Merge pull request msgpack#1018 from GeorgFritze/cpp_master

pack double and float more size efficient

Author: redboltz

include/msgpack/v1/pack.hpp

@@ -1138,6 +1138,17 @@ inline packer<Stream>& packer<Stream>::pack_unsigned_long_long(unsigned long lon
 template <typename Stream>
 inline packer<Stream>& packer<Stream>::pack_float(float d)
 {
+    if(d == d) { // check for nan 
+        // compare d to limits to avoid undefined behaviour
+        if(d >= 0 && d <= float(std::numeric_limits<uint64_t>::max()) && d == float(uint64_t(d))) {
+            pack_imp_uint64(uint64_t(d));
+            return *this;        
+        } else if(d < 0 && d >= float(std::numeric_limits<int64_t>::min()) && d == float(int64_t(d))) {
+            pack_imp_int64(int64_t(d));
+            return *this;
+        }
+    }
+
     union { float f; uint32_t i; } mem;
     mem.f = d;
     char buf[5];
@@ -1149,6 +1160,17 @@ inline packer<Stream>& packer<Stream>::pack_float(float d)
 template <typename Stream>
 inline packer<Stream>& packer<Stream>::pack_double(double d)
 {
+    if(d == d) { // check for nan 
+        // compare d to limits to avoid undefined behaviour
+        if(d >= 0 && d <= double(std::numeric_limits<uint64_t>::max()) && d == double(uint64_t(d))) {
+            pack_imp_uint64(uint64_t(d));
+            return *this;        
+        } else if(d < 0 && d >= double(std::numeric_limits<int64_t>::min()) && d == double(int64_t(d))) {
+            pack_imp_int64(int64_t(d));
+            return *this;
+        }
+    }
+
     union { double f; uint64_t i; } mem;
     mem.f = d;
     char buf[9];

test/msgpack_basic.cpp

@@ -154,6 +154,8 @@ BOOST_AUTO_TEST_CASE(simple_buffer_float)
     v.push_back(-0.0);
     v.push_back(1.0);
     v.push_back(-1.0);
+    v.push_back(1.1f);
+    v.push_back(-1.1f);
     v.push_back(numeric_limits<float>::min());
     v.push_back(numeric_limits<float>::max());
     v.push_back(nanf("tag"));
@@ -186,6 +188,12 @@ BOOST_AUTO_TEST_CASE(simple_buffer_float)
             BOOST_CHECK(std::isinf(val2));
         else
             BOOST_CHECK(fabs(val2 - val1) <= kEPS);
+
+        // check for compact storing of float
+        if (val1 == val1 && val1 >= float(std::numeric_limits<int64_t>::min()) && val1 <= float(std::numeric_limits<int64_t>::max()) && val1 == float(int64_t(val1)))
+            BOOST_REQUIRE_EQUAL(sbuf.size(),1);
+        else
+            BOOST_REQUIRE_EQUAL(sbuf.data()[0],char(0xca));
     }
 }
 
@@ -236,6 +244,8 @@ BOOST_AUTO_TEST_CASE(simple_buffer_double)
     v.push_back(-0.0);
     v.push_back(1.0);
     v.push_back(-1.0);
+    v.push_back(1.1);
+    v.push_back(-1.1);
     v.push_back(numeric_limits<double>::min());
     v.push_back(numeric_limits<double>::max());
     v.push_back(nanf("tag"));
@@ -272,6 +282,12 @@ BOOST_AUTO_TEST_CASE(simple_buffer_double)
             BOOST_CHECK(std::isinf(val2));
         else
             BOOST_CHECK(fabs(val2 - val1) <= kEPS);
+
+        // check for compact storing of double
+        if (val1 == val1 && val1 >= double(std::numeric_limits<int64_t>::min()) && val1 <= double(std::numeric_limits<int64_t>::max()) && val1 == double(int64_t(val1)))
+            BOOST_REQUIRE_EQUAL(sbuf.size(),1);
+        else
+            BOOST_REQUIRE_EQUAL(uint8_t(sbuf.data()[0]),uint8_t(0xcb));
     }
 }