beetle-pce-fast-libretro/mednafen/mempatcher.cpp

/* Mednafen - Multi-system Emulator
 *
 * 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
 */

#include "mednafen.h"

#include <string.h>
#include <ctype.h>
#include <trio/trio.h>
#include <errno.h>
#include <vector>

#include "general.h"
#include "md5.h"
#include "mempatcher.h"

#ifdef _WIN32
#include "msvc_compat.h"
#endif

static uint8 **RAMPtrs = NULL;
static uint32 PageSize;
static uint32 NumPages;

typedef struct
{
 bool excluded;
 uint8 value; 
} CompareStruct;

typedef struct __CHEATF
{
           char *name;
           char *conditions;

           uint32 addr;
           uint64 val;
           uint64 compare;

           unsigned int length;
           bool bigendian;
           unsigned int icount; // Instance count
           char type;   /* 'R' for replace, 'S' for substitute(GG), 'C' for substitute with compare */
           int status;
} CHEATF;

static std::vector<CHEATF> cheats;
static int savecheats;
static CompareStruct **CheatComp = NULL;
static uint32 resultsbytelen = 1;
static bool resultsbigendian = 0;
static bool CheatsActive = TRUE;

bool SubCheatsOn = 0;
std::vector<SUBCHEAT> SubCheats[8];

static void RebuildSubCheats(void)
{
 std::vector<CHEATF>::iterator chit;

 SubCheatsOn = 0;
 for(int x = 0; x < 8; x++)
  SubCheats[x].clear();

 if(!CheatsActive) return;

 for(chit = cheats.begin(); chit != cheats.end(); chit++)
 {
  if(chit->status && chit->type != 'R')
  {
   for(unsigned int x = 0; x < chit->length; x++)
   {
    SUBCHEAT tmpsub;
    unsigned int shiftie;

    if(chit->bigendian)
     shiftie = (chit->length - 1 - x) * 8;
    else
     shiftie = x * 8;
    
    tmpsub.addr = chit->addr + x;
    tmpsub.value = (chit->val >> shiftie) & 0xFF;
    if(chit->type == 'C')
     tmpsub.compare = (chit->compare >> shiftie) & 0xFF;
    else
     tmpsub.compare = -1;
    SubCheats[(chit->addr + x) & 0x7].push_back(tmpsub);
    SubCheatsOn = 1;
   }
  }
 }
}

bool MDFNMP_Init(uint32 ps, uint32 numpages)
{
 PageSize = ps;
 NumPages = numpages;

 RAMPtrs = (uint8 **)calloc(numpages, sizeof(uint8 *));
 CheatComp = (CompareStruct **)calloc(numpages, sizeof(CompareStruct *));

 CheatsActive = MDFN_GetSettingB("cheats");
 return(1);
}

void MDFNMP_Kill(void)
{
 if(CheatComp)
 {
  free(CheatComp);
  CheatComp = NULL;
 }
 if(RAMPtrs)
 {
  free(RAMPtrs);
  RAMPtrs = NULL;
 }
}


void MDFNMP_AddRAM(uint32 size, uint32 A, uint8 *RAM)
{
 uint32 AB = A / PageSize;
 
 size /= PageSize;

 for(unsigned int x = 0; x < size; x++)
 {
  RAMPtrs[AB + x] = RAM;
  if(RAM) // Don't increment the RAM pointer if we're passed a NULL pointer
   RAM += PageSize;
 }
}

void MDFNMP_InstallReadPatches(void)
{
 if(!CheatsActive) return;

 std::vector<SUBCHEAT>::iterator chit;

 for(unsigned int x = 0; x < 8; x++)
  for(chit = SubCheats[x].begin(); chit != SubCheats[x].end(); chit++)
  {
   if(MDFNGameInfo->InstallReadPatch)
    MDFNGameInfo->InstallReadPatch(chit->addr);
  }
}

void MDFNMP_RemoveReadPatches(void)
{
 if(MDFNGameInfo->RemoveReadPatches)
  MDFNGameInfo->RemoveReadPatches();
}

static void CheatMemErr(void)
{
 MDFN_PrintError(_("Error allocating memory for cheat data."));
}

