Index: trunk/FACT++/src/DimDescriptionService.cc
===================================================================
--- trunk/FACT++/src/DimDescriptionService.cc	(revision 10317)
+++ trunk/FACT++/src/DimDescriptionService.cc	(revision 10317)
@@ -0,0 +1,114 @@
+// **************************************************************************
+/** @class DimDescriptionService
+
+@brief A DimService which broadcasts descriptions for services and commands
+
+The DimDescriptionService creates a service with the name of the server like
+SERVER/SERVICE_DESC. This is meant in addition to the SERVICE_LIST service
+of each node to contain a description of the service and its arguments.
+
+Assume you have created a service (or command) with the format I:2;F:1
+a valid description string would look like
+
+   Description|int[addr]:Address range (from - to)|val[byte]:Value to be set
+
+Description is a general description of the command or service itself,
+int and val are the names of the arguments (e.g. names of FITS columns),
+addr and byte have the meaning of a unit (e.g. unit of FITS column)
+and the text after the colon is a description of the arguments
+(e.g. comment of a FITS column). The description must not contain a
+line-break character \n.
+
+You can omit either the name, the unit or the comment or any combination of them.
+The descriptions of the individual format strings are separated by a vertical line.
+
+The description should contain as many descriptions as format chunks, e.g.
+
+I:1          should contain one description chunks
+I:1;F:1      should contain two description chunks
+I:2;F:1      should contain two description chunks
+I:2;I:1;F:1  should contain three description chunks
+
+*/
+// **************************************************************************
+#include "DimDescriptionService.h"
+
+#include <stdexcept>
+
+#include "dis.hxx"
+
+using namespace std;
+
+DimService *DimDescriptionService::fService = 0;
+int         DimDescriptionService::fCount   = 0;
+std::string DimDescriptionService::fData    = "";
+
+// --------------------------------------------------------------------------
+//
+//! When the constructor is first called, a service with the name
+//! SERVER/SERVICE_DESC is created. The server name SERVER is retrieved
+//! from DimServer::itsName. If DimServer::itsName is empty, the
+//! server name is extracted from the given name as the part before the
+//! first '/'. A string "name=format\n" is added to fData and stored
+//! in fDescription.
+//!
+//! A counter fCount for the number of instantiations is increased.
+//!
+//! @param name
+//!     The name of the service or command to be described, e.g. SERVER/COMMAND
+//!
+//! @param desc
+//!     A description string. For details see class reference
+//!
+//! @throws
+//!     If a server name couldn't be reliably determined a runtime_error
+//!     exception is thrown.
+//
+DimDescriptionService::DimDescriptionService(const std::string &name, const std::string &desc)
+{
+    string service = DimServer::itsName;
+    if (service.empty())
+    {
+        const size_t p = name.find_first_of('/');
+        if (p==string::npos)
+            throw runtime_error("Could not determine server name");
+
+        service = name.substr(0, p);
+    }
+
+    service += "/SERVICE_DESC";
+    if (!fService)
+        fService = new DimService(service.c_str(), const_cast<char*>(""));
+
+    fCount++;
+
+    fDescription = name + '=' + desc;
+
+    if (fData.find(fDescription+'\n')!=std::string::npos)
+        return;
+
+    fData += fDescription + '\n';
+
+    fService->setData(const_cast<char*>(fData.c_str()));
+    fService->updateService();
+}
+
+
+// --------------------------------------------------------------------------
+//
+//! If fDescription is found in fData it is removed from fData.
+//! The counter fCount is decreased and fService deleted if the counter
+//! reached 0.
+//
+DimDescriptionService::~DimDescriptionService()
+{
+    const size_t pos = fData.find(fDescription+'\n');
+    if (pos!=std::string::npos)
+        fData.replace(pos, fDescription.size()+1, "");
+
+    if (--fCount>0)
+        return;
+
+    delete fService;
+    fService=0;
+}
Index: trunk/FACT++/src/DimDescriptionService.h
===================================================================
--- trunk/FACT++/src/DimDescriptionService.h	(revision 10317)
+++ trunk/FACT++/src/DimDescriptionService.h	(revision 10317)
@@ -0,0 +1,23 @@
+#ifndef FACT_DimDescriptionService
+#define FACT_DimDescriptionService
+
+#include <string>
+
+class DimService;
+
+class DimDescriptionService
+{
+    static int         fCount;     /// Counter to count the number of instatiations
+    static DimService *fService;   /// Pointer to the DimService distributing the desscriptions
+    static std::string fData;      /// Data to be distributed with the service
+
+    std::string fDescription;      /// Local storage for the applied description
+
+public:
+    DimDescriptionService(const std::string &name, const std::string &format);
+    ~DimDescriptionService();
+
+    std::string GetDescription() const { return fDescription; }
+};
+
+#endif