nsf.c

linux下的MPEG1

void nsf_init(void)
{
   nes6502_init();
}

/* Initialize NES CPU, hardware, etc. */
static int nsf_cpuinit(nsf_t *nsf)
{
   int i;
   
   nsf->cpu = malloc(sizeof(nes6502_context));
   if (NULL == nsf->cpu)
      return -1;

   memset(nsf->cpu, 0, sizeof(nes6502_context));

   nsf->cpu->mem_page[0] = malloc(0x800);
   if (NULL == nsf->cpu->mem_page[0])
      return -1;

   /* allocate some space for the NSF "player" MMC5 EXRAM, and WRAM */
   for (i = 5; i <= 7; i++)
   {
      nsf->cpu->mem_page[i] = malloc(0x1000);
      if (NULL == nsf->cpu->mem_page[i])
         return -1;
   }

   nsf->cpu->read_handler = nsf_readhandler;
   nsf->cpu->write_handler = nsf_writehandler;

   return 0;
}

static void nsf_setup(nsf_t *nsf)
{
   int i;

   nsf->current_song = nsf->start_song;

   if (nsf->pal_ntsc_bits & NSF_DEDICATED_PAL)
   {
      if (nsf->pal_speed)
         nsf->playback_rate = 1000000 / nsf->pal_speed;
      else
         nsf->playback_rate = 50; /* 50 Hz */
   }
   else
   {
      if (nsf->ntsc_speed)
         nsf->playback_rate = 1000000 / nsf->ntsc_speed;
      else
         nsf->playback_rate = 60; /* 60 Hz */
   }

   nsf->bankswitched = FALSE;

   for (i = 0; i < 8; i++)
   {
      if (nsf->bankswitch_info[i])
      {
         nsf->bankswitched = TRUE;
         break;
      }
   }
}

#ifdef HOST_LITTLE_ENDIAN
#define  SWAP_16(x)  (x)
#else /* !HOST_LITTLE_ENDIAN */
#define  SWAP_16(x)  (((uint16) x >> 8) | (((uint16) x & 0xFF) << 8))
#endif /* !HOST_LITTLE_ENDIAN */

/* Load a ROM image into memory */
nsf_t *nsf_load(char *filename, void *source, int length)
{
   FILE *fp = NULL;
   char *new_fn = NULL;
   nsf_t *temp_nsf;

   if (NULL == filename && NULL == source)
      return NULL;
 
   if (NULL == source)
   {
      fp = fopen(filename, "rb");

      /* Didn't find the file?  Maybe the .NSF extension was omitted */
      if (NULL == fp)
      {
         new_fn = malloc(strlen(filename) + 5);
         if (NULL == new_fn)
            return NULL;
         strcpy(new_fn, filename);

         if (NULL == strrchr(new_fn, '.'))
            strcat(new_fn, ".nsf");

         fp = fopen(new_fn, "rb");

         if (NULL == fp)
         {
            log_printf("could not find file '%s'\n", new_fn);
            free(new_fn);
            return NULL;
         }
      }
   }

   temp_nsf = malloc(sizeof(nsf_t));
   if (NULL == temp_nsf) {
     fclose(fp);
     free(new_fn);
     return NULL;
   }

   /* Read in the header */
   if (NULL == source)
      fread(temp_nsf, 1, NSF_HEADER_SIZE, fp);
   else
      memcpy(temp_nsf, source, NSF_HEADER_SIZE);

   if (memcmp(temp_nsf->id, NSF_MAGIC, 5))
   {
      if (NULL == source)
      {
         log_printf("%s is not an NSF format file\n", new_fn);
         fclose(fp);
         free(new_fn);
      }
      nsf_free(&temp_nsf);
      return NULL;
   }

   /* fixup endianness */
   temp_nsf->load_addr = SWAP_16(temp_nsf->load_addr);
   temp_nsf->init_addr = SWAP_16(temp_nsf->init_addr);
   temp_nsf->play_addr = SWAP_16(temp_nsf->play_addr);
   temp_nsf->ntsc_speed = SWAP_16(temp_nsf->ntsc_speed);
   temp_nsf->pal_speed = SWAP_16(temp_nsf->pal_speed);

   /* we're now at position 80h */
   if (NULL == source)
   {
      fseek(fp, 0, SEEK_END);
      temp_nsf->length = ftell(fp) - NSF_HEADER_SIZE;
   }
   else
   {
      temp_nsf->length = length - NSF_HEADER_SIZE;
   }

