From 0a2ce87d32be210f62800e8e5711551e8ba8fbc6 Mon Sep 17 00:00:00 2001
From: Phil Nash <github@philnash.me>
Date: Sun, 6 Aug 2017 00:13:00 +0100
Subject: [PATCH] Removed compare layer from expression evaluation

---
 include/internal/catch_evaluate.hpp       | 162 +++++-----------------
 include/internal/catch_expression_lhs.hpp |   2 +-
 2 files changed, 33 insertions(+), 131 deletions(-)

diff --git a/include/internal/catch_evaluate.hpp b/include/internal/catch_evaluate.hpp
index 9d9da64c..8c9a69f9 100644
--- a/include/internal/catch_evaluate.hpp
+++ b/include/internal/catch_evaluate.hpp
@@ -31,8 +31,7 @@ namespace Internal {
     const char* operatorName(Operator op);
 
     template<typename T>
-    T& opCast(T const& t) { return const_cast<T&>(t); }
-    std::nullptr_t opCast(std::nullptr_t);
+    T& removeConst(T const &t) { return const_cast<T&>(t); }
 
 
     // So the compare overloads can be operator agnostic we convey the operator as a template
@@ -43,162 +42,65 @@ namespace Internal {
     template<typename T1, typename T2>
     struct Evaluator<T1, T2, IsEqualTo> {
         static bool evaluate( T1 const& lhs, T2 const& rhs) {
-            return bool( opCast( lhs ) ==  opCast( rhs ) );
+            return bool(removeConst(lhs) == removeConst(rhs) );
         }
     };
     template<typename T1, typename T2>
     struct Evaluator<T1, T2, IsNotEqualTo> {
         static bool evaluate( T1 const& lhs, T2 const& rhs ) {
-            return bool( opCast( lhs ) != opCast( rhs ) );
+            return bool(removeConst(lhs) != removeConst(rhs) );
         }
     };
     template<typename T1, typename T2>
     struct Evaluator<T1, T2, IsLessThan> {
         static bool evaluate( T1 const& lhs, T2 const& rhs ) {
-            return bool( opCast( lhs ) < opCast( rhs ) );
+            return bool(removeConst(lhs) < removeConst(rhs) );
         }
     };
     template<typename T1, typename T2>
     struct Evaluator<T1, T2, IsGreaterThan> {
         static bool evaluate( T1 const& lhs, T2 const& rhs ) {
-            return bool( opCast( lhs ) > opCast( rhs ) );
+            return bool(removeConst(lhs) > removeConst(rhs) );
         }
     };
     template<typename T1, typename T2>
     struct Evaluator<T1, T2, IsGreaterThanOrEqualTo> {
         static bool evaluate( T1 const& lhs, T2 const& rhs ) {
-            return bool( opCast( lhs ) >= opCast( rhs ) );
+            return bool(removeConst(lhs) >= removeConst(rhs) );
         }
     };
     template<typename T1, typename T2>
     struct Evaluator<T1, T2, IsLessThanOrEqualTo> {
         static bool evaluate( T1 const& lhs, T2 const& rhs ) {
-            return bool( opCast( lhs ) <= opCast( rhs ) );
+            return bool(removeConst(lhs) <= removeConst(rhs) );
         }
     };
 
