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PJSIP的实现是为了能在嵌入式设备上高效实现SIP/VOIP.
1.PJSIP库的主要特征:
1).极具移植性.(Extremely portable)
当前可支持平台包括: * Win32/x86 (Win95/98/ME, NT/2000/XP/2003, mingw). * arm, WinCE and Windows Mobile. * Linux/x86, (user mode and as kernel module(!)). * Linux/alpha * Solaris/ultra. * MacOS X/powerpc * RTEMS (x86 and powerpc). * Symbian OS 2).非常小的足印.(Very small footprint)
官方宣称编译后的库<150Kb,我在PC上编译后加上strip后大概173Kb,这对于嵌入 式设备,是个好消息 3).高性能.(High performance)
这点我们后面可以看看是否如作者宣称的 2. PJSIP的组成.
其实说是PJSIP不是特别贴切,这个库实际上是几个部分组成的.
1).PJSIP - Open Source SIP Stack[开源的SIP协议栈] 2).PJMEDIA - Open Source Media Stack[开源的媒体栈] 3).PJNATH - Open Source NAT Traversal Helper Library[开源的NAT-T****库] 4).PJLIB-UTIL - Auxiliary Library[****工具库] 5).PJLIB - Ultra Portable Base Framework Library[基础框架库] PJLIB-UTIL****工具库：加解密MD5和CRC32的算法 PJNATH开源的NAT库包含ICE打洞 PJSUA-LIB库：最顶层的SIP库支持VOIP PJMEDIA库：最顶层的支持视频的库 3. PJLIB基础框架库提供的功能：
1).内存的处理、数据的存储
.数据结构的（hash表、link表、二叉树、等） .caching和pool；缓冲池和内存池 2).OS抽象 .线程、互斥、临界区、锁对象、事件对象 .定时器 .pj_str_t字符串 3).操作系统级别的函数抽象 .socket的抽象(tcp/udp) .文件的读写 4).使用前的初始化，使用后的清理 4.PJSIP的安装和配置：
1.安装和编辑pjsip库：
A.将pjproject-1.5.zip和DirectX-Lib.rar解压到当前目录的pjlib路径下； B.查看pjlib\pjproject-1.5\pjlib\include\pj下面是否有config_site.h，如果没有建一个空文件 C.将DirectX的x86的lib库拷贝到C:\Program Files\Microsoft Visual Studio 8\VC\PlatformSDK\Lib D.在环境变量中设置DXSDK_DIR=direx中的include目录 E.首先编译pjlib\pjproject-1.5\pjproject-vs8.sln [win32] F.然后打开工程开始编译 2.脱离pjsip环境的工程的配置
需要头文件的可以加入 $(SolutionDir)pjlib\pjproject-1.5\pjlib\include $(SolutionDir)pjlib\pjproject-1.5\pjlib-util\include $(SolutionDir)pjlib\pjproject-1.5\pjnath\include $(SolutionDir)pjlib\pjproject-1.5\pjsip\include $(SolutionDir)pjlib\pjproject-1.5\pjmedia\include 如果需要lib库文件的加入
$(SolutionDir)pjlib\pjproject-1.5\pjlib\lib $(SolutionDir)pjlib\pjproject-1.5\pjlib-util\lib $(SolutionDir)pjlib\pjproject-1.5\pjnath\lib $(SolutionDir)pjlib\pjproject-1.5\pjsip\lib $(SolutionDir)pjlib\pjproject-1.5\pjmedia\lib $(SolutionDir)pjlib\pjproject-1.5\lib 我的程序所依赖PJLIB的库有：
pjlib-i386-Win32-vc8-Debug.lib pjlib-util-i386-Win32-vc8-Debug.lib pjnath-i386-Win32-vc8-Debug.lib pjsip-core-i386-Win32-vc8-Debug.lib pjsip-simple-i386-Win32-vc8-Debug.lib pjsip-ua-i386-Win32-vc8-Debug.lib pjsua-lib-i386-Win32-vc8-Debug.lib pjmedia-audiodev-i386-Win32-vc8-Debug.lib pjmedia-codec-i386-Win32-vc8-Debug.lib pjmedia-i386-Win32-vc8-Debug.lib libpjproject-i386-Win32-vc8-Debug.lib 1.使用前的初始化和使用后的清理
PJSIP库里面封装了很多线程内存池；而且很多对象都是基于内存池创建的，所以几乎所以的库都需要初始化或创建
下面是pjlib,pjlib-util,pjnath,pjsua-lib库的初始化和关闭 显示行号
复制代码 这是一段程序代码。
2.缓冲池和内存池(caching,pool)
pjsip的内存池的使用规则：
