mednafen/cdrom/CDAccess_CCD.cpp

/******************************************************************************/
/* Mednafen - Multi-system Emulator                                           */
/******************************************************************************/
/* CDAccess_CCD.cpp:
**  Copyright (C) 2013-2016 Mednafen Team
**
** 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.,
** 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
*/

#include "CDAccess_CCD.h"

#include <limits>
#include <limits.h>
#include <map>

#include "../mednafen-types.h"
#include "../git.h"
#include "../general.h"

static void MDFN_strtoupper(std::string &str)
{
   const size_t len = str.length();

   for(size_t x = 0; x < len; x++)
   {
      if(str[x] >= 'a' && str[x] <= 'z')
         str[x] = str[x] - 'a' + 'A';
   }
}

typedef std::map<std::string, std::string> CCD_Section;

   template<typename T>
static T CCD_ReadInt(CCD_Section &s, const std::string &propname, const bool have_defval = false, const int defval = 0)
{
   CCD_Section::iterator zit = s.find(propname);

   if(zit == s.end())
   {
      if(have_defval)
         return defval;
      else
         throw MDFN_Error(0, "Missing property: %s", propname.c_str());
   }

   const std::string &v = zit->second;
   int scan_base = 10;
   size_t scan_offset = 0;
   long ret = 0;

   if(v.length() >= 3 && v[0] == '0' && v[1] == 'x')
   {
      scan_base = 16;
      scan_offset = 2;
   }

   const char *vp = v.c_str() + scan_offset;
   char *ep = NULL;

   if(std::numeric_limits<T>::is_signed)
      ret = strtol(vp, &ep, scan_base);
   else
      ret = strtoul(vp, &ep, scan_base);

   if(!vp[0] || ep[0])
   {
      throw MDFN_Error(0, "Property %s: Malformed integer: %s", propname.c_str(), v.c_str());
   }

   return ret;
}


CDAccess_CCD::CDAccess_CCD(const std::string& path, bool image_memcache) : img_numsectors(0)
{
   Load(path, image_memcache);
}

bool CDAccess_CCD::Load(const std::string& path, bool image_memcache)
{
   FileStream cf(path.c_str(), MODE_READ);
   std::map<std::string, CCD_Section> Sections;
   std::string linebuf;
   std::string cur_section_name;
   std::string dir_path, file_base, file_ext;
   char img_extsd[4] = { 'i', 'm', 'g', 0 };
   char sub_extsd[4] = { 's', 'u', 'b', 0 };

   MDFN_GetFilePathComponents(path, &dir_path, &file_base, &file_ext);

   if(file_ext.length() == 4 && file_ext[0] == '.')
   {
      signed char extupt[3] = { -1, -1, -1 };

      for(int i = 1; i < 4; i++)
      {
         if(file_ext[i] >= 'A' && file_ext[i] <= 'Z')
            extupt[i - 1] = 'A' - 'a';
         else if(file_ext[i] >= 'a' && file_ext[i] <= 'z')
            extupt[i - 1] = 0;
      }

      signed char av = -1;
      for(int i = 0; i < 3; i++)
      {
         if(extupt[i] != -1)
            av = extupt[i];
         else
            extupt[i] = av;
      }

      if(av == -1)
         av = 0;

      for(int i = 0; i < 3; i++)
      {
         if(extupt[i] == -1)
            extupt[i] = av;
      }

      for(int i = 0; i < 3; i++)
      {
         img_extsd[i] += extupt[i];
         sub_extsd[i] += extupt[i];
      }
   }

   //printf("%s %d %d %d\n", file_ext.c_str(), extupt[0], extupt[1], extupt[2]);

   linebuf.reserve(256);

   while(cf.get_line(linebuf) >= 0)
   {
      MDFN_rtrim(linebuf);
      MDFN_ltrim(linebuf);

      if(linebuf.length() == 0)	// Skip blank lines.
         continue;

      if(linebuf[0] == '[')
      {
         if(linebuf.length() < 3 || linebuf[linebuf.length() - 1] != ']')
         {
            log_cb(RETRO_LOG_ERROR, "Malformed section specifier: %s", linebuf.c_str());
            return false;
         }

         cur_section_name = linebuf.substr(1, linebuf.length() - 2);
         MDFN_strtoupper(cur_section_name);
      }
      else
      {
         const size_t feqpos = linebuf.find('=');
         const size_t leqpos = linebuf.rfind('=');
         std::string k, v;

         if(feqpos == std::string::npos || feqpos != leqpos)
         {
            log_cb(RETRO_LOG_ERROR, "Malformed value pair specifier: %s\n", linebuf.c_str());
            return false;
         }

         k = linebuf.substr(0, feqpos);
         v = linebuf.substr(feqpos + 1);

         MDFN_rtrim(k);
         MDFN_ltrim(k);

