simple_source模块可以在外部设置的属性
有四个局部统计量，分别为产生的bit速率、包速率、包大小，包间隔
状态机为三个非强制对象，在头文件里定义了自中断和转移条件。
/*Include files. */
#include <oms_dist_support.h>
/*Special attribute values. */
#define SSC_INFINITE_TIME -1.0
/*Interrupt code values. */ 自定义中断
#define SSC_START 0
#define SSC_GENERATE 1
#define SSC_STOP 2
/* Nodeconfiguration constants. */
#define SSC_STRM_TO_LOW 0
/* Macrodefinitions for state */
/*transitions. */定义转移条件
#define START (intrpt_code == SSC_START)
#define DISABLED (intrpt_code == SSC_STOP)
#define STOP (intrpt_code == SSC_STOP)
#define PACKET_GENERATE (intrpt_code == SSC_GENERATE)
/*Function prototypes. */
staticvoid ss_packet_generate(void);
Init非强制状态的入口程序为
/* Atthis initial state, we read the values of source attributes */包含源的属性定义
/* andschedule a selt interrupt that will indicate our start time */表明开始的时间
/* forpacket generation. */
/* Obtainthe object id of the surrounding module. */
own_id = op_id_self ();获得所属处理器或队列的对象ID
/* Readthe values of the packet generation parameters, i.e. the */
/*attribute values of the surrounding module. */获取给定对象的某属性
op_ima_obj_attr_get (own_id,"Packet Interarrival Time", interarrival_str);包间隔
op_ima_obj_attr_get(own_id, "Packet Size", size_str); 包大小
op_ima_obj_attr_get(own_id, "Packet Format", format_str);包格式
op_ima_obj_attr_get(own_id, "Start Time", &start_time);开始时间
op_ima_obj_attr_get(own_id, "Stop Time", &stop_time);停止时间
/* Loadthe PDFs that will be used in computing the packet */
/*interarrival times and packet sizes. */从PDF中加载分布
interarrival_dist_ptr= oms_dist_load_from_string (interarrival_str);
pksize_dist_ptr = oms_dist_load_from_string (size_str);
/* Verifythe existence of the packet format to be used for */
/*generated packets. */
if(strcmp (format_str, "NONE") == 0) 检查是否为无格式的包
{
/* We will generate unformattedpackets. Set the flag. */
generate_unformatted = OPC_TRUE;
}
else
{
/* We will generate formatted packets.Turn off the flag. */
generate_unformatted = OPC_FALSE;
/* Get the list of all available packetformats.*/函数返回一系列包格式的名字
pk_format_names_lptr =prg_tfile_name_list_get (PrgC_Tfile_Type_Packet_Format);
/* Search the list for the requestedpacket format.*/查找所需要的包格式
format_found = OPC_FALSE;
for (i = prg_list_size(pk_format_names_lptr); ((format_found == OPC_FALSE) && (i > 0));i--)
{
/* Access the next formatname and compare with requested */
/* format name. */
found_format_str = (char *)prg_list_access (pk_format_names_lptr, i - 1);
if (strcmp (found_format_str,format_str) == 0)
format_found =OPC_TRUE;找到了所需要的包格式
}
if (format_found == OPC_FALSE)
{
/* The requested format doesnot exist. Generate */
/* unformatted packets. */
generate_unformatted =OPC_TRUE;
/* Display an appropriatewarning.*/没有找到需要的包格式，输出警告
op_prg_odb_print_major("Warning from simple packet generator model (simple_source):",
"Thespecified packet format", format_str,
"isnot found. Generating unformatted packets instead.", OPC_NIL);
}
/* Destroy the lits and its elementssince we don't need it */
/* anymore. */
prg_list_free(pk_format_names_lptr);释放内存
prg_mem_free (pk_format_names_lptr);
}
/* Makesure we have valid start and stop times, i.e. stop time is */
/* notearlier than start time. */
if((stop_time <= start_time) && (stop_time != SSC_INFINITE_TIME))
{如果结束时间早于开始时间或结束时间不为无穷
/* Stop time is earlier than starttime. Disable the source. */
start_time = SSC_INFINITE_TIME; 设置开始时间为无穷并且输出警告
/* Display an appropriate warning. */
op_prg_odb_print_major ("Warningfrom simple packet generator model (simple_source):",
"Althoughthe generator is not disabled (start time is set to a finite value),",
"astop time that is not later than the start time is specified.",