-    template<Operator Op, typename T1, typename T2>
-    bool applyEvaluator( T1 const& lhs, T2 const& rhs ) {
-        return Evaluator<T1, T2, Op>::evaluate( lhs, rhs );
-    }
-
-    // This level of indirection allows us to specialise for integer types
-    // to avoid signed/ unsigned warnings
-
-    // "base" overload
-    template<Operator Op, typename T1, typename T2>
-    bool compare( T1 const& lhs, T2 const& rhs ) {
-        return Evaluator<T1, T2, Op>::evaluate( lhs, rhs );
-    }
-
-	template<Operator Op>
-	bool compare( void const* lhs, void const* rhs ) {
-		return Evaluator<void const*, void const*, Op>::evaluate( lhs, rhs );
-	}
-
-    // unsigned X to int
-    template<Operator Op> bool compare( unsigned int lhs, int rhs ) {
-        return applyEvaluator<Op>( lhs, static_cast<unsigned int>( rhs ) );
-    }
-    template<Operator Op> bool compare( unsigned long lhs, int rhs ) {
-        return applyEvaluator<Op>( lhs, static_cast<unsigned int>( rhs ) );
-    }
-    template<Operator Op> bool compare( unsigned char lhs, int rhs ) {
-        return applyEvaluator<Op>( lhs, static_cast<unsigned int>( rhs ) );
-    }
-
-    // unsigned X to long
-    template<Operator Op> bool compare( unsigned int lhs, long rhs ) {
-        return applyEvaluator<Op>( lhs, static_cast<unsigned long>( rhs ) );
-    }
-    template<Operator Op> bool compare( unsigned long lhs, long rhs ) {
-        return applyEvaluator<Op>( lhs, static_cast<unsigned long>( rhs ) );
-    }
-    template<Operator Op> bool compare( unsigned char lhs, long rhs ) {
-        return applyEvaluator<Op>( lhs, static_cast<unsigned long>( rhs ) );
-    }
-
-    // int to unsigned X
-    template<Operator Op> bool compare( int lhs, unsigned int rhs ) {
-        return applyEvaluator<Op>( static_cast<unsigned int>( lhs ), rhs );
-    }
-    template<Operator Op> bool compare( int lhs, unsigned long rhs ) {
-        return applyEvaluator<Op>( static_cast<unsigned int>( lhs ), rhs );
-    }
-    template<Operator Op> bool compare( int lhs, unsigned char rhs ) {
-        return applyEvaluator<Op>( static_cast<unsigned int>( lhs ), rhs );
-    }
-
-    // long to unsigned X
-    template<Operator Op> bool compare( long lhs, unsigned int rhs ) {
-        return applyEvaluator<Op>( static_cast<unsigned long>( lhs ), rhs );
-    }
-    template<Operator Op> bool compare( long lhs, unsigned long rhs ) {
-        return applyEvaluator<Op>( static_cast<unsigned long>( lhs ), rhs );
-    }
-    template<Operator Op> bool compare( long lhs, unsigned char rhs ) {
-        return applyEvaluator<Op>( static_cast<unsigned long>( lhs ), rhs );
-    }
-
-    // pointer to long (when comparing against NULL)
-    template<Operator Op, typename T> bool compare( long lhs, T* rhs ) {
-        return Evaluator<void const*, void const*, Op>::evaluate( reinterpret_cast<void const*>( lhs ), rhs );
-    }
-    template<Operator Op, typename T> bool compare( T* lhs, long rhs ) {
-        return Evaluator<void const*, void const*, Op>::evaluate( lhs, reinterpret_cast<void const*>( rhs ) );
-    }
-
-    // pointer to int (when comparing against NULL)
-    template<Operator Op, typename T> bool compare( int lhs, T* rhs ) {
-        return Evaluator<void const*, void const*, Op>::evaluate( reinterpret_cast<void const*>( lhs ), rhs );
-    }
-    template<Operator Op, typename T> bool compare( T* lhs, int rhs ) {
-        return Evaluator<void const*, void const*, Op>::evaluate( lhs, reinterpret_cast<void const*>( rhs ) );
-    }
-
-    // long long to unsigned X
-    template<Operator Op> bool compare( long long lhs, unsigned int rhs ) {
-        return applyEvaluator<Op>( static_cast<unsigned long>( lhs ), rhs );
-    }
-    template<Operator Op> bool compare( long long lhs, unsigned long rhs ) {
-        return applyEvaluator<Op>( static_cast<unsigned long>( lhs ), rhs );
-    }
-    template<Operator Op> bool compare( long long lhs, unsigned long long rhs ) {
-        return applyEvaluator<Op>( static_cast<unsigned long>( lhs ), rhs );
-    }
-    template<Operator Op> bool compare( long long lhs, unsigned char rhs ) {
-        return applyEvaluator<Op>( static_cast<unsigned long>( lhs ), rhs );
-    }
-
-    // unsigned long long to X
-    template<Operator Op> bool compare( unsigned long long lhs, int rhs ) {
-        return applyEvaluator<Op>( static_cast<long>( lhs ), rhs );
-    }
-    template<Operator Op> bool compare( unsigned long long lhs, long rhs ) {
-        return applyEvaluator<Op>( static_cast<long>( lhs ), rhs );
-    }
-    template<Operator Op> bool compare( unsigned long long lhs, long long rhs ) {
-        return applyEvaluator<Op>( static_cast<long>( lhs ), rhs );
-    }
-    template<Operator Op> bool compare( unsigned long long lhs, char rhs ) {
-        return applyEvaluator<Op>( static_cast<long>( lhs ), rhs );
-    }
-
-    // pointer to long long (when comparing against NULL)
-    template<Operator Op, typename T> bool compare( long long lhs, T* rhs ) {
-        return Evaluator<void const*, void const*, Op>::evaluate( reinterpret_cast<T*>( lhs ), rhs );
-    }
-    template<Operator Op, typename T> bool compare( T* lhs, long long rhs ) {
-        return Evaluator<void const*, void const*, Op>::evaluate( lhs, reinterpret_cast<T*>( rhs ) );
-    }
-
-    // pointer to nullptr_t (when comparing against nullptr)
-    template<Operator Op, typename T> bool compare( std::nullptr_t, T* rhs ) {
-        return Evaluator<void const*, void const*, Op>::evaluate( nullptr, rhs );
-    }
-    template<Operator Op, typename T> bool compare( T* lhs, std::nullptr_t ) {
-        return Evaluator<void const*, void const*, Op>::evaluate( lhs, nullptr );
-    }
+    // Special case for comparing a pointer to an int (deduced for p==0)
+    template<typename T>
+    struct Evaluator<int const&, T* const&, IsEqualTo> {
+        static bool evaluate( int lhs, T* rhs) {
+            return reinterpret_cast<void const*>( lhs ) ==  rhs;
+        }
+    };
+    template<typename T>
+    struct Evaluator<T* const&, int const&, IsEqualTo> {
+        static bool evaluate( T* lhs, int rhs) {
+            return lhs == reinterpret_cast<void const*>( rhs );
+        }
+    };
+    template<typename T>
+    struct Evaluator<int const&, T* const&, IsNotEqualTo> {
+        static bool evaluate( int lhs, T* rhs) {
+            return reinterpret_cast<void const*>( lhs ) !=  rhs;
+        }
+    };
+    template<typename T>
+    struct Evaluator<T* const&, int const&, IsNotEqualTo> {
+        static bool evaluate( T* lhs, int rhs) {
+            return lhs != reinterpret_cast<void const*>( rhs );
+        }
+    };
 
 } // end of namespace Internal
 } // end of namespace Catch
diff --git a/include/internal/catch_expression_lhs.hpp b/include/internal/catch_expression_lhs.hpp
index 192f001a..35675aee 100644
--- a/include/internal/catch_expression_lhs.hpp
+++ b/include/internal/catch_expression_lhs.hpp
@@ -113,7 +113,7 @@ public:
 
     void endExpression() const {
         m_rb
-            .setResultType( Internal::compare<Op>( m_lhs, m_rhs ) )
+            .setResultType(  Internal::Evaluator<LhsT, RhsT, Op>::evaluate( m_lhs, m_rhs ) )
             .endExpression( *this );
     }