/*??
本程序維護一個?256bytes*4?緩沖區，兩個信號量保護（讀和寫）。創建兩
個線程，一個用于采集聲卡數據并寫到緩沖區，數據采集線程使用ALSA接口
編程，設置采樣率?22333，周期幀數?128，幀格式?U8聲道數?2，每個周期
大約?5.73ms，每個周期?256bytes。另外一個將緩沖區數據廣播到網絡，每
次發送?256bytes。
*/??
??
#define?ALSA_PCM_NEW_HW_PARAMS_API???
??
#include???
#include???
#include???
#include???
#include???
#include?????/*?basic?system?data?types?*/??
#include????/*?basic?socket?definitions?*/??
#include????/*?sockaddr_in{}?and?other?Internet?defns?*/??
#include?????/*?inet（3）?functions?*/??
??
#define?RATE?22333??
#define?CHANNEL?2??
#define?FORMAT??SND_PCM_FORMAT_U8??
#define?frameS??128??
??
#define?SIZE?CHANNEL*frameS*1??
??
#define?NBUFF????4???
??
//?套接字端口??
#define?PORT?10000???
#define?SA??struct?sockaddr??
??
//?數據緩沖區及信號量??
struct?{??????
????char???buffer[1024];???
????sem_t?mutex?nempty?nstored;???
}?shared;??
??
char*?pRead?=?shared.buffer;?//讀指針??
char*?pWrite?=?shared.buffer;?//寫指針??
void*?sendData（void?*arg）;?//線程函數，廣播數據??
void*?generateData（void?*arg）;?//線程函數，讀聲卡??
??
//?計數變量??
long?produce=0;??
long?consume=0;??
long?totalTime?=?0;??
??
int?main（）???
{?????
????pthread_t???tid_generateData?tid_sendData;??
??
????//?初始化信號量??
????sem_init（&shared.mutex?0?1）;??//未用到??
????sem_init（&shared.nempty?0?NBUFF）;???
????sem_init（&shared.nstored?0?0）;???
?????
????//?創建讀聲卡線程，將數據保存到緩沖區??
????pthread_create（&tid_generateData?NULL?generateData?NULL）;??
????//?創建廣播線程，將緩沖區數據發送到網絡??
????pthread_create（&tid_sendData?NULL?sendData?NULL）;???
???
????pthread_join（tid_sendData?NULL）;???
????pthread_join（tid_generateData?NULL）;???
???
????sem_destroy（&shared.mutex）;???
????sem_destroy（&shared.nempty）;???
????sem_destroy（&shared.nstored）;???
????exit（0）;???
}???
??
void*?sendData（void?*arg）??
{??
????int?????????sockfd;??
????struct??????sockaddr_in?????servaddr;??
??????
????/*?socket?初始化?*/??
????const?int?on?=?1;??
????int?n;
????bzero（&servaddr?sizeof（servaddr））;??
????servaddr.sin_family?=?AF_INET;??
????servaddr.sin_port?=?htons（PORT）;??
????inet_pton（AF_INET?“172.19.73.113“?&servaddr.sin_addr）;??
????sockfd?=?socket（AF_INET?SOCK_DGRAM?0）;??
????setsockopt（sockfd?SOL_SOCKET?SO_BROADCAST?&on?sizeof（on））;??
??????
????printf（“\n\n\n\n\nData?generating?starts?Broadcasting?...\n\n\n\n\n\n\n\n\n\n“）;??
????printf（“|------------------------------------------------------------|\t0\tmin?|\n\033[1A|“）;??
????while（1）??
????{??
????????//?獲取nstored信號量??
????????sem_wait（&shared.nstored）;??
?????????
????????//?發送數據??
????????n?=?sendto（sockfd?pRead?256?0?pservaddr?servlen）;??
????????if（n!=256）?//printf（“send?short:?send?%d\n“n）??
????????{??
????????????sem_post（&shared.nstored）;??
????????????continue;??
????????}??
?????????
????????//?更新緩沖區讀指針??
????????pRead?+=?256;??
????????if（pRead-1024?==?shared.buffer）??
????????????pRead?=?shared.buffer;??
??????????????
????????//?釋放nempty信號量??
????????sem_post（&shared.nempty）;??
???????