[core] Fixed SRT_ASSERT definition for non-MSVC compilers (#2423).

* Define _DEBUG macro in Debug builds to enable SRT_ASSERT.
* Do not set _DEBUG/NDEBUG flags for MSVC.
* Use std::numeric_limits instead of INT_MAX.

CMakeLists.txt

@@ -63,15 +63,28 @@ if (NOT DEFINED ENABLE_DEBUG)
 	endif()
 endif()
 
-# Set CMAKE_BUILD_TYPE properly, now that you know
-# that ENABLE_DEBUG is set as it should.
-
-if (ENABLE_DEBUG EQUAL 2)
-	set (CMAKE_BUILD_TYPE "RelWithDebInfo")
-elseif (ENABLE_DEBUG) # 1, ON, YES, TRUE, Y, or any other non-zero number
-	set (CMAKE_BUILD_TYPE "Debug")
-else()
-	set (CMAKE_BUILD_TYPE "Release")
+# XXX This is a kind of workaround - this part to set the build
+# type and associated other flags should not be done for build
+# systems (cmake generators) that generate a multi-configuration
+# build definition. At least it is known that MSVC does it and it
+# sets _DEBUG and NDEBUG flags itself, so this shouldn't be done
+# at all in this case.
+if (NOT MICROSOFT)
+
+	# Set CMAKE_BUILD_TYPE properly, now that you know
+	# that ENABLE_DEBUG is set as it should.
+	if (ENABLE_DEBUG EQUAL 2)
+		set (CMAKE_BUILD_TYPE "RelWithDebInfo")
+		add_definitions(-DNDEBUG)
+	elseif (ENABLE_DEBUG) # 1, ON, YES, TRUE, Y, or any other non-zero number
+		set (CMAKE_BUILD_TYPE "Debug")
+
+		# Add _DEBUG macro in debug mode only, to enable SRT_ASSERT().
+		add_definitions(-D_DEBUG)
+	else()
+		set (CMAKE_BUILD_TYPE "Release")
+		add_definitions(-DNDEBUG)
+	endif()
 endif()
 
 message(STATUS "BUILD TYPE: ${CMAKE_BUILD_TYPE}")

srtcore/buffer_rcv.cpp

@@ -1,5 +1,6 @@
 #if ENABLE_NEW_RCVBUFFER
 #include <cmath>
+#include <limits>
 #include "buffer_rcv.h"
 #include "logging.h"
 
@@ -87,7 +88,7 @@ CRcvBufferNew::CRcvBufferNew(int initSeqNo, size_t size, CUnitQueue* unitqueue,
     , m_iPktsCount(0)
     , m_uAvgPayloadSz(SRT_LIVE_DEF_PLSIZE)
 {
-    SRT_ASSERT(size < INT_MAX); // All position pointers are integers
+    SRT_ASSERT(size < size_t(std::numeric_limits<int>::max())); // All position pointers are integers
 }
 
 CRcvBufferNew::~CRcvBufferNew()
@@ -135,7 +136,7 @@ int CRcvBufferNew::insert(CUnit* unit)
         m_iMaxPosInc = offset + 1;
 
     // Packet already exists
-    SRT_ASSERT(pos >= 0 && pos < m_szSize);
+    SRT_ASSERT(pos >= 0 && pos < int(m_szSize));
     if (m_entries[pos].status != EntryState_Empty)
     {
         IF_RCVBUF_DEBUG(scoped_log.ss << " returns -1");