Tools/Map extractor: Minor optimization in MCNK parsing loop - look up end iterator once

src/tools/map_extractor/System.cpp

@@ -28,6 +28,7 @@
 
 #include "Common.h"
 #include "MapDefines.h"
+#include "IteratorPair.h"
 #include "StringFormat.h"
 #include "Util.h"
 #ifdef PLATFORM_WINDOWS
@@ -484,9 +485,9 @@ bool ConvertADT(std::string const& inputPath, std::string const& outputPath, int
     bool hasHoles = false;
     bool hasFlightBox = false;
 
-    for (std::multimap<std::string, FileChunk*>::const_iterator itr = adt.chunks.lower_bound("MCNK"); itr != adt.chunks.upper_bound("MCNK"); ++itr)
+    for (auto const& [_, rawChunk] : Trinity::Containers::MapEqualRange(adt.chunks, "MCNK"))
     {
-        adt_MCNK* mcnk = itr->second->As<adt_MCNK>();
+        adt_MCNK* mcnk = rawChunk->As<adt_MCNK>();
 
         // Area data
         area_ids[mcnk->iy][mcnk->ix] = mcnk->areaid;
@@ -531,7 +532,7 @@ bool ConvertADT(std::string const& inputPath, std::string const& outputPath, int
         }
 
         // Get custom height
-        if (FileChunk* chunk = itr->second->GetSubChunk("MCVT"))
+        if (FileChunk* chunk = rawChunk->GetSubChunk("MCVT"))
         {
             adt_MCVT* mcvt = chunk->As<adt_MCVT>();
             // get V9 height map
@@ -560,7 +561,7 @@ bool ConvertADT(std::string const& inputPath, std::string const& outputPath, int
         // Liquid data
         if (mcnk->sizeMCLQ > 8)
         {
-            if (FileChunk* chunk = itr->second->GetSubChunk("MCLQ"))
+            if (FileChunk* chunk = rawChunk->GetSubChunk("MCLQ"))
             {
                 adt_MCLQ* liquid = chunk->As<adt_MCLQ>();
                 int count = 0;