m_cheat.c

// Emacs style mode select   -*- C++ -*- 
//-----------------------------------------------------------------------------
//
// $Id:$
//
// Copyright (C) 1993-1996 by id Software, Inc.
//
// This source is available for distribution and/or modification
// only under the terms of the DOOM Source Code License as
// published by id Software. All rights reserved.
//
// The source is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// FITNESS FOR A PARTICULAR PURPOSE. See the DOOM Source Code License
// for more details.
//
// $Log:$
//
// DESCRIPTION:
//	Cheat sequence checking.
//
// static const char rcsid[] = "$Id: m_cheat.c,v 1.1 1997/02/03 21:24:34 b1 Exp $";
//-----------------------------------------------------------------------------




#include "m_cheat.h"

//
// CHEAT SEQUENCE PACKAGE
//

static int		firsttime = 1;
static unsigned char	cheat_xlate_table[256];


//
// Called in st_stuff module, which handles the input.
// Returns a 1 if the cheat was successful, 0 if failed.
//
int
cht_CheckCheat
( cheatseq_t*	cht,
  char		key )
{
    int i;
    int rc = 0;

    if (firsttime)
    {
	firsttime = 0;
	for (i=0;i<256;i++) cheat_xlate_table[i] = SCRAMBLE(i);
    }

    if (!cht->p)
	cht->p = cht->sequence; // initialize if first time

    if (*cht->p == 0)
	*(cht->p++) = key;
    else if
	(cheat_xlate_table[(unsigned char)key] == *cht->p) cht->p++;
    else
	cht->p = cht->sequence;

    if (*cht->p == 1)
	cht->p++;
    else if (*cht->p == 0xff) // end of sequence character
    {
	cht->p = cht->sequence;
	rc = 1;
    }

    return rc;
}

void
cht_GetParam
( cheatseq_t*	cht,
  char*		buffer )
{

    unsigned char *p, c;

    p = cht->sequence;
    while (*(p++) != 1);
    
    do
    {
	c = *p;
	*(buffer++) = c;
	*(p++) = 0;
    }
    while (c && *p!=0xff );

    if (*p==0xff)
	*buffer = 0;

}