135 lines
5.6 KiB
C++
135 lines
5.6 KiB
C++
/*
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* Copyright (C) 2003-2019 Apple Inc. All rights reserved.
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*
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* This library is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Library General Public
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* License as published by the Free Software Foundation; either
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* version 2 of the License, or (at your option) any later version.
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*
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* This library is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Library General Public License for more details.
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*
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* You should have received a copy of the GNU Library General Public License
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* along with this library; see the file COPYING.LIB. If not, write to
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* the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
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* Boston, MA 02110-1301, USA.
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*
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*/
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#include "config.h"
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#include <wtf/dtoa.h>
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namespace WTF {
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const char* numberToString(float number, NumberToStringBuffer& buffer)
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{
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double_conversion::StringBuilder builder(&buffer[0], sizeof(buffer));
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double_conversion::DoubleToStringConverter::EcmaScriptConverter().ToShortestSingle(number, &builder);
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return builder.Finalize();
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}
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const char* numberToString(double d, NumberToStringBuffer& buffer)
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{
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double_conversion::StringBuilder builder(&buffer[0], sizeof(buffer));
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auto& converter = double_conversion::DoubleToStringConverter::EcmaScriptConverter();
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converter.ToShortest(d, &builder);
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return builder.Finalize();
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}
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static inline void truncateTrailingZeros(NumberToStringBuffer& buffer, double_conversion::StringBuilder& builder)
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{
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size_t length = builder.position();
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size_t decimalPointPosition = 0;
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for (; decimalPointPosition < length; ++decimalPointPosition) {
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if (buffer[decimalPointPosition] == '.')
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break;
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}
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// No decimal separator found, early exit.
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if (decimalPointPosition == length)
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return;
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size_t pastMantissa = decimalPointPosition + 1;
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for (; pastMantissa < length; ++pastMantissa) {
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if (buffer[pastMantissa] == 'e')
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break;
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}
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size_t truncatedLength = pastMantissa;
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for (; truncatedLength > decimalPointPosition + 1; --truncatedLength) {
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if (buffer[truncatedLength - 1] != '0')
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break;
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}
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// No trailing zeros found to strip.
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if (truncatedLength == pastMantissa)
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return;
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// If we removed all trailing zeros, remove the decimal point as well.
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if (truncatedLength == decimalPointPosition + 1)
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truncatedLength = decimalPointPosition;
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// Truncate the mantissa, and return the final result.
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builder.RemoveCharacters(truncatedLength, pastMantissa);
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}
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const char* numberToFixedPrecisionString(float number, unsigned significantFigures, NumberToStringBuffer& buffer, bool shouldTruncateTrailingZeros)
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{
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// For now, just call the double precision version.
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// Do that here instead of at callers to pave the way to add a more efficient code path later.
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return numberToFixedPrecisionString(static_cast<double>(number), significantFigures, buffer, shouldTruncateTrailingZeros);
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}
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const char* numberToFixedPrecisionString(double d, unsigned significantFigures, NumberToStringBuffer& buffer, bool shouldTruncateTrailingZeros)
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{
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// Mimic sprintf("%.[precision]g", ...).
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// "g": Signed value printed in f or e format, whichever is more compact for the given value and precision.
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// The e format is used only when the exponent of the value is less than –4 or greater than or equal to the
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// precision argument. Trailing zeros are truncated, and the decimal point appears only if one or more digits follow it.
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// "precision": The precision specifies the maximum number of significant digits printed.
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double_conversion::StringBuilder builder(&buffer[0], sizeof(buffer));
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auto& converter = double_conversion::DoubleToStringConverter::EcmaScriptConverter();
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converter.ToPrecision(d, significantFigures, &builder);
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if (shouldTruncateTrailingZeros)
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truncateTrailingZeros(buffer, builder);
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return builder.Finalize();
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}
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const char* numberToFixedWidthString(float number, unsigned decimalPlaces, NumberToStringBuffer& buffer)
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{
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// For now, just call the double precision version.
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// Do that here instead of at callers to pave the way to add a more efficient code path later.
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return numberToFixedWidthString(static_cast<double>(number), decimalPlaces, buffer);
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}
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const char* numberToFixedWidthString(double d, unsigned decimalPlaces, NumberToStringBuffer& buffer)
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{
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// Mimic sprintf("%.[precision]f", ...).
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// "f": Signed value having the form [ – ]dddd.dddd, where dddd is one or more decimal digits.
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// The number of digits before the decimal point depends on the magnitude of the number, and
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// the number of digits after the decimal point depends on the requested precision.
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// "precision": The precision value specifies the number of digits after the decimal point.
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// If a decimal point appears, at least one digit appears before it.
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// The value is rounded to the appropriate number of digits.
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double_conversion::StringBuilder builder(&buffer[0], sizeof(buffer));
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auto& converter = double_conversion::DoubleToStringConverter::EcmaScriptConverter();
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converter.ToFixed(d, decimalPlaces, &builder);
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return builder.Finalize();
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}
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namespace Internal {
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double parseDoubleFromLongString(const UChar* string, size_t length, size_t& parsedLength)
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{
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Vector<LChar> conversionBuffer(length);
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for (size_t i = 0; i < length; ++i)
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conversionBuffer[i] = isASCII(string[i]) ? string[i] : 0;
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return parseDouble(conversionBuffer.data(), length, parsedLength);
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}
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} // namespace Internal
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} // namespace WTF
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