for bug #241, support mr(merged-read) config and reload. 2.0.52.

@@ -485,6 +485,7 @@ Supported operating systems and hardware:
 * 2013-10-17, Created.<br/>
 
 ## History
+* v2.0, 2014-12-04, for [#241](https://github.com/winlinvip/simple-rtmp-server/issues/241), support mr(merged-read) config and reload. 2.0.52.
 * v2.0, 2014-12-04, enable [#241](https://github.com/winlinvip/simple-rtmp-server/issues/241) and [#248](https://github.com/winlinvip/simple-rtmp-server/issues/248), +25% performance, 2.5k publisher. 2.0.50
 * v2.0, 2014-12-04, fix [#248](https://github.com/winlinvip/simple-rtmp-server/issues/248), improve about 15% performance for fast buffer. 2.0.49
 * v2.0, 2014-12-03, fix [#244](https://github.com/winlinvip/simple-rtmp-server/issues/244), conn thread use cond to wait for recv thread error. 2.0.47.

@@ -142,6 +142,26 @@ http_stream {
 vhost __defaultVhost__ {
 }
 
+# the MR(merged-read) setting for publisher.
+vhost mr.srs.com {
+    # about MR, read https://github.com/winlinvip/simple-rtmp-server/issues/241
+    mr {
+        # whether enable the MR(merged-read)
+        # default: off
+        enabled     on;
+        # the latency in ms for MR(merged-read),
+        # the performance+ when latency+, and memory+,
+        #       memory(buffer) = latency * kbps / 8
+        # for example, latency=500ms, kbps=3000kbps, each publish connection will consume
+        #       memory = 500 * 3000 / 8 = 187500B = 183KB
+        # when there are 2500 publisher, the total memory of SRS atleast:
+        #       183KB * 2500 = 446MB
+        # the value recomment is [300, 2000]
+        # default: 500
+        latency     500;
+    }
+}
+
 # vhost for edge, edge and origin is the same vhost
 vhost same.edge.srs.com {
     # the mode of vhost, local or remote.

@@ -816,7 +816,18 @@ int SrsConfig::reload_vhost(SrsConfDirective* old_root)
                         return ret;
                     }
                 }
-                srs_trace("vhost %s reload hls success.", vhost.c_str());
+                srs_trace("vhost %s reload hlsdvrsuccess.", vhost.c_str());
+            }
+            // mr, only one per vhost
+            if (!srs_directive_equals(new_vhost->get("mr"), old_vhost->get("mr"))) {
+                for (it = subscribes.begin(); it != subscribes.end(); ++it) {
+                    ISrsReloadHandler* subscribe = *it;
+                    if ((ret = subscribe->on_reload_vhost_mr(vhost)) != ERROR_SUCCESS) {
+                        srs_error("vhost %s notify subscribes mr failed. ret=%d", vhost.c_str(), ret);
+                        return ret;
+                    }
+                }
+                srs_trace("vhost %s reload mr success.", vhost.c_str());
             }
             // http, only one per vhost.
             if (!srs_directive_equals(new_vhost->get("http"), old_vhost->get("http"))) {
@@ -1316,6 +1327,7 @@ int SrsConfig::check_config()
                 && n != "time_jitter" 
                 && n != "atc" && n != "atc_auto"
                 && n != "debug_srs_upnode"
+                && n != "mr"
             ) {
                 ret = ERROR_SYSTEM_CONFIG_INVALID;
                 srs_error("unsupported vhost directive %s, ret=%d", n.c_str(), ret);
@@ -1333,6 +1345,16 @@ int SrsConfig::check_config()
                         return ret;
                     }
                 }
+            } else if (n == "mr") {
+                for (int j = 0; j < (int)conf->directives.size(); j++) {
+                    string m = conf->at(j)->name.c_str();
+                    if (m != "enabled" && m != "latency"
+                    ) {
+                        ret = ERROR_SYSTEM_CONFIG_INVALID;
+                        srs_error("unsupported vhost mr directive %s, ret=%d", m.c_str(), ret);
+                        return ret;
+                    }
+                }
             } else if (n == "ingest") {
                 for (int j = 0; j < (int)conf->directives.size(); j++) {
                     string m = conf->at(j)->name.c_str();
@@ -2078,6 +2100,50 @@ int SrsConfig::get_chunk_size(string vhost)
     return ::atoi(conf->arg0().c_str());
 }
 