每个内存池都是基于内存池工厂创建的；pjsip有一个默认的内存池工厂pj_caching_pool； 我喜欢把它叫做缓冲池；将来清理内存池的时候，可以关闭内存池也可直接关闭缓冲池； pj_caching_pool cp; pj_caching_pool_init(&cp, NULL, 1024*1024 ); //缓冲池 pj_caching_pool_destroy(&cp); //释放工厂 pj_pool_t pool = pj_pool_create(&cp.factory, "name", 1024, 1024, NULL); //创建内存池
pj_pool_release(&pool); //释放内存池到工厂中，直接释放工厂可省略这一步 void* p = pj_pool_alloc(pool, size); //在内存中开辟一个空间 注：适当的初始化大小；内存池只能增加不能减小 由于pjlib很多内部对象都用内存池，所以在对象释放之前不能释放内存池。 使用缓冲池和内存池
3.线程的介绍，及其线程的封装和使用
1.外部函数或线程使用到pjsip的时候，必须注册线程
隐藏行号
复制代码 注册线程
function CopyCode(key){var codeElement=null;var trElements=document.all.tags("ol");var i;for(i=0;i 2.线程的创建和使用 pj_thread_create(pool*,"", function, *arg, stack_size, flag, **pj_thread_t)//创建一个线程 pj_thread_destroy(thread); //注销一个线程 pj_thread_resume(thread); //线程继续 pj_thread_sleep(1500); //当前的线程暂停1500毫秒 pj_thread_join(thrad); //等待线程结束 pj_thread_proc函数原型是：int thread_func(void * argv); 3.对pjlib的thread的线程的封装
1: class CSipThread
2: {
3: //1.实现一个int ()(void*)的函数，且在结束的地方设置m_thread_t=NULL
4: pj_thread_t *m_thread_t;
5: protected:
6:
7: /* int (pj_thread_proc)(void*);
8: * 线程函数；子类需要使用static函数来实现
9: * 子类函数中在结束的时候：必须将m_thread_t = NULL;
10: */
11: pj_thread_proc *m_thread_function;
12:
13: /* 这个是实现函数；
14: * 子类需要实现一个run()的函数；在run函数中调用run_父类的函数
15: */
16: virtual void run_(pj_pool_t *pool, pj_thread_proc *function);
17: public:
18: CSipThread();
19: virtual ~CSipThread();
20: virtual bool thread_running();
21:
22: //等待线程结束，自动释放资源，且会将m_thread_t=NULL
23: virtual void thread_join();
24:
25: //在线程自己退出的时候，没有需要手工释放资源，和设置m_thread_t=NULL
26: virtual void thread_destroy();
27: };
28: CSipThread::CSipThread()
29: {
30: this->m_thread_t = NULL;
31: }
32: CSipThread::~CSipThread()
33: {
34:
35: }
36: void CSipThread::run_(pj_pool_t *pool, pj_thread_proc *function)
37: {
38: if ( this->thread_running())
39: return;
40: pj_status_t status = pj_thread_create(pool, "", function, this,
41: PJ_THREAD_DEFAULT_STACK_SIZE, NULL, &this->m_thread_t);
42: if (status != PJ_SUCCESS)
43: {
44: CFunctions::write_log(LM_ERROR, "Can't create timer thread. [result=%d]..\n", status);
45: }
46: }
47: bool CSipThread::thread_running()
48: {
49: if (this->m_thread_t == NULL)
50: return false;
51: else
52: return true;
53: }
54:
55: void CSipThread::thread_join()
56: {
57: if (this->m_thread_t == NULL)
58: return;
59:
60: // 等待线程结束
61: pj_thread_join(this->m_thread_t);
62: }
63:
64: void CSipThread::thread_destroy()
65: {
66: pj_thread_destroy(this->m_thread_t);
67: this->m_thread_t = NULL;
68: }
1: /* 使用封装后的线程注意事项
2: * 1. 必须定义一个static的静态函数
3: * 2. 在静态函数结束的时候必须调用thread_destroy();
4: */
5: class CSendThread : public CSipThread
6: {
7: //线程函数；在函数退出的时候必须调用thread_destroy();
8: static int thread_func(void * argv);
9: public:
10: CSendThread(void);
11: virtual ~CSendThread(void);
12:
13: //再次封装了run_函数
14: void run();
