alc_rx.c

这个程序实现了FLUTE协议

		if(!object_exists) {

			while(to != NULL) {
				if(to->toi == toi) {
					object_exists = 1;
					break;
				}
				to = to->next;
			}

			if(to == NULL) {
				continue;
			}
		}

		obj_completed = object_completed(to);

		if(((s->state == STxStopped) && (!obj_completed))) {
			/*printf("alc_recv() STxStopped, toi: %i\n", toi);
			fflush(stdout);*/
			*retval = -3;
			return NULL;	
		}

#ifdef WIN32
		Sleep(1);
#else
		usleep(1000);
#endif
	}
	printf("\n");

	remove_wanted_object(s_id, toi);

	/* Parse data from object to data buffer, return buffer and buffer length */

	to = object_exist(toi, s, 1);

	if(to->fec_enc_id == COM_NO_C_FEC_ENC_ID) {
		buf = null_fec_decode_object(to, data_len, s);
	}

        else if(to->fec_enc_id == SIMPLE_XOR_FEC_ENC_ID) {
                buf = xor_fec_decode_object(to, data_len, s);
        }

	else if(to->fec_enc_id == SB_SYS_FEC_ENC_ID && to->fec_inst_id == REED_SOL_FEC_INST_ID) {
		buf = rs_fec_decode_object(to, data_len, s);
	}
			
	if(buf == NULL) {
		*retval = -1;
	}

	free_object(to, s, 1);
	return buf;
}

/* 
 * This function gives any object to application, when it is completely received.
 *
 * Params:	int s_id: Session identifier,
 *			ULONGLONG/unsigned long long *toi: Pointer to Transport Object Identifier,
 *			ULONGLONG/unsigned long long *datalen: Pointer to object length,
 *			int *retval: Return value in error cases/stopping situations.
 *
 * Return:	char*: Pointer to buffer which contains object's data,
 *			NULL: In errors/stopping situations
 *
 */

char* alc_recv2(int s_id,
#ifdef WIN32			   
			   ULONGLONG *toi,
			   ULONGLONG *data_len,
#else
			   unsigned long long *toi,
			   unsigned long long *data_len,
#endif
			   int *retval) {

	bool obj_completed = false;
	alc_session_t *s;

#ifdef WIN32			   
	ULONGLONG tmp_toi = 0;
#else
	unsigned long long tmp_toi = 0;
#endif

	char *buf = NULL; /* Buffer where to construct the object from data units */
	trans_obj_t *to;
	
	s = get_alc_session(s_id);

	while(1) {
		
		to = s->obj_list;

		if(s->state == SExiting) {
			/*printf("alc_recv2() SExiting\n");
			fflush(stdout);*/
			*retval = -2;
			return NULL;	
		}
		else if(s->state == SClosed) {
			/*printf("alc_recv2() SClosed\n");
			fflush(stdout);*/
			*retval = 0;
			return NULL;	
		}
		else if(((s->state == STxStopped) && (to == NULL))) {
			/*printf("alc_recv2() STxStopped\n");
			fflush(stdout);*/
			*retval = -3;
			return NULL;	
		}

		while(to != NULL) {

			if(s->state == SExiting) {
				/*printf("alc_recv2() SExiting\n");
				fflush(stdout);*/
				*retval = -2;
				return NULL;	
			}
			else if(s->state == SClosed) {
				/*printf("alc_recv2() SClosed\n");
				fflush(stdout);*/
				*retval = 0;
				return NULL;	
			}

			obj_completed = object_completed(to);

			if(obj_completed) {
				tmp_toi = to->toi;
				break;
			}

			if(((s->state == STxStopped) && (!obj_completed))) {
				/*printf("alc_recv2() STxStopped\n");
				fflush(stdout);*/
				*retval = -3;
				return NULL;	
			}

			to = to->next;
		}
	
		if(obj_completed) {
			break;
		}

#ifdef WIN32
		Sleep(1);
#else
		usleep(1000);
#endif
	}

	printf("\n");

	remove_wanted_object(s_id, tmp_toi);

	/* Parse data from object to data buffer, return buffer length */

	to = object_exist(tmp_toi, s, 1);

	if(to->fec_enc_id == COM_NO_C_FEC_ENC_ID) {
		buf = null_fec_decode_object(to, data_len, s);
	}

        else if(to->fec_enc_id == SIMPLE_XOR_FEC_ENC_ID) {
                buf = xor_fec_decode_object(to, data_len, s);
        }

	else if(to->fec_enc_id == SB_SYS_FEC_ENC_ID && to->fec_inst_id == REED_SOL_FEC_INST_ID) {
		buf = rs_fec_decode_object(to, data_len, s);
	}
			
	if(buf == NULL) {
		*retval = -1;
	}
	else {
		*toi = tmp_toi;
	}

	free_object(to, s, 1);
	return buf;
}

/*
 * This function gives temp filename of object to application, when object is completely received.
 *
 * Params:	int s_id: Session identifier,
 *			ULONGLONG/unsigned long long *toi: Pointer to Transport Object Identifier,
 *			char *tmp_filename: Pointer to object's temporary filename.
 *			int *retval: Return value in error cases/stopping situations.
 *
 * Return:	char*: Pointer to buffer which contains temporary filename,
 *			NULL: In errors/stopping situations.
 *
 */

char* alc_recv3(int s_id,
#ifdef WIN32			   
				ULONGLONG *toi,
#else
				unsigned long long *toi,
#endif
				int *retval) {

	bool obj_completed = false;
	alc_session_t *s;