+bool SrsConfig::get_mr_enabled(string vhost)
+{
+    
+    SrsConfDirective* conf = get_vhost(vhost);
+
+    if (!conf) {
+        return SRS_CONSTS_RTMP_MR;
+    }
+
+    conf = conf->get("mr");
+    if (!conf) {
+        return SRS_CONSTS_RTMP_MR;
+    }
+
+    conf = conf->get("enabled");
+    if (!conf || conf->arg0() != "on") {
+        return SRS_CONSTS_RTMP_MR;
+    }
+
+    return true;
+}
+
+int SrsConfig::get_mr_sleep_ms(string vhost)
+{
+    
+    SrsConfDirective* conf = get_vhost(vhost);
+
+    if (!conf) {
+        return SRS_CONSTS_RTMP_MR_SLEEP;
+    }
+
+    conf = conf->get("mr");
+    if (!conf) {
+        return SRS_CONSTS_RTMP_MR_SLEEP;
+    }
+
+    conf = conf->get("latency");
+    if (!conf || conf->arg0().empty()) {
+        return SRS_CONSTS_RTMP_MR_SLEEP;
+    }
+
+    return ::atoi(conf->arg0().c_str());
+}
+
 int SrsConfig::get_global_chunk_size()
 {
     SrsConfDirective* conf = root->get("chunk_size");

@@ -530,6 +530,16 @@ public:
     * @remark, default 60000.
     */
     virtual int                 get_chunk_size(std::string vhost);
+    /**
+    * whether mr is enabled for vhost.
+    * @param vhost, the vhost to get the mr.
+    */
+    virtual bool                get_mr_enabled(std::string vhost);
+    /**
+    * get the mr sleep time in ms for vhost.
+    * @param vhost, the vhost to get the mr sleep time.
+    */
+    virtual int                 get_mr_sleep_ms(std::string vhost);
 private:
     /**
     * get the global chunk size.

@@ -29,6 +29,9 @@ CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 #include <srs_protocol_buffer.hpp>
 #include <srs_kernel_utility.hpp>
 #include <srs_core_performance.hpp>
+#include <srs_app_config.hpp>
+
+using namespace std;
 
 ISrsMessageHandler::ISrsMessageHandler()
 {
@@ -221,11 +224,13 @@ void SrsQueueRecvThread::on_thread_stop()
 }
 
 SrsPublishRecvThread::SrsPublishRecvThread(
-    SrsRtmpServer* rtmp_sdk, int fd, int timeout_ms,
+    SrsRtmpServer* rtmp_sdk, 
+    SrsRequest* _req, int mr_sock_fd, int timeout_ms, 
     SrsRtmpConn* conn, SrsSource* source, bool is_fmle, bool is_edge
 ): trd(this, rtmp_sdk, timeout_ms)
 {
     rtmp = rtmp_sdk;
+
     _conn = conn;
     _source = source;
     _is_fmle = is_fmle;
@@ -235,11 +240,21 @@ SrsPublishRecvThread::SrsPublishRecvThread(
     _nb_msgs = 0;
     error = st_cond_new();
     
-    mr_fd = fd;
+    req = _req;
+    mr_fd = mr_sock_fd;
+
+    // the mr settings, 
+    // @see https://github.com/winlinvip/simple-rtmp-server/issues/241
+    mr = _srs_config->get_mr_enabled(req->vhost);
+    mr_sleep = _srs_config->get_mr_sleep_ms(req->vhost);
+    
+    _srs_config->subscribe(this);
 }
 
 SrsPublishRecvThread::~SrsPublishRecvThread()
 {
+    _srs_config->unsubscribe(this);
+    
     trd.stop();
     st_cond_destroy(error);
 }
@@ -282,20 +297,8 @@ void SrsPublishRecvThread::on_thread_start()
     // for the main thread never send message.
 