/* This function doesn't allocate any memory for "name" */
static int AddCheatEntry(char *name, char *conditions, uint32 addr, uint64 val, uint64 compare, int status, char type, unsigned int length, bool bigendian)
{
 CHEATF temp;

 memset(&temp, 0, sizeof(CHEATF));

 temp.name=name;
 temp.conditions = conditions;
 temp.addr=addr;
 temp.val=val;
 temp.status=status;
 temp.compare=compare;
 temp.length = length;
 temp.bigendian = bigendian;
 temp.type=type;

 cheats.push_back(temp);
 return(1);
}

static bool SeekToOurSection(void *fp_ptr)
{
   FILE *fp = (FILE*)fp_ptr;
   char buf[2048];

   while(fgets(buf,2048,fp) > 0)
   {
      if(buf[0] == '[')
      {
         if(!strncmp((char *)buf + 1, md5_context::asciistr(MDFNGameInfo->MD5, 0).c_str(), 16))
            return(1);
      }
   }
   return(0);
}

void MDFN_LoadGameCheats(void *override_ptr)
{
 char linebuf[2048];
 FILE *fp;
 FILE *override = (FILE*)override_ptr;

 unsigned int addr;
 unsigned long long val;
 unsigned int status;
 char type;
 unsigned long long compare;
 unsigned int x;
 unsigned int length;
 unsigned int icount;
 bool bigendian;

 int tc=0;

 savecheats=0;

 if(override)
  fp = override;
 else
 {
  std::string fn = MDFN_MakeFName(MDFNMKF_CHEAT,0,0).c_str();

  MDFN_printf("\n");
  MDFN_printf(_("Loading cheats from %s...\n"), fn.c_str());
  MDFN_indent(1);

  if(!(fp = fopen(fn.c_str(),"rb")))
  {
   ErrnoHolder ene(errno);

   MDFN_printf(_("Error opening file: %s\n"), ene.StrError());
   MDFN_indent(-1);
   return;
  }
 }

 if(SeekToOurSection(fp))
 {
  while(fgets(linebuf,2048,fp) > 0)
  { 
   char namebuf[2048];
   char *tbuf=linebuf;

   addr=val=compare=status=type=0;
   bigendian = 0;
   icount = 0;

   if(tbuf[0] == '[') // No more cheats for this game, so sad :(
   {
    break;
   }

   if(tbuf[0] == '\n' || tbuf[0] == '\r' || tbuf[0] == '\t' || tbuf[0] == ' ') // Don't parse if the line starts(or is just) white space
    continue;

   if(tbuf[0] != 'R' && tbuf[0] != 'C' && tbuf[0] != 'S')
   {
    MDFN_printf(_("Invalid cheat type: %c\n"), tbuf[0]);
    break;
   }
   type = tbuf[0];
   namebuf[0] = 0;

   char status_tmp, endian_tmp;
   if(type == 'C')
    trio_sscanf(tbuf, "%c %c %d %c %d %08x %16llx %16llx %.2047[^\r\n]", &type, &status_tmp, &length, &endian_tmp, &icount, &addr, &val, &compare, namebuf);
   else
    trio_sscanf(tbuf, "%c %c %d %c %d %08x %16llx %.2047[^\r\n]", &type, &status_tmp, &length, &endian_tmp, &icount, &addr, &val, namebuf);

   status = (status_tmp == 'A') ? 1 : 0;
   bigendian = (endian_tmp == 'B') ? 1 : 0;

   for(x=0;x<strlen(namebuf);x++)
   {
    if(namebuf[x]==10 || namebuf[x]==13)
    {
     namebuf[x]=0;
    break;
    }
    else if(namebuf[x]<0x20) namebuf[x]=' ';
   }

   // November 9, 2009 return value fix.
   if(fgets(linebuf, 2048, fp) == NULL)
    linebuf[0] = 0;

   for(x=0;x<strlen(linebuf);x++)
   {
    if(linebuf[x]==10 || linebuf[x]==13)
    {
     linebuf[x]=0;
     break;
    }
    else if(linebuf[x]<0x20) linebuf[x]=' ';
   }

   AddCheatEntry(strdup(namebuf), strdup(linebuf), addr, val, compare, status, type, length, bigendian);
   tc++;
  }
 }

