path: root/src/m_cheat.c

/* Emacs style mode select   -*- C++ -*-
 *-----------------------------------------------------------------------------
 *
 *
 *  PrBoom: a Doom port merged with LxDoom and LSDLDoom
 *  based on BOOM, a modified and improved DOOM engine
 *  Copyright (C) 1999 by
 *  id Software, Chi Hoang, Lee Killough, Jim Flynn, Rand Phares, Ty Halderman
 *  Copyright (C) 1999-2002 by
 *  Jess Haas, Nicolas Kalkhof, Colin Phipps, Florian Schulze
 *  Copyright 2005, 2006 by
 *  Florian Schulze, Colin Phipps, Neil Stevens, Andrey Budko
 *
 *  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.
 *
 * DESCRIPTION:
 *      Cheat sequence checking.
 *
 *-----------------------------------------------------------------------------*/

#include "doomstat.h"
#include "g_game.h"
#include "r_data.h"
#include "p_inter.h"
#include "p_tick.h"
#include "m_cheat.h"
#include "m_argv.h"
#include "s_sound.h"
#include "sounds.h"
#include "dstrings.h"
#include "r_main.h"
#include "p_map.h"
#include "d_deh.h"  // Ty 03/27/98 - externalized strings
/* cph 2006/07/23 - needs direct access to thinkercap */
#include "p_tick.h"

#define plyr (players+consoleplayer)     /* the console player */

//-----------------------------------------------------------------------------
//
// CHEAT SEQUENCE PACKAGE
//
//-----------------------------------------------------------------------------

static void cheat_mus();
static void cheat_choppers();
static void cheat_god();
static void cheat_fa();
static void cheat_k();
static void cheat_kfa();
static void cheat_noclip();
static void cheat_pw();
static void cheat_behold();
static void cheat_clev();
static void cheat_mypos();
static void cheat_rate();
static void cheat_comp();
static void cheat_friction();
static void cheat_pushers();
static void cheat_tnttran();
static void cheat_massacre();
static void cheat_ddt();
static void cheat_hom();
static void cheat_fast();
static void cheat_tntkey();
static void cheat_tntkeyx();
static void cheat_tntkeyxx();
static void cheat_tntweap();
static void cheat_tntweapx();
static void cheat_tntammo();
static void cheat_tntammox();
static void cheat_smart();
static void cheat_pitch();
static void cheat_megaarmour();
static void cheat_health();

//-----------------------------------------------------------------------------
//
// List of cheat codes, functions, and special argument indicators.
//
// The first argument is the cheat code.
//
// The second argument is its DEH name, or NULL if it's not supported by -deh.
//
// The third argument is a combination of the bitmasks:
// {always, not_dm, not_coop, not_net, not_menu, not_demo, not_deh},
// which excludes the cheat during certain modes of play.
//
// The fourth argument is the handler function.
//
// The fifth argument is passed to the handler function if it's non-negative;
// if negative, then its negative indicates the number of extra characters
// expected after the cheat code, which are passed to the handler function
// via a pointer to a buffer (after folding any letters to lowercase).
//
//-----------------------------------------------------------------------------

struct cheat_s cheat[] = {
  {"idmus",      "Change music",      always,
   cheat_mus,      -2},

  {"idchoppers", "Chainsaw",          not_net | not_demo,
   cheat_choppers },

  {"iddqd",      "God mode",          not_net | not_demo,
   cheat_god      },

#if 0
  {"idk",        NULL,                not_net | not_demo | not_deh,
   cheat_k },  // The most controversial cheat code in Doom history!!!
#endif

  {"idkfa",      "Ammo & Keys",       not_net | not_demo,
   cheat_kfa },

  {"idfa",       "Ammo",              not_net | not_demo,
   cheat_fa  },

  {"idspispopd", "No Clipping 1",     not_net | not_demo,
   cheat_noclip },

  {"idclip",     "No Clipping 2",     not_net | not_demo,
   cheat_noclip },

  {"idbeholdh",  "Invincibility",     not_net | not_demo,
   cheat_health },

  {"idbeholdm",  "Invincibility",     not_net | not_demo,
   cheat_megaarmour },

  {"idbeholdv",  "Invincibility",     not_net | not_demo,
   cheat_pw,  pw_invulnerability },

  {"idbeholds",  "Berserk",           not_net | not_demo,
   cheat_pw,  pw_strength        },

