From 88a37010d6cfa808ddfa9559a15285b8291ad187 Mon Sep 17 00:00:00 2001
From: Niels Lohmann <mail@nlohmann.me>
Date: Wed, 17 Jun 2020 21:14:23 +0200
Subject: [PATCH] :bug: serialize 32-bit floating-point numbers as float 32 in
MessagePack (0xCA) #2196
---
.../features/binary_formats/messagepack.md | 7 ++--
.../nlohmann/detail/output/binary_writer.hpp | 14 ++++++--
include/nlohmann/json.hpp | 6 ++--
single_include/nlohmann/json.hpp | 20 +++++++----
test/src/unit-msgpack.cpp | 34 +++++++++++++++++++
5 files changed, 64 insertions(+), 17 deletions(-)
diff --git a/doc/mkdocs/docs/features/binary_formats/messagepack.md b/doc/mkdocs/docs/features/binary_formats/messagepack.md
index ed061056..3e041bb7 100644
--- a/doc/mkdocs/docs/features/binary_formats/messagepack.md
+++ b/doc/mkdocs/docs/features/binary_formats/messagepack.md
@@ -31,7 +31,8 @@ number_unsigned | 128..255 | uint 8 | 0xCC
number_unsigned | 256..65535 | uint 16 | 0xCD
number_unsigned | 65536..4294967295 | uint 32 | 0xCE
number_unsigned | 4294967296..18446744073709551615 | uint 64 | 0xCF
-number_float | *any value* | float 64 | 0xCB
+number_float | *any value representable by a float* | float 32 | 0xCA
+number_float | *any value NOT representable by a float* | float 64 | 0xCB
string | *length*: 0..31 | fixstr | 0xA0..0xBF
string | *length*: 32..255 | str 8 | 0xD9
string | *length*: 256..65535 | str 16 | 0xDA
@@ -61,10 +62,6 @@ binary | *size*: 65536..4294967295 | bin 32 | 0xC6
- arrays with more than 4294967295 elements
- objects with more than 4294967295 elements
-!!! info "Unused MessagePack types"
-
- The following MessagePack types are not used in the conversion: float 32 (0xCA)
-
!!! info "NaN/infinity handling"
If NaN or Infinity are stored inside a JSON number, they are serialized properly. function which serializes NaN or Infinity to `null`.
diff --git a/include/nlohmann/detail/output/binary_writer.hpp b/include/nlohmann/detail/output/binary_writer.hpp
index 269df0d5..f3221191 100644
--- a/include/nlohmann/detail/output/binary_writer.hpp
+++ b/include/nlohmann/detail/output/binary_writer.hpp
@@ -504,8 +504,18 @@ class binary_writer
case value_t::number_float:
{
- oa->write_character(get_msgpack_float_prefix(j.m_value.number_float));
- write_number(j.m_value.number_float);
+ if (static_cast<double>(j.m_value.number_float) >= static_cast<double>(std::numeric_limits<float>::lowest()) and
+ static_cast<double>(j.m_value.number_float) <= static_cast<double>((std::numeric_limits<float>::max)()) and
+ static_cast<double>(static_cast<float>(j.m_value.number_float)) == static_cast<double>(j.m_value.number_float))
+ {
+ oa->write_character(get_msgpack_float_prefix(static_cast<float>(j.m_value.number_float)));
+ write_number(static_cast<float>(j.m_value.number_float));
+ }
+ else
+ {
+ oa->write_character(get_msgpack_float_prefix(j.m_value.number_float));
+ write_number(j.m_value.number_float);
+ }
break;
}
diff --git a/include/nlohmann/json.hpp b/include/nlohmann/json.hpp
index 409a6e79..790ecd4b 100644
--- a/include/nlohmann/json.hpp
+++ b/include/nlohmann/json.hpp
@@ -7040,7 +7040,8 @@ class basic_json
number_unsigned | 256..65535 | uint 16 | 0xCD
number_unsigned | 65536..4294967295 | uint 32 | 0xCE
number_unsigned | 4294967296..18446744073709551615 | uint 64 | 0xCF
- number_float | *any value* | float 64 | 0xCB
+ number_float | *any value representable by a float* | float 32 | 0xCA
+ number_float | *any value NOT representable by a float* | float 64 | 0xCB
string | *length*: 0..31 | fixstr | 0xA0..0xBF
string | *length*: 32..255 | str 8 | 0xD9
string | *length*: 256..65535 | str 16 | 0xDA
@@ -7064,9 +7065,6 @@ class basic_json
- arrays with more than 4294967295 elements
- objects with more than 4294967295 elements
- @note The following MessagePack types are not used in the conversion:
- - float 32 (0xCA)
-
@note Any MessagePack output created @ref to_msgpack can be successfully
parsed by @ref from_msgpack.
