From 239fd62dbec8bca1db3b4e46e2df8dc13c47bfce Mon Sep 17 00:00:00 2001
From: John Maddock <john@johnmaddock.co.uk>
Date: Thu, 21 Nov 2013 13:04:20 +0000
Subject: [PATCH] Add some better error checks to interval construction.

[SVN r86779]
---
 include/boost/multiprecision/mpfi.hpp | 37 +++++++++++++++++++++++++--
 1 file changed, 35 insertions(+), 2 deletions(-)

diff --git a/include/boost/multiprecision/mpfi.hpp b/include/boost/multiprecision/mpfi.hpp
index e0c628fe7..76605be02 100644
--- a/include/boost/multiprecision/mpfi.hpp
+++ b/include/boost/multiprecision/mpfi.hpp
@@ -179,6 +179,8 @@ struct mpfi_float_imp
    }
    mpfi_float_imp& operator = (const char* s)
    {
+      using default_ops::eval_fpclassify;
+   
       if(m_data[0].left._mpfr_d == 0)
          mpfi_init2(m_data, multiprecision::detail::digits10_2_2(digits10 ? digits10 : get_default_precision()));
 
@@ -203,7 +205,22 @@ struct mpfi_float_imp
             part.erase();
          b = part.c_str();
 
-         mpfi_interv_fr(m_data, a.data(), b.data());
+         if(eval_fpclassify(a) == FP_NAN)
+         {
+            mpfi_set_fr(this->data(), a.data());
+         }
+         else if(eval_fpclassify(b) == FP_NAN)
+         {
+            mpfi_set_fr(this->data(), b.data());
+         }
+         else
+         {
+            if(a.compare(b) > 0)
+            {
+               BOOST_THROW_EXCEPTION(std::runtime_error("Attempt to create interval with invalid range (start is greater than end)."));
+            }
+            mpfi_interv_fr(m_data, a.data(), b.data());
+         }
       }
       else if(mpfi_set_str(m_data, s, 10) != 0)
       {
@@ -745,7 +762,23 @@ inline void eval_convert_to(long double* result, const mpfi_float_backend<digits
 template <unsigned D1, unsigned D2, mpfr_allocation_type AllocationType>
 inline void assign_components(mpfi_float_backend<D1>& result, const mpfr_float_backend<D2, AllocationType>& a, const mpfr_float_backend<D2, AllocationType>& b)
 {
-   mpfi_interv_fr(result.data(), a.data(), b.data());
+   using default_ops::eval_fpclassify;
+   if(eval_fpclassify(a) == FP_NAN)
+   {
+      mpfi_set_fr(result.data(), a.data());
+   }
+   else if(eval_fpclassify(b) == FP_NAN)
+   {
+      mpfi_set_fr(result.data(), b.data());
+   }
+   else
+   {
+      if(a.compare(b) > 0)
+      {
+         BOOST_THROW_EXCEPTION(std::runtime_error("Attempt to create interval with invalid range (start is greater than end)."));
+      }
+      mpfi_interv_fr(result.data(), a.data(), b.data());
+   }
 }
 
 template <unsigned Digits10, class V>