[libcxx] Properly convert the count arguments to the *_n algorithms before use.

Summary:
The requirement on the `Size` type passed to *_n algorithms is that it is convertible to an integral type. This means we can't use a variable of type `Size` directly. Instead we need to convert it to an integral type first.  The problem is finding out what integral type to convert it to.  `__convert_to_integral` figures out what integral type to convert it to and performs the conversion, It also promotes the resulting integral type so that it is at least as big as an integer. `__convert_to_integral` also has a special case for converting enums. This should only work on non-scoped enumerations because it does not apply an explicit conversion from the enum to its underlying type.



Reviewers: chandlerc, mclow.lists

Reviewed By: mclow.lists

Subscribers: cfe-commits

Differential Revision: http://reviews.llvm.org/D7449

git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@228704 91177308-0d34-0410-b5e6-96231b3b80d8

include/algorithm

@@ -1672,7 +1672,8 @@ search_n(_ForwardIterator __first, _ForwardIterator __last,
          _Size __count, const _Tp& __value_, _BinaryPredicate __pred)
 {
     return _VSTD::__search_n<typename add_lvalue_reference<_BinaryPredicate>::type>
-           (__first, __last, __count, __value_, __pred, typename iterator_traits<_ForwardIterator>::iterator_category());
+           (__first, __last, __convert_to_integral(__count), __value_, __pred,
+           typename iterator_traits<_ForwardIterator>::iterator_category());
 }
 
 template <class _ForwardIterator, class _Size, class _Tp>
@@ -1681,7 +1682,8 @@ _ForwardIterator
 search_n(_ForwardIterator __first, _ForwardIterator __last, _Size __count, const _Tp& __value_)
 {
     typedef typename iterator_traits<_ForwardIterator>::value_type __v;
-    return _VSTD::search_n(__first, __last, __count, __value_, __equal_to<__v, _Tp>());
+    return _VSTD::search_n(__first, __last, __convert_to_integral(__count),
+                           __value_, __equal_to<__v, _Tp>());
 }
 
 // copy
@@ -1839,8 +1841,10 @@ typename enable_if
    !__is_random_access_iterator<_InputIterator>::value,
     _OutputIterator
 >::type
-copy_n(_InputIterator __first, _Size __n, _OutputIterator __result)
+copy_n(_InputIterator __first, _Size __orig_n, _OutputIterator __result)
 {
+    typedef decltype(__convert_to_integral(__orig_n)) _IntegralSize;
+    _IntegralSize __n = __orig_n;
     if (__n > 0)
     {
         *__result = *__first;
@@ -1862,8 +1866,10 @@ typename enable_if
     __is_random_access_iterator<_InputIterator>::value,
     _OutputIterator
 >::type
-copy_n(_InputIterator __first, _Size __n, _OutputIterator __result)
+copy_n(_InputIterator __first, _Size __orig_n, _OutputIterator __result)
 {
+    typedef decltype(__convert_to_integral(__orig_n)) _IntegralSize;
+    _IntegralSize __n = __orig_n;
     return _VSTD::copy(__first, __first + __n, __result);
 }
 
@@ -2055,7 +2061,7 @@ inline _LIBCPP_INLINE_VISIBILITY
 _OutputIterator
 fill_n(_OutputIterator __first, _Size __n, const _Tp& __value_)
 {
-   return _VSTD::__fill_n(__first, __n, __value_);
+   return _VSTD::__fill_n(__first, __convert_to_integral(__n), __value_);
 }
 
 // fill
@@ -2101,8 +2107,10 @@ generate(_ForwardIterator __first, _ForwardIterator __last, _Generator __gen)
 template <class _OutputIterator, class _Size, class _Generator>
 inline _LIBCPP_INLINE_VISIBILITY
 _OutputIterator
-generate_n(_OutputIterator __first, _Size __n, _Generator __gen)
+generate_n(_OutputIterator __first, _Size __orig_n, _Generator __gen)
 {
+    typedef decltype(__convert_to_integral(__orig_n)) _IntegralSize;
+    _IntegralSize __n = __orig_n;
     for (; __n > 0; ++__first, (void) --__n)
         *__first = __gen();
     return __first;

