Utils: Add startWith to string view

We will add more function if they are needed.

Change-Id: Iac6b432327be32a0778a82c23ed2de5996c555a1
Reviewed-by: Tim Jenssen <tim.jenssen@qt.io>

src/libs/utils/smallstringview.h

@@ -116,6 +116,19 @@ public:
         return std::string(data(), size());
     }
 
+    bool startsWith(SmallStringView subStringToSearch) const noexcept
+    {
+        if (size() >= subStringToSearch.size())
+            return !std::memcmp(m_pointer, subStringToSearch.data(), subStringToSearch.size());
+
+        return false;
+    }
+
+    bool startsWith(char characterToSearch) const noexcept
+    {
+        return m_pointer[0] == characterToSearch;
+    }
+
 private:
     const char *m_pointer;
     size_type m_size;

tests/unit/unittest/smallstring-test.cpp

@@ -866,6 +866,19 @@ TEST(SmallString, StartsWith)
 {
     SmallString text("$column");
 
+    ASSERT_FALSE(text.startsWith("$columnxxx"));
+    ASSERT_TRUE(text.startsWith("$column"));
+    ASSERT_TRUE(text.startsWith("$col"));
+    ASSERT_FALSE(text.startsWith("col"));
+    ASSERT_TRUE(text.startsWith('$'));
+    ASSERT_FALSE(text.startsWith('@'));
+}
+
+TEST(SmallString, StartsWithStringView)
+{
+    SmallStringView text("$column");
+
+    ASSERT_FALSE(text.startsWith("$columnxxx"));
     ASSERT_TRUE(text.startsWith("$column"));
     ASSERT_TRUE(text.startsWith("$col"));
     ASSERT_FALSE(text.startsWith("col"));