         MDFN_rtrim(v);
         MDFN_ltrim(v);

         MDFN_strtoupper(k);

         Sections[cur_section_name][k] = v;
      }
   }

   {
      CCD_Section& ds = Sections["DISC"];
      unsigned toc_entries = CCD_ReadInt<unsigned>(ds, "TOCENTRIES");
      unsigned num_sessions = CCD_ReadInt<unsigned>(ds, "SESSIONS");
      bool data_tracks_scrambled = CCD_ReadInt<unsigned>(ds, "DATATRACKSSCRAMBLED");

      if(num_sessions != 1)
      {
         log_cb(RETRO_LOG_ERROR, "Unsupported number of sessions: %u\n", num_sessions);
         return false;
      }

      if(data_tracks_scrambled)
      {
         log_cb(RETRO_LOG_ERROR, "Scrambled CCD data tracks currently not supported.\n");
         return false;
      }

      //printf("MOO: %d\n", toc_entries);

      for(unsigned te = 0; te < toc_entries; te++)
      {
         char tmpbuf[64];
         snprintf(tmpbuf, sizeof(tmpbuf), "ENTRY %u", te);
         CCD_Section& ts = Sections[std::string(tmpbuf)];
         unsigned session = CCD_ReadInt<unsigned>(ts, "SESSION");
         uint8_t point = CCD_ReadInt<uint8_t>(ts, "POINT");
         uint8_t adr = CCD_ReadInt<uint8_t>(ts, "ADR");
         uint8_t control = CCD_ReadInt<uint8_t>(ts, "CONTROL");
         uint8_t pmin = CCD_ReadInt<uint8_t>(ts, "PMIN");
         uint8_t psec = CCD_ReadInt<uint8_t>(ts, "PSEC");
         //uint8_t pframe = CCD_ReadInt<uint8_t>(ts, "PFRAME");
         signed plba = CCD_ReadInt<signed>(ts, "PLBA");

         if(session != 1)
         {
            log_cb(RETRO_LOG_ERROR, "Unsupported TOC entry Session value: %u\n", session);
            return false;
         }

         // Reference: ECMA-394, page 5-14
         if(point >= 1 && point <= 99)
         {
            tocd.tracks[point].adr = adr;
            tocd.tracks[point].control = control;
            tocd.tracks[point].lba = plba;
            tocd.tracks[point].valid = true;
         }
         else switch(point)
         {
            default:
               log_cb(RETRO_LOG_ERROR, "Unsupported TOC entry Point value: %u\n", point);
               return false;
            case 0xA0:
               tocd.first_track = pmin;
               tocd.disc_type = psec;
               break;

            case 0xA1:
               tocd.last_track = pmin;
               break;

            case 0xA2:
               tocd.tracks[100].adr = adr;
               tocd.tracks[100].control = control;
               tocd.tracks[100].lba = plba;
               tocd.tracks[100].valid = true;
               break;
         }
      }
   }

   // Open image stream.
   {
      std::string image_path = MDFN_EvalFIP(dir_path, file_base + std::string(".") + std::string(img_extsd), true);

      if(image_memcache)
         img_stream = new MemoryStream(new FileStream(image_path.c_str(), MODE_READ));
      else
         img_stream = new FileStream(image_path.c_str(), MODE_READ);

      uint64 ss = img_stream->size();

      if(ss % 2352)
      {
         log_cb(RETRO_LOG_ERROR, "CCD image size is not evenly divisible by 2352.\n");
         return false;
      }

      if(ss > 0x7FFFFFFF)
      {
         log_cb(RETRO_LOG_ERROR, "CCD image is too large.\n");
         return false;
      }

      img_numsectors = ss / 2352;
   }

   // Open subchannel stream
   {
      std::string sub_path = MDFN_EvalFIP(dir_path, file_base + std::string(".") + std::string(sub_extsd), true);
      RFILE *sub_stream    = filestream_open(
            sub_path.c_str(),
            RETRO_VFS_FILE_ACCESS_READ,
            RETRO_VFS_FILE_ACCESS_HINT_NONE);

      if(!sub_stream || filestream_get_size(sub_stream) != (uint64)img_numsectors * 96)
      {
         log_cb(RETRO_LOG_ERROR, "CCD SUB file size mismatch.\n");
         if (sub_stream)
            filestream_close(sub_stream);
         return false;
      }

      sub_data = new uint8_t[(uint64)img_numsectors * 96];
      filestream_read(sub_stream, sub_data, (uint64)img_numsectors * 96);
      filestream_close(sub_stream);
   }

