sector.c

linux下的MPEG1

/*
    $Id: sector.c,v 1.2 2004/04/11 12:20:32 miguelfreitas Exp $

    Copyright (C) 2000 Herbert Valerio Riedel <[e-mail]>
              (C) 1998 Heiko Eissfeldt <[e-mail]>
                  portions used & Chris Smith

    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
*/

#ifdef HAVE_CONFIG_H
# include "config.h"
#endif

#include <string.h>

#include <cdio/cdio.h>

#include <libvcd/types.h>

#include <libvcd/sector.h>

/* Private includes */
#include "vcd_assert.h"
#include "bytesex.h"
#include "salloc.h"
#include "sector_private.h"

static const char _rcsid[] = "$Id: sector.c,v 1.2 2004/04/11 12:20:32 miguelfreitas Exp $";

static const uint8_t sync_pattern[12] = {
  0x00, 0xff, 0xff, 0xff,
  0xff, 0xff, 0xff, 0xff,
  0xff, 0xff, 0xff, 0x00
};

static void
build_address (void *buf, sectortype_t sectortype, uint32_t address)
{
  raw_cd_sector_t *sector = buf;
  
  vcd_assert (sizeof(raw_cd_sector_t) == CDIO_CD_FRAMESIZE_RAW-DATA_LEN);

  cdio_lba_to_msf(address, &(sector->msf));

  switch(sectortype) {
  case MODE_0:
    sector->mode = 0;
    break;
  case MODE_2:
  case MODE_2_FORM_1:
  case MODE_2_FORM_2:
    sector->mode = 2;
    break;
  default:
    vcd_assert_not_reached ();
    break;
  }
}

/* From cdrtools-1.11a25 */
static uint32_t
build_edc(const uint8_t inout[], int from, int upto)
{
  const uint8_t *p = inout+from;
  uint32_t result = 0;

  upto -= from-1;
  upto /= 4;
  while (--upto >= 0) {
    result = EDC_crctable[(result ^ *p++) & 0xffL] ^ (result >> 8);
    result = EDC_crctable[(result ^ *p++) & 0xffL] ^ (result >> 8);
    result = EDC_crctable[(result ^ *p++) & 0xffL] ^ (result >> 8);
    result = EDC_crctable[(result ^ *p++) & 0xffL] ^ (result >> 8);
  }
  return (result);
}

/* From cdrtools-1.11a40 */
static void
encode_L2_Q(uint8_t inout[4 + L2_RAW + 4 + 8 + L2_P + L2_Q])
{
  uint8_t *dps;
  uint8_t *dp;
  uint8_t *Q;
  int i, j;
        
  Q = inout + 4 + L2_RAW + 4 + 8 + L2_P;
  
  dps = inout;
  for (j = 0; j < 26; j++) {
    uint16_t a, b;

    a = b = 0;
    dp = dps;
    for (i = 0; i < 43; i++) {
      
      /* LSB */
      a ^= L2sq[i][*dp++];
      
      /* MSB */
      b ^= L2sq[i][*dp];
      
      dp += 2*44-1;
      if (dp >= &inout[(4 + L2_RAW + 4 + 8 + L2_P)]) {
        dp -= (4 + L2_RAW + 4 + 8 + L2_P);
      } 
    }
    Q[0]      = a >> 8;
    Q[26*2]   = a;
    Q[1]      = b >> 8;
    Q[26*2+1] = b;
    
    Q += 2;
    dps += 2*43;
  }
}

static void
encode_L2_P (uint8_t inout[4 + L2_RAW + 4 + 8 + L2_P])
{
  uint8_t *dp;
  unsigned char *P;
  int i, j;
  
  P = inout + 4 + L2_RAW + 4 + 8;
  
  for (j = 0; j < 43; j++) {
    uint16_t a;
    uint16_t b;
    
    a = b = 0;
    dp = inout;
    for (i = 19; i < 43; i++) {
      
      /* LSB */
      a ^= L2sq[i][*dp++];
      
