Debugger: always hex encode the value of assignments in cdbext

Fixes assigning negative values to locals

Change-Id: Ief6e7f47e8e6f0a5d38458396164dfcd24e408a5
Fixes: QTCREATORBUG-17269
Reviewed-by: Christian Stenger <christian.stenger@qt.io>

src/libs/qtcreatorcdbext/stringutils.cpp

@@ -33,6 +33,7 @@
 #include <cstring>
 #include <iostream>
 #include <sstream>
+#include <codecvt>
 #include <iomanip>
 
 static const char whiteSpace[] = " \t\r\n";
@@ -149,6 +150,11 @@ std::string wStringToString(const std::wstring &w)
     return rc;
 }
 
+std::wstring utf8ToUtf16(const std::string &s)
+{
+    return std::wstring_convert<std::codecvt_utf8_utf16<wchar_t>>().from_bytes(s.data());
+}
+
 // Convert an ASCII hex digit to its value 'A'->10
 static inline unsigned hexDigit(char c)
 {
@@ -210,6 +216,11 @@ std::string stringFromHex(const char *p, const char *end)
     return rc;
 }
 
+std::string stringFromHex(const std::string &hexEncoded)
+{
+    return stringFromHex(hexEncoded.c_str(), hexEncoded.c_str() + hexEncoded.size());
+}
+
 // Helper for dumping memory
 std::string dumpMemory(const unsigned char *p, size_t size,
                        bool wantQuotes)