   CheckSubQSanity();

   return true;
}

//
// Checks for Q subchannel mode 1(current time) data that has a correct checksum, but the data is nonsensical or corrupted nonetheless; this is the
// case for some bad rips floating around on the Internet.  Allowing these bad rips to be used will cause all sorts of problems during emulation, so we
// error out here if a bad rip is detected.
//
// This check is not as aggressive or exhaustive as it could be, and will not detect all potential Q subchannel rip errors; as such, it should definitely NOT be
// used in an effort to "repair" a broken rip.
//
bool CDAccess_CCD::CheckSubQSanity(void)
{
   size_t checksum_pass_counter = 0;
   int prev_lba = INT_MAX;
   uint8_t prev_track = 0;

   for(size_t s = 0; s < img_numsectors; s++)
   {
      union
      {
         uint8_t full[96];
         struct
         {
            uint8_t pbuf[12];
            uint8_t qbuf[12];
         };
      } buf;

      memcpy(buf.full, &sub_data[s * 96], 96);

      if(subq_check_checksum(buf.qbuf))
      {
         uint8_t adr = buf.qbuf[0] & 0xF;

         if(adr == 0x01)
         {
            uint8_t track_bcd = buf.qbuf[1];
            uint8_t index_bcd = buf.qbuf[2];
            uint8_t rm_bcd = buf.qbuf[3];
            uint8_t rs_bcd = buf.qbuf[4];
            uint8_t rf_bcd = buf.qbuf[5];
            uint8_t am_bcd = buf.qbuf[7];
            uint8_t as_bcd = buf.qbuf[8];
            uint8_t af_bcd = buf.qbuf[9];

            //printf("%2x %2x %2x\n", am_bcd, as_bcd, af_bcd);

            if(!BCD_is_valid(track_bcd) || !BCD_is_valid(index_bcd) || !BCD_is_valid(rm_bcd) || !BCD_is_valid(rs_bcd) || !BCD_is_valid(rf_bcd) ||
                  !BCD_is_valid(am_bcd) || !BCD_is_valid(as_bcd) || !BCD_is_valid(af_bcd) ||
                  rs_bcd > 0x59 || rf_bcd > 0x74 || as_bcd > 0x59 || af_bcd > 0x74)
            {
               log_cb(RETRO_LOG_ERROR, "Garbage subchannel Q data detected(bad BCD/out of range): %02x:%02x:%02x %02x:%02x:%02x\n", rm_bcd, rs_bcd, rf_bcd, am_bcd, as_bcd, af_bcd);
               return false;
            }
            else
            {
               int lba = ((BCD_to_U8(am_bcd) * 60 + BCD_to_U8(as_bcd)) * 75 + BCD_to_U8(af_bcd)) - 150;
               uint8_t track = BCD_to_U8(track_bcd);

               if(prev_lba != INT_MAX && abs(lba - prev_lba) > 100)
               {
                  log_cb(RETRO_LOG_ERROR, "Garbage subchannel Q data detected(excessively large jump in AMSF)\n");
                  return false;
               }

               if(abs((int)(lba - s)) > 100)
               {
                  log_cb(RETRO_LOG_ERROR, "Garbage subchannel Q data detected(AMSF value is out of tolerance)\n");
                  return false;
               }

               prev_lba = lba;

               if(track < prev_track)
               {
                  log_cb(RETRO_LOG_ERROR, "Garbage subchannel Q data detected(bad track number)\n");
                  return false;
               }

               prev_track = track;
            }
            checksum_pass_counter++;
         }
      }
   }

   //printf("%u/%u\n", checksum_pass_counter, img_numsectors);
   return true;
}

CDAccess_CCD::~CDAccess_CCD()
{
   if (img_stream)
      delete img_stream;
   if (sub_data)
      delete[] sub_data;
}

bool CDAccess_CCD::Read_Raw_Sector(uint8_t *buf, int32_t lba)
{
   if(lba < 0)
   {
      synth_udapp_sector_lba(0xFF, tocd, lba, 0, buf);
      return true; /* TODO/FIXME - see if we need to return false here? */
   }

   if((size_t)lba >= img_numsectors)
   {
      synth_leadout_sector_lba(0xFF, tocd, lba, buf);
      return true; /* TODO/FIXME - see if we need to return false here? */
   }

   img_stream->seek(lba * 2352, SEEK_SET);
   img_stream->read(buf, 2352);

   subpw_interleave(&sub_data[lba * 96], buf + 2352);

   return true;
}

bool CDAccess_CCD::Fast_Read_Raw_PW_TSRE(uint8_t* pwbuf, int32_t lba)
{
   if(lba < 0)
   {
      subpw_synth_udapp_lba(tocd, lba, 0, pwbuf);
      return true;
   }

   if((size_t)lba >= img_numsectors)
   {
      subpw_synth_leadout_lba(tocd, lba, pwbuf);
      return true;
   }

   subpw_interleave(&sub_data[lba * 96], pwbuf);

   return true;
}

bool CDAccess_CCD::Read_TOC(TOC *toc)
{
   *toc = tocd;
   return true;
}