Reworked to_string test to verify the overload with a custom allocator even when explicit conversion operators are not supported. Made the custom allocator more standard-compliant.

test/string_view_test2.cpp

@@ -7,13 +7,14 @@
     For more information, see http://www.boost.org
 */
 
+#include <new>        // for placement new
 #include <iostream>
-#include <cstring>    // for std::strchr
+#include <cstddef>    // for NULL, std::size_t, std::ptrdiff_t
-#ifndef BOOST_NO_CXX11_EXPLICIT_CONVERSION_OPERATORS
+#include <cstring>    // for std::strchr and std::strcmp
 #include <cstdlib>    // for std::malloc and std::free
-#endif
 
 #include <boost/utility/string_view.hpp>
+#include <boost/config.hpp>
 
 #define BOOST_TEST_MAIN
 #include <boost/test/unit_test.hpp>
@@ -86,7 +87,7 @@ void reverse ( const char *arg ) {
     BOOST_CHECK ( std::equal ( sr1.begin (), sr1.end (), string2.begin ()));
     }
 
-//	This helper function eliminates signed vs. unsigned warnings
+//  This helper function eliminates signed vs. unsigned warnings
 string_view::size_type ptr_diff ( const char *res, const char *base ) {
     BOOST_CHECK ( res >= base );
     return static_cast<string_view::size_type> ( res - base );
@@ -115,7 +116,7 @@ void find ( const char *arg ) {
       ++p;
       }
 
-//	Look for pairs on characters (searching from the start)
+//  Look for pairs on characters (searching from the start)
     sr1 = arg;
     p = arg;
     while ( *p && *(p+1)) {
@@ -244,29 +245,86 @@ void find ( const char *arg ) {
 
     }
 
-#ifndef BOOST_NO_CXX11_EXPLICIT_CONVERSION_OPERATORS
 template <typename T>
-class alloc_holder{
+class custom_allocator {
 public:
     typedef T value_type;
-    explicit alloc_holder(){}
+    typedef T* pointer;
-    T *allocate(std::size_t n){
+    typedef const T* const_pointer;
-        return reinterpret_cast<T *>(std::malloc(sizeof(T) * n));
+    typedef void* void_pointer;
-    }
+    typedef const void* const_void_pointer;
-    void deallocate(T *p, std::size_t n){
+    typedef std::size_t size_type;
+    typedef std::ptrdiff_t difference_type;
+    typedef T& reference;
+    typedef const T& const_reference;
+
+    template<class U>
+    struct rebind {
+        typedef custom_allocator<U> other;
+        };
+
+    custom_allocator() BOOST_NOEXCEPT {}
+    template <typename U>
+    custom_allocator(custom_allocator<U> const&) BOOST_NOEXCEPT {}
+
+    pointer allocate(size_type n) const {
+        return static_cast<pointer>(std::malloc(sizeof(value_type) * n));
+        }
+    void deallocate(pointer p, size_type) const BOOST_NOEXCEPT {
         std::free(p);
-    }
+        }
-};
+
+    pointer address(reference value) const BOOST_NOEXCEPT {
+        return &value;
+        }
+
+    const_pointer address(const_reference value) const BOOST_NOEXCEPT {
+        return &value;
+        }
+
+    BOOST_CONSTEXPR size_type max_size() const BOOST_NOEXCEPT {
+        return (~(size_type)0u) / sizeof(value_type);
+        }
+
+#if !defined(BOOST_NO_CXX11_RVALUE_REFERENCES)
+#if !defined(BOOST_NO_CXX11_VARIADIC_TEMPLATES)
+    template <class U, class... Args>
+    void construct(U* ptr, Args&&... args) const {
+        ::new((void*)ptr) U(static_cast<Args&&>(args)...);
+        }
+#else
+    template <class U, class V>
+    void construct(U* ptr, V&& value) const {
+        ::new((void*)ptr) U(static_cast<V&&>(value));
+        }
+#endif
+#else
+    template <class U, class V>
+    void construct(U* ptr, const V& value) const {
+        ::new((void*)ptr) U(value);
+        }
+#endif
+
+    template <class U>
+    void construct(U* ptr) const {
+        ::new((void*)ptr) U();
+        }
+
+    template <class U>
+    void destroy(U* ptr) const {
+        (void)ptr;
+        ptr->~U();
+        }
+    };
 
 template <typename T, typename U>
-bool operator==(const alloc_holder<T> &, const alloc_holder<U> &){
+BOOST_CONSTEXPR bool operator==(const custom_allocator<T> &, const custom_allocator<U> &) BOOST_NOEXCEPT {
     return true;
-}
+    }
 template <typename T, typename U>
-bool operator!=(const alloc_holder<T> &, const alloc_holder<U> &){
+BOOST_CONSTEXPR bool operator!=(const custom_allocator<T> &, const custom_allocator<U> &) BOOST_NOEXCEPT {
     return false;
-}
+    }
-#endif
 
 void to_string ( const char *arg ) {
     string_view sr1;
@@ -275,15 +333,16 @@ void to_string ( const char *arg ) {
 
     str1.assign ( arg );
     sr1 = arg;
-//	str2 = sr1.to_string<std::allocator<char> > ();
+//  str2 = sr1.to_string<std::allocator<char> > ();
     str2 = sr1.to_string ();
     BOOST_CHECK ( str1 == str2 );
 
-#ifndef BOOST_NO_CXX11_EXPLICIT_CONVERSION_OPERATORS
+    std::basic_string<char, std::char_traits<char>, custom_allocator<char> > str3 = sr1.to_string(custom_allocator<char>());
-    std::string str3 = static_cast<std::string> ( sr1 );
+    BOOST_CHECK ( std::strcmp(str1.c_str(), str3.c_str()) == 0 );
-    BOOST_CHECK ( str1 == str3 );
 
-    std::basic_string<char, std::char_traits<char>, alloc_holder<char>> alloc_str = sr1.to_string(alloc_holder<char>());
+#ifndef BOOST_NO_CXX11_EXPLICIT_CONVERSION_OPERATORS
+    std::string str4 = static_cast<std::string> ( sr1 );
+    BOOST_CHECK ( str1 == str4 );
 #endif
     }
 
@@ -294,11 +353,11 @@ void compare ( const char *arg ) {
 
     str1.assign ( arg );
     sr1 = arg;
-    BOOST_CHECK ( sr1  == sr1);	    // compare string_view and string_view
+    BOOST_CHECK ( sr1  == sr1);    // compare string_view and string_view
-    BOOST_CHECK ( sr1  == str1);	// compare string and string_view
+    BOOST_CHECK ( sr1  == str1);   // compare string and string_view
-    BOOST_CHECK ( str1 == sr1 );	// compare string_view and string
+    BOOST_CHECK ( str1 == sr1 );   // compare string_view and string
-    BOOST_CHECK ( sr1  == arg );	// compare string_view and pointer
+    BOOST_CHECK ( sr1  == arg );   // compare string_view and pointer
-    BOOST_CHECK ( arg  == sr1 );	// compare pointer and string_view
+    BOOST_CHECK ( arg  == sr1 );   // compare pointer and string_view
 
     if ( sr1.size () > 0 ) {
         (*str1.rbegin())++;