From 89ab7eca7f3290d47770a569ae99982a7cee3a08 Mon Sep 17 00:00:00 2001
From: Brendan Drew <brendan.drew@daqri.com>
Date: Thu, 27 Oct 2016 04:43:04 -0700
Subject: [PATCH] Ensure that the fact that a float was provided on input is
 preserved when writing output; update tests to reflect this fact

---
 src/lib_json/json_writer.cpp |  8 +++++++-
 src/test_lib_json/main.cpp   | 10 +++++-----
 2 files changed, 12 insertions(+), 6 deletions(-)

diff --git a/src/lib_json/json_writer.cpp b/src/lib_json/json_writer.cpp
index 1bb3b21..a03f0eb 100644
--- a/src/lib_json/json_writer.cpp
+++ b/src/lib_json/json_writer.cpp
@@ -139,7 +139,7 @@ namespace {
 JSONCPP_STRING valueToString(double value, bool useSpecialFloats, unsigned int precision) {
   // Allocate a buffer that is more than large enough to store the 16 digits of
   // precision requested below.
-  char buffer[32];
+  char buffer[36];
   int len = -1;
 
   char formatString[6];
@@ -150,6 +150,12 @@ JSONCPP_STRING valueToString(double value, bool useSpecialFloats, unsigned int p
   // concepts of reals and integers.
   if (isfinite(value)) {
     len = snprintf(buffer, sizeof(buffer), formatString, value);
+    
+    // try to ensure we preserve the fact that this was given to us as a double on input
+    if (!strstr(buffer, ".") && !strstr(buffer, "e")) {
+      strcat(buffer, ".0");
+    }
+
   } else {
     // IEEE standard states that NaN values will not compare to themselves
     if (value != value) {
diff --git a/src/test_lib_json/main.cpp b/src/test_lib_json/main.cpp
index 1a1216e..47cd981 100644
--- a/src/test_lib_json/main.cpp
+++ b/src/test_lib_json/main.cpp
@@ -479,7 +479,7 @@ JSONTEST_FIXTURE(ValueTest, integers) {
   JSONTEST_ASSERT_EQUAL(0.0, val.asDouble());
   JSONTEST_ASSERT_EQUAL(0.0, val.asFloat());
   JSONTEST_ASSERT_EQUAL(false, val.asBool());
-  JSONTEST_ASSERT_STRING_EQUAL("0", val.asString());
+  JSONTEST_ASSERT_STRING_EQUAL("0.0", val.asString());
 
   // Zero (signed constructor arg)
   val = Json::Value(0);
@@ -563,7 +563,7 @@ JSONTEST_FIXTURE(ValueTest, integers) {
   JSONTEST_ASSERT_EQUAL(0.0, val.asDouble());
   JSONTEST_ASSERT_EQUAL(0.0, val.asFloat());
   JSONTEST_ASSERT_EQUAL(false, val.asBool());
-  JSONTEST_ASSERT_STRING_EQUAL("0", val.asString());
+  JSONTEST_ASSERT_STRING_EQUAL("0.0", val.asString());
 
   // 2^20 (signed constructor arg)
   val = Json::Value(1 << 20);
@@ -646,7 +646,7 @@ JSONTEST_FIXTURE(ValueTest, integers) {
   JSONTEST_ASSERT_EQUAL((1 << 20), val.asDouble());
   JSONTEST_ASSERT_EQUAL((1 << 20), val.asFloat());
   JSONTEST_ASSERT_EQUAL(true, val.asBool());
-  JSONTEST_ASSERT_STRING_EQUAL("1048576",
+  JSONTEST_ASSERT_STRING_EQUAL("1048576.0",
                                normalizeFloatingPointStr(JsonTest::ToJsonString(val.asString())));
 
   // -2^20
@@ -887,7 +887,7 @@ JSONTEST_FIXTURE(ValueTest, integers) {
   JSONTEST_ASSERT_EQUAL((Json::Int64(1) << 40), val.asDouble());
   JSONTEST_ASSERT_EQUAL((Json::Int64(1) << 40), val.asFloat());
   JSONTEST_ASSERT_EQUAL(true, val.asBool());
-  JSONTEST_ASSERT_STRING_EQUAL("1099511627776",
+  JSONTEST_ASSERT_STRING_EQUAL("1099511627776.0",
                                normalizeFloatingPointStr(JsonTest::ToJsonString(val.asString())));
 
   // -2^40
@@ -1259,7 +1259,7 @@ JSONTEST_FIXTURE(ValueTest, nonIntegers) {
   // A 16-digit floating point number.
   val = Json::Value(2199023255552000.0f);
   JSONTEST_ASSERT_EQUAL(float(2199023255552000.0f), val.asFloat());
-  JSONTEST_ASSERT_STRING_EQUAL("2199023255552000",
+  JSONTEST_ASSERT_STRING_EQUAL("2199023255552000.0",
                                normalizeFloatingPointStr(JsonTest::ToJsonString(val.asString())));
 
   // A very large floating point number.