From d68e2ae966f4fe259ddf426c3ff78196d3bd3795 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Daniel=20Marjam=C3=A4ki?= <hyd_danmar@users.sourceforge.net>
Date: Sat, 22 Nov 2008 17:53:22 +0000
Subject: [PATCH] tokenizer: simplifyConditions tries to simplify conditions..
 those that are always true to '( true )' and those that are always false to
 '( false )'

---
 CheckMemoryLeak.cpp |  4 +--
 testtokenize.cpp    | 42 +++---------------------------
 tokenize.cpp        | 63 +++++++++++++++++++++++++++++++--------------
 tokenize.h          |  7 +++--
 4 files changed, 52 insertions(+), 64 deletions(-)

diff --git a/CheckMemoryLeak.cpp b/CheckMemoryLeak.cpp
index b6997c392..06e01c024 100644
--- a/CheckMemoryLeak.cpp
+++ b/CheckMemoryLeak.cpp
@@ -382,11 +382,11 @@ TOKEN *CheckMemoryLeakClass::getcode(const TOKEN *tok, std::list<const TOKEN *>
         {
             addtoken("if(!var)");
         }
-        else if ( Tokenizer::Match(tok, "if (") && _tokenizer->alwaysTrue(tok->next) )
+        else if ( Tokenizer::Match(tok, "if ( true )") )
         {
             addtoken("if(true)");
         }
-        else if ( Tokenizer::Match(tok, "if (") && _tokenizer->alwaysTrue(tok->next) )
+        else if ( Tokenizer::Match(tok, "if ( false )") )
         {
             addtoken("if(false)");
         }
diff --git a/testtokenize.cpp b/testtokenize.cpp
index fcc66984a..f24d980c5 100644
--- a/testtokenize.cpp
+++ b/testtokenize.cpp
@@ -43,8 +43,7 @@ private:
 
         TEST_CASE( dupfuncname );
 
-        TEST_CASE( alwaysTrue );
-        TEST_CASE( alwaysFalse );
+        TEST_CASE( simplifyConditions );
     }
 
 
@@ -154,46 +153,11 @@ private:
         ASSERT_EQUALS( std::string("b"), tokenizer.FunctionList[0]->str );
     }
 
-
-    bool alwaysTrueCheck(const char condition[])
+    void simplifyConditions()
     {
-        // tokenize..
-        Tokenizer tokenizer( this );
-        tokenizer.getFiles()->push_back( "test.cpp" );
-        std::istringstream istr(condition);
-        tokenizer.TokenizeCode(istr, 0);
+        // TODO Simplify various conditions..
 
-        // check..
-        return tokenizer.alwaysTrue( tokenizer.tokens() );
     }
-
-    void alwaysTrue()
-    {
-        ASSERT_EQUALS(true, alwaysTrueCheck("(1)"));
-        ASSERT_EQUALS(true, alwaysTrueCheck("(true)"));
-        ASSERT_EQUALS(true, alwaysTrueCheck("(true || false)"));
-        ASSERT_EQUALS(false, alwaysTrueCheck("(true && false)"));
-    }
-
-    bool alwaysFalseCheck(const char condition[])
-    {
-        // tokenize..
-        Tokenizer tokenizer( this );
-        tokenizer.getFiles()->push_back( "test.cpp" );
-        std::istringstream istr(condition);
-        tokenizer.TokenizeCode(istr, 0);
-
-        // check..
-        return tokenizer.alwaysFalse( tokenizer.tokens() );
-    }
-
-    void alwaysFalse()
-    {
-        ASSERT_EQUALS(true, alwaysFalseCheck("(0)"));
-        ASSERT_EQUALS(true, alwaysFalseCheck("(false)"));
-        ASSERT_EQUALS(true, alwaysFalseCheck("(false && true)"));
-        ASSERT_EQUALS(false, alwaysFalseCheck("(false || true)"));
-    }
 };
 