   /* Allocate NSF space, and load it up! */
   temp_nsf->data = malloc(temp_nsf->length);
   if (NULL == temp_nsf->data)
   {
      log_printf("error allocating memory for NSF data\n");
      nsf_free(&temp_nsf);
      return NULL;
   }

   /* seek to end of header, read in data */
   if (NULL == source)
   {
      fseek(fp, NSF_HEADER_SIZE, SEEK_SET);
      fread(temp_nsf->data, temp_nsf->length, 1, fp);

      fclose(fp);

      if (new_fn)
         free(new_fn);
   }
   else
      memcpy(temp_nsf->data, (uint8 *) source + NSF_HEADER_SIZE, length - NSF_HEADER_SIZE);

   /* Set up some variables */
   nsf_setup(temp_nsf);

   temp_nsf->apu = NULL; /* just make sure */

   if (nsf_cpuinit(temp_nsf))
   {
      nsf_free(&temp_nsf);
      return NULL;
   }

   return temp_nsf;
}

/* Free an NSF */
void nsf_free(nsf_t **nsf)
{
   if (*nsf)
   {
      if ((*nsf)->apu)
         apu_destroy((*nsf)->apu);

      nes_shutdown(*nsf);

      if ((*nsf)->data)
         free((*nsf)->data);

      free(*nsf);
   }
}

void nsf_setchan(nsf_t *nsf, int chan, boolean enabled)
{
   if (nsf)
   {
      nsf_setcontext(nsf);
      apu_setchan(chan, enabled);
   }
}

void nsf_playtrack(nsf_t *nsf, int track, int sample_rate, int sample_bits, boolean stereo)
{
   ASSERT(nsf);

   /* make this NSF the current context */
   nsf_setcontext(nsf);

   /* create the APU */
   if (nsf->apu)
      apu_destroy(nsf->apu);

   nsf->apu = apu_create(sample_rate, nsf->playback_rate, sample_bits, stereo);
   if (NULL == nsf->apu)
   {
      nsf_free(&nsf);
      return;
   }

   apu_setext(nsf->apu, nsf_getext(nsf));

   /* go ahead and init all the read/write handlers */
   build_address_handlers(nsf);

   /* convenience? */
   nsf->process = nsf->apu->process;

   nes6502_setcontext(nsf->cpu);

   if (track > nsf->num_songs)
      track = nsf->num_songs;
   else if (track < 1)
      track = 1;

   nsf->current_song = track;
   
   apu_reset();

   nsf_inittune(nsf);
}

void nsf_setfilter(nsf_t *nsf, int filter_type)
{
   if (nsf)
   {
      nsf_setcontext(nsf);
      apu_setfilter(filter_type);
   }
}

/*
** $Log: nsf.c,v $
** Revision 1.4  2006/09/26 00:52:17  dgp85
** Free the filename string and close the file pointer when returning.
**
** Found by Coverity Scan.
**
** Revision 1.3  2003/08/25 21:51:43  f1rmb
** Reduce GCC verbosity (various prototype declaration fixes). ffmpeg, wine and fft*post are untouched (fft: for now).
**
** Revision 1.2  2003/01/09 18:36:40  jkeil
** memcpy copies too much, corrupts malloc heap
**
** Revision 1.1  2003/01/08 07:04:35  tmmm
** initial import of Nosefart sources
**
** Revision 1.14  2000/07/05 14:54:45  matt
** fix for naughty Crystalis rip
**
** Revision 1.13  2000/07/04 04:59:38  matt
** removed DOS-specific stuff, fixed bug in address handlers
**
** Revision 1.12  2000/07/03 02:19:36  matt
** dynamic address range handlers, cleaner and faster
**
** Revision 1.11  2000/06/23 03:27:58  matt
** cleaned up external sound inteface
**
** Revision 1.10  2000/06/20 20:42:47  matt
** accuracy changes
**
** Revision 1.9  2000/06/20 00:05:58  matt
** changed to driver-based external sound generation
**
** Revision 1.8  2000/06/13 03:51:54  matt
** update API to take freq/sample data on nsf_playtrack
**
** Revision 1.7  2000/06/12 03:57:14  matt
** more robust checking for winamp plugin
**
** Revision 1.6  2000/06/12 01:13:00  matt
** added CPU/APU as members of the nsf struct
**
** Revision 1.5  2000/06/11 16:09:21  matt
** nsf_free is more robust
**
** Revision 1.4  2000/06/09 15:12:26  matt
** initial revision
**
*/