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Diffstat (limited to 'include/lib/ArduinoJson/Serialization/FloatParts.hpp')
-rw-r--r-- | include/lib/ArduinoJson/Serialization/FloatParts.hpp | 89 |
1 files changed, 89 insertions, 0 deletions
diff --git a/include/lib/ArduinoJson/Serialization/FloatParts.hpp b/include/lib/ArduinoJson/Serialization/FloatParts.hpp new file mode 100644 index 0000000..c14e3b5 --- /dev/null +++ b/include/lib/ArduinoJson/Serialization/FloatParts.hpp @@ -0,0 +1,89 @@ +// ArduinoJson - arduinojson.org +// Copyright Benoit Blanchon 2014-2018 +// MIT License + +#pragma once + +#include "../Configuration.hpp" +#include "../Polyfills/math.hpp" +#include "../TypeTraits/FloatTraits.hpp" + +namespace ArduinoJson { +namespace Internals { + +template <typename TFloat> +struct FloatParts { + uint32_t integral; + uint32_t decimal; + int16_t exponent; + int8_t decimalPlaces; + + FloatParts(TFloat value) { + uint32_t maxDecimalPart = sizeof(TFloat) >= 8 ? 1000000000 : 1000000; + decimalPlaces = sizeof(TFloat) >= 8 ? 9 : 6; + + exponent = normalize(value); + + integral = uint32_t(value); + // reduce number of decimal places by the number of integral places + for (uint32_t tmp = integral; tmp >= 10; tmp /= 10) { + maxDecimalPart /= 10; + decimalPlaces--; + } + + TFloat remainder = (value - TFloat(integral)) * TFloat(maxDecimalPart); + + decimal = uint32_t(remainder); + remainder = remainder - TFloat(decimal); + + // rounding: + // increment by 1 if remainder >= 0.5 + decimal += uint32_t(remainder * 2); + if (decimal >= maxDecimalPart) { + decimal = 0; + integral++; + if (exponent && integral >= 10) { + exponent++; + integral = 1; + } + } + + // remove trailing zeros + while (decimal % 10 == 0 && decimalPlaces > 0) { + decimal /= 10; + decimalPlaces--; + } + } + + static int16_t normalize(TFloat& value) { + typedef FloatTraits<TFloat> traits; + int16_t powersOf10 = 0; + + int8_t index = sizeof(TFloat) == 8 ? 8 : 5; + int bit = 1 << index; + + if (value >= ARDUINOJSON_POSITIVE_EXPONENTIATION_THRESHOLD) { + for (; index >= 0; index--) { + if (value >= traits::positiveBinaryPowerOfTen(index)) { + value *= traits::negativeBinaryPowerOfTen(index); + powersOf10 = int16_t(powersOf10 + bit); + } + bit >>= 1; + } + } + + if (value > 0 && value <= ARDUINOJSON_NEGATIVE_EXPONENTIATION_THRESHOLD) { + for (; index >= 0; index--) { + if (value < traits::negativeBinaryPowerOfTenPlusOne(index)) { + value *= traits::positiveBinaryPowerOfTen(index); + powersOf10 = int16_t(powersOf10 - bit); + } + bit >>= 1; + } + } + + return powersOf10; + } +}; +} +} |