Diff: src/ArduinoJson/Numbers/parseNumber.hpp

Revision:

0:18ba3960b5dd

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/ArduinoJson/Numbers/parseNumber.hpp	Fri Mar 19 19:30:50 2021 +0000
@@ -0,0 +1,147 @@
+// ArduinoJson - arduinojson.org
+// Copyright Benoit Blanchon 2014-2021
+// MIT License
+
+#pragma once
+
+#include <ArduinoJson/Numbers/FloatTraits.hpp>
+#include <ArduinoJson/Numbers/convertNumber.hpp>
+#include <ArduinoJson/Polyfills/assert.hpp>
+#include <ArduinoJson/Polyfills/ctype.hpp>
+#include <ArduinoJson/Polyfills/math.hpp>
+#include <ArduinoJson/Polyfills/type_traits.hpp>
+#include <ArduinoJson/Variant/VariantAs.hpp>
+#include <ArduinoJson/Variant/VariantData.hpp>
+
+namespace ARDUINOJSON_NAMESPACE {
+
+template <typename A, typename B>
+struct choose_largest : conditional<(sizeof(A) > sizeof(B)), A, B> {};
+
+inline bool parseNumber(const char* s, VariantData& result) {
+  typedef FloatTraits<Float> traits;
+  typedef choose_largest<traits::mantissa_type, UInt>::type mantissa_t;
+  typedef traits::exponent_type exponent_t;
+
+  ARDUINOJSON_ASSERT(s != 0);
+
+  bool is_negative = false;
+  switch (*s) {
+    case '-':
+      is_negative = true;
+      s++;
+      break;
+    case '+':
+      s++;
+      break;
+  }
+
+#if ARDUINOJSON_ENABLE_NAN
+  if (*s == 'n' || *s == 'N') {
+    result.setFloat(traits::nan());
+    return true;
+  }
+#endif
+
+#if ARDUINOJSON_ENABLE_INFINITY
+  if (*s == 'i' || *s == 'I') {
+    result.setFloat(is_negative ? -traits::inf() : traits::inf());
+    return true;
+  }
+#endif
+
+  if (!isdigit(*s) && *s != '.')
+    return false;
+
+  mantissa_t mantissa = 0;
+  exponent_t exponent_offset = 0;
+  const mantissa_t maxUint = UInt(-1);
+
+  while (isdigit(*s)) {
+    uint8_t digit = uint8_t(*s - '0');
+    if (mantissa > maxUint / 10)
+      break;
+    mantissa *= 10;
+    if (mantissa > maxUint - digit)
+      break;
+    mantissa += digit;
+    s++;
+  }
+
+  if (*s == '\0') {
+    if (is_negative)
+      result.setNegativeInteger(UInt(mantissa));
+    else
+      result.setPositiveInteger(UInt(mantissa));
+    return true;
+  }
+
+  // avoid mantissa overflow
+  while (mantissa > traits::mantissa_max) {
+    mantissa /= 10;
+    exponent_offset++;
+  }
+
+  // remaing digits can't fit in the mantissa
+  while (isdigit(*s)) {
+    exponent_offset++;
+    s++;
+  }
+
+  if (*s == '.') {
+    s++;
+    while (isdigit(*s)) {
+      if (mantissa < traits::mantissa_max / 10) {
+        mantissa = mantissa * 10 + uint8_t(*s - '0');
+        exponent_offset--;
+      }
+      s++;
+    }
+  }
+
+  int exponent = 0;
+  if (*s == 'e' || *s == 'E') {
+    s++;
+    bool negative_exponent = false;
+    if (*s == '-') {
+      negative_exponent = true;
+      s++;
+    } else if (*s == '+') {
+      s++;
+    }
+
+    while (isdigit(*s)) {
+      exponent = exponent * 10 + (*s - '0');
+      if (exponent + exponent_offset > traits::exponent_max) {
+        if (negative_exponent)
+          result.setFloat(is_negative ? -0.0f : 0.0f);
+        else
+          result.setFloat(is_negative ? -traits::inf() : traits::inf());
+        return true;
+      }
+      s++;
+    }
+    if (negative_exponent)
+      exponent = -exponent;
+  }
+  exponent += exponent_offset;
+
+  // we should be at the end of the string, otherwise it's an error
+  if (*s != '\0')
+    return false;
+
+  Float final_result =
+      traits::make_float(static_cast<Float>(mantissa), exponent);
+
+  result.setFloat(is_negative ? -final_result : final_result);
+  return true;
+}
+
+template <typename T>
+inline T parseNumber(const char* s) {
+  VariantData value;
+  value.init();  // VariantData is a POD, so it has no constructor
+  parseNumber(s, value);
+  return variantAs<T>(&value);
+}
+}  // namespace ARDUINOJSON_NAMESPACE