463 lines
16 KiB
C++
463 lines
16 KiB
C++
// © 2018 and later: Unicode, Inc. and others.
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// License & terms of use: http://www.unicode.org/copyright.html
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//
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// From the double-conversion library. Original license:
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//
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// Copyright 2010 the V8 project authors. All rights reserved.
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// Redistribution and use in source and binary forms, with or without
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// modification, are permitted provided that the following conditions are
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// met:
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//
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// * Redistributions of source code must retain the above copyright
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// notice, this list of conditions and the following disclaimer.
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// * Redistributions in binary form must reproduce the above
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// copyright notice, this list of conditions and the following
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// disclaimer in the documentation and/or other materials provided
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// with the distribution.
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// * Neither the name of Google Inc. nor the names of its
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// contributors may be used to endorse or promote products derived
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// from this software without specific prior written permission.
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//
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// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
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// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
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// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
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// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
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// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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// ICU PATCH: ifdef around UCONFIG_NO_FORMATTING
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#include "unicode/utypes.h"
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#if !UCONFIG_NO_FORMATTING
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#include <algorithm>
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#include <climits>
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#include <cmath>
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// ICU PATCH: Customize header file paths for ICU.
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// The file fixed-dtoa.h is not needed.
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#include "double-conversion-double-to-string.h"
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#include "double-conversion-bignum-dtoa.h"
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#include "double-conversion-fast-dtoa.h"
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#include "double-conversion-ieee.h"
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#include "double-conversion-utils.h"
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// ICU PATCH: Wrap in ICU namespace
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U_NAMESPACE_BEGIN
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namespace double_conversion {
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#if 0 // not needed for ICU
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const DoubleToStringConverter& DoubleToStringConverter::EcmaScriptConverter() {
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int flags = UNIQUE_ZERO | EMIT_POSITIVE_EXPONENT_SIGN;
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static DoubleToStringConverter converter(flags,
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"Infinity",
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"NaN",
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'e',
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-6, 21,
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6, 0);
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return converter;
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}
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bool DoubleToStringConverter::HandleSpecialValues(
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double value,
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StringBuilder* result_builder) const {
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Double double_inspect(value);
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if (double_inspect.IsInfinite()) {
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if (infinity_symbol_ == NULL) return false;
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if (value < 0) {
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result_builder->AddCharacter('-');
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}
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result_builder->AddString(infinity_symbol_);
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return true;
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}
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if (double_inspect.IsNan()) {
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if (nan_symbol_ == NULL) return false;
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result_builder->AddString(nan_symbol_);
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return true;
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}
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return false;
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}
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void DoubleToStringConverter::CreateExponentialRepresentation(
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const char* decimal_digits,
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int length,
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int exponent,
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StringBuilder* result_builder) const {
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DOUBLE_CONVERSION_ASSERT(length != 0);
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result_builder->AddCharacter(decimal_digits[0]);
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if (length != 1) {
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result_builder->AddCharacter('.');
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result_builder->AddSubstring(&decimal_digits[1], length-1);
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}
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result_builder->AddCharacter(exponent_character_);
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if (exponent < 0) {
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result_builder->AddCharacter('-');
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exponent = -exponent;
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} else {
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if ((flags_ & EMIT_POSITIVE_EXPONENT_SIGN) != 0) {
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result_builder->AddCharacter('+');
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}
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}
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DOUBLE_CONVERSION_ASSERT(exponent < 1e4);
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// Changing this constant requires updating the comment of DoubleToStringConverter constructor
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const int kMaxExponentLength = 5;
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char buffer[kMaxExponentLength + 1];
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buffer[kMaxExponentLength] = '\0';
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int first_char_pos = kMaxExponentLength;
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if (exponent == 0) {
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buffer[--first_char_pos] = '0';
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} else {
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while (exponent > 0) {
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buffer[--first_char_pos] = '0' + (exponent % 10);
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exponent /= 10;
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}
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}
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// Add prefix '0' to make exponent width >= min(min_exponent_with_, kMaxExponentLength)
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// For example: convert 1e+9 -> 1e+09, if min_exponent_with_ is set to 2
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while(kMaxExponentLength - first_char_pos < std::min(min_exponent_width_, kMaxExponentLength)) {
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buffer[--first_char_pos] = '0';
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}
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result_builder->AddSubstring(&buffer[first_char_pos],
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kMaxExponentLength - first_char_pos);
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}
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void DoubleToStringConverter::CreateDecimalRepresentation(
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const char* decimal_digits,
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int length,
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int decimal_point,
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int digits_after_point,
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StringBuilder* result_builder) const {
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// Create a representation that is padded with zeros if needed.
