Incorporate cast simplifications from #880

Add tests and make sure everything is covered, and fix resulting errors.

include/boost/math/cstdfloat/cstdfloat_cmath.hpp

@@ -918,62 +918,6 @@ namespace std
    using boost::math::cstdfloat::detail::isunordered;
    //   end more functions
 
-   //
-   // Very basic iostream operator:
-   //
-   inline std::ostream& operator << (std::ostream& os, __float128 m_value)
-   {
-      std::streamsize digits = os.precision();
-      std::ios_base::fmtflags f = os.flags();
-      std::string s;
-
-      char buf[100];
-      std::unique_ptr<char[]> buf2;
-      std::string format = "%";
-      if (f & std::ios_base::showpos)
-         format += "+";
-      if (f & std::ios_base::showpoint)
-         format += "#";
-      format += ".*";
-      if (digits == 0)
-         digits = 36;
-      format += "Q";
-      if (f & std::ios_base::scientific)
-         format += "e";
-      else if (f & std::ios_base::fixed)
-         format += "f";
-      else
-         format += "g";
-
-      int v = quadmath_snprintf(buf, 100, format.c_str(), digits, m_value);
-
-      if ((v < 0) || (v >= 99))
-      {
-         int v_max = v;
-         buf2.reset(new char[v + 3]);
-         v = quadmath_snprintf(&buf2[0], v_max + 3, format.c_str(), digits, m_value);
-         if (v >= v_max + 3)
-         {
-            BOOST_MATH_THROW_EXCEPTION(std::runtime_error("Formatting of float128_type failed."));
-         }
-         s = &buf2[0];
-      }
-      else
-         s = buf;
-      std::streamsize ss = os.width();
-      if (ss > static_cast<std::streamsize>(s.size()))
-      {
-         char fill = os.fill();
-         if ((os.flags() & std::ios_base::left) == std::ios_base::left)
-            s.append(static_cast<std::string::size_type>(ss - s.size()), fill);
-         else
-            s.insert(static_cast<std::string::size_type>(0), static_cast<std::string::size_type>(ss - s.size()), fill);
-      }
-
-      return os << s;
-   }
-
-
 } // namespace std
 
 // We will now remove the preprocessor symbols representing quadruple-precision <cmath>

include/boost/math/cstdfloat/cstdfloat_iostream.hpp

@@ -32,8 +32,7 @@
   #include <boost/math/tools/nothrow.hpp>
   #include <boost/math/tools/throw_exception.hpp>
 
-//  #if (0)
-  #if defined(__GNUC__)
+#if defined(__GNUC__) && !defined(BOOST_MATH_TEST_IO_AS_INTEL_QUAD)
 
   // Forward declarations of quadruple-precision string functions.
   extern "C" int quadmath_snprintf(char *str, size_t size, const char *format, ...) BOOST_MATH_NOTHROW;
@@ -96,7 +95,7 @@
         // So we have to use dynamic memory allocation for the output
         // string buffer.
 
-        char* my_buffer2 = static_cast<char*>(0U);
+        char* my_buffer2 = nullptr;
 
 #ifndef BOOST_NO_EXCEPTIONS
         try
@@ -160,8 +159,7 @@
     }
   }
 
-//  #elif defined(__GNUC__)
-  #elif defined(__INTEL_COMPILER)
+#elif defined(__INTEL_COMPILER) || defined(BOOST_MATH_TEST_IO_AS_INTEL_QUAD)
 
   // The section for I/O stream support for the ICC compiler is particularly
   // long, because these functions must be painstakingly synthesized from
@@ -172,6 +170,7 @@
   // used in Boost.Multiprecision by John Maddock and Christopher Kormanyos.
   // This methodology has been slightly modified here for boost::float128_t.
 
+
   #include <cstring>
   #include <cctype>
 
@@ -266,7 +265,7 @@
     {
       // Pad out the end with zero's if we need to.
 
-      int chars = static_cast<int>(str.size());
+      std::ptrdiff_t chars = static_cast<std::ptrdiff_t>(str.size());
       chars = digits - chars;
 
       if(scientific)
@@ -507,6 +506,8 @@
         eval_subtract(t, digit);
         eval_multiply(t, ten);
       }
+      if (result.size() == 0)
+         result = "0";
 
       // Possibly round the result.
       if(digits >= 0)
@@ -522,11 +523,13 @@
           if((static_cast<int>(*result.rbegin() - '0') & 1) != 0)
           {
             round_string_up_at(result, static_cast<int>(result.size() - 1U), expon);
+            if (digits == 0) digits = 1;
           }
         }
         else if(cdigit >= 5)
         {
-          round_string_up_at(result, static_cast<int>(result.size() - 1), expon);
+          round_string_up_at(result, static_cast<int>(result.size() - 1u), expon);
+          if (digits == 0) digits = 1;
         }
       }
     }
@@ -569,7 +572,7 @@
   {
     value = 0;
 
-    if((p == static_cast<const char*>(0U)) || (*p == static_cast<char>(0)))
+    if((p == nullptr) || (*p == '\0'))
     {
       return false;
     }
@@ -584,11 +587,11 @@
 
     constexpr int max_digits = std::numeric_limits<float_type>::max_digits10 + 1;
 
-    if(*p == static_cast<char>('+'))
+    if(*p == '+')
     {
       ++p;
     }
-    else if(*p == static_cast<char>('-'))
+    else if(*p == '-')
     {
       is_neg = true;
       ++p;
@@ -632,7 +635,7 @@
       ++digits_seen;
     }
 
-    if(*p == static_cast<char>('.'))
+    if(*p == '.')
     {
       // Grab everything after the point, stop when we've seen
       // enough digits, even if there are actually more available.
@@ -659,15 +662,15 @@
     }
 
     // Parse the exponent.
-    if((*p == static_cast<char>('e')) || (*p == static_cast<char>('E')))
+    if((*p == 'e') || (*p == 'E'))
     {
       ++p;
 
-      if(*p == static_cast<char>('+'))
+      if(*p == '+')
       {
         ++p;
       }
-      else if(*p == static_cast<char>('-'))
+      else if(*p == '-')
       {
         is_neg_expon = true;
         ++p;
@@ -718,7 +721,7 @@
       value = -value;
     }
 
-    return (*p == static_cast<char>(0));
+    return (*p == '\0');
   }
   } } } } // boost::math::cstdfloat::detail
 

test/Jamfile.v2

@@ -909,6 +909,8 @@ test-suite new_floats :
    [ compile compile_test/float32.cpp ]
    [ compile compile_test/float64.cpp ]
    [ compile compile_test/float128.cpp ]
+   [ run test_float_io.cpp : : : [ check-target-builds ../config//has_float128 "GCC libquadmath and __float128 support" : <define>BOOST_MATH_TEST_FLOAT128 <linkflags>"-Bstatic -lquadmath -Bdynamic" ] ]
+   [ run test_float_io.cpp : : : <define>BOOST_MATH_TEST_IO_AS_INTEL_QUAD=1 [ check-target-builds ../config//has_float128 "GCC libquadmath and __float128 support" : <define>BOOST_MATH_TEST_FLOAT128 <linkflags>"-Bstatic -lquadmath -Bdynamic" ] : test_float_io_quad ]
 ;
 
 test-suite mp :