  {"idbeholdi",  "Invisibility",      not_net | not_demo,
   cheat_pw,  pw_invisibility    },

  {"idbeholdr",  "Radiation Suit",    not_net | not_demo,
   cheat_pw,  pw_ironfeet        },

  {"idbeholda",  "Auto-map",          not_dm,
   cheat_pw,  pw_allmap          },

  {"idbeholdl",  "Lite-Amp Goggles",  not_dm,
   cheat_pw,  pw_infrared        },

  {"idbehold",   "BEHOLD menu",       not_dm,
   cheat_behold   },

  {"idclev",     "Level Warp",        not_net | not_demo | not_menu,
   cheat_clev,    -2},

  {"idmypos",    "Player Position",   not_dm,
   cheat_mypos    },

  {"idrate",     "Frame rate",        0,
   cheat_rate     },

  {"tntcomp",    NULL,                not_net | not_demo,
   cheat_comp     },     // phares

  {"tntem",      NULL,                not_net | not_demo,
   cheat_massacre },     // jff 2/01/98 kill all monsters

  {"iddt",       "Map cheat",         not_dm,
   cheat_ddt      },     // killough 2/07/98: moved from am_map.c

  {"tnthom",     NULL,                always,
   cheat_hom      },     // killough 2/07/98: HOM autodetector

  {"tntkey",     NULL,                not_net | not_demo,
   cheat_tntkey   },     // killough 2/16/98: generalized key cheats

  {"tntkeyr",    NULL,                not_net | not_demo,
   cheat_tntkeyx  },

  {"tntkeyy",    NULL,                not_net | not_demo,
   cheat_tntkeyx  },

  {"tntkeyb",    NULL,                not_net | not_demo,
   cheat_tntkeyx  },

  {"tntkeyrc",   NULL,                not_net | not_demo,
   cheat_tntkeyxx, it_redcard    },

  {"tntkeyyc",   NULL,                not_net | not_demo,
   cheat_tntkeyxx, it_yellowcard },

  {"tntkeybc",   NULL,                not_net | not_demo,
   cheat_tntkeyxx, it_bluecard   },

  {"tntkeyrs",   NULL,                not_net | not_demo,
   cheat_tntkeyxx, it_redskull   },

  {"tntkeyys",   NULL,                not_net | not_demo,
   cheat_tntkeyxx, it_yellowskull},

  {"tntkeybs",   NULL,                not_net | not_demo,
   cheat_tntkeyxx, it_blueskull  },  // killough 2/16/98: end generalized keys

  {"tntka",      NULL,                not_net | not_demo,
   cheat_k    },         // Ty 04/11/98 - Added TNTKA

  {"tntweap",    NULL,                not_net | not_demo,
   cheat_tntweap  },     // killough 2/16/98: generalized weapon cheats

  {"tntweap",    NULL,                not_net | not_demo,
   cheat_tntweapx, -1},

  {"tntammo",    NULL,                not_net | not_demo,
   cheat_tntammo  },

  {"tntammo",    NULL,                not_net | not_demo,
   cheat_tntammox, -1},  // killough 2/16/98: end generalized weapons

  {"tnttran",    NULL,                always,
   cheat_tnttran  },     // invoke translucency         // phares

  {"tntsmart",   NULL,                not_net | not_demo,
   cheat_smart},         // killough 2/21/98: smart monster toggle

  {"tntpitch",   NULL,                always,
   cheat_pitch},         // killough 2/21/98: pitched sound toggle

  // killough 2/21/98: reduce RSI injury by adding simpler alias sequences:
  {"tntran",     NULL,                always,
   cheat_tnttran    },   // killough 2/21/98: same as tnttran

  {"tntamo",     NULL,                not_net | not_demo,
   cheat_tntammo    },   // killough 2/21/98: same as tntammo

  {"tntamo",     NULL,                not_net | not_demo,
   cheat_tntammox, -1},  // killough 2/21/98: same as tntammo

  {"tntfast",    NULL,                not_net | not_demo,
   cheat_fast       },   // killough 3/6/98: -fast toggle

  {"tntice",     NULL,                not_net | not_demo,
   cheat_friction   },   // phares 3/10/98: toggle variable friction effects

  {"tntpush",    NULL,                not_net | not_demo,
   cheat_pushers    },   // phares 3/10/98: toggle pushers

  {NULL}                 // end-of-list marker
};

