[libc++] Replace several uses of 0 by nullptr

Differential Revision: https://reviews.llvm.org/D43159

GitOrigin-RevId: 527a7fdfbd7461e2aaa9eb279543c5d9dc8efa5a
diff --git a/include/fstream b/include/fstream
index 1e2d607..af8476c 100644
--- a/include/fstream
+++ b/include/fstream
@@ -287,13 +287,13 @@
 
 template <class _CharT, class _Traits>
 basic_filebuf<_CharT, _Traits>::basic_filebuf()
-    : __extbuf_(0),
-      __extbufnext_(0),
-      __extbufend_(0),
+    : __extbuf_(nullptr),
+      __extbufnext_(nullptr),
+      __extbufend_(nullptr),
       __ebs_(0),
-      __intbuf_(0),
+      __intbuf_(nullptr),
       __ibs_(0),
-      __file_(0),
+      __file_(nullptr),
       __cv_(nullptr),
       __st_(),
       __st_last_(),
@@ -308,7 +308,7 @@
         __cv_ = &use_facet<codecvt<char_type, char, state_type> >(this->getloc());
         __always_noconv_ = __cv_->always_noconv();
     }
-    setbuf(0, 4096);
+    setbuf(nullptr, 4096);
 }
 
 #ifndef _LIBCPP_CXX03_LANG
@@ -360,13 +360,13 @@
                        (char_type*)__extbuf_ + (__rhs.gptr() - __rhs.eback()),
                        (char_type*)__extbuf_ + (__rhs.egptr() - __rhs.eback()));
     }
-    __rhs.__extbuf_ = 0;
-    __rhs.__extbufnext_ = 0;
-    __rhs.__extbufend_ = 0;
+    __rhs.__extbuf_ = nullptr;
+    __rhs.__extbufnext_ = nullptr;
+    __rhs.__extbufend_ = nullptr;
     __rhs.__ebs_ = 0;
     __rhs.__intbuf_ = 0;
     __rhs.__ibs_ = 0;
-    __rhs.__file_ = 0;
+    __rhs.__file_ = nullptr;
     __rhs.__st_ = state_type();
     __rhs.__st_last_ = state_type();
     __rhs.__om_ = 0;
@@ -500,7 +500,7 @@
 bool
 basic_filebuf<_CharT, _Traits>::is_open() const
 {
-    return __file_ != 0;
+    return __file_ != nullptr;
 }
 
