Tools/VMAPs: Fix extractor crash when some .mpq files does not exist (#18130)

src/tools/vmap4_extractor/mpq_libmpq.cpp

@@ -19,6 +19,7 @@
 #include "mpq_libmpq04.h"
 #include <deque>
 #include <cstdio>
+#include <algorithm>
 
 ArchiveSet gOpenArchives;
 
@@ -52,6 +53,11 @@ MPQArchive::MPQArchive(const char* filename)
     gOpenArchives.push_front(this);
 }
 
+bool MPQArchive::isOpened() const
+{
+    return std::find(gOpenArchives.begin(), gOpenArchives.end(), this) != gOpenArchives.end();
+}
+
 void MPQArchive::close()
 {
     //gOpenArchives.erase(erase(&mpq_a);

src/tools/vmap4_extractor/mpq_libmpq04.h

@@ -34,7 +34,7 @@ public:
     mpq_archive_s *mpq_a;
 
     MPQArchive(const char* filename);
-    ~MPQArchive() { close(); }
+    ~MPQArchive() { if (isOpened()) close(); }
 
     void GetFileListTo(std::vector<std::string>& filelist) {
         uint32_t filenum;
@@ -66,6 +66,7 @@ public:
 
 private:
     void close();
+    bool isOpened() const;
 };
 typedef std::deque<MPQArchive*> ArchiveSet;
 
@@ -95,13 +96,8 @@ public:
 
 inline void flipcc(char *fcc)
 {
-    char t;
-    t=fcc[0];
-    fcc[0]=fcc[3];
-    fcc[3]=t;
-    t=fcc[1];
-    fcc[1]=fcc[2];
-    fcc[2]=t;
+    std::swap(fcc[0], fcc[3]);
+    std::swap(fcc[1], fcc[2]);
 }
 
 #endif