Tokenizer::simplifyEmptyNamespaces: new function.

It removes from the token list, if found, the following tokens: 'namespace %var% { }'. It won't involve C code.

lib/tokenize.cpp

@@ -2008,6 +2008,8 @@ bool Tokenizer::tokenize(std::istream &code,
 
     simplifyRedundantConsecutiveBraces();
 
+    simplifyEmptyNamespaces();
+
     bool valid = validate();
     if (valid)
         createSymbolDatabase();
@@ -3427,6 +3429,8 @@ bool Tokenizer::simplifyTokenList()
 
     simplifyRedundantConsecutiveBraces();
 
+    simplifyEmptyNamespaces();
+
     if (!validate())
         return false;
 
@@ -3608,6 +3612,41 @@ void Tokenizer::simplifyRealloc()
     }
 }
 
+void Tokenizer::simplifyEmptyNamespaces()
+{
+    if (isC())
+        return;
+
+    bool goback = false;
+    for (Token *tok = list.front(); tok; tok = tok->next()) {
+        if (goback) {
+            tok = tok->previous();
+            goback = false;
+        }
+        if (tok->str() == "(" || tok->str() == "[" || tok->str() == "{") {
+            tok = tok->link();
+            continue;
+        }
+        if (!Token::Match(tok, "namespace %var% {"))
+            continue;
+        if (tok->strAt(3) == "}") {
+            tok->deleteNext(3);             // remove '%var% { }'
+            if (tok->next()) {              // '%empty% namespace %anytoken%'?
+                if (!tok->previous()) {
+                    tok->deleteThis();      // remove 'namespace'
+                    goback = true;
+                } else {                    // '%any% namespace %any%'
+                    tok = tok->previous();  // goto previous token
+                    tok->deleteNext();      // remove next token: 'namespace'
+                }
+            } else                          // '%empty% namespace %empty%'?
+                tok->str(";");              // change 'namespace' to ';'
+        } else {
+            tok = tok->tokAt(2);
+        }
+    }
+}
+
 void Tokenizer::simplifyFlowControl()
 {
 

lib/tokenize.h

@@ -341,6 +341,9 @@ public:
     /** Replace a "goto" with the statements */
     void simplifyGoto();
 
+    /** Simplify useless C++ empty namespaces, like: 'namespace %var% { }'*/
+    void simplifyEmptyNamespaces();
+
     /** Simplify redundant code placed after control flow statements :
      * 'return', 'throw', 'goto', 'break' and 'continue'
      */

test/testsimplifytokens.cpp

@@ -2379,6 +2379,12 @@ private:
 
 
     void namespaces() {
+        {
+            const char code[] = "namespace std { }";
+
+            ASSERT_EQUALS(";", tok(code));
+        }
+
         {
             const char code[] = "using namespace std; namespace a{ namespace b{ void f(){} } }";
 
@@ -2395,14 +2401,6 @@ private:
             ASSERT_EQUALS(expected, tok(code));
         }
 
-        {
-            const char code[] = "int a; namespace b{ }";
-
-            const std::string expected("int a ; namespace b { }");
-
-            ASSERT_EQUALS(expected, tok(code));
-        }
-
         {
             const char code[] = "void f(int namespace) { }";
 
@@ -5629,11 +5627,9 @@ private:
         const char code[] = "typedef long Long;\n"
                             "namespace NS {\n"
                             "}\n";
-        const char expected[] = "namespace NS { "
-                                "}";
 
         checkSimplifyTypedef(code);
-        ASSERT_EQUALS(expected, tok(code));
+        ASSERT_EQUALS(";", tok(code));
         ASSERT_EQUALS("", errout.str());
     }