//-----------------------------------------------------------------------------

static void cheat_mus(buf)
char buf[3];
{
  int musnum;

  //jff 3/20/98 note: this cheat allowed in netgame/demorecord

  //jff 3/17/98 avoid musnum being negative and crashing
  if (!isdigit(buf[0]) || !isdigit(buf[1]))
    return;

  plyr->message = s_STSTR_MUS; // Ty 03/27/98 - externalized

  if (gamemode == commercial)
    {
      musnum = mus_runnin + (buf[0]-'0')*10 + buf[1]-'0' - 1;

      //jff 4/11/98 prevent IDMUS00 in DOOMII and IDMUS36 or greater
      if (musnum < mus_runnin ||  ((buf[0]-'0')*10 + buf[1]-'0') > 35)
        plyr->message = s_STSTR_NOMUS; // Ty 03/27/98 - externalized
      else
        {
          S_ChangeMusic(musnum, 1);
          idmusnum = musnum; //jff 3/17/98 remember idmus number for restore
        }
    }
  else
    {
      musnum = mus_e1m1 + (buf[0]-'1')*9 + (buf[1]-'1');

      //jff 4/11/98 prevent IDMUS0x IDMUSx0 in DOOMI and greater than introa
      if (buf[0] < '1' || buf[1] < '1' || ((buf[0]-'1')*9 + buf[1]-'1') > 31)
        plyr->message = s_STSTR_NOMUS; // Ty 03/27/98 - externalized
      else
        {
          S_ChangeMusic(musnum, 1);
          idmusnum = musnum; //jff 3/17/98 remember idmus number for restore
        }
    }
}

// 'choppers' invulnerability & chainsaw
static void cheat_choppers()
{
  plyr->weaponowned[wp_chainsaw] = true;
  plyr->powers[pw_invulnerability] = true;
  plyr->message = s_STSTR_CHOPPERS; // Ty 03/27/98 - externalized
}

static void cheat_god()
{                                    // 'dqd' cheat for toggleable god mode
  plyr->cheats ^= CF_GODMODE;
  if (plyr->cheats & CF_GODMODE)
    {
      if (plyr->mo)
        plyr->mo->health = god_health;  // Ty 03/09/98 - deh

      plyr->health = god_health;
      plyr->message = s_STSTR_DQDON; // Ty 03/27/98 - externalized
    }
  else
    plyr->message = s_STSTR_DQDOFF; // Ty 03/27/98 - externalized
}

// CPhipps - new health and armour cheat codes
static void cheat_health()
{
  if (!(plyr->cheats & CF_GODMODE)) {
    if (plyr->mo)
      plyr->mo->health = mega_health;
    plyr->health = mega_health;
    plyr->message = s_STSTR_BEHOLDX; // Ty 03/27/98 - externalized
  }
}

static void cheat_megaarmour()
{
  plyr->armorpoints = idfa_armor;      // Ty 03/09/98 - deh
  plyr->armortype = idfa_armor_class;  // Ty 03/09/98 - deh
  plyr->message = s_STSTR_BEHOLDX; // Ty 03/27/98 - externalized
}

static void cheat_fa()
{
  int i;

  if (!plyr->backpack)
    {
      for (i=0 ; i<NUMAMMO ; i++)
        plyr->maxammo[i] *= 2;
      plyr->backpack = true;
    }

  plyr->armorpoints = idfa_armor;      // Ty 03/09/98 - deh
  plyr->armortype = idfa_armor_class;  // Ty 03/09/98 - deh

  // You can't own weapons that aren't in the game // phares 02/27/98
  for (i=0;i<NUMWEAPONS;i++)
    if (!(((i == wp_plasma || i == wp_bfg) && gamemode == shareware) ||
          (i == wp_supershotgun && gamemode != commercial)))
      plyr->weaponowned[i] = true;

  for (i=0;i<NUMAMMO;i++)
    if (i!=am_cell || gamemode!=shareware)
      plyr->ammo[i] = plyr->maxammo[i];

  plyr->message = s_STSTR_FAADDED;
}

static void cheat_k()
{
  int i;
  for (i=0;i<NUMCARDS;i++)
    if (!plyr->cards[i])     // only print message if at least one key added
      {                      // however, caller may overwrite message anyway
        plyr->cards[i] = true;
        plyr->message = "Keys Added";
      }
}

static void cheat_kfa()
{
  cheat_k();
  cheat_fa();
  plyr->message = STSTR_KFAADDED;
}

static void cheat_noclip()
{
  // Simplified, accepting both "noclip" and "idspispopd".
  // no clipping mode cheat

  plyr->message = (plyr->cheats ^= CF_NOCLIP) & CF_NOCLIP ?
    s_STSTR_NCON : s_STSTR_NCOFF; // Ty 03/27/98 - externalized
}

