From b8a5196a89a5e7c298f962c8965e9778b69493ce Mon Sep 17 00:00:00 2001
From: Thulinma <jaron@vietors.com>
Date: Thu, 23 Oct 2014 15:13:16 +0200
Subject: [PATCH] Added CRC field to statistics class.

---
 lib/shared_memory.cpp | 17 +++++++++++++++++
 lib/shared_memory.h   |  7 ++++++-
 2 files changed, 23 insertions(+), 1 deletion(-)

diff --git a/lib/shared_memory.cpp b/lib/shared_memory.cpp
index d8a7cea6..85dd0d16 100644
--- a/lib/shared_memory.cpp
+++ b/lib/shared_memory.cpp
@@ -39,6 +39,11 @@ namespace IPC {
     val = ((long)p[0] << 24) | ((long)p[1] << 16) | ((long)p[2] << 8) | p[3];
   }
 
+  /// Reads a long value of p in host order to val.
+  static void btohl(char * p, unsigned int & val) {
+    val = ((long)p[0] << 24) | ((long)p[1] << 16) | ((long)p[2] << 8) | p[3];
+  }
+  
   /// Reads a long long value of p in host order to val.
   static void btohll(char * p, long long & val) {
     val = ((long long)p[0] << 56) | ((long long)p[1] << 48) | ((long long)p[2] << 40) | ((long long)p[3] << 32) | ((long long)p[4] << 24) | ((long long)p[5] << 16) | ((long long)p[6] << 8) | p[7];
@@ -577,6 +582,18 @@ namespace IPC {
     return std::string(data + 68, std::min((int)strlen(data + 68), 20));
   }
 
+  ///\brief Sets checksum field
+  void statExchange::crc(unsigned int sum) {
+    htobl(data + 88, sum);
+  }
+
+  ///\brief Gets checksum field
+  unsigned int statExchange::crc() {
+    unsigned int result;
+    btohl(data + 88, result);
+    return result;
+  }
+
   ///\brief Creates a semaphore guard, locks the semaphore on call
   semGuard::semGuard(semaphore * thisSemaphore) : mySemaphore(thisSemaphore) {
     mySemaphore->wait();
diff --git a/lib/shared_memory.h b/lib/shared_memory.h
index 87cb4f08..2c58f4d7 100644
--- a/lib/shared_memory.h
+++ b/lib/shared_memory.h
@@ -10,6 +10,8 @@
 #include <semaphore.h>
 #endif
 
+#define STAT_EX_SIZE 92
+
 namespace IPC {
 
   ///\brief A class used for the exchange of statistics over shared memory.
@@ -32,7 +34,9 @@ namespace IPC {
       std::string streamName();
       void connector(std::string name);
       std::string connector();
-    private:
+      void crc(unsigned int sum);
+      unsigned int crc();
+  private:
       ///\brief The payload for the stat exchange
       /// - 8 byte - now (timestamp of last statistics)
       /// - 4 byte - time (duration of the current connection)
@@ -42,6 +46,7 @@ namespace IPC {
       /// - 16 byte - host (ip address of the peer)
       /// - 20 byte - streamName (name of the stream peer is viewing)
       /// - 20 byte - connector (name of the connector the peer is using)
+      /// - 4 byte - CRC32 of user agent (or zero if none)
       char * data;
   };