 RebuildSubCheats();

 if(!override)
 {
  MDFN_printf(_("%lu cheats loaded.\n"), (unsigned long)cheats.size());
  MDFN_indent(-1);
  fclose(fp);
 }
}

static void WriteOurCheats(FILE *tmp_fp, bool needheader)
{
     if(needheader)
      trio_fprintf(tmp_fp, "[%s] %s\n", md5_context::asciistr(MDFNGameInfo->MD5, 0).c_str(), MDFNGameInfo->name ? (char *)MDFNGameInfo->name : "");

     std::vector<CHEATF>::iterator next;

     for(next = cheats.begin(); next != cheats.end(); next++)
     {
      if(next->type == 'C')
      {
       if(next->length == 1)
        trio_fprintf(tmp_fp, "%c %c %d %c %d %08x %02llx %02llx %s\n", next->type, next->status ? 'A' : 'I', next->length, next->bigendian ? 'B' : 'L', next->icount, next->addr, next->val, next->compare, next->name);
       else if(next->length == 2)
        trio_fprintf(tmp_fp, "%c %c %d %c %d %08x %04llx %04llx %s\n", next->type, next->status ? 'A' : 'I', next->length, next->bigendian ? 'B' : 'L', next->icount, next->addr, next->val, next->compare, next->name);
       else
        trio_fprintf(tmp_fp, "%c %c %d %c %d %08x %016llx %016llx %s\n", next->type, next->status ? 'A' : 'I', next->length, next->bigendian ? 'B' : 'L', next->icount, next->addr, next->val, next->compare, next->name);
      }
      else
      {
       if(next->length == 1)
        trio_fprintf(tmp_fp, "%c %c %d %c %d %08x %02llx %s\n", next->type, next->status ? 'A' : 'I', next->length, next->bigendian ? 'B' : 'L', next->icount, next->addr, next->val, next->name);
       else if(next->length == 2)
        trio_fprintf(tmp_fp, "%c %c %d %c %d %08x %04llx %s\n", next->type, next->status ? 'A' : 'I', next->length, next->bigendian ? 'B' : 'L', next->icount, next->addr, next->val, next->name);
       else
        trio_fprintf(tmp_fp, "%c %c %d %c %d %08x %016llx %s\n", next->type, next->status ? 'A' : 'I', next->length, next->bigendian ? 'B' : 'L', next->icount, next->addr, next->val, next->name);
      }
      trio_fprintf(tmp_fp, "%s\n", next->conditions ? next->conditions : "");
      free(next->name);
      if(next->conditions)
       free(next->conditions);
     }
}

void MDFN_FlushGameCheats(int nosave)
{
 if(CheatComp)
 {
  free(CheatComp);
  CheatComp = 0;
 }

 if(!savecheats || nosave)
 {
  std::vector<CHEATF>::iterator chit;

  for(chit = cheats.begin(); chit != cheats.end(); chit++)
  {
   free(chit->name);
   if(chit->conditions)
    free(chit->conditions);
  }
  cheats.clear();
 }
 else
 {
  uint8 linebuf[2048];
  std::string fn, tmp_fn;

  fn = MDFN_MakeFName(MDFNMKF_CHEAT, 0, 0);
  tmp_fn = MDFN_MakeFName(MDFNMKF_CHEAT_TMP, 0, 0);

  FILE *fp;
  int insection = 0;

  if((fp = fopen(fn.c_str(), "rb")))
  {
   FILE *tmp_fp = fopen(tmp_fn.c_str(), "wb");

   while(fgets((char*)linebuf, 2048, fp) > 0)
   {
    if(linebuf[0] == '[' && !insection)
    {
     if(!strncmp((char *)linebuf + 1, md5_context::asciistr(MDFNGameInfo->MD5, 0).c_str(), 16))
     {
      insection = 1;
      if(cheats.size())
       fputs((char*)linebuf, tmp_fp);
     }
     else
      fputs((char*)linebuf, tmp_fp);
    }
    else if(insection == 1)
    {
     if(linebuf[0] == '[') 
     {
      // Write any of our game cheats here.
      WriteOurCheats(tmp_fp, 0);
      insection = 2;     
      fputs((char*)linebuf, tmp_fp);
     }
    }
    else
    {
     fputs((char*)linebuf, tmp_fp);
    }
   }

   if(cheats.size())
   {
    if(!insection)
     WriteOurCheats(tmp_fp, 1);
    else if(insection == 1)
     WriteOurCheats(tmp_fp, 0);
   }

   fclose(fp);
   fclose(tmp_fp);

