Merge pull request json-c#289 from jgerhards/i-278

bugfix: floating point representaion without fractional part

json_object.c

@@ -693,6 +693,7 @@ static int json_object_double_to_json_string_format(struct json_object* jso,
 {
   char buf[128], *p, *q;
   int size;
+  double dummy; /* needed for modf() */
   /* Although JSON RFC does not support
      NaN or Infinity as numeric values
      ECMA 262 section 9.8.1 defines
@@ -706,7 +707,9 @@ static int json_object_double_to_json_string_format(struct json_object* jso,
       size = snprintf(buf, sizeof(buf), "-Infinity");
   else
     size = snprintf(buf, sizeof(buf),
-        format ? format : "%.17g", jso->o.c_double);
+        format ? format : 
+          (modf(jso->o.c_double, &dummy) == 0) ? "%.17g.0" : "%.17g",
+          jso->o.c_double);
 
   p = strchr(buf, ',');
   if (p) {

tests/Makefile.am

@@ -7,6 +7,7 @@ LIBJSON_LA=$(top_builddir)/libjson-c.la
 
 TESTS=
 TESTS+= test_util_file.test
+TESTS+= test_float.test
 TESTS+= test1.test
 TESTS+= test2.test
 TESTS+= test4.test

tests/test_float.c

@@ -0,0 +1,24 @@
+/* Copyright (C) 2016 by Rainer Gerhards 
+ * Released under ASL 2.0 */
+#include "config.h"
+#include <stdio.h>
+#include "../json_object.h"
+#include "../json_tokener.h"
+int main(void)
+{
+  json_object *json;
+
+  json = json_object_new_double(1.0);
+  printf("json = %s\n", json_object_to_json_string_ext(json, JSON_C_TO_STRING_PRETTY));
+  json_object_put(json);
+  json = json_object_new_double(1.23);
+  printf("json = %s\n", json_object_to_json_string_ext(json, JSON_C_TO_STRING_PRETTY));
+  json_object_put(json);
+  json = json_object_new_double(123456789.0);
+  printf("json = %s\n", json_object_to_json_string_ext(json, JSON_C_TO_STRING_PRETTY));
+  json_object_put(json);
+  json = json_object_new_double(123456789.123);
+  printf("json = %s\n", json_object_to_json_string_ext(json, JSON_C_TO_STRING_PRETTY));
+  json_object_put(json);
+  return 0;
+}

tests/test_float.expected

@@ -0,0 +1,4 @@
+json = 1.0
+json = 1.23
+json = 123456789.0
+json = 123456789.123

tests/test_float.test

@@ -0,0 +1,12 @@
+#!/bin/sh
+
+# Common definitions
+if test -z "$srcdir"; then
+    srcdir="${0%/*}"
+    test "$srcdir" = "$0" && srcdir=.
+    test -z "$srcdir" && srcdir=.
+fi
+. "$srcdir/test-defs.sh"
+
+run_output_test test_float
+exit $?

tests/test_parse.expected

@@ -31,8 +31,8 @@ new_obj.to_string()={ "foo": "bar", "baz": null, "bool0": true }
 new_obj.to_string()={ "foo": [ null, "foo" ] }
 new_obj.to_string()={ "abc": 12, "foo": "bar", "bool0": false, "bool1": true, "arr": [ 1, 2, 3, null, 5 ] }
 new_obj.to_string()={ "abc": "blue\nred\ngreen" }
-new_obj.to_string()=[ 0 ]
-new_obj.to_string()=[ 0 ]
+new_obj.to_string()=[ 0.0 ]
+new_obj.to_string()=[ 0.0 ]
 new_obj.to_string()=null
 new_obj.to_string()=[ 9223372036854775807 ]
 ==================================