filterx/object-primitive: fix double repr method to generate JSON lik…

…e result

Our double repr was different to JSON a number of ways:
  * in JSON we need a ".0" even if we have an integer value to indicate that
    a member is floating point
  * we should not include trailing zeroes
  * we should use Infinite and NaN tokens to indicate these values

Signed-off-by: Balazs Scheidler <[email protected]>

lib/filterx/object-primitive.c

@@ -32,8 +32,8 @@
 #include "filterx/filterx-object-istype.h"
 #include "str-utils.h"
 #include "timeutils/misc.h"
-
 #include "compat/json.h"
+#include <math.h>
 
 static gboolean
 _truthy(FilterXObject *s)
@@ -139,12 +139,43 @@ _double_add(FilterXObject *s, FilterXObject *object)
 }
 
 gboolean
-double_repr(double val, GString *repr)
+double_repr(double dbl, GString *repr)
 {
-  gsize init_len = repr->len;
-  g_string_set_size(repr, init_len + G_ASCII_DTOSTR_BUF_SIZE);
-  g_ascii_dtostr(repr->str + init_len, G_ASCII_DTOSTR_BUF_SIZE, val);
-  g_string_set_size(repr, init_len + strlen(repr->str + init_len));
+  if (isnan(dbl))
+    {
+      g_string_append_len(repr, "NaN", 3);
+    }
+  else if (isinf(dbl))
+    {
+      if (dbl < 0)
+        g_string_append_c(repr, '-');
+      g_string_append_len(repr, "Infinity", 8);
+    }
+  else
+    {
+      gchar buf[G_ASCII_DTOSTR_BUF_SIZE];
+
+      g_ascii_dtostr(buf, sizeof(buf), dbl);
+      gchar *dot = strchr(buf, '.');
+      if (!dot && strchr(buf, 'e') == NULL)
+        {
+          /* no fractions, not scientific notation */
+          strcat(buf, ".0");
+        }
+      else if (dot)
+        {
+          gchar *last_useful_digit = NULL;
+          for (gchar *c = dot+1; *c; c++)
+            {
+              if (*c != '0')
+                last_useful_digit = c;
+            }
+          /* truncate trailing zeroes */
+          if (last_useful_digit)
+            *(last_useful_digit+1) = 0;
+        }
+      g_string_append(repr, buf);
+    }
   return TRUE;
 }
 

lib/filterx/object-primitive.h

@@ -55,7 +55,7 @@ FilterXObject *filterx_typecast_integer(FilterXExpr *s, FilterXObject *args[], g
 FilterXObject *filterx_typecast_double(FilterXExpr *s, FilterXObject *args[], gsize args_len);
 
 gboolean bool_repr(gboolean bool_val, GString *repr);
-gboolean double_repr(double val, GString *repr);
+gboolean double_repr(gdouble val, GString *repr);
 gboolean integer_repr(gint64 val, GString *repr);
 
 /* NOTE: Consider using filterx_object_extract_integer() to also support message_value. */

lib/filterx/tests/test_expr_comparison.c

@@ -466,10 +466,10 @@ Test(expr_comparison, test_string_to_numeric_string_based_comparison)
   _assert_comparison(filterx_string_new("3", 1), filterx_integer_new(3), FCMPX_GT | FCMPX_STRING_BASED, FALSE);
   _assert_comparison(filterx_string_new("3", 1), filterx_integer_new(3), FCMPX_NE | FCMPX_STRING_BASED, FALSE);
 
-  _assert_comparison(filterx_string_new("3", 1), filterx_double_new(3.0), FCMPX_EQ | FCMPX_STRING_BASED, TRUE);
-  _assert_comparison(filterx_string_new("3", 1), filterx_double_new(3.0), FCMPX_LT | FCMPX_STRING_BASED, FALSE);
-  _assert_comparison(filterx_string_new("3", 1), filterx_double_new(3.0), FCMPX_GT | FCMPX_STRING_BASED, FALSE);
-  _assert_comparison(filterx_string_new("3", 1), filterx_double_new(3.0), FCMPX_NE | FCMPX_STRING_BASED, FALSE);
+  _assert_comparison(filterx_string_new("3.0", 3), filterx_double_new(3.0), FCMPX_EQ | FCMPX_STRING_BASED, TRUE);
+  _assert_comparison(filterx_string_new("3.0", 3), filterx_double_new(3.0), FCMPX_LT | FCMPX_STRING_BASED, FALSE);
+  _assert_comparison(filterx_string_new("3.0", 3), filterx_double_new(3.0), FCMPX_GT | FCMPX_STRING_BASED, FALSE);
+  _assert_comparison(filterx_string_new("3.0", 3), filterx_double_new(3.0), FCMPX_NE | FCMPX_STRING_BASED, FALSE);
 
   _assert_comparison(filterx_string_new("3", 1), filterx_double_new(3.1), FCMPX_EQ | FCMPX_STRING_BASED, FALSE);
   _assert_comparison(filterx_string_new("3", 1), filterx_double_new(3.1), FCMPX_LT | FCMPX_STRING_BASED,

lib/filterx/tests/test_object_double.c

@@ -155,9 +155,9 @@ Test(filterx_double, test_filterx_double_repr)
   GString *repr = scratch_buffers_alloc();
   g_string_assign(repr, "foo");
   cr_assert(filterx_object_repr(obj, repr));
-  cr_assert_str_eq("123.456", repr->str);
+  cr_assert_str_eq(repr->str, "123.456");
   cr_assert(filterx_object_repr_append(obj, repr));
-  cr_assert_str_eq("123.456123.456", repr->str);
+  cr_assert_str_eq(repr->str, "123.456123.456");
   filterx_object_unref(obj);
 }
 

lib/filterx/tests/test_object_primitive.c

@@ -28,10 +28,37 @@
 #include "filterx/object-message-value.h"
 #include "apphook.h"
 
-Test(filterx_object, test_filterx_object_construction_and_free)
+static void
+_assert_repr_equals(FilterXObject *fobj, const gchar *expected)
+{
+  GString *repr = g_string_sized_new(0);
+  filterx_object_repr(fobj, repr);
+  cr_assert_str_eq(repr->str, expected);
+  g_string_free(repr, TRUE);
+}
+
+Test(filterx_object, test_filterx_double_should_always_have_fraction_part)
+{
+  FilterXObject *fobj = filterx_double_new(4.0);
+  _assert_repr_equals(fobj, "4.0");
+  filterx_object_unref(fobj);
+}
+
+Test(filterx_object, test_filterx_double_trailing_zeroes_are_removed)
 {
-  FilterXObject *fobj = filterx_object_new(&FILTERX_TYPE_NAME(object));
+  /* we produce enough granularity when needed but do not produce trailing
+   * zeroes */
+
+  FilterXObject *fobj = filterx_double_new(4.1);
+  _assert_repr_equals(fobj, "4.0999999999999996");
+  filterx_object_unref(fobj);
+
+  fobj = filterx_double_new(4.2);
+  _assert_repr_equals(fobj, "4.2000000000000002");
+  filterx_object_unref(fobj);
 
+  fobj = filterx_double_new(4.5);
+  _assert_repr_equals(fobj, "4.5");
   filterx_object_unref(fobj);
 }