pat.c

libdvbpsi4-0.1.5版本

                       " whereas no TS discontinuity has occured");
          b_reinit = 1;
        }
        else if(p_pat_decoder->p_building_pat->i_version
                                                != p_section->i_version)
        {
          /* version_number */
          DVBPSI_ERROR("PAT decoder",
                       "'version_number' differs"
                       " whereas no discontinuity has occured");
          b_reinit = 1;
        }
        else if(p_pat_decoder->i_last_section_number !=
                                                p_section->i_last_number)
        {
          /* last_section_number */
          DVBPSI_ERROR("PAT decoder",
                       "'last_section_number' differs"
                       " whereas no discontinuity has occured");
          b_reinit = 1;
        }
      }
      else
      {
        if(    (p_pat_decoder->b_current_valid)
            && (p_pat_decoder->current_pat.i_version == p_section->i_version))
        {
          /* Signal a new PAT if the previous one wasn't active */
          if(    (!p_pat_decoder->current_pat.b_current_next)
              && (p_section->b_current_next))
          {
            dvbpsi_pat_t* p_pat = (dvbpsi_pat_t*)malloc(sizeof(dvbpsi_pat_t));

            p_pat_decoder->current_pat.b_current_next = 1;
            *p_pat = p_pat_decoder->current_pat;
            p_pat_decoder->pf_callback(p_pat_decoder->p_cb_data, p_pat);
          }

          /* Don't decode since this version is already decoded */
          b_append = 0;
        }
      }
    }
  }

  /* Reinit the decoder if wanted */
  if(b_reinit)
  {
    /* Force redecoding */
    p_pat_decoder->b_current_valid = 0;
    /* Free structures */
    if(p_pat_decoder->p_building_pat)
    {
      free(p_pat_decoder->p_building_pat);
      p_pat_decoder->p_building_pat = NULL;
    }
    /* Clear the section array */
    for(i = 0; i <= 255; i++)
    {
      if(p_pat_decoder->ap_sections[i] != NULL)
      {
        dvbpsi_DeletePSISections(p_pat_decoder->ap_sections[i]);
        p_pat_decoder->ap_sections[i] = NULL;
      }
    }
  }

  /* Append the section to the list if wanted */
  if(b_append)
  {
    int b_complete;

    /* Initialize the structures if it's the first section received */
    if(!p_pat_decoder->p_building_pat)
    {
      p_pat_decoder->p_building_pat =
                                (dvbpsi_pat_t*)malloc(sizeof(dvbpsi_pat_t));
      dvbpsi_InitPAT(p_pat_decoder->p_building_pat,
                     p_section->i_extension,
                     p_section->i_version,
                     p_section->b_current_next);
      p_pat_decoder->i_last_section_number = p_section->i_last_number;
    }

    /* Fill the section array */
    if(p_pat_decoder->ap_sections[p_section->i_number] != NULL)
    {
      DVBPSI_DEBUG_ARG("PAT decoder", "overwrite section number %d",
                       p_section->i_number);
      dvbpsi_DeletePSISections(p_pat_decoder->ap_sections[p_section->i_number]);
    }
    p_pat_decoder->ap_sections[p_section->i_number] = p_section;

    /* Check if we have all the sections */
    b_complete = 0;
    for(i = 0; i <= p_pat_decoder->i_last_section_number; i++)
    {
      if(!p_pat_decoder->ap_sections[i])
        break;

      if(i == p_pat_decoder->i_last_section_number)
        b_complete = 1;
    }

    if(b_complete)
    {
      /* Save the current information */
      p_pat_decoder->current_pat = *p_pat_decoder->p_building_pat;
      p_pat_decoder->b_current_valid = 1;
      /* Chain the sections */
      if(p_pat_decoder->i_last_section_number)
      {
        for(i = 0; i <= p_pat_decoder->i_last_section_number - 1; i++)
          p_pat_decoder->ap_sections[i]->p_next =
                                        p_pat_decoder->ap_sections[i + 1];
      }
      /* Decode the sections */
      dvbpsi_DecodePATSections(p_pat_decoder->p_building_pat,
                               p_pat_decoder->ap_sections[0]);
      /* Delete the sections */
      dvbpsi_DeletePSISections(p_pat_decoder->ap_sections[0]);
      /* signal the new PAT */
      p_pat_decoder->pf_callback(p_pat_decoder->p_cb_data,
                                 p_pat_decoder->p_building_pat);
      /* Reinitialize the structures */
      p_pat_decoder->p_building_pat = NULL;
      for(i = 0; i <= p_pat_decoder->i_last_section_number; i++)
        p_pat_decoder->ap_sections[i] = NULL;
    }
  }
  else
  {
    dvbpsi_DeletePSISections(p_section);
  }
}