// 'behold?' power-up cheats (modified for infinite duration -- killough)
static void cheat_pw(int pw)
{
  if (plyr->powers[pw])
    plyr->powers[pw] = pw!=pw_strength && pw!=pw_allmap;  // killough
  else
    {
      P_GivePower(plyr, pw);
      if (pw != pw_strength)
        plyr->powers[pw] = -1;      // infinite duration -- killough
    }
  plyr->message = s_STSTR_BEHOLDX; // Ty 03/27/98 - externalized
}

// 'behold' power-up menu
static void cheat_behold()
{
  plyr->message = s_STSTR_BEHOLD; // Ty 03/27/98 - externalized
}

// 'clev' change-level cheat
static void cheat_clev(char buf[3])
{
  int epsd, map;

  if (gamemode == commercial)
    {
      epsd = 1; //jff was 0, but espd is 1-based
      map = (buf[0] - '0')*10 + buf[1] - '0';
    }
  else
    {
      epsd = buf[0] - '0';
      map = buf[1] - '0';
    }

  // Catch invalid maps.
  if (epsd < 1 || map < 1 ||   // Ohmygod - this is not going to work.
      (gamemode == retail     && (epsd > 4 || map > 9  )) ||
      (gamemode == registered && (epsd > 3 || map > 9  )) ||
      (gamemode == shareware  && (epsd > 1 || map > 9  )) ||
      (gamemode == commercial && (epsd > 1 || map > 32 )) )  //jff no 33 and 34
    return;                                                  //8/14/98 allowed

  // So be it.

  idmusnum = -1; //jff 3/17/98 revert to normal level music on IDCLEV

  plyr->message = s_STSTR_CLEV; // Ty 03/27/98 - externalized

  G_DeferedInitNew(gameskill, epsd, map);
}

// 'mypos' for player position
// killough 2/7/98: simplified using dprintf and made output more user-friendly
static void cheat_mypos()
{
  doom_printf("Position (%d,%d,%d)\tAngle %-.0f",
          players[consoleplayer].mo->x >> FRACBITS,
          players[consoleplayer].mo->y >> FRACBITS,
          players[consoleplayer].mo->z >> FRACBITS,
          players[consoleplayer].mo->angle * (90.0/ANG90));
}

// cph - cheat to toggle frame rate/rendering stats display
static void cheat_rate()
{
  rendering_stats ^= 1;
}

// compatibility cheat

static void cheat_comp()
{
  // CPhipps - modified for new compatibility system
  compatibility_level++; compatibility_level %= MAX_COMPATIBILITY_LEVEL;
  // must call G_Compatibility after changing compatibility_level
  // (fixes sf bug number 1558738)
  G_Compatibility();
  doom_printf("New compatibility level:\n%s",
        comp_lev_str[compatibility_level]);
}

// variable friction cheat
static void cheat_friction()
{
  plyr->message =                       // Ty 03/27/98 - *not* externalized
    (variable_friction = !variable_friction) ? "Variable Friction enabled" :
                                               "Variable Friction disabled";
}


// Pusher cheat
// phares 3/10/98
static void cheat_pushers()
{
  plyr->message =                      // Ty 03/27/98 - *not* externalized
    (allow_pushers = !allow_pushers) ? "Pushers enabled" : "Pushers disabled";
}

// translucency cheat
static void cheat_tnttran()
{
  plyr->message =                      // Ty 03/27/98 - *not* externalized
    (general_translucency = !general_translucency) ? "Translucency enabled" :
                                                     "Translucency disabled";

  // killough 3/1/98, 4/11/98: cache translucency map on a demand basis
  if (general_translucency && !main_tranmap)
    R_InitTranMap(0);
}

static void cheat_massacre()    // jff 2/01/98 kill all monsters
{
  // jff 02/01/98 'em' cheat - kill all monsters
  // partially taken from Chi's .46 port
  //
  // killough 2/7/98: cleaned up code and changed to use dprintf;
  // fixed lost soul bug (LSs left behind when PEs are killed)

  int killcount=0;
  thinker_t *currentthinker = NULL;
  extern void A_PainDie(mobj_t *);