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if (decimal_point <= 0) {
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// "0.00000decimal_rep" or "0.000decimal_rep00".
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result_builder->AddCharacter('0');
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if (digits_after_point > 0) {
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result_builder->AddCharacter('.');
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result_builder->AddPadding('0', -decimal_point);
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DOUBLE_CONVERSION_ASSERT(length <= digits_after_point - (-decimal_point));
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result_builder->AddSubstring(decimal_digits, length);
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int remaining_digits = digits_after_point - (-decimal_point) - length;
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result_builder->AddPadding('0', remaining_digits);
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}
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} else if (decimal_point >= length) {
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// "decimal_rep0000.00000" or "decimal_rep.0000".
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result_builder->AddSubstring(decimal_digits, length);
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result_builder->AddPadding('0', decimal_point - length);
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if (digits_after_point > 0) {
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result_builder->AddCharacter('.');
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result_builder->AddPadding('0', digits_after_point);
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}
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} else {
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// "decima.l_rep000".
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DOUBLE_CONVERSION_ASSERT(digits_after_point > 0);
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result_builder->AddSubstring(decimal_digits, decimal_point);
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result_builder->AddCharacter('.');
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DOUBLE_CONVERSION_ASSERT(length - decimal_point <= digits_after_point);
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result_builder->AddSubstring(&decimal_digits[decimal_point],
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length - decimal_point);
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int remaining_digits = digits_after_point - (length - decimal_point);
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result_builder->AddPadding('0', remaining_digits);
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}
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if (digits_after_point == 0) {
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if ((flags_ & EMIT_TRAILING_DECIMAL_POINT) != 0) {
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result_builder->AddCharacter('.');
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}
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if ((flags_ & EMIT_TRAILING_ZERO_AFTER_POINT) != 0) {
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result_builder->AddCharacter('0');
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}
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}
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}
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bool DoubleToStringConverter::ToShortestIeeeNumber(
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double value,
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StringBuilder* result_builder,
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DoubleToStringConverter::DtoaMode mode) const {
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DOUBLE_CONVERSION_ASSERT(mode == SHORTEST || mode == SHORTEST_SINGLE);
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if (Double(value).IsSpecial()) {
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return HandleSpecialValues(value, result_builder);
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}
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int decimal_point;
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bool sign;
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const int kDecimalRepCapacity = kBase10MaximalLength + 1;
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char decimal_rep[kDecimalRepCapacity];
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int decimal_rep_length;
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DoubleToAscii(value, mode, 0, decimal_rep, kDecimalRepCapacity,
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&sign, &decimal_rep_length, &decimal_point);
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bool unique_zero = (flags_ & UNIQUE_ZERO) != 0;
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if (sign && (value != 0.0 || !unique_zero)) {
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result_builder->AddCharacter('-');
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}
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int exponent = decimal_point - 1;
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if ((decimal_in_shortest_low_ <= exponent) &&
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(exponent < decimal_in_shortest_high_)) {
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CreateDecimalRepresentation(decimal_rep, decimal_rep_length,
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decimal_point,
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(std::max)(0, decimal_rep_length - decimal_point),
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result_builder);
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} else {
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CreateExponentialRepresentation(decimal_rep, decimal_rep_length, exponent,
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result_builder);
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}
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return true;
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}
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bool DoubleToStringConverter::ToFixed(double value,
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int requested_digits,
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StringBuilder* result_builder) const {
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DOUBLE_CONVERSION_ASSERT(kMaxFixedDigitsBeforePoint == 60);
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const double kFirstNonFixed = 1e60;
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if (Double(value).IsSpecial()) {
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return HandleSpecialValues(value, result_builder);
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}
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if (requested_digits > kMaxFixedDigitsAfterPoint) return false;
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if (value >= kFirstNonFixed || value <= -kFirstNonFixed) return false;
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// Find a sufficiently precise decimal representation of n.
