Change behaviour of string_utils, also fix file io.

src/common/string_utils.cpp

@@ -55,9 +55,15 @@ void SplitStringAlongWhitespace(const std::string &input,
 
 bool HexStringToUInt(const std::string &input, unsigned int *uintOut)
 {
+    unsigned int offset = 0;
+
+    if (input.size() >= 2 && input[0] == '0' && input[1] == 'x')
+    {
+        offset = 2u;
+    }
+
     // Simple validity check
-    if (input[0] != '0' || input[1] != 'x' ||
-        input.find_first_not_of("0123456789ABCDEFabcdef", 2) != std::string::npos)
+    if (input.find_first_not_of("0123456789ABCDEFabcdef", offset) != std::string::npos)
     {
         return false;
     }
@@ -70,13 +76,16 @@ bool HexStringToUInt(const std::string &input, unsigned int *uintOut)
 bool ReadFileToString(const std::string &path, std::string *stringOut)
 {
     std::ifstream inFile(path.c_str());
-    std::string str;
+    if (inFile.fail())
+    {
+        return false;
+    }
 
     inFile.seekg(0, std::ios::end);
-    str.reserve(static_cast<std::string::size_type>(inFile.tellg()));
+    stringOut->reserve(static_cast<std::string::size_type>(inFile.tellg()));
     inFile.seekg(0, std::ios::beg);
 
-    str.assign(std::istreambuf_iterator<char>(inFile), std::istreambuf_iterator<char>());
+    stringOut->assign(std::istreambuf_iterator<char>(inFile), std::istreambuf_iterator<char>());
     return !inFile.fail();
 }
 

src/common/string_utils_unittest.cpp

@@ -49,8 +49,12 @@ TEST(StringUtilsTest, SplitStringAlongWhitespaceBasic)
 // Basic functionality tests for HexStringToUInt
 TEST(StringUtilsTest, HexStringToUIntBasic)
 {
-    std::string testStringA("0xBADF00D");
     unsigned int uintValue;
+
+    std::string emptyString;
+    ASSERT_FALSE(HexStringToUInt(emptyString, &uintValue));
+
+    std::string testStringA("0xBADF00D");
     ASSERT_TRUE(HexStringToUInt(testStringA, &uintValue));
     EXPECT_EQ(0xBADF00Du, uintValue);
 
@@ -58,7 +62,11 @@ TEST(StringUtilsTest, HexStringToUIntBasic)
     EXPECT_FALSE(HexStringToUInt(testStringB, &uintValue));
 
     std::string testStringC("BADF00D");
-    EXPECT_FALSE(HexStringToUInt(testStringC, &uintValue));
+    EXPECT_TRUE(HexStringToUInt(testStringC, &uintValue));
+    EXPECT_EQ(0xBADF00Du, uintValue);
+
+    std::string testStringD("0x BADF00D");
+    EXPECT_FALSE(HexStringToUInt(testStringD, &uintValue));
 }
 
 // Note: ReadFileToString is harder to test