another little helper for FbTk::StringUtil: extractNumber()

src/FbTk/StringUtil.cc

@@ -48,6 +48,11 @@
   #include <string.h>
 #endif
 
+#ifdef HAVE_CERRNO
+  #include <cerrno>
+#else
+  #include <errno.h>
+#endif
 
 #include <memory>
 #include <algorithm>
@@ -56,10 +61,51 @@
 using std::string;
 using std::transform;
 
+namespace {
+
+int extractLongNumber(const char* in, long long int& out) {
+
+    errno = 0;
+
+    int ret = 0;
+    char* end = 0;
+    long long int result = strtoll(in, &end, 0);
+
+    if (errno == 0 && end != in) {
+        out = result;
+        ret = 1;
+    }
+
+    return ret;
+}
+
+template<typename T>
+int extractNumber(const std::string& in, T& out) {
+
+    long long int result = 0;
+
+    if (::extractLongNumber(in.c_str(), result) && out >= 0) {
+        out = static_cast<T>(result);
+        return 1;
+    }
+
+    return 0;
+}
+
+}
+
+
 namespace FbTk {
 
 namespace StringUtil {
 
+int extractNumber(const std::string& in, int& out) {
+    return ::extractNumber<int>(in, out);
+}
+
+int extractNumber(const std::string& in, unsigned int& out) {
+    return ::extractNumber<unsigned int>(in, out);
+}
 
 std::string number2String(int num) {
     char s[128];

src/FbTk/StringUtil.hh

@@ -30,6 +30,14 @@ namespace FbTk {
 
 namespace StringUtil {
 
+/// \@{
+/// @param in - input string, might be 0xab or 0123
+/// @param out - result if extraction was ok
+/// @return 1 - ok, result stored in 'out'
+int extractNumber(const std::string& in, unsigned int& out);
+int extractNumber(const std::string& in, int& out);
+/// \@}
+
 /// creates a number to a string
 std::string number2String(int num);
 

src/Layer.hh

@@ -48,7 +48,7 @@ public:
     static int getNumFromString(const std::string &str) {
         int tempnum = 0;
         std::string v = FbTk::StringUtil::toLower(str);
-        if (sscanf(str.c_str(), "%d", &tempnum) == 1)
+        if (FbTk::StringUtil::extractNumber(str, tempnum))
             return tempnum;
         if (v == "menu")
             return ::Layer::MENU;