1 files changed, 31 insertions, 1 deletions
diff --git a/CPP/Common/Common.h b/CPP/Common/Common.h
index 9dd30f4b..5430a92d 100644
--- a/CPP/Common/Common.h
+++ b/CPP/Common/Common.h
@@ -3,11 +3,41 @@
 #ifndef __COMMON_COMMON_H
 #define __COMMON_COMMON_H
 
+/*
+This file is included to all cpp files in 7-Zip.
+Each folder contains StdAfx.h file that includes "Common.h".
+So 7-Zip includes "Common.h" in both modes:
+  with precompiled StdAfx.h
+and
+  without precompiled StdAfx.h
+
+If you use 7-Zip code, you must include "Common.h" before other h files of 7-zip.
+If you don't need some things that are used in 7-Zip,
+you can change this h file or h files included in this file.
+*/
+
+// compiler pragmas to disable some warnings
 #include "../../C/Compiler.h"
 
+// it's <windows.h> or code that defines windows things, if it's not _WIN32
 #include "MyWindows.h"
+
+// NewHandler.h and NewHandler.cpp redefine operator new() to throw exceptions, if compiled with old MSVC compilers
 #include "NewHandler.h"
 
-#define ARRAY_SIZE(a) (sizeof(a) / sizeof((a)[1]))
+
+
+#define ARRAY_SIZE(a) (sizeof(a) / sizeof((a)[0]))
+
+
+/* There is BUG in MSVC 6.0 compiler for operator new[]:
+   It doesn't check overflow, when it calculates size in bytes for allocated array.
+   So we can use MY_ARRAY_NEW macro instead of new[] operator. */
+
+#if defined(_MSC_VER) && (_MSC_VER == 1200) && !defined(_WIN64)
+  #define MY_ARRAY_NEW(p, T, size) p = new T[(size > (unsigned)0xFFFFFFFF / sizeof(T)) ? (unsigned)0xFFFFFFFF / sizeof(T) : size];
+#else
+  #define MY_ARRAY_NEW(p, T, size) p = new T[size];
+#endif
 
 #endif