include/type_traits

@@ -3646,6 +3646,48 @@ struct underlying_type
 
 #endif // _LIBCPP_UNDERLYING_TYPE
 
+
+template <class _Tp, bool = std::is_enum<_Tp>::value>
+struct __sfinae_underlying_type
+{
+    typedef typename underlying_type<_Tp>::type type;
+    typedef decltype(((type)1) + 0) __promoted_type;
+};
+
+template <class _Tp>
+struct __sfinae_underlying_type<_Tp, false> {};
+
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_ALWAYS_INLINE
+int __convert_to_integral(int __val) { return __val; }
+
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_ALWAYS_INLINE
+unsigned __convert_to_integral(unsigned __val) { return __val; }
+
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_ALWAYS_INLINE
+long __convert_to_integral(long __val) { return __val; }
+
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_ALWAYS_INLINE
+unsigned long __convert_to_integral(unsigned long __val) { return __val; }
+
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_ALWAYS_INLINE
+long long __convert_to_integral(long long __val) { return __val; }
+
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_ALWAYS_INLINE
+unsigned long long __convert_to_integral(unsigned long long __val) {return __val; }
+
+#ifndef _LIBCPP_HAS_NO_INT128
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_ALWAYS_INLINE
+__int128_t __convert_to_integral(__int128_t __val) { return __val; }
+
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_ALWAYS_INLINE
+__uint128_t __convert_to_integral(__uint128_t __val) { return __val; }
+#endif
+
+template <class _Tp>
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_ALWAYS_INLINE
+typename __sfinae_underlying_type<_Tp>::__promoted_type
+__convert_to_integral(_Tp __val) { return __val; }
+
 #ifndef _LIBCPP_HAS_NO_ADVANCED_SFINAE
 
 template <class _Tp>

test/libcxx/type_traits/convert_to_integral.pass.cpp

@@ -0,0 +1,89 @@
+
+#include <limits>
+#include <type_traits>
+#include <cstdint>
+#include <cassert>
+
+#include "user_defined_integral.hpp"
+
+template <class T>
+struct EnumType
+{
+  enum type : T {E_zero, E_one};
+};
+
+
+template <class From, class To>
+void check_integral_types()
+{
+  typedef std::numeric_limits<From> Limits;
+  const From max = Limits::max();
+  const From min = Limits::min();
+  {
+  auto ret = std::__convert_to_integral((From)max);
+  assert(ret == max);
+  ret = std::__convert_to_integral((From)min);
+  assert(ret == min);
+  static_assert(std::is_same<decltype(ret), To>::value, "");
+  }
+  {
+  UserDefinedIntegral<From> f(max);
+  auto ret = std::__convert_to_integral(f);
+  assert(ret == max);
+  f.value = min;
+  ret = std::__convert_to_integral(f);
+  assert(ret == min);
+  static_assert(std::is_same<decltype(ret), To>::value, "");
+  }
+  {
+  typedef typename EnumType<From>::type Enum;
+  Enum e(static_cast<Enum>(max));
+  auto ret = std::__convert_to_integral(e);
+  assert(ret == max);
+  e = static_cast<Enum>(min);
+  ret = std::__convert_to_integral(min);
+  assert(ret == min);
+  static_assert(std::is_same<decltype(ret), To>::value, "");
+  }
+}
+
+
+template <class From, class To>
+void check_enum_types()
+{
+  auto ret = std::__convert_to_integral((From)1);
+  assert(ret == 1);
+  static_assert(std::is_same<decltype(ret), To>::value, "");
+}
+
+
+enum enum1 {};
+enum enum2 {
+  value = std::numeric_limits<unsigned long>::max()
+};
+
+int main()
+{
+  check_integral_types<bool, int>();
+  check_integral_types<char, int>();
+  check_integral_types<signed char, int>();
+  check_integral_types<unsigned char, int>();
+  check_integral_types<wchar_t, int>();
+  check_integral_types<char16_t, int>();
+  check_integral_types<char32_t, uint32_t>();
+  check_integral_types<short, int>();
+  check_integral_types<unsigned short, int>();
+  check_integral_types<int, int>();
+  check_integral_types<unsigned, unsigned>();
+  check_integral_types<long, long>();
+  check_integral_types<unsigned long, unsigned long>();
+  check_integral_types<long long, long long>();
+  check_integral_types<unsigned long long, unsigned long long>();
+#ifndef _LIBCPP_HAS_NO_INT128
+  check_integral_types<__int128_t, __int128_t>();
+  check_integral_types<__uint128_t, __uint128_t>();
+#endif
+    // TODO(ericwf): Not standard
+  check_enum_types<enum1, unsigned>();
+  check_enum_types<enum2, unsigned long>();
+}

test/std/algorithms/alg.modifying.operations/alg.copy/copy_n.pass.cpp

@@ -17,6 +17,9 @@
 #include <cassert>
 
 #include "test_iterators.h"
+#include "user_defined_integral.hpp"
+
+typedef UserDefinedIntegral<unsigned> UDI;
 
 template <class InIter, class OutIter>
 void
@@ -28,7 +31,7 @@ test()
         ia[i] = i;
     int ib[N] = {0};
 