#ifdef WIN32			   
	ULONGLONG tmp_toi = 0;
#else
	unsigned long long tmp_toi = 0;
#endif

	trans_obj_t *to;
	char *tmp_filename = NULL;
	
	s = get_alc_session(s_id);

	while(1) {
		
		to = s->obj_list;

		if(s->state == SExiting) {
			/*printf("alc_recv3() SExiting\n");
			fflush(stdout);*/
			*retval = -2;
			return NULL;	
		}
		else if(s->state == SClosed) {
			/*printf("alc_recv3() SClosed\n");
			fflush(stdout);*/
			*retval = 0;
			return NULL;	
		}
		else if(((s->state == STxStopped) && (to == NULL))) {
			/*printf("alc_recv3() STxStopped, to == NULL\n");
			fflush(stdout);*/
			*retval = -3;
			return NULL;	
		}

		while(to != NULL) {

			obj_completed = false;

			if(s->state == SExiting) {
				/*printf("alc_recv3() SExiting\n");
				fflush(stdout);*/
				*retval = -2;
				return NULL;	
			}
			else if(s->state == SClosed) {
				/*printf("alc_recv3() SClosed\n");
				fflush(stdout);*/
				*retval = 0;
				return NULL;	
			}
			else if(s->state == STxStopped) {
				break;
                	}

			obj_completed = object_completed(to);

			if(obj_completed) {
				tmp_toi = to->toi;
				break;
			}

			to = to->next;
		}
	
		if(obj_completed) {
			break;
		}
		else if(s->state == STxStopped) {

			/* Check if there is completed object after A-flag is received */

			to = s->obj_list;

			while(to != NULL) {

                        	obj_completed = object_completed(to);

                        	if(obj_completed) {
                                	tmp_toi = to->toi;
                                	break;
                        	}

                        	to = to->next;
                	}

			if(obj_completed) {
                        	break;
                	}
			else {
                        	/*printf("alc_recv3() STxStopped, any object not completed\n");
                        	fflush(stdout);*/
                        	*retval = -3;
                        	return NULL;
                	}	
		}

#ifdef WIN32
		Sleep(1);
#else
		usleep(1000);
#endif
	}

	remove_wanted_object(s_id, tmp_toi);

	if(!(tmp_filename = (char*)calloc((strlen(to->tmp_filename) + 1), sizeof(char)))) {
		printf("Could not alloc memory for tmp_filename!\n");
		*retval = -1;
		return NULL;    
	}

	memcpy(tmp_filename, to->tmp_filename, strlen(to->tmp_filename));
	free_object(to, s, 1);
	*toi = tmp_toi;

  	return tmp_filename;
}

/* 
 * This function gives an FDT Instance to application, when it is completely received.
 *
 * Params:	int s_id: Session identifier,
 *			ULONGLONG/unsigne dlong long *data_len: Pointer to FDT Instance length,
 *			int *retval: Return value in error cases/stopping situations.
 *			unsigned char *content_enc_algo: Location where to store used content encoding,
 *
 * Return:	char*: Pointer to buffer which contains FDT Instance's data,
 *			NULL: in errors/stopping situations
 *
 */
 

char* fdt_recv(int s_id,
#ifdef WIN32
				ULONGLONG *data_len,
#else
				unsigned long long *data_len,
#endif
				int *retval,
				unsigned char *content_enc_algo,
	                        int* fdt_instance_id) {
	
	alc_session_t *s;                                                                                                                                          
	char *buf = NULL; /* Buffer where to construct the object from data units */                                                                                                                                     
	trans_obj_t *to;
        
	s = get_alc_session(s_id);
        
	while(1) {
		to = s->fdt_list;

		if(s->state == SExiting) {
			/*printf("fdt_recv() SExiting\n");
			fflush(stdout);*/
            *retval = -2;
            return NULL;
        }
        else if(s->state == SClosed) {
            /*printf("fdt_recv() SClosed\n");
            fflush(stdout);*/
            *retval = 0;
            return NULL;
        }
		else if(s->state == STxStopped) {
			/*printf("fdt_recv() STxStopped\n");
			fflush(stdout);*/
			*retval = -3;
			return NULL;	
		}
	
		if(to == NULL) {
			                                                                                                                                              
#ifdef WIN32
			Sleep(1);
#else
			usleep(1000);
#endif
			continue;	
		}
		
		do {
			if(object_completed(to)) {
				set_received_instance(s, (unsigned int)to->toi);