      /* MSB */
      b ^= L2sq[i][*dp];
      
      dp += 2*43 -1;
    }
    P[0]      = a >> 8;
    P[43*2]   = a;
    P[1]      = b >> 8;
    P[43*2+1] = b;
    
    P += 2;
    inout += 2;
  }
}

/* Layer 2 Product code en/decoder */
static void
do_encode_L2 (void *buf, sectortype_t sectortype, uint32_t address)
{
  raw_cd_sector_t *raw_sector = buf;

  vcd_assert (buf != NULL);

  vcd_assert (sizeof (sync_pattern) == SYNC_LEN);
  vcd_assert (sizeof (mode2_form1_sector_t) == CDIO_CD_FRAMESIZE_RAW);
  vcd_assert (sizeof (mode2_form2_sector_t) == CDIO_CD_FRAMESIZE_RAW);
  vcd_assert (sizeof (mode0_sector_t) == CDIO_CD_FRAMESIZE_RAW);
  vcd_assert (sizeof (raw_cd_sector_t) == SYNC_LEN+HEADER_LEN);
  
  memset (raw_sector, 0, SYNC_LEN+HEADER_LEN);
  memcpy (raw_sector->sync, sync_pattern, sizeof (sync_pattern));

  switch (sectortype) {
  case MODE_0:
    {
      mode0_sector_t *sector = buf;

      memset(sector->data, 0, sizeof(sector->data));
    }
    break;
  case MODE_2:
    break;
  case MODE_2_FORM_1:
    {
      mode2_form1_sector_t *sector = buf;

      sector->edc = uint32_to_le(build_edc(buf, 16, 16+8+2048-1));

      encode_L2_P((uint8_t*)buf+SYNC_LEN);
      encode_L2_Q((uint8_t*)buf+SYNC_LEN);
    }
    break;
  case MODE_2_FORM_2:
    {
      mode2_form2_sector_t *sector = buf;

      sector->edc = uint32_to_le(build_edc(buf, 16, 16+8+2324-1));
    }
    break;
  default:
    vcd_assert_not_reached ();
  }

  build_address (buf, sectortype, address);
}

void
_vcd_make_mode2 (void *raw_sector, const void *data, uint32_t extent,
                 uint8_t fnum, uint8_t cnum, uint8_t sm, uint8_t ci)
{
  uint8_t *subhdr = (uint8_t*)raw_sector+16;

  vcd_assert (raw_sector != NULL);
  vcd_assert (data != NULL);
  vcd_assert (extent != SECTOR_NIL);

  memset (raw_sector, 0, CDIO_CD_FRAMESIZE_RAW);
  
  subhdr[0] = subhdr[4] = fnum;
  subhdr[1] = subhdr[5] = cnum;
  subhdr[2] = subhdr[6] = sm;
  subhdr[3] = subhdr[7] = ci;

  if (sm & SM_FORM2) 
    {
      memcpy ((char*)raw_sector+CDIO_CD_XA_SYNC_HEADER, data, 
              M2F2_SECTOR_SIZE);
      do_encode_L2 (raw_sector, MODE_2_FORM_2, extent+CDIO_PREGAP_SECTORS);
    } 
  else 
    {
      memcpy ((char*)raw_sector+CDIO_CD_XA_SYNC_HEADER, data, 
              CDIO_CD_FRAMESIZE);
      do_encode_L2 (raw_sector, MODE_2_FORM_1, extent+CDIO_PREGAP_SECTORS);
    } 
}

void
_vcd_make_raw_mode2 (void *raw_sector, const void *data, uint32_t extent)
{
  vcd_assert (raw_sector != NULL);
  vcd_assert (data != NULL);
  vcd_assert (extent != SECTOR_NIL);
  
  memset (raw_sector, 0, CDIO_CD_FRAMESIZE_RAW);

  memcpy ((char*)raw_sector+12+4, data, M2RAW_SECTOR_SIZE);
  do_encode_L2 (raw_sector, MODE_2, extent+CDIO_PREGAP_SECTORS);
}


/* 
 * Local variables:
 *  c-file-style: "gnu"
 *  tab-width: 8
 *  indent-tabs-mode: nil
 * End:
 */