diff --git a/single_include/nlohmann/json.hpp b/single_include/nlohmann/json.hpp
index cc822a54..85fffc7c 100644
--- a/single_include/nlohmann/json.hpp
+++ b/single_include/nlohmann/json.hpp
@@ -12714,8 +12714,18 @@ class binary_writer
case value_t::number_float:
{
- oa->write_character(get_msgpack_float_prefix(j.m_value.number_float));
- write_number(j.m_value.number_float);
+ if (static_cast<double>(j.m_value.number_float) >= static_cast<double>(std::numeric_limits<float>::lowest()) and
+ static_cast<double>(j.m_value.number_float) <= static_cast<double>((std::numeric_limits<float>::max)()) and
+ static_cast<double>(static_cast<float>(j.m_value.number_float)) == static_cast<double>(j.m_value.number_float))
+ {
+ oa->write_character(get_msgpack_float_prefix(static_cast<float>(j.m_value.number_float)));
+ write_number(static_cast<float>(j.m_value.number_float));
+ }
+ else
+ {
+ oa->write_character(get_msgpack_float_prefix(j.m_value.number_float));
+ write_number(j.m_value.number_float);
+ }
break;
}
@@ -22821,7 +22831,8 @@ class basic_json
number_unsigned | 256..65535 | uint 16 | 0xCD
number_unsigned | 65536..4294967295 | uint 32 | 0xCE
number_unsigned | 4294967296..18446744073709551615 | uint 64 | 0xCF
- number_float | *any value* | float 64 | 0xCB
+ number_float | *any value representable by a float* | float 32 | 0xCA
+ number_float | *any value NOT representable by a float* | float 64 | 0xCB
string | *length*: 0..31 | fixstr | 0xA0..0xBF
string | *length*: 32..255 | str 8 | 0xD9
string | *length*: 256..65535 | str 16 | 0xDA
@@ -22845,9 +22856,6 @@ class basic_json
- arrays with more than 4294967295 elements
- objects with more than 4294967295 elements
- @note The following MessagePack types are not used in the conversion:
- - float 32 (0xCA)
-
@note Any MessagePack output created @ref to_msgpack can be successfully
parsed by @ref from_msgpack.
diff --git a/test/src/unit-msgpack.cpp b/test/src/unit-msgpack.cpp
index 2744a67b..5baecf02 100644
--- a/test/src/unit-msgpack.cpp
+++ b/test/src/unit-msgpack.cpp
@@ -783,6 +783,40 @@ TEST_CASE("MessagePack")
CHECK(json::from_msgpack(result) == v);
CHECK(json::from_msgpack(result, true, false) == j);
}
+
+ SECTION("1.0")
+ {
+ double v = 1.0;
+ json j = v;
+ std::vector<uint8_t> expected =
+ {
+ 0xca, 0x3f, 0x80, 0x00, 0x00
+ };
+ const auto result = json::to_msgpack(j);
+ CHECK(result == expected);
+
+ // roundtrip
+ CHECK(json::from_msgpack(result) == j);
+ CHECK(json::from_msgpack(result) == v);
+ CHECK(json::from_msgpack(result, true, false) == j);
+ }
+
+ SECTION("128.128")
+ {
+ double v = 128.1280059814453125;
+ json j = v;
+ std::vector<uint8_t> expected =
+ {
+ 0xca, 0x43, 0x00, 0x20, 0xc5
+ };
+ const auto result = json::to_msgpack(j);
+ CHECK(result == expected);
+
+ // roundtrip
+ CHECK(json::from_msgpack(result) == j);
+ CHECK(json::from_msgpack(result) == v);
+ CHECK(json::from_msgpack(result, true, false) == j);
+ }
}
}