Fix an issue in LOCALE_IO class, used to switch to/back locale "C" when reading/writing files: the back to locale was broken, and created issues in countries using the ',' as fp separator, especially when the non default language was used.

It was reported in many bugs.

common/common.cpp

@@ -44,6 +44,8 @@
 #include <wx/utils.h>
 #include <wx/stdpaths.h>
 
+#include <pgm_base.h>
+
 
 /**
  * Global variables definitions.
@@ -58,30 +60,40 @@ EDA_UNITS_T    g_UserUnit;
 EDA_COLOR_T    g_GhostColor;
 
 
-/**
- * Function to use local notation or C standard notation for floating point numbers
- * some countries use 1,5 and others (and C) 1.5
- * so we switch from local to C and C to local when reading or writing files
- * And other problem is a bug when cross compiling under linux:
- * a printf print 1,5 and the read functions expects 1.5
- * (depending on version print = 1.5 and read = 1,5
- * Very annoying and we detect this and use a stupid but necessary workaround
-*/
-bool g_DisableFloatingPointLocalNotation = false;
+/* Class LOCALE_IO
+ * is a class that can be instantiated within a scope in which you are expecting
+ * exceptions to be thrown.  Its constructor sets a "C" locale, to read/print files
+ * with fp numbers.
+ * Its destructor insures that the default locale is restored if an exception
+ * is thrown, or not.
+ */
 
+int LOCALE_IO::m_c_count = 0;
 
-int LOCALE_IO::C_count;
-
-
-void SetLocaleTo_C_standard()
+LOCALE_IO::LOCALE_IO()
 {
-    setlocale( LC_NUMERIC, "C" );    // Switch the locale to standard C
+    wxASSERT_MSG( m_c_count >= 0, wxT( "LOCALE_IO::m_c_count mismanaged." ) );
+
+    // use thread safe, atomic operation
+    if( __sync_fetch_and_add( &m_c_count, 1 ) == 0 )
+    {
+        // Store the user locale name, to restore this locale later, in dtor
+        m_user_locale = setlocale( LC_ALL, 0 );
+        // Switch the locale to C locale, to read/write files with fp numbers
+        setlocale( LC_ALL, "C" );
+    }
 }
 
-void SetLocaleTo_Default()
+LOCALE_IO::~LOCALE_IO()
 {
-    if( !g_DisableFloatingPointLocalNotation )
-        setlocale( LC_NUMERIC, "" );      // revert to the current locale
+    // use thread safe, atomic operation
+    if( __sync_sub_and_fetch( &m_c_count, 1 ) == 0 )
+    {
+        // revert to the user locale
+        setlocale( LC_ALL, m_user_locale.c_str() );
+    }
+
+    wxASSERT_MSG( m_c_count >= 0, wxT( "LOCALE_IO::m_c_count mismanaged." ) );
 }