mirror of
https://github.com/eledio-devices/thirdparty-ArduinoJson.git
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90 lines
1.9 KiB
C++
90 lines
1.9 KiB
C++
// Copyright Benoit Blanchon 2014-2017
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// MIT License
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//
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// Arduino JSON library
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// https://bblanchon.github.io/ArduinoJson/
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// If you like this project, please add a star!
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#pragma once
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#include "../TypeTraits/FloatTraits.hpp"
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#include "./ctype.hpp"
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#include "./math.hpp"
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namespace ArduinoJson {
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namespace Polyfills {
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template <typename T>
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inline T parseFloat(const char* s) {
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typedef TypeTraits::FloatTraits<T> traits;
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typedef typename traits::mantissa_type mantissa_t;
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typedef typename traits::exponent_type exponent_t;
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if (!s) return 0;
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bool negative_result = false;
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switch (*s) {
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case '-':
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negative_result = true;
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case '+':
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s++;
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}
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if (*s == 'n' || *s == 'N') return traits::nan();
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if (*s == 'i' || *s == 'I')
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return negative_result ? -traits::inf() : traits::inf();
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mantissa_t mantissa = 0;
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exponent_t exponent_offset = 0;
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while (isdigit(*s)) {
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if (mantissa < traits::mantissa_max / 10)
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mantissa = mantissa * 10 + (*s - '0');
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else
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exponent_offset++;
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s++;
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}
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if (*s == '.') {
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s++;
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while (isdigit(*s)) {
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if (mantissa < traits::mantissa_max / 10) {
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mantissa = mantissa * 10 + (*s - '0');
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exponent_offset--;
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}
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s++;
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}
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}
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int exponent = 0;
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if (*s == 'e' || *s == 'E') {
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s++;
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bool negative_exponent = false;
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if (*s == '-') {
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negative_exponent = true;
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s++;
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} else if (*s == '+') {
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s++;
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}
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while (isdigit(*s)) {
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exponent = exponent * 10 + (*s - '0');
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if (exponent + exponent_offset > traits::exponent_max) {
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if (negative_exponent)
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return negative_result ? -0.0f : 0.0f;
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else
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return negative_result ? -traits::inf() : traits::inf();
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}
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s++;
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}
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if (negative_exponent) exponent = -exponent;
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}
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exponent += exponent_offset;
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T result = traits::make_float(static_cast<T>(mantissa), exponent);
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return negative_result ? -result : result;
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}
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}
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}
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