-    OutIter r = std::copy_n(InIter(ia), N/2, OutIter(ib));
+    OutIter r = std::copy_n(InIter(ia), UDI(N/2), OutIter(ib));
     assert(base(r) == ib+N/2);
     for (unsigned i = 0; i < N/2; ++i)
         assert(ia[i] == ib[i]);

test/std/algorithms/alg.modifying.operations/alg.fill/fill_n.pass.cpp

@@ -18,6 +18,9 @@
 #include <cassert>
 
 #include "test_iterators.h"
+#include "user_defined_integral.hpp"
+
+typedef UserDefinedIntegral<unsigned> UDI;
 
 template <class Iter>
 void
@@ -25,7 +28,7 @@ test_char()
 {
     const unsigned n = 4;
     char ca[n] = {0};
-    assert(std::fill_n(Iter(ca), n, char(1)) == std::next(Iter(ca), n));
+    assert(std::fill_n(Iter(ca), UDI(n), char(1)) == std::next(Iter(ca), n));
     assert(ca[0] == 1);
     assert(ca[1] == 1);
     assert(ca[2] == 1);
@@ -38,7 +41,7 @@ test_int()
 {
     const unsigned n = 4;
     int ia[n] = {0};
-    assert(std::fill_n(Iter(ia), n, 1) == std::next(Iter(ia), n));
+    assert(std::fill_n(Iter(ia), UDI(n), 1) == std::next(Iter(ia), n));
     assert(ia[0] == 1);
     assert(ia[1] == 1);
     assert(ia[2] == 1);
@@ -50,7 +53,7 @@ test_int_array()
 {
     const unsigned n = 4;
     int ia[n] = {0};
-    assert(std::fill_n(ia, n, static_cast<char>(1)) == std::next(ia, n));
+    assert(std::fill_n(ia, UDI(n), static_cast<char>(1)) == std::next(ia, n));
     assert(ia[0] == 1);
     assert(ia[1] == 1);
     assert(ia[2] == 1);
@@ -69,7 +72,7 @@ test_int_array_struct_source()
 {
     const unsigned n = 4;
     int ia[n] = {0};
-    assert(std::fill_n(ia, n, source()) == std::next(ia, n));
+    assert(std::fill_n(ia, UDI(n), source()) == std::next(ia, n));
     assert(ia[0] == 0);
     assert(ia[1] == 1);
     assert(ia[2] == 2);
@@ -87,7 +90,7 @@ test_struct_array()
 {
     const unsigned n = 4;
     test1 test1a[n] = {0};
-    assert(std::fill_n(test1a, n, static_cast<char>(10)) == std::next(test1a, n));    
+    assert(std::fill_n(test1a, UDI(n), static_cast<char>(10)) == std::next(test1a, n));
     assert(test1a[0].c == 11);
     assert(test1a[1].c == 11);
     assert(test1a[2].c == 11);
@@ -110,7 +113,7 @@ void
 test5()
 {
     A a[3];
-    assert(std::fill_n(&a[0], 3, A('a')) == a+3);
+    assert(std::fill_n(&a[0], UDI(3), A('a')) == a+3);
     assert(a[0] == A('a'));
     assert(a[1] == A('a'));
     assert(a[2] == A('a'));
@@ -124,11 +127,11 @@ struct Storage
     unsigned char b;
   };
 };
- 
+
 void test6()
 {
   Storage foo[5];
-  std::fill_n(&foo[0], 5, Storage());
+  std::fill_n(&foo[0], UDI(5), Storage());
 }
 
