From 606bb7829741cf5452745d974eb1701f0677cc7b Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Daniel=20Marjam=C3=A4ki?= <daniel.marjamaki@gmail.com>
Date: Tue, 20 Dec 2016 19:32:21 +0100
Subject: [PATCH] ValueFlow: Better handling of casts

---
 lib/valueflow.cpp      | 35 ++++++++++++++++++++++++++++++-----
 test/testother.cpp     |  2 +-
 test/testvalueflow.cpp |  6 ++++--
 3 files changed, 35 insertions(+), 8 deletions(-)

diff --git a/lib/valueflow.cpp b/lib/valueflow.cpp
index 5dc8d2035..79921a840 100644
--- a/lib/valueflow.cpp
+++ b/lib/valueflow.cpp
@@ -284,6 +284,21 @@ static bool addValue(Token *tok, const ValueFlow::Value &value)
     return true;
 }
 
+static ValueFlow::Value castValue(ValueFlow::Value value, const ValueType::Sign sign, unsigned int bit)
+{
+    if (value.isFloatValue()) {
+        value.valueType = ValueFlow::Value::INT;
+        value.intvalue = value.floatValue;
+    }
+    if (bit < 64) {
+        value.intvalue &= (1ULL << bit) - 1ULL;
+        if (sign == ValueType::Sign::SIGNED && value.intvalue & (1ULL << (bit - 1ULL))) {
+            value.intvalue |= ~((1ULL << bit) - 1ULL);
+        }
+    }
+    return value;
+}
+
 /** set ValueFlow value and perform calculations if possible */
 static void setTokenValue(Token* tok, const ValueFlow::Value &value, const Settings *settings)
 {
@@ -294,13 +309,23 @@ static void setTokenValue(Token* tok, const ValueFlow::Value &value, const Setti
     if (!parent)
         return;
 
-    // TODO: Cast..
-    /*
     if (parent->str() == "(" && tok == parent->link()->next()) {
-        setTokenValue(parent,value,settings);
-    } else .. */
+        const ValueType &valueType = ValueType::parseDecl(parent->next(), settings);
+        if (valueType.pointer)
+            setTokenValue(parent,value,settings);
+        else if (valueType.type == ValueType::Type::CHAR)
+            setTokenValue(parent, castValue(value, valueType.sign, settings->char_bit), settings);
+        else if (valueType.type == ValueType::Type::SHORT)
+            setTokenValue(parent, castValue(value, valueType.sign, settings->short_bit), settings);
+        else if (valueType.type == ValueType::Type::INT)
+            setTokenValue(parent, castValue(value, valueType.sign, settings->int_bit), settings);
+        else if (valueType.type == ValueType::Type::LONG)
+            setTokenValue(parent, castValue(value, valueType.sign, settings->long_bit), settings);
+        else if (valueType.type == ValueType::Type::LONGLONG)
+            setTokenValue(parent, castValue(value, valueType.sign, settings->long_long_bit), settings);
+    }
 
-    if (parent->str() == ":") {
+    else if (parent->str() == ":") {
         setTokenValue(parent,value,settings);
     }
 
diff --git a/test/testother.cpp b/test/testother.cpp
index 849b3c86d..e029e899c 100644
--- a/test/testother.cpp
+++ b/test/testother.cpp
@@ -271,7 +271,7 @@ private:
         check("void foo() {\n"
               "    cout << 42 / (int)0;\n"
               "}");
-        TODO_ASSERT_EQUALS("[test.cpp:2]: (error) Division by zero.\n", "", errout.str());
+        ASSERT_EQUALS("[test.cpp:2]: (error) Division by zero.\n", errout.str());
     }
 
     void zeroDiv2() {
diff --git a/test/testvalueflow.cpp b/test/testvalueflow.cpp
index cde61e9e3..5559f428a 100644
--- a/test/testvalueflow.cpp
+++ b/test/testvalueflow.cpp
@@ -378,8 +378,10 @@ private:
         ASSERT_EQUALS(0, valueOfTok("3 <= (a ? b : 2);", "<=").intvalue);
 
         ASSERT(tokenValues("(UNKNOWN_TYPE)123;","(").empty());
-        ASSERT(tokenValues("(unsigned char)~0;", "(").empty()); // TODO: should get value 255
-        ASSERT(tokenValues("(int)0;", "(").empty()); // TODO: should get value 0
+        ASSERT_EQUALS(255, valueOfTok("(unsigned char)~0;", "(").intvalue);
+        ASSERT_EQUALS(0, valueOfTok("(int)0;", "(").intvalue);
+        ASSERT_EQUALS(0, valueOfTok("(UNKNOWN_TYPE*)0;","(").intvalue);
+        ASSERT_EQUALS(100, valueOfTok("(int)100.0;", "(").intvalue);
 
         // Don't calculate if there is UB
         ASSERT(tokenValues(";-1<<10;","<<").empty());