   #ifdef WIN32
   unlink(fn.c_str()); // Windows is evil. EVIIILL.  rename() won't overwrite an existing file.  TODO:  Change this to an autoconf define or something
		      // if we ever come across other platforms with lame rename().
   #endif
   rename(tmp_fn.c_str(), fn.c_str());
  }
  else if(errno == ENOENT) // Only overwrite the cheats file if it doesn't exist...heh.  Race conditions abound!
  {
   fp = fopen(fn.c_str(), "wb");
   WriteOurCheats(fp, 1);
   fclose(fp);
  }
 }
 RebuildSubCheats();
}

int MDFNI_AddCheat(const char *name, uint32 addr, uint64 val, uint64 compare, char type, unsigned int length, bool bigendian)
{
 char *t;

 if(!(t = strdup(name)))
 {
  CheatMemErr();
  return(0);
 }

 if(!AddCheatEntry(t, NULL, addr,val,compare,1,type, length, bigendian))
 {
  free(t);
  return(0);
 }

 savecheats = 1;

 MDFNMP_RemoveReadPatches();
 RebuildSubCheats();
 MDFNMP_InstallReadPatches();

 return(1);
}

int MDFNI_DelCheat(uint32 which)
{
 free(cheats[which].name);
 cheats.erase(cheats.begin() + which);

 savecheats=1;

 MDFNMP_RemoveReadPatches();
 RebuildSubCheats();
 MDFNMP_InstallReadPatches();

 return(1);
}

/*
 Condition format(ws = white space):
 
  <variable size><ws><endian><ws><address><ws><operation><ws><value>
	  [,second condition...etc.]

  Value should be unsigned integer, hex(with a 0x prefix) or
  base-10.  

  Operations:
   >=
   <=
   >
   <
   ==
   !=
   &	// Result of AND between two values is nonzero
   !&   // Result of AND between two values is zero
   ^    // same, XOR
   !^
   |	// same, OR
   !|

  Full example:

  2 L 0xADDE == 0xDEAD, 1 L 0xC000 == 0xA0

*/

static bool TestConditions(const char *string)
{
 char address[64];
 char operation[64];
 char value[64];
 char endian;
 unsigned int bytelen;
 bool passed = 1;

 //printf("TR: %s\n", string);
 while(trio_sscanf(string, "%u %c %.63s %.63s %.63s", &bytelen, &endian, address, operation, value) == 5 && passed)
 {
  uint32 v_address;
  uint64 v_value;
  uint64 value_at_address;

  if(address[0] == '0' && address[1] == 'x')
   v_address = strtoul(address + 2, NULL, 16);
  else
   v_address = strtoul(address, NULL, 10);

  if(value[0] == '0' && value[1] == 'x')
   v_value = strtoull(value + 2, NULL, 16);
  else
   v_value = strtoull(value, NULL, 0);

  value_at_address = 0;
  for(unsigned int x = 0; x < bytelen; x++)
  {
   unsigned int shiftie;

   if(endian == 'B')
    shiftie = (bytelen - 1 - x) * 8;
   else
    shiftie = x * 8;
   value_at_address |= MDFNGameInfo->MemRead(v_address + x) << shiftie;
  }

  //printf("A: %08x, V: %08llx, VA: %08llx, OP: %s\n", v_address, v_value, value_at_address, operation);
  if(!strcmp(operation, ">="))
  {
   if(!(value_at_address >= v_value))
    passed = 0;
  }
  else if(!strcmp(operation, "<="))
  {
   if(!(value_at_address <= v_value))
    passed = 0;
  }
  else if(!strcmp(operation, ">"))
  {
   if(!(value_at_address > v_value))
    passed = 0;
  }
  else if(!strcmp(operation, "<"))
  {
   if(!(value_at_address < v_value))
    passed = 0;
  }
  else if(!strcmp(operation, "==")) 
  {
   if(!(value_at_address == v_value))
    passed = 0;
  }
  else if(!strcmp(operation, "!="))
  {
   if(!(value_at_address != v_value))
    passed = 0;
  }
  else if(!strcmp(operation, "&"))
  {
   if(!(value_at_address & v_value))
    passed = 0;
  }
  else if(!strcmp(operation, "!&"))
  {
   if(value_at_address & v_value)
    passed = 0;
  }
  else if(!strcmp(operation, "^"))
  {
   if(!(value_at_address ^ v_value))
    passed = 0;
  }
  else if(!strcmp(operation, "!^"))
  {
   if(value_at_address ^ v_value)
    passed = 0;
  }
  else if(!strcmp(operation, "|"))
  {
   if(!(value_at_address | v_value))
    passed = 0;
  }
  else if(!strcmp(operation, "!|"))
  {
   if(value_at_address | v_value)
    passed = 0;
  }
  else
   puts("Invalid operation");
  string = strchr(string, ',');
  if(string == NULL)
   break;
  else
   string++;
  //printf("Foo: %s\n", string);
 }

 return(passed);
}

void MDFNMP_ApplyPeriodicCheats(void)
{
 std::vector<CHEATF>::iterator chit;


 if(!CheatsActive)
  return;