 template <class _CharT, class _Traits>
@@ -548,8 +548,8 @@
 basic_filebuf<_CharT, _Traits>*
 basic_filebuf<_CharT, _Traits>::open(const char* __s, ios_base::openmode __mode)
 {
-    basic_filebuf<_CharT, _Traits>* __rt = 0;
-    if (__file_ == 0)
+    basic_filebuf<_CharT, _Traits>* __rt = nullptr;
+    if (__file_ == nullptr)
     {
       if (const char* __mdstr = __make_mdstring(__mode)) {
         __rt = this;
@@ -559,12 +559,12 @@
           if (__mode & ios_base::ate) {
             if (fseek(__file_, 0, SEEK_END)) {
               fclose(__file_);
-              __file_ = 0;
-              __rt = 0;
+              __file_ = nullptr;
+              __rt = nullptr;
             }
           }
         } else
-          __rt = 0;
+          __rt = nullptr;
       }
     }
     return __rt;
@@ -574,8 +574,8 @@
 inline _LIBCPP_INLINE_VISIBILITY
 basic_filebuf<_CharT, _Traits>*
 basic_filebuf<_CharT, _Traits>::__open(int __fd, ios_base::openmode __mode) {
-  basic_filebuf<_CharT, _Traits>* __rt = 0;
-  if (__file_ == 0) {
+  basic_filebuf<_CharT, _Traits>* __rt = nullptr;
+  if (__file_ == nullptr) {
     if (const char* __mdstr = __make_mdstring(__mode)) {
       __rt = this;
       __file_ = fdopen(__fd, __mdstr);
@@ -584,12 +584,12 @@
         if (__mode & ios_base::ate) {
           if (fseek(__file_, 0, SEEK_END)) {
             fclose(__file_);
-            __file_ = 0;
-            __rt = 0;
+            __file_ = nullptr;
+            __rt = nullptr;
           }
         }
       } else
-        __rt = 0;
+        __rt = nullptr;
     }
   }
   return __rt;
@@ -602,8 +602,8 @@
 basic_filebuf<_CharT, _Traits>*
 basic_filebuf<_CharT, _Traits>::open(const wchar_t* __s, ios_base::openmode __mode)
 {
-    basic_filebuf<_CharT, _Traits>* __rt = 0;
-    if (__file_ == 0)
+    basic_filebuf<_CharT, _Traits>* __rt = nullptr;
+    if (__file_ == nullptr)
     {
         __rt = this;
         const wchar_t* __mdstr;
@@ -652,7 +652,7 @@
             __mdstr = L"a+b";
             break;
         default:
-            __rt = 0;
+            __rt = nullptr;
             break;
         }
         if (__rt)
@@ -666,13 +666,13 @@
                     if (fseek(__file_, 0, SEEK_END))
                     {
                         fclose(__file_);
-                        __file_ = 0;
-                        __rt = 0;
+                        __file_ = nullptr;
+                        __rt = nullptr;
                     }
                 }
             }
             else
-                __rt = 0;
+                __rt = nullptr;
         }
     }
     return __rt;
@@ -692,16 +692,16 @@
 basic_filebuf<_CharT, _Traits>*
 basic_filebuf<_CharT, _Traits>::close()
 {
-    basic_filebuf<_CharT, _Traits>* __rt = 0;
+    basic_filebuf<_CharT, _Traits>* __rt = nullptr;
     if (__file_)
     {
         __rt = this;
         unique_ptr<FILE, int(*)(FILE*)> __h(__file_, fclose);
         if (sync())
-            __rt = 0;
+            __rt = nullptr;
         if (fclose(__h.release()))
-            __rt = 0;
-        __file_ = 0;
+            __rt = nullptr;
+        __file_ = nullptr;
         setbuf(0, 0);
     }
     return __rt;
@@ -711,11 +711,11 @@
 typename basic_filebuf<_CharT, _Traits>::int_type
 basic_filebuf<_CharT, _Traits>::underflow()
 {
-    if (__file_ == 0)
+    if (__file_ == nullptr)
         return traits_type::eof();
     bool __initial = __read_mode();
     char_type __1buf;
-    if (this->gptr() == 0)
+    if (this->gptr() == nullptr)
         this->setg(&__1buf, &__1buf+1, &__1buf+1);
     const size_t __unget_sz = __initial ? 0 : min<size_t>((this->egptr() - this->eback()) / 2, 4);
     int_type __c = traits_type::eof();
@@ -773,7 +773,7 @@
     else
         __c = traits_type::to_int_type(*this->gptr());
     if (this->eback() == &__1buf)
-        this->setg(0, 0, 0);
+        this->setg(nullptr, nullptr, nullptr);
     return __c;
 }
 
@@ -803,7 +803,7 @@
 typename basic_filebuf<_CharT, _Traits>::int_type
 basic_filebuf<_CharT, _Traits>::overflow(int_type __c)
 {
-    if (__file_ == 0)
+    if (__file_ == nullptr)
         return traits_type::eof();
     __write_mode();
     char_type __1buf;
@@ -811,7 +811,7 @@
     char_type* __epb_save = this->epptr();
     if (!traits_type::eq_int_type(__c, traits_type::eof()))
     {
-        if (this->pptr() == 0)
+        if (this->pptr() == nullptr)
             this->setp(&__1buf, &__1buf+1);
         *this->pptr() = traits_type::to_char_type(__c);
         this->pbump(1);
@@ -868,8 +868,8 @@
 basic_streambuf<_CharT, _Traits>*
 basic_filebuf<_CharT, _Traits>::setbuf(char_type* __s, streamsize __n)
 {
-    this->setg(0, 0, 0);
-    this->setp(0, 0);
+    this->setg(nullptr, nullptr, nullptr);
+    this->setp(nullptr, nullptr);
     if (__owns_eb_)
         delete [] __extbuf_;
     if (__owns_ib_)
@@ -911,7 +911,7 @@
     else
     {
         __ibs_ = 0;
-        __intbuf_ = 0;
+        __intbuf_ = nullptr;
         __owns_ib_ = false;
     }
     return this;
@@ -926,7 +926,7 @@
         __throw_bad_cast();
 