 #ifdef SRS_PERF_MERGED_READ
-    // socket recv buffer, system will double it.
-    int nb_rbuf = SRS_MR_SOCKET_BUFFER / 2;
-    socklen_t sock_buf_size = sizeof(int);
-    if (setsockopt(mr_fd, SOL_SOCKET, SO_RCVBUF, &nb_rbuf, sock_buf_size) < 0) {
-        srs_warn("set sock SO_RCVBUF=%d failed.", nb_rbuf);
-    }
-    getsockopt(mr_fd, SOL_SOCKET, SO_RCVBUF, &nb_rbuf, &sock_buf_size);
-
-    srs_trace("merged read sockbuf=%d, actual=%d, sleep %d when nread<=%d", 
-        SRS_MR_SOCKET_BUFFER, nb_rbuf, SRS_MR_MAX_SLEEP_MS, SRS_MR_SMALL_BYTES);
-
-    // enable the merge read
-    // @see https://github.com/winlinvip/simple-rtmp-server/issues/241
-    rtmp->set_merge_read(true, this);
+    // for mr.
+    update_buffer(mr, mr_sleep);
 #endif
 }
 
@@ -349,7 +352,11 @@ void SrsPublishRecvThread::on_recv_error(int ret)
 #ifdef SRS_PERF_MERGED_READ
 void SrsPublishRecvThread::on_read(ssize_t nread)
 {
-    if (nread < 0 || SRS_MR_MAX_SLEEP_MS <= 0) {
+    if (!mr) {
+        return;
+    }
+    
+    if (nread < 0 || mr_sleep <= 0) {
         return;
     }
     
@@ -360,7 +367,72 @@ void SrsPublishRecvThread::on_read(ssize_t nread)
     * @see https://github.com/winlinvip/simple-rtmp-server/issues/241
     */
     if (nread < SRS_MR_SMALL_BYTES) {
-        st_usleep(SRS_MR_MAX_SLEEP_MS * 1000);
+        st_usleep(mr_sleep * 1000);
     }
 }
 #endif
+
+int SrsPublishRecvThread::on_reload_vhost_mr(string vhost)
+{
+    int ret = ERROR_SUCCESS;
+
+    // the mr settings, 
+    // @see https://github.com/winlinvip/simple-rtmp-server/issues/241
+    bool mr_enabled = _srs_config->get_mr_enabled(req->vhost);
+    int sleep_ms = _srs_config->get_mr_sleep_ms(req->vhost);
+    update_buffer(mr_enabled, sleep_ms);
+    
+    return ret;
+}
+
+void SrsPublishRecvThread::update_buffer(bool mr_enabled, int sleep_ms)
+{
+    // TODO: FIXME: refine it.
+    
+#ifdef SRS_PERF_MERGED_READ
+    // previous enabled mr, update the buffer.
+    if (mr && mr_sleep != sleep_ms) {
+        // the underlayer api will set to SRS_MR_SOCKET_BUFFER bytes.
+        //      4KB=4096, 8KB=8192, 16KB=16384, 32KB=32768, 64KB=65536, 
+        //      128KB=131072, 256KB=262144, 512KB=524288
+        // the buffer should set to SRS_MR_MAX_SLEEP_MS*kbps/8,
+        // for example, your system delivery stream in 1000kbps, 
+        // sleep 800ms for small bytes, the buffer should set to:
+        //      800*1000/8=100000B(about 128KB).
+        //      2000*3000/8=750000B(about 732KB).
+        int kbps = 3000;
+        int socket_buffer_size = mr_sleep * kbps / 8;
+        
+        // socket recv buffer, system will double it.
+        int nb_rbuf = socket_buffer_size / 2;
+        socklen_t sock_buf_size = sizeof(int);
+        if (setsockopt(mr_fd, SOL_SOCKET, SO_RCVBUF, &nb_rbuf, sock_buf_size) < 0) {
+            srs_warn("set sock SO_RCVBUF=%d failed.", nb_rbuf);
+        }
+        getsockopt(mr_fd, SOL_SOCKET, SO_RCVBUF, &nb_rbuf, &sock_buf_size);
+    
+        srs_trace("merged read sockbuf=%d, actual=%d, sleep %d when nread<=%d", 
+            socket_buffer_size, nb_rbuf, mr_sleep, SRS_MR_SMALL_BYTES);
+    
+        rtmp->set_recv_buffer(nb_rbuf);
+    }
+#endif
+
+    // update to new state
+    mr = mr_enabled;
+    mr_sleep = sleep_ms;
+    
+#ifdef SRS_PERF_MERGED_READ
+    // apply new state.
+    if (mr) {
+        // enable the merge read
+        // @see https://github.com/winlinvip/simple-rtmp-server/issues/241
+        rtmp->set_merge_read(true, this);
+    } else {
+        // disable the merge read
+        // @see https://github.com/winlinvip/simple-rtmp-server/issues/241
+        rtmp->set_merge_read(false, NULL);
+    }
+#endif
+}
+