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int decimal_point;
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bool sign;
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// Add space for the '\0' byte.
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const int kDecimalRepCapacity =
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kMaxFixedDigitsBeforePoint + kMaxFixedDigitsAfterPoint + 1;
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char decimal_rep[kDecimalRepCapacity];
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int decimal_rep_length;
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DoubleToAscii(value, FIXED, requested_digits,
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decimal_rep, kDecimalRepCapacity,
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&sign, &decimal_rep_length, &decimal_point);
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bool unique_zero = ((flags_ & UNIQUE_ZERO) != 0);
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if (sign && (value != 0.0 || !unique_zero)) {
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result_builder->AddCharacter('-');
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}
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CreateDecimalRepresentation(decimal_rep, decimal_rep_length, decimal_point,
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requested_digits, result_builder);
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return true;
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}
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bool DoubleToStringConverter::ToExponential(
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double value,
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int requested_digits,
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StringBuilder* result_builder) const {
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if (Double(value).IsSpecial()) {
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return HandleSpecialValues(value, result_builder);
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}
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if (requested_digits < -1) return false;
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if (requested_digits > kMaxExponentialDigits) return false;
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int decimal_point;
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bool sign;
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// Add space for digit before the decimal point and the '\0' character.
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const int kDecimalRepCapacity = kMaxExponentialDigits + 2;
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DOUBLE_CONVERSION_ASSERT(kDecimalRepCapacity > kBase10MaximalLength);
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char decimal_rep[kDecimalRepCapacity];
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#ifndef NDEBUG
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// Problem: there is an assert in StringBuilder::AddSubstring() that
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// will pass this buffer to strlen(), and this buffer is not generally
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// null-terminated.
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memset(decimal_rep, 0, sizeof(decimal_rep));
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#endif
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int decimal_rep_length;
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if (requested_digits == -1) {
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DoubleToAscii(value, SHORTEST, 0,
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decimal_rep, kDecimalRepCapacity,
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&sign, &decimal_rep_length, &decimal_point);
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} else {
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DoubleToAscii(value, PRECISION, requested_digits + 1,
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decimal_rep, kDecimalRepCapacity,
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&sign, &decimal_rep_length, &decimal_point);
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DOUBLE_CONVERSION_ASSERT(decimal_rep_length <= requested_digits + 1);
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for (int i = decimal_rep_length; i < requested_digits + 1; ++i) {
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decimal_rep[i] = '0';
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}
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decimal_rep_length = requested_digits + 1;
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}
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bool unique_zero = ((flags_ & UNIQUE_ZERO) != 0);
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if (sign && (value != 0.0 || !unique_zero)) {
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result_builder->AddCharacter('-');
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}
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int exponent = decimal_point - 1;
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CreateExponentialRepresentation(decimal_rep,
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decimal_rep_length,
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exponent,
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result_builder);
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return true;
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}
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bool DoubleToStringConverter::ToPrecision(double value,
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int precision,
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StringBuilder* result_builder) const {
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if (Double(value).IsSpecial()) {
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return HandleSpecialValues(value, result_builder);
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}
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if (precision < kMinPrecisionDigits || precision > kMaxPrecisionDigits) {
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return false;
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}
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// Find a sufficiently precise decimal representation of n.
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int decimal_point;
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bool sign;
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// Add one for the terminating null character.
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const int kDecimalRepCapacity = kMaxPrecisionDigits + 1;
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char decimal_rep[kDecimalRepCapacity];
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int decimal_rep_length;
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DoubleToAscii(value, PRECISION, precision,
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decimal_rep, kDecimalRepCapacity,
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&sign, &decimal_rep_length, &decimal_point);
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DOUBLE_CONVERSION_ASSERT(decimal_rep_length <= precision);
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bool unique_zero = ((flags_ & UNIQUE_ZERO) != 0);
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if (sign && (value != 0.0 || !unique_zero)) {
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result_builder->AddCharacter('-');
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}
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// The exponent if we print the number as x.xxeyyy. That is with the
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// decimal point after the first digit.