     int __width = __cv_->encoding();
-    if (__file_ == 0 || (__width <= 0 && __off != 0) || sync())
+    if (__file_ == nullptr || (__width <= 0 && __off != 0) || sync())
         return pos_type(off_type(-1));
     // __width > 0 || __off == 0
     int __whence;
@@ -961,7 +961,7 @@
 typename basic_filebuf<_CharT, _Traits>::pos_type
 basic_filebuf<_CharT, _Traits>::seekpos(pos_type __sp, ios_base::openmode)
 {
-    if (__file_ == 0 || sync())
+    if (__file_ == nullptr || sync())
         return pos_type(off_type(-1));
 #if defined(_LIBCPP_HAS_NO_OFF_T_FUNCTIONS)
     if (fseek(__file_, __sp, SEEK_SET))
@@ -978,7 +978,7 @@
 int
 basic_filebuf<_CharT, _Traits>::sync()
 {
-    if (__file_ == 0)
+    if (__file_ == nullptr)
         return 0;
     if (!__cv_)
         __throw_bad_cast();
@@ -1037,7 +1037,7 @@
         if (__update_st)
             __st_ = __state;
         __extbufnext_ = __extbufend_ = __extbuf_;
-        this->setg(0, 0, 0);
+        this->setg(nullptr, nullptr, nullptr);
         __cm_ = 0;
     }
     return 0;
@@ -1053,8 +1053,8 @@
     __always_noconv_ = __cv_->always_noconv();
     if (__old_anc != __always_noconv_)
     {
-        this->setg(0, 0, 0);
-        this->setp(0, 0);
+        this->setg(nullptr, nullptr, nullptr);
+        this->setp(nullptr, nullptr);
         // invariant, char_type is char, else we couldn't get here
         if (__always_noconv_)  // need to dump __intbuf_
         {
@@ -1064,7 +1064,7 @@
             __ebs_ = __ibs_;
             __extbuf_ = (char*)__intbuf_;
             __ibs_ = 0;
-            __intbuf_ = 0;
+            __intbuf_ = nullptr;
             __owns_ib_ = false;
         }
         else  // need to obtain an __intbuf_.
@@ -1093,7 +1093,7 @@
 {
     if (!(__cm_ & ios_base::in))
     {
-        this->setp(0, 0);
+        this->setp(nullptr, nullptr);
         if (__always_noconv_)
             this->setg((char_type*)__extbuf_,
                        (char_type*)__extbuf_ + __ebs_,
@@ -1112,7 +1112,7 @@
 {
     if (!(__cm_ & ios_base::out))
     {
-        this->setg(0, 0, 0);
+        this->setg(nullptr, nullptr, nullptr);
         if (__ebs_ > sizeof(__extbuf_min_))
         {
             if (__always_noconv_)
@@ -1122,7 +1122,7 @@
                 this->setp(__intbuf_, __intbuf_ + (__ibs_ - 1));
         }
         else
-            this->setp(0, 0);
+            this->setp(nullptr, nullptr);
         __cm_ = ios_base::out;
     }
 }
@@ -1208,7 +1208,7 @@
 basic_ifstream<_CharT, _Traits>::basic_ifstream(const char* __s, ios_base::openmode __mode)
     : basic_istream<char_type, traits_type>(&__sb_)
 {
-    if (__sb_.open(__s, __mode | ios_base::in) == 0)
+    if (__sb_.open(__s, __mode | ios_base::in) == nullptr)
         this->setstate(ios_base::failbit);
 }
 
