Add boost/thread/detail/string_to_unsigned.hpp

include/boost/thread/detail/string_to_unsigned.hpp

@@ -0,0 +1,55 @@
+#ifndef BOOST_THREAD_DETAIL_STRING_TO_UNSIGNED_HPP_INCLUDED
+#define BOOST_THREAD_DETAIL_STRING_TO_UNSIGNED_HPP_INCLUDED
+
+// Copyright 2023 Peter Dimov
+// Distributed under the Boost Software License, Version 1.0.
+// https://www.boost.org/LICENSE_1_0.txt
+
+#include <string>
+#include <climits>
+
+namespace boost
+{
+namespace thread_detail
+{
+
+inline bool string_to_unsigned( std::string const& s, unsigned& v )
+{
+    v = 0;
+
+    if( s.empty() )
+    {
+        return false;
+    }
+
+    for( char const* p = s.c_str(); *p; ++p )
+    {
+        unsigned char ch = static_cast<unsigned char>( *p );
+
+        if( ch < '0' || ch > '9' )
+        {
+            return false;
+        }
+
+        if( v > UINT_MAX / 10 )
+        {
+            return false;
+        }
+
+        unsigned q = static_cast<unsigned>( ch - '0' );
+
+        if( v == UINT_MAX / 10 && q > UINT_MAX % 10 )
+        {
+            return false;
+        }
+
+        v = v * 10 + q;
+    }
+
+    return true;
+}
+
+} // namespace thread_detail
+} // namespace boost
+
+#endif // #ifndef BOOST_THREAD_DETAIL_STRING_TO_UNSIGNED_HPP_INCLUDED