 //TestConditions("2 L 0x1F00F5 == 0xDEAD");
 //if(TestConditions("1 L 0x1F0058 > 0")) //, 1 L 0xC000 == 0x01"));
 for(chit = cheats.begin(); chit != cheats.end(); chit++)
 {
  if(chit->status && chit->type == 'R')
  {
   if(!chit->conditions || TestConditions(chit->conditions))
    for(unsigned int x = 0; x < chit->length; x++)
    {
     uint32 page = ((chit->addr + x) / PageSize) % NumPages;
     if(RAMPtrs[page])
     {
      uint64 tmpval = chit->val;

      if(chit->bigendian)
       tmpval >>= (chit->length - 1 - x) * 8;
      else
       tmpval >>= x * 8;

      RAMPtrs[page][(chit->addr + x) % PageSize] = tmpval;
     }
   }
  }
 }
}


void MDFNI_ListCheats(int (*callb)(char *name, uint32 a, uint64 v, uint64 compare, int s, char type, unsigned int length, bool bigendian, void *data), void *data)
{
 std::vector<CHEATF>::iterator chit;

 for(chit = cheats.begin(); chit != cheats.end(); chit++)
 {
  if(!callb(chit->name, chit->addr, chit->val, chit->compare, chit->status, chit->type, chit->length, chit->bigendian, data)) break;
 }
}

int MDFNI_GetCheat(uint32 which, char **name, uint32 *a, uint64 *v, uint64 *compare, int *s, char *type, unsigned int *length, bool *bigendian)
{
 CHEATF *next = &cheats[which];

 if(name)
  *name=next->name;
 if(a)
  *a=next->addr; 
 if(v)
  *v=next->val;
 if(s)
  *s=next->status;
 if(compare)
  *compare=next->compare;
 if(type)
  *type=next->type;
 if(length)
  *length = next->length;
 if(bigendian)
  *bigendian = next->bigendian;
 return(1);
}

static uint8 CharToNibble(char thechar)
{
 const char lut[16] = {'0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'A', 'B', 'C', 'D', 'E', 'F' };

 thechar = toupper(thechar);

 for(int x = 0; x < 16; x++)
  if(lut[x] == thechar)
   return(x);

 return(0xFF);
}

bool MDFNI_DecodeGBGG(const char *instr, uint32 *a, uint8 *v, uint8 *c, char *type)
{
 char str[10];
 int len;

 for(int x = 0; x < 9; x++)
 {
  while(*instr && CharToNibble(*instr) == 255)
   instr++;
  if(!(str[x] = *instr)) break;
  instr++;
 }
 str[9] = 0;

 len = strlen(str);

 if(len != 9 && len != 6)
  return(0);

 uint32 tmp_address;
 uint8 tmp_value;
 uint8 tmp_compare = 0;

 tmp_address =  (CharToNibble(str[5]) << 12) | (CharToNibble(str[2]) << 8) | (CharToNibble(str[3]) << 4) | (CharToNibble(str[4]) << 0);
 tmp_address ^= 0xF000;
 tmp_value = (CharToNibble(str[0]) << 4) | (CharToNibble(str[1]) << 0);

 if(len == 9)
 {
  tmp_compare = (CharToNibble(str[6]) << 4) | (CharToNibble(str[8]) << 0);
  tmp_compare = (tmp_compare >> 2) | ((tmp_compare << 6) & 0xC0);
  tmp_compare ^= 0xBA;
 }

 *a = tmp_address;
 *v = tmp_value;

 if(len == 9)
 {
  *c = tmp_compare;
  *type = 'C';
 }
 else
 {
  *c = 0;
  *type = 'S';
 }

 return(1);
}

static int GGtobin(char c)
{
 static char lets[16]={'A','P','Z','L','G','I','T','Y','E','O','X','U','K','S','V','N'};
 int x;

 for(x=0;x<16;x++)
  if(lets[x] == toupper(c)) return(x);
 return(0);
}

/* Returns 1 on success, 0 on failure. Sets *a,*v,*c. */
int MDFNI_DecodeGG(const char *str, uint32 *a, uint8 *v, uint8 *c, char *type)
{
 uint16 A;
 uint8 V,C;
 uint8 t;
 int s;