"Disablingthe generator.", OPC_NIL);
}
/*Schedule a self interrupt that will indicate our start time for */
/* packetgeneration activities. If the source is disabled, */
/*schedule it at current time with the appropriate code value. */
if(start_time == SSC_INFINITE_TIME) 如果开始时间是无穷，安排自中断开始时间为仿真时间，否则为实际开始时间
{
op_intrpt_schedule_self (op_sim_time(), SSC_STOP);
}
else
{
op_intrpt_schedule_self (start_time, SSC_START);
/* In this case, also schedule theinterrupt when we will stop */
/* generating packets, unless we areconfigured to run until */
/* the end of the simulation. */ 仿真结束时间安排一个自中断
if (stop_time != SSC_INFINITE_TIME)
{
op_intrpt_schedule_self(stop_time,SSC_STOP);
}
next_intarr_time = oms_dist_outcome(interarrival_dist_ptr);通过一个分布生成一个浮点数
/* Make sure that interarrival time isnot negative. In that case it */
/* will be set to 0. */确认间隔时间不为负，否则设为0
if (next_intarr_time <0)
{
next_intarr_time = 0.0;
}
}
/*Register the statistics that will be maintained by this model. */声明局部统计量
bits_sent_hndl =op_stat_reg ("Generator.Traffic Sent (bits/sec)", OPC_STAT_INDEX_NONE,OPC_STAT_LOCAL);
packets_sent_hndl = op_stat_reg ("Generator.Traffic Sent(packets/sec)", OPC_STAT_INDEX_NONE,OPC_STAT_LOCAL);
packet_size_hndl = op_stat_reg ("Generator.Packet Size(bits)", OPC_STAT_INDEX_NONE, OPC_STAT_LOCAL);
interarrivals_hndl = op_stat_reg ("Generator.PacketInterarrival Time (secs)", OPC_STAT_INDEX_NONE, OPC_STAT_LOCAL);
init出口程序
/*Determine the code of the interrupt, which is used in evaluating */
/* statetransition conditions. */
intrpt_code= op_intrpt_code ();
init转到generate状态时的执行的函数代码
staticvoid
ss_packet_generate(void)
{
Packet* pkptr;
double pksize;
/** This function creates a packetbased on the packet generation**/
/** specifications of the source modeland sends it to the lower layer.**/
FIN (ss_packet_generate ());
/* Generate a packet size outcome. */
pksize = (double) ceil(oms_dist_outcome (pksize_dist_ptr));
ceil返回大于或等于指定表达式的最小整数
/* Create a packet of specified formatand size.*/
if (generate_unformatted == OPC_TRUE)
{
/* We produce unformattedpackets. Create one. */
pkptr = op_pk_create(pksize);
}
else
{
/* Create a packet with the specifiedformat.*/
pkptr = op_pk_create_fmt(format_str);创建一个预定义结构的包，返回包格式
op_pk_total_size_set (pkptr,pksize); 设置包的大小
}
/* Update the packet generationstatistics. */
op_stat_write (packets_sent_hndl, 1.0);
op_stat_write (packets_sent_hndl, 0.0);
op_stat_write (bits_sent_hndl, (double)pksize);
op_stat_write (bits_sent_hndl, 0.0);
op_stat_write (packet_size_hndl,(double) pksize);
op_stat_write (interarrivals_hndl,next_intarr_time);
/* Send the packet via the stream tothe lower layer. */
op_pk_send (pkptr, SSC_STRM_TO_LOW);将包发送到输出包流中
FOUT;
}
generate状态的入口代码
/* At theenter execs of the "generate" state we schedule the */
/*arrival of the next packet. */
next_intarr_time= oms_dist_outcome (interarrival_dist_ptr);
/* Makesure that interarrival time is not negative. In that case it */
/* will beset to 0. */ 确定包生成的间隔时间是有效的
if(next_intarr_time <0)
{
next_intarr_time = 0;
}
next_pk_evh= op_intrpt_schedule_self (op_sim_time () + next_intarr_time, SSC_GENERATE);
generate的出口代码
/*Determine the code of the interrupt, which is used in evaluating */
/* statetransition conditions. */
intrpt_code= op_intrpt_code ();
stop状态的入口代码
/* Whenwe enter into the "stop" state, it is the time for us to */
/* stopgenerating traffic. We simply cancel the generation of the */
/* nextpacket and go into a silent mode by not scheduling anything */
/* else. */
if(op_ev_valid (next_pk_evh) == OPC_TRUE)
{
op_ev_cancel (next_pk_evh); 撤销事件
}
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