From 3a1403409fc12d042608b381e891ca377de300b6 Mon Sep 17 00:00:00 2001
From: Trevor Welsby <welsby.trevorr@gmail.com>
Date: Sat, 23 Jan 2016 17:45:30 +1000
Subject: [PATCH] Issue #185 - remove approx() and use #pragma to kill warnings

---
 src/json.hpp      | 27 +++++++++++++++------------
 src/json.hpp.re2c | 27 +++++++++++++++------------
 test/unit.cpp     |  5 +++++
 3 files changed, 35 insertions(+), 24 deletions(-)

diff --git a/src/json.hpp b/src/json.hpp
index ac362dcf..3af7dbf9 100644
--- a/src/json.hpp
+++ b/src/json.hpp
@@ -65,6 +65,12 @@ Class @ref nlohmann::basic_json is a good entry point for the documentation.
     #endif
 #endif
 
+// disable float-equal warnings on GCC/clang
+#if defined(__clang__) || defined(__GNUC__) || defined(__GNUG__)
+    #pragma GCC diagnostic push
+    #pragma GCC diagnostic ignored "-Wfloat-equal"
+#endif
+
 // enable ssize_t for MSVC
 #ifdef _MSC_VER
     #include <basetsd.h>
@@ -100,12 +106,6 @@ struct has_mapped_type
     static constexpr bool value = sizeof(test<T>(0)) == 1;
 };
 
-/// "equality" comparison for floating point numbers
-template<typename T>
-static bool approx(const T a, const T b)
-{
-    return not (a > b or a < b);
-}
 }
 
 /*!
@@ -4785,7 +4785,7 @@ class basic_json
                 }
                 case value_t::number_float:
                 {
-                    return approx(lhs.m_value.number_float, rhs.m_value.number_float);
+                    return lhs.m_value.number_float == rhs.m_value.number_float;
                 }
                 default:
                 {
@@ -4795,13 +4795,11 @@ class basic_json
         }
         else if (lhs_type == value_t::number_integer and rhs_type == value_t::number_float)
         {
-            return approx(static_cast<number_float_t>(lhs.m_value.number_integer),
-                          rhs.m_value.number_float);
+            return static_cast<number_float_t>(lhs.m_value.number_integer == rhs.m_value.number_float);
         }
         else if (lhs_type == value_t::number_float and rhs_type == value_t::number_integer)
         {
-            return approx(lhs.m_value.number_float,
-                          static_cast<number_float_t>(rhs.m_value.number_integer));
+            return lhs.m_value.number_float == static_cast<number_float_t>(rhs.m_value.number_integer);
         }
         return false;
     }
@@ -7560,7 +7558,7 @@ basic_json_parser_64:
 
                     // check if conversion loses precision
                     const auto int_val = static_cast<number_integer_t>(float_val);
-                    if (approx(float_val, static_cast<long double>(int_val)))
+                    if (float_val == static_cast<long double>(int_val))
                     {
                         // we would not lose precision -> return int
                         result.m_type = value_t::number_integer;
@@ -7705,4 +7703,9 @@ inline nlohmann::json operator "" _json(const char* s, std::size_t)
     return nlohmann::json::parse(reinterpret_cast<const nlohmann::json::string_t::value_type*>(s));
 }
 
+// restore GCC/clang diagnostic settings
+#if defined(__clang__) || defined(__GNUC__) || defined(__GNUG__)
+    #pragma GCC diagnostic pop
+#endif
+
 #endif
diff --git a/src/json.hpp.re2c b/src/json.hpp.re2c
index c7ee44f5..bacc3feb 100644
--- a/src/json.hpp.re2c
+++ b/src/json.hpp.re2c
@@ -65,6 +65,12 @@ Class @ref nlohmann::basic_json is a good entry point for the documentation.
     #endif
 #endif
 
+// disable float-equal warnings on GCC/clang
+#if defined(__clang__) || defined(__GNUC__) || defined(__GNUG__)
+    #pragma GCC diagnostic push
+    #pragma GCC diagnostic ignored "-Wfloat-equal"
+#endif
+
 // enable ssize_t for MSVC
 #ifdef _MSC_VER
     #include <basetsd.h>
@@ -100,12 +106,6 @@ struct has_mapped_type
     static constexpr bool value = sizeof(test<T>(0)) == 1;
 };
 
-/// "equality" comparison for floating point numbers
-template<typename T>
-static bool approx(const T a, const T b)
-{
-    return not (a > b or a < b);
-}
 }
 
 /*!
@@ -4785,7 +4785,7 @@ class basic_json
                 }
                 case value_t::number_float:
                 {
-                    return approx(lhs.m_value.number_float, rhs.m_value.number_float);
+                    return lhs.m_value.number_float == rhs.m_value.number_float;
                 }
                 default:
                 {
@@ -4795,13 +4795,11 @@ class basic_json
         }
         else if (lhs_type == value_t::number_integer and rhs_type == value_t::number_float)
         {
-            return approx(static_cast<number_float_t>(lhs.m_value.number_integer),
-                          rhs.m_value.number_float);
+            return static_cast<number_float_t>(lhs.m_value.number_integer == rhs.m_value.number_float);
         }
         else if (lhs_type == value_t::number_float and rhs_type == value_t::number_integer)
         {
-            return approx(lhs.m_value.number_float,
-                          static_cast<number_float_t>(rhs.m_value.number_integer));
+            return lhs.m_value.number_float == static_cast<number_float_t>(rhs.m_value.number_integer);
         }
         return false;
     }
@@ -7242,7 +7240,7 @@ class basic_json
 
                     // check if conversion loses precision
                     const auto int_val = static_cast<number_integer_t>(float_val);
-                    if (approx(float_val, static_cast<long double>(int_val)))
+                    if (float_val == static_cast<long double>(int_val))
                     {
                         // we would not lose precision -> return int
                         result.m_type = value_t::number_integer;
@@ -7387,4 +7385,9 @@ inline nlohmann::json operator "" _json(const char* s, std::size_t)
     return nlohmann::json::parse(reinterpret_cast<const nlohmann::json::string_t::value_type*>(s));
 }
 
+// restore GCC/clang diagnostic settings
+#if defined(__clang__) || defined(__GNUC__) || defined(__GNUG__)
+    #pragma GCC diagnostic pop
+#endif
+
 #endif
diff --git a/test/unit.cpp b/test/unit.cpp
index 8b3bc19b..8f12eca0 100644
--- a/test/unit.cpp
+++ b/test/unit.cpp
@@ -25,6 +25,11 @@
 #include "json.hpp"
 using nlohmann::json;
 
+// disable float-equal warnings on GCC/clang
+#if defined(__clang__) || defined(__GNUC__) || defined(__GNUG__)
+#pragma GCC diagnostic ignored "-Wfloat-equal"
+#endif
+
 TEST_CASE("constructors")
 {
     SECTION("create an empty value with a given type")