 A=0x8000;
 V=0;
 C=0;

 s=strlen(str);
 if(s!=6 && s!=8) return(0);

 t=GGtobin(*str++);
 V|=(t&0x07);
 V|=(t&0x08)<<4;

 t=GGtobin(*str++);
 V|=(t&0x07)<<4;
 A|=(t&0x08)<<4;

 t=GGtobin(*str++);
 A|=(t&0x07)<<4;
 //if(t&0x08) return(0);	/* 8-character code?! */

 t=GGtobin(*str++);
 A|=(t&0x07)<<12;
 A|=(t&0x08);

 t=GGtobin(*str++);
 A|=(t&0x07);
 A|=(t&0x08)<<8;

 if(s==6)
 {
  t=GGtobin(*str++);
  A|=(t&0x07)<<8;
  V|=(t&0x08);

  *a=A;
  *v=V;
  *type = 'S';
  *c = 0;
  return(1);
 }
 else
 {
  t=GGtobin(*str++);
  A|=(t&0x07)<<8;
  C|=(t&0x08);

  t=GGtobin(*str++);
  C|=(t&0x07);
  C|=(t&0x08)<<4;
  
  t=GGtobin(*str++);
  C|=(t&0x07)<<4;
  V|=(t&0x08);
  *a=A;
  *v=V;
  *c=C;
  *type = 'C';
  return(1);
 }
 return(0);
}

int MDFNI_DecodePAR(const char *str, uint32 *a, uint8 *v, uint8 *c, char *type)
{
 int boo[4];
 if(strlen(str)!=8) return(0);

 trio_sscanf(str,"%02x%02x%02x%02x",boo,boo+1,boo+2,boo+3);

 *c = 0;

 if(1)
 {
  *a=(boo[3]<<8)|(boo[2]+0x7F);
  *v=0;
 }
 else
 {
  *v=boo[3];
  *a=boo[2]|(boo[1]<<8);
 }

 *type = 'S';
 return(1);
}

/* name can be NULL if the name isn't going to be changed. */
int MDFNI_SetCheat(uint32 which, const char *name, uint32 a, uint64 v, uint64 compare, int s, char type, unsigned int length, bool bigendian)
{
 CHEATF *next = &cheats[which];

 if(name)
 {
  char *t;

  if((t=(char *)realloc(next->name,strlen(name+1))))
  {
   next->name=t;
   strcpy(next->name,name);
  }
  else
   return(0);
 }
 next->addr=a;
 next->val=v;
 next->status=s;
 next->compare=compare;
 next->type=type;
 next->length = length;
 next->bigendian = bigendian;

 RebuildSubCheats();
 savecheats=1;

 return(1);
}

/* Convenience function. */
int MDFNI_ToggleCheat(uint32 which)
{
 cheats[which].status = !cheats[which].status;
 savecheats = 1;
 RebuildSubCheats();

 return(cheats[which].status);
}

void MDFNI_CheatSearchSetCurrentAsOriginal(void)
{
 for(uint32 page = 0; page < NumPages; page++)
 {
  if(CheatComp[page])
  {
   for(uint32 addr = 0; addr < PageSize; addr++)
   {
    if(!CheatComp[page][addr].excluded)
    {
     CheatComp[page][addr].value = RAMPtrs[page][addr];
    }
   }
  }
 }
}

void MDFNI_CheatSearchShowExcluded(void)
{
 for(uint32 page = 0; page < NumPages; page++)
 {
  if(CheatComp[page])
  {
   for(uint32 addr = 0; addr < PageSize; addr++)
   {
    CheatComp[page][addr].excluded = 0;
   }
  }
 }
}


int32 MDFNI_CheatSearchGetCount(void)
{
 uint32 count = 0;

 for(uint32 page = 0; page < NumPages; page++)
 {
  if(CheatComp[page])
  {
   for(uint32 addr = 0; addr < PageSize; addr++)
   {
    if(!CheatComp[page][addr].excluded)
     count++;
   }
  }
 }
 return count;
}

