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42 lines
1.1 KiB
42 lines
1.1 KiB
export default function parse(input) { |
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input = input.toUpperCase(); |
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var splitIndex = input.indexOf("P"); |
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var mantissa, exponent; |
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if (splitIndex !== -1) { |
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mantissa = input.substring(0, splitIndex); |
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exponent = parseInt(input.substring(splitIndex + 1)); |
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} else { |
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mantissa = input; |
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exponent = 0; |
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} |
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var dotIndex = mantissa.indexOf("."); |
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if (dotIndex !== -1) { |
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var integerPart = parseInt(mantissa.substring(0, dotIndex), 16); |
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var sign = Math.sign(integerPart); |
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integerPart = sign * integerPart; |
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var fractionLength = mantissa.length - dotIndex - 1; |
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var fractionalPart = parseInt(mantissa.substring(dotIndex + 1), 16); |
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var fraction = fractionLength > 0 ? fractionalPart / Math.pow(16, fractionLength) : 0; |
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if (sign === 0) { |
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if (fraction === 0) { |
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mantissa = sign; |
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} else { |
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if (Object.is(sign, -0)) { |
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mantissa = -fraction; |
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} else { |
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mantissa = fraction; |
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} |
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} |
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} else { |
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mantissa = sign * (integerPart + fraction); |
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} |
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} else { |
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mantissa = parseInt(mantissa, 16); |
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} |
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return mantissa * (splitIndex !== -1 ? Math.pow(2, exponent) : 1); |
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} |