Added custom implementation of strtod() (issue #453)

include/ArduinoJson/Polyfills/isFloat.hpp

@@ -0,0 +1,40 @@
+// Copyright Benoit Blanchon 2014-2017
+// MIT License
+//
+// Arduino JSON library
+// https://github.com/bblanchon/ArduinoJson
+// If you like this project, please add a star!
+
+#pragma once
+
+#include "./ctype.hpp"
+#include "./math.hpp"
+
+namespace ArduinoJson {
+namespace Polyfills {
+
+inline bool isFloat(const char* s) {
+  if (!strcmp(s, "NaN")) return true;
+  if (issign(*s)) s++;
+  if (!strcmp(s, "Infinity")) return true;
+
+  while (isdigit(*s)) s++;
+
+  bool has_dot = *s == '.';
+  if (has_dot) {
+    s++;
+    while (isdigit(*s)) s++;
+  }
+
+  bool has_exponent = *s == 'e' || *s == 'E';
+  if (has_exponent) {
+    s++;
+    if (issign(*s)) s++;
+    if (!isdigit(*s)) return false;
+    while (isdigit(*s)) s++;
+  }
+
+  return (has_dot || has_exponent) && *s == '\0';
+}
+}
+}