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int exponent = decimal_point - 1;
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int extra_zero = ((flags_ & EMIT_TRAILING_ZERO_AFTER_POINT) != 0) ? 1 : 0;
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bool as_exponential =
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(-decimal_point + 1 > max_leading_padding_zeroes_in_precision_mode_) ||
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(decimal_point - precision + extra_zero >
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max_trailing_padding_zeroes_in_precision_mode_);
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if ((flags_ & NO_TRAILING_ZERO) != 0) {
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// Truncate trailing zeros that occur after the decimal point (if exponential,
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// that is everything after the first digit).
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int stop = as_exponential ? 1 : std::max(1, decimal_point);
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while (decimal_rep_length > stop && decimal_rep[decimal_rep_length - 1] == '0') {
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--decimal_rep_length;
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}
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// Clamp precision to avoid the code below re-adding the zeros.
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precision = std::min(precision, decimal_rep_length);
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}
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if (as_exponential) {
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// Fill buffer to contain 'precision' digits.
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// Usually the buffer is already at the correct length, but 'DoubleToAscii'
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// is allowed to return less characters.
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for (int i = decimal_rep_length; i < precision; ++i) {
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decimal_rep[i] = '0';
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}
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CreateExponentialRepresentation(decimal_rep,
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precision,
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exponent,
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result_builder);
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} else {
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CreateDecimalRepresentation(decimal_rep, decimal_rep_length, decimal_point,
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(std::max)(0, precision - decimal_point),
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result_builder);
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}
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return true;
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}
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#endif // not needed for ICU
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static BignumDtoaMode DtoaToBignumDtoaMode(
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DoubleToStringConverter::DtoaMode dtoa_mode) {
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switch (dtoa_mode) {
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case DoubleToStringConverter::SHORTEST: return BIGNUM_DTOA_SHORTEST;
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case DoubleToStringConverter::SHORTEST_SINGLE:
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return BIGNUM_DTOA_SHORTEST_SINGLE;
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case DoubleToStringConverter::FIXED: return BIGNUM_DTOA_FIXED;
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case DoubleToStringConverter::PRECISION: return BIGNUM_DTOA_PRECISION;
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default:
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DOUBLE_CONVERSION_UNREACHABLE();
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}
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}
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void DoubleToStringConverter::DoubleToAscii(double v,
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DtoaMode mode,
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int requested_digits,
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char* buffer,
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int buffer_length,
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bool* sign,
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int* length,
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int* point) {
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Vector<char> vector(buffer, buffer_length);
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DOUBLE_CONVERSION_ASSERT(!Double(v).IsSpecial());
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DOUBLE_CONVERSION_ASSERT(mode == SHORTEST || mode == SHORTEST_SINGLE || requested_digits >= 0);
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if (Double(v).Sign() < 0) {
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*sign = true;
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v = -v;
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} else {
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*sign = false;
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}
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if (mode == PRECISION && requested_digits == 0) {
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vector[0] = '\0';
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*length = 0;
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return;
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}
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if (v == 0) {
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vector[0] = '0';
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vector[1] = '\0';
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*length = 1;
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*point = 1;
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return;
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}
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bool fast_worked;
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switch (mode) {
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case SHORTEST:
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fast_worked = FastDtoa(v, FAST_DTOA_SHORTEST, 0, vector, length, point);
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break;
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#if 0 // not needed for ICU
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case SHORTEST_SINGLE:
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fast_worked = FastDtoa(v, FAST_DTOA_SHORTEST_SINGLE, 0,
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vector, length, point);
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break;
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case FIXED:
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fast_worked = FastFixedDtoa(v, requested_digits, vector, length, point);
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break;
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case PRECISION:
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fast_worked = FastDtoa(v, FAST_DTOA_PRECISION, requested_digits,
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vector, length, point);
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break;
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#endif // not needed for ICU
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default:
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fast_worked = false;
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DOUBLE_CONVERSION_UNREACHABLE();
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}
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if (fast_worked) return;
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// If the fast dtoa didn't succeed use the slower bignum version.
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BignumDtoaMode bignum_mode = DtoaToBignumDtoaMode(mode);
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BignumDtoa(v, bignum_mode, requested_digits, vector, length, point);
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vector[*length] = '\0';
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}
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} // namespace double_conversion
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// ICU PATCH: Close ICU namespace
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U_NAMESPACE_END
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#endif // ICU PATCH: close #if !UCONFIG_NO_FORMATTING
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