 REGISTER_TEST( TestTokenizer )
diff --git a/tokenize.cpp b/tokenize.cpp
index a6bfb3c5d..2e23a3564 100644
--- a/tokenize.cpp
+++ b/tokenize.cpp
@@ -820,12 +820,8 @@ void Tokenizer::SimplifyTokenList()
 
 
     // Simple calculations..
-
-    bool done = false;
-    while (!done)
+    for ( bool done = false; !done; done = true )
     {
-        done = true;
-
         for (TOKEN *tok = _tokens; tok; tok = tok->next)
         {
             if (Tokenizer::Match(tok->next, "* 1") || Tokenizer::Match(tok->next, "1 *"))
@@ -1036,11 +1032,53 @@ void Tokenizer::SimplifyTokenList()
             while (!Tokenizer::Match(tok->next,"0"))
                 DeleteNextToken(tok);
         }
-    }
+    }
+
+
+    for ( bool done = false; !done; done = true)
+    {
+        done &= simplifyConditions();
+    };
 }
 //---------------------------------------------------------------------------
 
 
+bool Tokenizer::simplifyConditions()
+{
+    bool ret = true;
+
+    for ( TOKEN *tok = _tokens; tok; tok = tok->next )
+    {
+        if (Match(tok, "( true &&") || Match(tok, "&& true &&") || Match(tok->next, "&& true )"))
+        {
+            DeleteNextToken( tok );
+            DeleteNextToken( tok );
+            ret = false;
+        }
+
+        else if (Match(tok, "( false ||") || Match(tok, "|| false ||") || Match(tok->next, "|| false )"))
+        {
+            DeleteNextToken( tok );
+            DeleteNextToken( tok );
+            ret = false;
+        }
+
+        // Change numeric constant in condition to "true" or "false"
+        const TOKEN *tok2 = gettok(tok, 2);
+        if ((Match(tok, "(") || Match(tok, "&&") || Match(tok, "||")) &&
+            Match(tok->next, "%num%")                                 &&
+            (Match(tok2, ")") || Match(tok2, "&&") || Match(tok2, "||")) )
+        {
+            tok->next->setstr((strcmp(tok->next->str, "0")!=0) ? "true" : "false");
+            ret = false;
+        }
+    }
+
+    return ret;
+}
+
+
+
 
 
 
@@ -1518,16 +1556,3 @@ bool Tokenizer::IsStandardType(const char str[])
     return Ret;
 }
 //---------------------------------------------------------------------------
-
-bool Tokenizer::alwaysTrue( const TOKEN *tok )
-{
-    return (Match(tok,"( 1 [|)]") | Match(tok,"( 1 ||") |
-            Match(tok,"( true [|)]") | Match(tok,"( true ||"));
-}
-//---------------------------------------------------------------------------
-bool Tokenizer::alwaysFalse( const TOKEN *tok )
-{
-    return (Match(tok,"( 0 [&)]") | Match(tok,"( 0 &&") |
-            Match(tok,"( false [&)]") | Match(tok,"( false &&"));
-}
-//---------------------------------------------------------------------------
diff --git a/tokenize.h b/tokenize.h
index 1a3e12649..e9fdeaf03 100644
--- a/tokenize.h
+++ b/tokenize.h
@@ -90,9 +90,6 @@ public:
     static bool IsNumber(const char str[]);
     static bool IsStandardType(const char str[]);
 
-    bool alwaysTrue( const TOKEN *tok );
-    bool alwaysFalse( const TOKEN *tok );
-
     std::string fileLine( const TOKEN *tok );
 
     // Return size.
@@ -146,7 +143,9 @@ private:
 
     void combine_2tokens(TOKEN *tok, const char str1[], const char str2[]);
 
-    void DeleteNextToken(TOKEN *tok);
+    void DeleteNextToken(TOKEN *tok);
+
+    bool simplifyConditions();
 
     TOKEN *_gettok(TOKEN *tok, int index);