@@ -35,11 +35,13 @@ CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 #include <srs_app_thread.hpp>
 #include <srs_protocol_buffer.hpp>
 #include <srs_core_performance.hpp>
+#include <srs_app_reload.hpp>
 
 class SrsRtmpServer;
 class SrsMessage;
 class SrsRtmpConn;
 class SrsSource;
+class SrsRequest;
 
 /**
  * for the recv thread to handle the message.
@@ -138,15 +140,19 @@ class SrsPublishRecvThread : virtual public ISrsMessageHandler
 #ifdef SRS_PERF_MERGED_READ
     , virtual public IMergeReadHandler
 #endif
+    , virtual public ISrsReloadHandler
 {
 private:
     SrsRecvThread trd;
     SrsRtmpServer* rtmp;
+    SrsRequest* req;
     // the msgs already got.
     int64_t _nb_msgs;
     // for mr(merged read),
     // @see https://github.com/winlinvip/simple-rtmp-server/issues/241
+    bool mr;
     int mr_fd;
+    int mr_sleep;
     // the recv thread error code.
     int recv_error_code;
     SrsRtmpConn* _conn;
@@ -158,7 +164,8 @@ private:
     // @see https://github.com/winlinvip/simple-rtmp-server/issues/244
     st_cond_t error;
 public:
-    SrsPublishRecvThread(SrsRtmpServer* rtmp_sdk, int fd, int timeout_ms,
+    SrsPublishRecvThread(SrsRtmpServer* rtmp_sdk, 
+        SrsRequest* _req, int mr_sock_fd, int timeout_ms, 
         SrsRtmpConn* conn, SrsSource* source, bool is_fmle, bool is_edge);
     virtual ~SrsPublishRecvThread();
 public:
@@ -183,6 +190,11 @@ public:
 #ifdef SRS_PERF_MERGED_READ
     virtual void on_read(ssize_t nread);
 #endif
+// interface ISrsReloadHandler
+public:
+    virtual int on_reload_vhost_mr(std::string vhost);
+private:
+    virtual void update_buffer(bool mr_enabled, int sleep_ms);
 };
 
 #endif

@@ -140,6 +140,11 @@ int ISrsReloadHandler::on_reload_vhost_dvr(string /*vhost*/)
     return ERROR_SUCCESS;
 }
 
+int ISrsReloadHandler::on_reload_vhost_mr(string /*vhost*/)
+{
+    return ERROR_SUCCESS;
+}
+
 int ISrsReloadHandler::on_reload_vhost_transcode(string /*vhost*/)
 {
     return ERROR_SUCCESS;

@@ -65,6 +65,7 @@ public:
     virtual int on_reload_vhost_forward(std::string vhost);
     virtual int on_reload_vhost_hls(std::string vhost);
     virtual int on_reload_vhost_dvr(std::string vhost);
+    virtual int on_reload_vhost_mr(std::string vhost);
     virtual int on_reload_vhost_transcode(std::string vhost);
     virtual int on_reload_ingest_removed(std::string vhost, std::string ingest_id);
     virtual int on_reload_ingest_added(std::string vhost, std::string ingest_id);

@@ -660,9 +660,8 @@ int SrsRtmpConn::fmle_publishing(SrsSource* source)
 
