cat.c

ts流的解复用

          DVBPSI_ERROR("CAT decoder",
                       "'version_number' differs"
                       " whereas no discontinuity has occured");
          b_reinit = 1;
        }
        else if(p_cat_decoder->i_last_section_number
                                                != p_section->i_last_number)
        {
          /* last_section_number */
          DVBPSI_ERROR("CAT decoder",
                       "'last_section_number' differs"
                       " whereas no discontinuity has occured");
          b_reinit = 1;
        }
      }
      else
      {
        if(    (p_cat_decoder->b_current_valid)
            && (p_cat_decoder->current_cat.i_version == p_section->i_version))
        {
          /* Signal a new CAT if the previous one wasn't active */
          if(    (!p_cat_decoder->current_cat.b_current_next)
              && (p_section->b_current_next))
          {
            dvbpsi_cat_t* p_cat = (dvbpsi_cat_t*)malloc(sizeof(dvbpsi_cat_t));

            p_cat_decoder->current_cat.b_current_next = 1;
            *p_cat = p_cat_decoder->current_cat;
            p_cat_decoder->pf_callback(p_cat_decoder->p_cb_data, p_cat);
          }

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

  /* Reinit the decoder if wanted */
  if(b_reinit)
  {
    /* Force redecoding */
    p_cat_decoder->b_current_valid = 0;
    /* Free structures */
    if(p_cat_decoder->p_building_cat)
    {
      free(p_cat_decoder->p_building_cat);
      p_cat_decoder->p_building_cat = NULL;
    }
    /* Clear the section array */
    for(i = 0; i <= 255; i++)
    {
      if(p_cat_decoder->ap_sections[i] != NULL)
      {
        dvbpsi_DeletePSISections(p_cat_decoder->ap_sections[i]);
        p_cat_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_cat_decoder->p_building_cat)
    {
      p_cat_decoder->p_building_cat =
                                (dvbpsi_cat_t*)malloc(sizeof(dvbpsi_cat_t));
      dvbpsi_InitCAT(p_cat_decoder->p_building_cat,
                     p_section->i_version,
                     p_section->b_current_next);
      p_cat_decoder->i_last_section_number = p_section->i_last_number;
    }

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

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

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

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


/*****************************************************************************
 * dvbpsi_DecodeCATSections
 *****************************************************************************
 * CAT decoder.
 *****************************************************************************/
void dvbpsi_DecodeCATSections(dvbpsi_cat_t* p_cat,
                              dvbpsi_psi_section_t* p_section)
{
  uint8_t* p_byte;

  while(p_section)
  {
    /* CAT descriptors */
    p_byte = p_section->p_payload_start;
    while(p_byte + 5 <= p_section->p_payload_end)
    {
      uint8_t i_tag = p_byte[0];
      uint8_t i_length = p_byte[1];
      if(i_length + 2 <= p_section->p_payload_end - p_byte)
        dvbpsi_CATAddDescriptor(p_cat, i_tag, i_length, p_byte + 2);
      p_byte += 2 + i_length;
    }

    p_section = p_section->p_next;
  }
}


/*****************************************************************************
 * dvbpsi_GenCATSections
 *****************************************************************************
 * Generate CAT sections based on the dvbpsi_cat_t structure.
 *****************************************************************************/
dvbpsi_psi_section_t* dvbpsi_GenCATSections(dvbpsi_cat_t* p_cat)
{
  dvbpsi_psi_section_t* p_result = dvbpsi_NewPSISection(1024);
  dvbpsi_psi_section_t* p_current = p_result;
  dvbpsi_psi_section_t* p_prev;
  dvbpsi_descriptor_t* p_descriptor = p_cat->p_first_descriptor;

  p_current->i_table_id = 0x01;
  p_current->b_syntax_indicator = 1;
  p_current->b_private_indicator = 0;
  p_current->i_length = 9;                      /* header + CRC_32 */
  p_current->i_extension = 0;                   /* Not used in the CAT */
  p_current->i_version = p_cat->i_version;
  p_current->b_current_next = p_cat->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_data + 8;

  /* CAT descriptors */
  while(p_descriptor != NULL)
  {
    /* New section if needed */
    /* written_data_length + descriptor_length + 2 > 1024 - CRC_32_length */
    if(   (p_current->p_payload_end - p_current->p_data)
                                + p_descriptor->i_length > 1018)
    {
      p_prev = p_current;
      p_current = dvbpsi_NewPSISection(1024);
      p_prev->p_next = p_current;

      p_current->i_table_id = 0x01;
      p_current->b_syntax_indicator = 1;
      p_current->b_private_indicator = 0;
      p_current->i_length = 9;                  /* header + CRC_32 */
      p_current->i_extension = 0;               /* Not used in the CAT */
      p_current->i_version = p_cat->i_version;
      p_current->b_current_next = p_cat->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_data + 8;
    }

    /* p_payload_end is where the descriptor begins */
    p_current->p_payload_end[0] = p_descriptor->i_tag;
    p_current->p_payload_end[1] = p_descriptor->i_length;
    memcpy(p_current->p_payload_end + 2,
           p_descriptor->p_data,
           p_descriptor->i_length);

    /* Increase length by descriptor_length + 2 */
    p_current->p_payload_end += p_descriptor->i_length + 2;
    p_current->i_length += p_descriptor->i_length + 2;

    p_descriptor = p_descriptor->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;
}