Added comparisons between JsonVariants

src/ArduinoJson/Numbers/arithmeticCompare.hpp

@@ -0,0 +1,121 @@
+// ArduinoJson - arduinojson.org
+// Copyright Benoit Blanchon 2014-2020
+// MIT License
+
+#pragma once
+
+#include <ArduinoJson/Numbers/Integer.hpp>
+#include <ArduinoJson/Polyfills/type_traits.hpp>
+
+namespace ARDUINOJSON_NAMESPACE {
+
+enum CompareResult {
+  COMPARE_RESULT_DIFFER = 0,
+  COMPARE_RESULT_EQUAL = 1,
+  COMPARE_RESULT_GREATER = 2,
+  COMPARE_RESULT_LESS = 4,
+
+  COMPARE_RESULT_GREATER_OR_EQUAL = 3,
+  COMPARE_RESULT_LESS_OR_EQUAL = 5
+};
+
+template <typename T>
+CompareResult arithmeticCompare(const T &lhs, const T &rhs) {
+  if (lhs < rhs)
+    return COMPARE_RESULT_LESS;
+  else if (lhs > rhs)
+    return COMPARE_RESULT_GREATER;
+  else
+    return COMPARE_RESULT_EQUAL;
+}
+
+template <typename T1, typename T2>
+CompareResult arithmeticCompare(
+    const T1 &lhs, const T2 &rhs,
+    typename enable_if<is_integral<T1>::value && is_integral<T2>::value &&
+                           sizeof(T1) < sizeof(T2),
+                       int  // Using int instead of void to avoid C2572 on
+                            // Visual Studio 2012, 2013, and 2015
+                       >::type * = 0) {
+  return arithmeticCompare<T2>(static_cast<T2>(lhs), rhs);
+}
+
+template <typename T1, typename T2>
+CompareResult arithmeticCompare(
+    const T1 &lhs, const T2 &rhs,
+    typename enable_if<is_integral<T1>::value && is_integral<T2>::value &&
+                       sizeof(T2) < sizeof(T1)>::type * = 0) {
+  return arithmeticCompare<T1>(lhs, static_cast<T1>(rhs));
+}
+
+template <typename T1, typename T2>
+CompareResult arithmeticCompare(
+    const T1 &lhs, const T2 &rhs,
+    typename enable_if<is_integral<T1>::value && is_integral<T2>::value &&
+                       is_signed<T1>::value == is_signed<T2>::value &&
+                       sizeof(T2) == sizeof(T1)>::type * = 0) {
+  return arithmeticCompare<T1>(lhs, static_cast<T1>(rhs));
+}
+
+template <typename T1, typename T2>
+CompareResult arithmeticCompare(
+    const T1 &lhs, const T2 &rhs,
+    typename enable_if<is_integral<T1>::value && is_integral<T2>::value &&
+                       is_unsigned<T1>::value && is_signed<T2>::value &&
+                       sizeof(T2) == sizeof(T1)>::type * = 0) {
+  if (rhs < 0)
+    return COMPARE_RESULT_GREATER;
+  return arithmeticCompare<T1>(lhs, static_cast<T1>(rhs));
+}
+
+template <typename T1, typename T2>
+CompareResult arithmeticCompare(
+    const T1 &lhs, const T2 &rhs,
+    typename enable_if<is_integral<T1>::value && is_integral<T2>::value &&
+                       is_signed<T1>::value && is_unsigned<T2>::value &&
+                       sizeof(T2) == sizeof(T1)>::type * = 0) {
+  if (lhs < 0)
+    return COMPARE_RESULT_LESS;
+  return arithmeticCompare<T2>(static_cast<T2>(lhs), rhs);
+}
+
+template <typename T1, typename T2>
+CompareResult arithmeticCompare(
+    const T1 &lhs, const T2 &rhs,
+    typename enable_if<is_floating_point<T1>::value ||
+                       is_floating_point<T2>::value>::type * = 0) {
+  return arithmeticCompare<double>(static_cast<double>(lhs),
+                                   static_cast<double>(rhs));
+}
+
+template <typename T2>
+CompareResult arithmeticCompareNegateLeft(
+    UInt, const T2 &, typename enable_if<is_unsigned<T2>::value>::type * = 0) {
+  return COMPARE_RESULT_LESS;
+}
+
+template <typename T2>
+CompareResult arithmeticCompareNegateLeft(
+    UInt lhs, const T2 &rhs,
+    typename enable_if<is_signed<T2>::value>::type * = 0) {
+  if (rhs > 0)
+    return COMPARE_RESULT_LESS;
+  return arithmeticCompare(-rhs, static_cast<T2>(lhs));
+}
+
+template <typename T1>
+CompareResult arithmeticCompareNegateRight(
+    const T1 &, UInt, typename enable_if<is_unsigned<T1>::value>::type * = 0) {
+  return COMPARE_RESULT_GREATER;
+}
+
+template <typename T1>
+CompareResult arithmeticCompareNegateRight(
+    const T1 &lhs, UInt rhs,
+    typename enable_if<is_signed<T1>::value>::type * = 0) {
+  if (lhs > 0)
+    return COMPARE_RESULT_GREATER;
+  return arithmeticCompare(static_cast<T1>(rhs), -lhs);
+}
+
+}  // namespace ARDUINOJSON_NAMESPACE