/*****************************************************************************
 * dvbpsi_DecodePATSection
 *****************************************************************************
 * PAT decoder.
 *****************************************************************************/
void dvbpsi_DecodePATSections(dvbpsi_pat_t* p_pat,
                               dvbpsi_psi_section_t* p_section)
{
  uint8_t* p_byte;

  while(p_section)
  {
    for(p_byte = p_section->p_payload_start;
        p_byte < p_section->p_payload_end;
        p_byte += 4)
    {
      uint16_t i_program_number = ((uint16_t)(p_byte[0]) << 8) | p_byte[1];
      uint16_t i_pid = ((uint16_t)(p_byte[2] & 0x1f) << 8) | p_byte[3];
      dvbpsi_PATAddProgram(p_pat, i_program_number, i_pid);
    }

    p_section = p_section->p_next;
  }
}


/*****************************************************************************
 * dvbpsi_GenPATSections
 *****************************************************************************
 * Generate PAT sections based on the dvbpsi_pat_t structure. The third
 * argument is used to limit the number of program in each section (max: 253).
 *****************************************************************************/
dvbpsi_psi_section_t* dvbpsi_GenPATSections(dvbpsi_pat_t* p_pat,
                                            int i_max_pps)
{
  dvbpsi_psi_section_t* p_result = dvbpsi_NewPSISection(1024);
  dvbpsi_psi_section_t* p_current = p_result;
  dvbpsi_psi_section_t* p_prev;
  dvbpsi_pat_program_t* p_program = p_pat->p_first_program;
  int i_count = 0;

  /* A PAT section can carry up to 253 programs */
  if((i_max_pps <= 0) || (i_max_pps > 253))
    i_max_pps = 253;

  p_current->i_table_id = 0;
  p_current->b_syntax_indicator = 1;
  p_current->b_private_indicator = 0;
  p_current->i_length = 9;                      /* header + CRC_32 */
  p_current->i_extension = p_pat->i_ts_id;
  p_current->i_version = p_pat->i_version;
  p_current->b_current_next = p_pat->b_current_next;
  p_current->i_number = 0;
  p_current->p_payload_end += 8;                /* just after the header */
  p_current->p_payload_start = p_current->p_payload_end;

  /* PAT programs */
  while(p_program != NULL)
  {
    /* New section if needed */
    if(++i_count > i_max_pps)
    {
      p_prev = p_current;
      p_current = dvbpsi_NewPSISection(1024);
      p_prev->p_next = p_current;
      i_count = 1;

      p_current->i_table_id = 0;
      p_current->b_syntax_indicator = 1;
      p_current->b_private_indicator = 0;
      p_current->i_length = 9;                  /* header + CRC_32 */
      p_current->i_extension = p_pat->i_ts_id;
      p_current->i_version = p_pat->i_version;
      p_current->b_current_next = p_pat->b_current_next;
      p_current->i_number = p_prev->i_number + 1;
      p_current->p_payload_end += 8;            /* just after the header */
      p_current->p_payload_start = p_current->p_payload_end;
    }

    /* p_payload_end is where the program begins */
    p_current->p_payload_end[0] = p_program->i_number >> 8;
    p_current->p_payload_end[1] = p_program->i_number;
    p_current->p_payload_end[2] = (p_program->i_pid >> 8) | 0xe0;
    p_current->p_payload_end[3] = p_program->i_pid;

    /* Increase length by 4 */
    p_current->p_payload_end += 4;
    p_current->i_length += 4;

    p_program = p_program->p_next;
  }

  /* Finalization */
  p_prev = p_result;
  while(p_prev != NULL)
  {
    p_prev->i_last_number = p_current->i_number;
    dvbpsi_BuildPSISection(p_prev);
    p_prev = p_prev->p_next;
  }

  return p_result;
}