				*content_enc_algo = to->content_enc_algo;
				*fdt_instance_id = (int)to->toi;

				if(to->fec_enc_id == COM_NO_C_FEC_ENC_ID) {
			      		buf = null_fec_decode_object(to, data_len, s);
				}
        			else if(to->fec_enc_id == SIMPLE_XOR_FEC_ENC_ID) {
                			buf = xor_fec_decode_object(to, data_len, s);
        			}
				else if(to->fec_enc_id == SB_SYS_FEC_ENC_ID && to->fec_inst_id == REED_SOL_FEC_INST_ID) {
					buf = rs_fec_decode_object(to, data_len, s);
				}
				if(buf == NULL) {
					*retval = -1;
				}

				free_object(to, s, 0);
				return buf;
			}
			to = to->next;
		} while(to != NULL);

#ifdef WIN32
        Sleep(1);
#else
		usleep(1000);
#endif
	}

	return buf;
}


/* 
 * This function checks if received unit belongs to an object which already exists in session or not. 
 *
 * Params:	ULONGLONG/unsigned long long toi: Transport Object Identifier,
 *			alc_session_t *s: Pointer to session,
 *			int type: Type of object to be checked (0 = FDT Instance, 1 = normal object)
 *
 * Return:	trans_obj_t*: Pointer to object in success, NULL otherwise 
 *
 */

trans_obj_t* object_exist(
#ifdef WIN32
						  ULONGLONG toi,
#else
						  unsigned long long toi,
#endif
						  alc_session_t *s, int type) {
	
	trans_obj_t *trans_obj = NULL;

	if(type == 0) {
		trans_obj = s->fdt_list;
	}
	else if(type == 1) {
		trans_obj = s->obj_list;
	}

	if(trans_obj != NULL) {
		for(;;) {
			if(trans_obj->toi == toi) {
				break;
			}
			if(trans_obj->next == NULL) {
				trans_obj = NULL;
				break;
			}
			trans_obj = trans_obj->next;
		}
	}

	return trans_obj;
}

/*
 * This function checks if received unit belongs to a source block, which already exists or not. 
 *
 * Params:	unsigned int sbn: Source Block Number,
 *			trans_obj_t *trans_obj: Pointer to object
 *
 * Return:	trans_block_t*: Pointer to block in success, NULL otherwise 
 *
 */

/*

trans_block_t* block_exist(unsigned int sbn, trans_obj_t *trans_obj) {
	
	trans_block_t *trans_block;

	trans_block = trans_obj->block_list_start;

	if(trans_block != NULL) {
		for(;;) {
			if(trans_block->sbn == sbn) {
				break;
			}
			if(trans_block->next == NULL) {
				trans_block = NULL;
				break;
			}
			trans_block = trans_block->next;
		}
	}

	return trans_block;
}

*/

/*
 * This function checks if the object has been received completely.
 *
 * Params:	trans_obj_t *to: Transport Object to be checked
 *
 * Return:	bool: true when object ready, false otherwise
 *
 */

/*

bool object_completed(trans_obj_t *to) {

  bool ready = false;
  trans_block_t *tb = to->block_list_start;

  if(to->nb_of_created_blocks != to->bs->N) {
    return ready;
  }
  
  while(tb != NULL) {
    
    if(tb->nb_of_rx_units < tb->k) {
      return ready;
    }
    tb = tb->next;
  }
  
  ready = true;
  
  return ready;
}

*/

/*
 * This function checks if the object has been received completely.
 *
 * Params:      trans_obj_t *to: Transport Object to be checked
 *
 * Return:      bool: true when object ready, false otherwise
 *
 */

bool object_completed(trans_obj_t *to) {
   
  bool ready = false;
  
  /*

  trans_block_t *tb = to->block_list_start;
  
  if(to->nb_of_created_blocks != to->bs->N) {
    return ready;
  }
  
  while(tb != NULL) {
    
    if(!tb->completed) {
      return ready;
    }
    tb = tb->next;
  }
  
  ready = true;
 
  */
    
  if(to->nb_of_ready_blocks == to->bs->N) {
    ready = true;
  }
  
  return ready;
}

/*
 * This function checks if the block has been received completely.
 *
 * Params:      trans_block_t *tb: Pointer to block
 *
 * Return:      bool: true when object ready, false otherwise
 *
 */

bool block_ready_to_decode(trans_block_t *tb) {

	bool ready = false;

	if(tb->nb_of_rx_units >= tb->k) {
		ready = true;
	}

	return ready;
}