15: }
16:
17: void CSendThread::run()
18: {
19: if ( this->thread_running())
20: return;
21:
22: SIP_GUARD(CInterFace::instance()->m_pool_mutex, obj);
23:
24: //调用父类的run_函数进行创建函数，开始运行；注意如果线程已经存在，那么直接返回
25: //不会再创建一个线程
26: this->run_(CInterFace::instance()->m_pool, &CSendThread::thread_func);
27: }
28:
29: int CSendThread::thread_func(void * argv)
30: {
31: // 线程函数的参数默认是当前对象，等同于this指针
32: CSendThread *this_thread = (CSendThread*)argv;
33:
34: thread_end:
35: // 在线程结束的时候，一定要调用thread_destroy();来删除线程
36: this_thread->thread_destroy();
37: return 0;
38: }
4.互斥和锁,及其封装(mutex)
pj_mutex_create(this->m_pool, "",
PJ_MUTEX_SIMPLE, &this->m_pool_mutex);
//创建一个锁指针
pj_mutex_destroy(this->m_pool_mutex); //删除锁指针 pj_mutex_lock(m_mutex); //加锁 pj_mutex_unlock(m_mutex); //解锁
1: /* 封装了mutex的使用方法
2: * 在创建对象时加锁、删除对象时解锁
3: */
4: class Sip_Lock
5: {
6: pj_mutex_t *m_mutex;
7: public:
8: Sip_Lock(pj_mutex_t *mutex)
9: {
10: this->m_mutex = mutex;
11: pj_mutex_lock(m_mutex);
12: }
13: virtual ~Sip_Lock()
14: {
15: pj_mutex_unlock(m_mutex);
16: this->m_mutex = NULL;
17: }
18: };
19:
20: /* 封装了sip_lock的使用，直接使用宏定义进行互斥 */
21: #define SIP_GUARD(MUTEX, OBJ) Sip_Lock OBJ(MUTEX);
5.定时器(heap,callback,thread)
//创建定时器堆，设置定时器堆pool大小
pj_timer_heap_create(this->m_pool, MAX_TIMER_COUTN, &this->timer_heap); pj_timer_heap_set_max_timed_out_per_poll(this->timer_heap, 20); //对定时器加锁是lcok类型
pj_timer_heap_set_lock(this->timer_heap, this->timer_heap_lock, true); //启动定时器轮询的线程
this->run_(this->m_pool, &CInterFace::timer_thread_fun); //设置一个定时器
pj_timer_heap_schedule(this->timer_heap, entry, delay); //取消一个定时器
pj_timer_heap_cancel(this->timer_heap, entry); //定时器的入口点定义
struct pj_timer_entry { void *user_data; // 定时器的用户数据；C++通常用类对象；C通常用struct int id; // 绝对的ID号；用来区分当user_data和cb都相同的情况 pj_timer_heap_callback *cb; // 定时器中的回调函数 }; //定时器回调函数的原型
void timer_callback(pj_timer_heap_t *timer_heap,struct pj_timer_entry *entry); 一个定时器的使用例子：
1. 创建一个定时器、创建一个线程 2. 创建一个定时器入口entry 3. 创建一个定时器的回调函数，在回调函数中必须重新将entry加入堆中
1: //创建定时器堆，设置定时器堆pool大小; 加锁；
2: pj_timer_heap_create(this->m_pool, MAX_TIMER_COUTN, &this->timer_heap);
3: pj_timer_heap_set_max_timed_out_per_poll(this->timer_heap, 20);
4: pj_timer_heap_set_lock(this->timer_heap, this->timer_heap_lock, true);
5:
6: //启动定时器轮询的线程
7: this->run_(this->m_pool, &CInterFace::timer_thread_fun);
8:
9:
10: //定时器的线程函数
11: int CInterFace::timer_thread_fun(void* argv)
12: {
13: CInterFace *this_thread = (CInterFace*)argv;
14: int rc;
15: while ( !CInterFace::instance()->application_exit() )
16: {
17: pj_thread_sleep(1);
18:
19: #if defined(PJ_SYMBIAN) && PJ_SYMBIAN!=0
20: /* On Symbian, we must use OS poll (Active Scheduler poll) since
21: * timer is implemented using Active Object.