 
@@ -143,7 +146,7 @@ int main()
     test_int<bidirectional_iterator<int*> >();
     test_int<random_access_iterator<int*> >();
     test_int<int*>();
-    
+
     test_int_array();
     test_int_array_struct_source();
     test_struct_array();

test/std/algorithms/alg.modifying.operations/alg.generate/generate_n.pass.cpp

@@ -19,6 +19,9 @@
 #include <cassert>
 
 #include "test_iterators.h"
+#include "user_defined_integral.hpp"
+
+typedef UserDefinedIntegral<unsigned> UDI;
 
 struct gen_test
 {
@@ -31,7 +34,7 @@ test()
 {
     const unsigned n = 4;
     int ia[n] = {0};
-    assert(std::generate_n(Iter(ia), n, gen_test()) == Iter(ia+n));
+    assert(std::generate_n(Iter(ia), UDI(n), gen_test()) == Iter(ia+n));
     assert(ia[0] == 2);
     assert(ia[1] == 2);
     assert(ia[2] == 2);

test/std/algorithms/alg.nonmodifying/alg.search/search_n.pass.cpp

@@ -18,6 +18,7 @@
 #include <cassert>
 
 #include "test_iterators.h"
+#include "user_defined_integral.hpp"
 
 template <class Iter>
 void
@@ -63,6 +64,9 @@ test()
     assert(std::search_n(Iter(ic), Iter(ic+sc), 2, 0) == Iter(ic));
     assert(std::search_n(Iter(ic), Iter(ic+sc), 3, 0) == Iter(ic));
     assert(std::search_n(Iter(ic), Iter(ic+sc), 4, 0) == Iter(ic+sc));
+
+    // Check that we properly convert the size argument to an integral.
+    std::search_n(Iter(ic), Iter(ic+sc), UserDefinedIntegral<unsigned>(0), 0);
 }
 
 int main()

test/std/algorithms/alg.nonmodifying/alg.search/search_n_pred.pass.cpp

@@ -18,6 +18,7 @@
 #include <cassert>
 
 #include "test_iterators.h"
+#include "user_defined_integral.hpp"
 
 struct count_equal
 {
@@ -29,6 +30,7 @@ struct count_equal
 
 unsigned count_equal::count = 0;
 
+
 template <class Iter>
 void
 test()
@@ -138,6 +140,10 @@ test()
     assert(std::search_n(Iter(ic), Iter(ic+sc), 4, 0, count_equal()) == Iter(ic+sc));
     assert(count_equal::count <= sc);
     count_equal::count = 0;
+
+    // Check that we properly convert the size argument to an integral.
+    std::search_n(Iter(ic), Iter(ic+sc), UserDefinedIntegral<unsigned>(4), 0, count_equal());
+    count_equal::count = 0;
 }
 
 int main()

test/support/user_defined_integral.hpp

@@ -0,0 +1,44 @@
+#ifndef SUPPORT_USER_DEFINED_INTEGRAL_HPP
+#define SUPPORT_USER_DEFINED_INTEGRAL_HPP
+
+template <class T>
+struct UserDefinedIntegral
+{
+    UserDefinedIntegral() : value(0) {}
+    UserDefinedIntegral(T v) : value(v) {}
+    operator T() const { return value; }
+    T value;
+};
+
+// Poison the arithmetic and comparison operations
+template <class T, class U>
+void operator+(UserDefinedIntegral<T>, UserDefinedIntegral<U>);
+
+template <class T, class U>
+void operator-(UserDefinedIntegral<T>, UserDefinedIntegral<U>);
+
+template <class T, class U>
+void operator*(UserDefinedIntegral<T>, UserDefinedIntegral<U>);
+
+template <class T, class U>
+void operator/(UserDefinedIntegral<T>, UserDefinedIntegral<U>);
+
+template <class T, class U>
+void operator==(UserDefinedIntegral<T>, UserDefinedIntegral<U>);
+
+template <class T, class U>
+void operator!=(UserDefinedIntegral<T>, UserDefinedIntegral<U>);
+
+template <class T, class U>
+void operator<(UserDefinedIntegral<T>, UserDefinedIntegral<U>);
+
+template <class T, class U>
+void operator>(UserDefinedIntegral<T>, UserDefinedIntegral<U>);
+
+template <class T, class U>
+void operator<=(UserDefinedIntegral<T>, UserDefinedIntegral<U>);
+
+template <class T, class U>
+void operator>=(UserDefinedIntegral<T>, UserDefinedIntegral<U>);
+
+#endif // SUPPORT_USER_DEFINED_INTEGRAL_HPP