     // use isolate thread to recv,
     // @see: https://github.com/winlinvip/simple-rtmp-server/issues/237
-    SrsPublishRecvThread trd(rtmp, st_netfd_fileno(stfd),
-        SRS_CONSTS_RTMP_RECV_TIMEOUT_US / 1000, 
-        this, source, true, vhost_is_edge);
+    SrsPublishRecvThread trd(rtmp, req, 
+        st_netfd_fileno(stfd), 0, this, source, true, vhost_is_edge);
 
     srs_info("start to publish stream %s success", req->stream.c_str());
     ret = do_publishing(source, &trd);
@@ -696,9 +695,8 @@ int SrsRtmpConn::flash_publishing(SrsSource* source)
 
     // use isolate thread to recv,
     // @see: https://github.com/winlinvip/simple-rtmp-server/issues/237
-    SrsPublishRecvThread trd(rtmp, st_netfd_fileno(stfd),
-        SRS_CONSTS_RTMP_RECV_TIMEOUT_US / 1000, 
-        this, source, false, vhost_is_edge);
+    SrsPublishRecvThread trd(rtmp, req, 
+        st_netfd_fileno(stfd), 0, this, source, true, vhost_is_edge);
 
     srs_info("start to publish stream %s success", req->stream.c_str());
     ret = do_publishing(source, &trd);

@@ -31,7 +31,7 @@ CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 // current release version
 #define VERSION_MAJOR       2
 #define VERSION_MINOR       0
-#define VERSION_REVISION    51
+#define VERSION_REVISION    52
 // server info.
 #define RTMP_SIG_SRS_KEY "SRS"
 #define RTMP_SIG_SRS_ROLE "origin/edge server"

@@ -42,22 +42,23 @@ CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 * @example, for the default settings, this algorithm will use:
 *       that is, when got nread bytes smaller than 4KB, sleep(780ms).
 */
-#if 1
-    // to enable merged read.
-    #define SRS_PERF_MERGED_READ
-    // the max sleep time in ms
-    #define SRS_MR_MAX_SLEEP_MS 780
-    // the max small bytes to group
-    #define SRS_MR_SMALL_BYTES 4096
-    // the underlayer api will set to SRS_MR_SOCKET_BUFFER bytes.
-    //      4KB=4096, 8KB=8192, 16KB=16384, 32KB=32768, 64KB=65536, 
-    //      128KB=131072, 256KB=262144, 512KB=524288
-    // the buffer should set to SRS_MR_MAX_SLEEP_MS*kbps/8,
-    // for example, your system delivery stream in 1000kbps, 
-    // sleep 800ms for small bytes, the buffer should set to:
-    //      800*1000/8=100000B(about 128KB).
-    #define SRS_MR_SOCKET_BUFFER 65536
-#endif
+/**
+* https://github.com/winlinvip/simple-rtmp-server/issues/241#issuecomment-65554690
+* The merged read algorithm is ok and can be simplified for:
+*   1. Suppose the client network is ok. All algorithm go wrong when netowrk is not ok.
+*   2. Suppose the client send each packet one by one. Although send some together, it's same.
+*   3. SRS MR algorithm will read all data then sleep.
+* So, the MR algorithm is:
+*   while true:
+*       read all data from socket.
+*       sleep a while
+* For example, sleep 120ms. Then there is, and always 120ms data in buffer.
+* That is, the latency is 120ms(the sleep time).
+*/
+// to enable merged read.
+#undef SRS_PERF_MERGED_READ
+// the max sleep time in ms
+#define SRS_MR_MAX_SLEEP_MS 800
 
 /**
 * the send cache time in ms.

@@ -50,6 +50,10 @@ CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 // 6. Chunking, RTMP protocol default chunk size.
 #define SRS_CONSTS_RTMP_PROTOCOL_CHUNK_SIZE 128
 
+// the default setting of mr.
+#define SRS_CONSTS_RTMP_MR false
+#define SRS_CONSTS_RTMP_MR_SLEEP 500
+
 /**
 * 6. Chunking
 * The chunk size is configurable. It can be set using a control

@@ -28,6 +28,11 @@ CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 #include <srs_kernel_utility.hpp>
 #include <srs_core_performance.hpp>
 
+// the max small bytes to group
+#define SRS_MR_SMALL_BYTES 4096
+// the default recv buffer size
+#define SRS_DEFAULT_RECV_BUFFER_SIZE 8192
+
 // the max header size,
 // @see SrsProtocol::read_message_header().
 #define SRS_RTMP_MAX_MESSAGE_HEADER 11
@@ -90,11 +95,30 @@ SrsFastBuffer::SrsFastBuffer()
     _handler = NULL;
 #endif
     