22: */
23: rc = 0;
24: while (pj_symbianos_poll(-1, 0))
25: ++rc;
26: #else
27: PJ_USE_EXCEPTION;
28: PJ_TRY
29: {
30: rc = pj_timer_heap_poll(CInterFace::instance()->timer_heap, NULL);
31: }
32: PJ_CATCH_ANY
33: {
34:
35: }
36: PJ_END;
37: #endif
38: }
39:
40: // 定时器轮询的线程退出；必须手工删除pj_thread_t指针，因为它使用了内存池！
41: CFunctions::write_log(LM_DEBUG, "pj_timer_heap_pool, ending.\n");
42: this_thread->thread_destroy();
43: return 0;
44: }
45:
46:
47: //启动一个定时器：也就是将一个entry添加到堆上面
48: void CInterFace::start_timer(pj_timer_entry* entry, pj_time_val *delay)
49: {
50: if ( !this->thread_running())
51: return;
52:
53: SIP_GUARD(this->timer_heap_mutex, obj);
54: pj_timer_heap_schedule(this->timer_heap, entry, delay);
55: }
56:
57: //取消一个定时器：从堆上删除一个entry
58: void CInterFace::stop_timer(pj_timer_entry* entry)
59: {
60: if ( !this->thread_running())
61: return;
62:
63: SIP_GUARD(this->timer_heap_mutex, obj);
64: pj_timer_heap_cancel(this->timer_heap, entry);
65: }
66:
67: //启动上报速度和进度的定时器
68: bool CBaseFile::start_timer_speedProgress()
69: {
70: this->m_timer_speed_tval.msec = 0;
71: this->m_timer_speed_tval.sec = 1;
72: this->m_timer_speed.user_data = this;
73: this->m_timer_speed.cb = &CBaseFile::callback_speed;
74: SIP_GUARD(this->m_run_speed_mutex, obj);
75: this->m_run_speed = true;
76: CInterFace::instance()->start_timer(&this->m_timer_speed, &this->m_timer_speed_tval);
77: return true;
78: }
79:
80: //取消上报进度和速度的定时器
81: void CBaseFile::stop_timer_speedProgress()
82: {
83: SIP_GUARD(this->m_run_speed_mutex, obj);
84: this->m_run_speed = false;
85: CInterFace::instance()->stop_timer(&this->m_timer_speed);
86: }
87:
88: //上报进度和速度的回调函数
89: void CBaseFile::callback_speed(pj_timer_heap_t *timer_heap, pj_timer_entry *entry)
90: {
91: // 上报速度和状态的的
92: if (entry->user_data != NULL)
93: {
94: CBaseFile *file = (CBaseFile*)entry->user_data;
95:
96: uint speed_ = 0;
97: uint progress_ = 0;
98: file->get_speed_progress(speed_, progress_);
99:
100: if ( file->m_ice_session->is_running())
101: {
102: CInterFace::instance()->report_speed(
103: file->get_userid().c_str(),
104: file->get_fileName().c_str(),
105: file->get_guid(),
106: speed_,
107: progress_);
108: }
109:
110: // 由于定时select出来后，就从堆上删除了；所以需要一直触发的定时器，
111: // 就必须在回调函数中，重新想堆中添加entry！
112: SIP_GUARD(file->m_run_speed_mutex, obj);
113: if ( file->m_run_speed)
114: CInterFace::instance()->start_timer(entry, &file->m_timer_speed_tval);
115: }
116: }
6.pj_str_t字符串
7.socket的封装和使用
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