  // killough 7/20/98: kill friendly monsters only if no others to kill
  uint_64_t mask = MF_FRIEND;
  P_MapStart();
  do
    while ((currentthinker = P_NextThinker(currentthinker,th_all)) != NULL)
    if (currentthinker->function == P_MobjThinker &&
  !(((mobj_t *) currentthinker)->flags & mask) && // killough 7/20/98
        (((mobj_t *) currentthinker)->flags & MF_COUNTKILL ||
         ((mobj_t *) currentthinker)->type == MT_SKULL))
      { // killough 3/6/98: kill even if PE is dead
        if (((mobj_t *) currentthinker)->health > 0)
          {
            killcount++;
            P_DamageMobj((mobj_t *)currentthinker, NULL, NULL, 10000);
          }
        if (((mobj_t *) currentthinker)->type == MT_PAIN)
          {
            A_PainDie((mobj_t *) currentthinker);    // killough 2/8/98
            P_SetMobjState ((mobj_t *) currentthinker, S_PAIN_DIE6);
          }
      }
  while (!killcount && mask ? mask=0, 1 : 0); // killough 7/20/98
  P_MapEnd();
  // killough 3/22/98: make more intelligent about plural
  // Ty 03/27/98 - string(s) *not* externalized
  doom_printf("%d Monster%s Killed", killcount, killcount==1 ? "" : "s");
}

// killough 2/7/98: move iddt cheat from am_map.c to here
// killough 3/26/98: emulate Doom better
static void cheat_ddt()
{
  extern int ddt_cheating;
  if (automapmode & am_active)
    ddt_cheating = (ddt_cheating+1) % 3;
}

// killough 2/7/98: HOM autodetection
static void cheat_hom()
{
  extern int autodetect_hom;           // Ty 03/27/98 - *not* externalized
  plyr->message = (autodetect_hom = !autodetect_hom) ? "HOM Detection On" :
    "HOM Detection Off";
}

// killough 3/6/98: -fast parameter toggle
static void cheat_fast()
{
  plyr->message = (fastparm = !fastparm) ? "Fast Monsters On" :
    "Fast Monsters Off";  // Ty 03/27/98 - *not* externalized
  G_SetFastParms(fastparm); // killough 4/10/98: set -fast parameter correctly
}

// killough 2/16/98: keycard/skullkey cheat functions
static void cheat_tntkey()
{
  plyr->message = "Red, Yellow, Blue";  // Ty 03/27/98 - *not* externalized
}

static void cheat_tntkeyx()
{
  plyr->message = "Card, Skull";        // Ty 03/27/98 - *not* externalized
}

static void cheat_tntkeyxx(int key)
{
  plyr->message = (plyr->cards[key] = !plyr->cards[key]) ?
    "Key Added" : "Key Removed";  // Ty 03/27/98 - *not* externalized
}

// killough 2/16/98: generalized weapon cheats

static void cheat_tntweap()
{                                   // Ty 03/27/98 - *not* externalized
  plyr->message = gamemode==commercial ?           // killough 2/28/98
    "Weapon number 1-9" : "Weapon number 1-8";
}

static void cheat_tntweapx(buf)
char buf[3];
{
  int w = *buf - '1';

  if ((w==wp_supershotgun && gamemode!=commercial) ||      // killough 2/28/98
      ((w==wp_bfg || w==wp_plasma) && gamemode==shareware))
    return;

  if (w==wp_fist)           // make '1' apply beserker strength toggle
    cheat_pw(pw_strength);
  else
    if (w >= 0 && w < NUMWEAPONS) {
      if ((plyr->weaponowned[w] = !plyr->weaponowned[w]))
        plyr->message = "Weapon Added";  // Ty 03/27/98 - *not* externalized
      else
        {
          plyr->message = "Weapon Removed"; // Ty 03/27/98 - *not* externalized
          if (w==plyr->readyweapon)         // maybe switch if weapon removed
            plyr->pendingweapon = P_SwitchWeapon(plyr);
        }
    }
}

