strtbl[-num]);
		num = -num;
		if (num >= 2 * MAX_PRSTR)
		{
			Con_Printf("PR_GetString: num = %d\n", num);// May be will be better to generate PR_RunError?
			return NULL;
		}
		if (num >= MAX_PRSTR)
			return pr_newstrtbl[num - MAX_PRSTR];

		return pr_strtbl[num];
	}
	return pr_strings + num;
}

int PR_SetString(char *s)
{
	int i;

	if (s - pr_strings < 0)
	{
		for (i = 0; i <= num_prstr; i++)
			if (pr_strtbl[i] == s)
				break;
		if (i < num_prstr)
			return -i;
		if (num_prstr == MAX_PRSTR - 1)
			Sys_Error("MAX_PRSTR");
		num_prstr++;
		pr_strtbl[num_prstr] = s;
		//Con_DPrintf("SET:%d == %s\n", -num_prstr, s);
		return -num_prstr;
	}
	return (int)(s - pr_strings);
}

/*
==============
PR_SetTmpString

temp strings are used for qc function parameters
many calls to function could cause strtbl overflow
==============
*/

int PR_SetTmpString(char *s)
{
	static int index1;
	static char tmp[8][2048];

	index1 = (index1 + 1) & 7;

	strlcpy(tmp[index1], s, sizeof(tmp[index1]));
	return PR_SetString(tmp[index1]);
}