-    nb_buffer = SRS_MR_SOCKET_BUFFER;
+    nb_buffer = SRS_DEFAULT_RECV_BUFFER_SIZE;
     buffer = new char[nb_buffer];
     p = end = buffer;
 }
 
+void SrsFastBuffer::set_buffer(int buffer_size)
+{
+    // only realloc when buffer changed bigger
+    if (buffer_size <= nb_buffer) {
+        return;
+    }
+    
+    int start = p - buffer;
+    int cap = end - p;
+    
+    char* buf = new char[buffer_size];
+    memcpy(buf, buffer, nb_buffer);
+    srs_freep(buffer);
+    
+    buffer = buf;
+    p = buffer + start;
+    end = p + cap;
+}
+
 SrsFastBuffer::~SrsFastBuffer()
 {
     srs_freep(buffer);

@@ -124,6 +124,15 @@ public:
     virtual ~SrsFastBuffer();
 public:
     /**
+    * create buffer with specifeid size.
+    * @param buffer the size of buffer.
+    * @remark when MR(SRS_PERF_MERGED_READ) disabled, always set to 8K.
+    * @remark when buffer changed, the previous ptr maybe invalid.
+    * @see https://github.com/winlinvip/simple-rtmp-server/issues/241
+    */
+    virtual void set_buffer(int buffer_size);
+public:
+    /**
     * read 1byte from buffer, move to next bytes.
     * @remark assert buffer already grow(1).
     */

@@ -750,6 +750,11 @@ void SrsRtmpServer::set_merge_read(bool v, IMergeReadHandler* handler)
 {
     protocol->set_merge_read(v, handler);
 }
+
+void SrsRtmpServer::set_recv_buffer(int buffer_size)
+{
+    protocol->set_recv_buffer(buffer_size);
+}
 #endif
 
 void SrsRtmpServer::set_recv_timeout(int64_t timeout_us)

@@ -354,6 +354,14 @@ public:
     * @see https://github.com/winlinvip/simple-rtmp-server/issues/241
     */
     virtual void set_merge_read(bool v, IMergeReadHandler* handler);
+    /**
+    * create buffer with specifeid size.
+    * @param buffer the size of buffer.
+    * @remark when MR(SRS_PERF_MERGED_READ) disabled, always set to 8K.
+    * @remark when buffer changed, the previous ptr maybe invalid.
+    * @see https://github.com/winlinvip/simple-rtmp-server/issues/241
+    */
+    virtual void set_recv_buffer(int buffer_size);
 #endif
     /**
     * set/get the recv timeout in us.

@@ -504,6 +504,11 @@ void SrsProtocol::set_merge_read(bool v, IMergeReadHandler* handler)
 {
     in_buffer->set_merge_read(v, handler);
 }
+
+void SrsProtocol::set_recv_buffer(int buffer_size)
+{
+    in_buffer->set_buffer(buffer_size);
+}
 #endif
 
 void SrsProtocol::set_recv_timeout(int64_t timeout_us)

@@ -257,10 +257,6 @@ private:
     */
     int32_t out_chunk_size;
 public:
-    /**
-    * use io to create the protocol stack,
-    * @param io, provides io interfaces, user must free it.
-    */
     SrsProtocol(ISrsProtocolReaderWriter* io);
     virtual ~SrsProtocol();
 public:
@@ -288,6 +284,14 @@ public:
     * @see https://github.com/winlinvip/simple-rtmp-server/issues/241
     */
     virtual void set_merge_read(bool v, IMergeReadHandler* handler);
+    /**
+    * create buffer with specifeid size.
+    * @param buffer the size of buffer.
+    * @remark when MR(SRS_PERF_MERGED_READ) disabled, always set to 8K.
+    * @remark when buffer changed, the previous ptr maybe invalid.
+    * @see https://github.com/winlinvip/simple-rtmp-server/issues/241
+    */
+    virtual void set_recv_buffer(int buffer_size);
 #endif
 public:
     /**