/* This function will give the initial value of the search and the current value at a location. */

void MDFNI_CheatSearchGet(int (*callb)(uint32 a, uint64 last, uint64 current, void *data), void *data)
{
 for(uint32 page = 0; page < NumPages; page++)
 {
  if(CheatComp[page])
  {
   for(uint32 addr = 0; addr < PageSize; addr++)
   {
    if(!CheatComp[page][addr].excluded)
    {
     uint64 ccval;
     uint64 ramval;

     ccval = ramval = 0;
     for(unsigned int x = 0; x < resultsbytelen; x++)
     {
      uint32 curpage = (page + (addr + x) / PageSize) % NumPages;
      if(CheatComp[curpage])
      {
       unsigned int shiftie;

       if(resultsbigendian)
        shiftie = (resultsbytelen - 1 - x) * 8;
       else
        shiftie = x * 8;
       ccval |= CheatComp[curpage][(addr + x) % PageSize].value << shiftie;
       ramval |= RAMPtrs[curpage][(addr + x) % PageSize] << shiftie;
      }
     }

     if(!callb(page * PageSize + addr, ccval, ramval, data))
      return;
    }
   }
  }
 }
}

void MDFNI_CheatSearchBegin(void)
{
 resultsbytelen = 1;
 resultsbigendian = 0;

 for(uint32 page = 0; page < NumPages; page++)
 {
  if(RAMPtrs[page])
  {
   if(!CheatComp[page])
    CheatComp[page] = (CompareStruct *)calloc(PageSize, sizeof(CompareStruct));

   for(uint32 addr = 0; addr < PageSize; addr++)
   {
    CheatComp[page][addr].excluded = 0;
    CheatComp[page][addr].value = RAMPtrs[page][addr];
   }
  }
 }
}


static uint64 INLINE CAbs(uint64 x)
{
 if(x < 0)
  return(0 - x);
 return x;
}

void MDFNI_CheatSearchEnd(int type, uint64 v1, uint64 v2, unsigned int bytelen, bool bigendian)
{
 v1 &= (~0ULL) >> (8 - bytelen);
 v2 &= (~0ULL) >> (8 - bytelen);

 resultsbytelen = bytelen;
 resultsbigendian = bigendian;

 for(uint32 page = 0; page < NumPages; page++)
 {
  if(CheatComp[page])
  {
   for(uint32 addr = 0; addr < PageSize; addr++)
   {
    if(!CheatComp[page][addr].excluded)
    {
     bool doexclude = 0;
     uint64 ccval;
     uint64 ramval;

     ccval = ramval = 0;
     for(unsigned int x = 0; x < bytelen; x++)
     {
      uint32 curpage = (page + (addr + x) / PageSize) % NumPages;
      if(CheatComp[curpage])
      {
       unsigned int shiftie;

       if(bigendian)
        shiftie = (bytelen - 1 - x) * 8;
       else
        shiftie = x * 8;
       ccval |= CheatComp[curpage][(addr + x) % PageSize].value << shiftie;
       ramval |= RAMPtrs[curpage][(addr + x) % PageSize] << shiftie;
      }
     }

     switch(type)
     {
      case 0: // Change to a specific value.
	if(!(ccval == v1 && ramval == v2))
	 doexclude = 1;
	break;
	 
      case 1: // Search for relative change(between values).
	if(!(ccval == v1 && CAbs(ccval - ramval) == v2))
	 doexclude = 1;
	break;

      case 2: // Purely relative change.
	if(!(CAbs(ccval - ramval) == v2))
	 doexclude = 1;
	break;
      case 3: // Any change
        if(!(ccval != ramval))
         doexclude = 1;
        break;
      case 4: // Value decreased
        if(ramval >= ccval)
         doexclude = 1;
        break;
      case 5: // Value increased
        if(ramval <= ccval)
         doexclude = 1;
        break;
     }
     if(doexclude)
      CheatComp[page][addr].excluded = TRUE;
    }
   }
  }
 }

 if(type >= 4)
  MDFNI_CheatSearchSetCurrentAsOriginal();
}

static void SettingChanged(const char *name)
{
 MDFNMP_RemoveReadPatches();

 CheatsActive = MDFN_GetSettingB("cheats");

 RebuildSubCheats();

 MDFNMP_InstallReadPatches();
}


MDFNSetting MDFNMP_Settings[] =
{
 { "cheats", MDFNSF_NOFLAGS, "Enable cheats.", NULL, MDFNST_BOOL, "1", NULL, NULL, NULL, SettingChanged },
 { NULL}
};