// killough 2/16/98: generalized ammo cheats
static void cheat_tntammo()
{
  plyr->message = "Ammo 1-4, Backpack";  // Ty 03/27/98 - *not* externalized
}

static void cheat_tntammox(buf)
char buf[1];
{
  int a = *buf - '1';
  if (*buf == 'b')  // Ty 03/27/98 - strings *not* externalized
    if ((plyr->backpack = !plyr->backpack))
      for (plyr->message = "Backpack Added",   a=0 ; a<NUMAMMO ; a++)
        plyr->maxammo[a] <<= 1;
    else
      for (plyr->message = "Backpack Removed", a=0 ; a<NUMAMMO ; a++)
        {
          if (plyr->ammo[a] > (plyr->maxammo[a] >>= 1))
            plyr->ammo[a] = plyr->maxammo[a];
        }
  else
    if (a>=0 && a<NUMAMMO)  // Ty 03/27/98 - *not* externalized
      { // killough 5/5/98: switch plasma and rockets for now -- KLUDGE
        a = a==am_cell ? am_misl : a==am_misl ? am_cell : a;  // HACK
        plyr->message = (plyr->ammo[a] = !plyr->ammo[a]) ?
          plyr->ammo[a] = plyr->maxammo[a], "Ammo Added" : "Ammo Removed";
      }
}

static void cheat_smart()
{
  plyr->message = (monsters_remember = !monsters_remember) ?
    "Smart Monsters Enabled" : "Smart Monsters Disabled";
}

static void cheat_pitch()
{
  plyr->message=(pitched_sounds = !pitched_sounds) ? "Pitch Effects Enabled" :
    "Pitch Effects Disabled";
}

//-----------------------------------------------------------------------------
// 2/7/98: Cheat detection rewritten by Lee Killough, to avoid
// scrambling and to use a more general table-driven approach.
//-----------------------------------------------------------------------------

#define CHEAT_ARGS_MAX 8  /* Maximum number of args at end of cheats */

boolean M_FindCheats(int key)
{
  static uint_64_t sr;
  static char argbuf[CHEAT_ARGS_MAX+1], *arg;
  static int init, argsleft, cht;
  int i, ret, matchedbefore;

  // If we are expecting arguments to a cheat
  // (e.g. idclev), put them in the arg buffer

  if (argsleft)
    {
      *arg++ = tolower(key);             // store key in arg buffer
      if (!--argsleft)                   // if last key in arg list,
        cheat[cht].func(argbuf);         // process the arg buffer
      return 1;                          // affirmative response
    }

  key = tolower(key) - 'a';
  if (key < 0 || key >= 32)              // ignore most non-alpha cheat letters
    {
      sr = 0;        // clear shift register
      return 0;
    }

  if (!init)                             // initialize aux entries of table
    {
      init = 1;
      for (i=0;cheat[i].cheat;i++)
        {
          uint_64_t c=0, m=0;
          const char *p;

          for (p=cheat[i].cheat; *p; p++)
            {
              unsigned key = tolower(*p)-'a';  // convert to 0-31
              if (key >= 32)            // ignore most non-alpha cheat letters
                continue;
              c = (c<<5) + key;         // shift key into code
              m = (m<<5) + 31;          // shift 1's into mask
            }
          cheat[i].code = c;            // code for this cheat key
          cheat[i].mask = m;            // mask for this cheat key
        }
    }

  sr = (sr<<5) + key;                   // shift this key into shift register

  for (matchedbefore = ret = i = 0; cheat[i].cheat; i++)
    if ((sr & cheat[i].mask) == cheat[i].code &&      // if match found
        !(cheat[i].when & not_dm   && deathmatch) &&  // and if cheat allowed
        !(cheat[i].when & not_coop && netgame && !deathmatch) &&
        !(cheat[i].when & not_demo && (demorecording || demoplayback)) &&
        !(cheat[i].when & not_menu && menuactive) &&
        !(cheat[i].when & not_deh  && M_CheckParm("-deh"))) {
      if (cheat[i].arg < 0)               // if additional args are required
        {
          cht = i;                        // remember this cheat code
          arg = argbuf;                   // point to start of arg buffer
          argsleft = -cheat[i].arg;       // number of args expected
          ret = 1;                        // responder has eaten key
        }
      else
        if (!matchedbefore)               // allow only one cheat at a time
          {
            matchedbefore = ret = 1;      // responder has eaten key
            cheat[i].func(cheat[i].arg);  // call cheat handler
          }
    }
  return ret;
}