@@ -1218,7 +1218,7 @@
 basic_ifstream<_CharT, _Traits>::basic_ifstream(const wchar_t* __s, ios_base::openmode __mode)
     : basic_istream<char_type, traits_type>(&__sb_)
 {
-    if (__sb_.open(__s, __mode | ios_base::in) == 0)
+    if (__sb_.open(__s, __mode | ios_base::in) == nullptr)
         this->setstate(ios_base::failbit);
 }
 #endif
@@ -1228,7 +1228,7 @@
 basic_ifstream<_CharT, _Traits>::basic_ifstream(const string& __s, ios_base::openmode __mode)
     : basic_istream<char_type, traits_type>(&__sb_)
 {
-    if (__sb_.open(__s, __mode | ios_base::in) == 0)
+    if (__sb_.open(__s, __mode | ios_base::in) == nullptr)
         this->setstate(ios_base::failbit);
 }
 #endif
@@ -1421,7 +1421,7 @@
 basic_ofstream<_CharT, _Traits>::basic_ofstream(const char* __s, ios_base::openmode __mode)
     : basic_ostream<char_type, traits_type>(&__sb_)
 {
-    if (__sb_.open(__s, __mode | ios_base::out) == 0)
+    if (__sb_.open(__s, __mode | ios_base::out) == nullptr)
         this->setstate(ios_base::failbit);
 }
 
@@ -1431,7 +1431,7 @@
 basic_ofstream<_CharT, _Traits>::basic_ofstream(const wchar_t* __s, ios_base::openmode __mode)
     : basic_ostream<char_type, traits_type>(&__sb_)
 {
-    if (__sb_.open(__s, __mode | ios_base::out) == 0)
+    if (__sb_.open(__s, __mode | ios_base::out) == nullptr)
         this->setstate(ios_base::failbit);
 }
 #endif
@@ -1441,7 +1441,7 @@
 basic_ofstream<_CharT, _Traits>::basic_ofstream(const string& __s, ios_base::openmode __mode)
     : basic_ostream<char_type, traits_type>(&__sb_)
 {
-    if (__sb_.open(__s, __mode | ios_base::out) == 0)
+    if (__sb_.open(__s, __mode | ios_base::out) == nullptr)
         this->setstate(ios_base::failbit);
 }
 #endif
@@ -1550,7 +1550,7 @@
 void
 basic_ofstream<_CharT, _Traits>::close()
 {
-    if (__sb_.close() == 0)
+    if (__sb_.close() == nullptr)
         this->setstate(ios_base::failbit);
 }
 
@@ -1634,7 +1634,7 @@
 basic_fstream<_CharT, _Traits>::basic_fstream(const char* __s, ios_base::openmode __mode)
     : basic_iostream<char_type, traits_type>(&__sb_)
 {
-    if (__sb_.open(__s, __mode) == 0)
+    if (__sb_.open(__s, __mode) == nullptr)
         this->setstate(ios_base::failbit);
 }
 
@@ -1644,7 +1644,7 @@
 basic_fstream<_CharT, _Traits>::basic_fstream(const wchar_t* __s, ios_base::openmode __mode)
     : basic_iostream<char_type, traits_type>(&__sb_)
 {
-    if (__sb_.open(__s, __mode) == 0)
+    if (__sb_.open(__s, __mode) == nullptr)
         this->setstate(ios_base::failbit);
 }
 #endif
@@ -1654,7 +1654,7 @@
 basic_fstream<_CharT, _Traits>::basic_fstream(const string& __s, ios_base::openmode __mode)
     : basic_iostream<char_type, traits_type>(&__sb_)
 {
-    if (__sb_.open(__s, __mode) == 0)
+    if (__sb_.open(__s, __mode) == nullptr)
         this->setstate(ios_base::failbit);
 }
 #endif
@@ -1754,7 +1754,7 @@
 void
 basic_fstream<_CharT, _Traits>::close()
 {
-    if (__sb_.close() == 0)
+    if (__sb_.close() == nullptr)
         this->setstate(ios_base::failbit);
 }