537 lines
26 KiB
C
537 lines
26 KiB
C
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// Copyright 2012 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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#ifndef DOUBLE_CONVERSION_DOUBLE_CONVERSION_H_
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#define DOUBLE_CONVERSION_DOUBLE_CONVERSION_H_
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#include "utils.h"
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namespace double_conversion {
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class DoubleToStringConverter {
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public:
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// When calling ToFixed with a double > 10^kMaxFixedDigitsBeforePoint
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// or a requested_digits parameter > kMaxFixedDigitsAfterPoint then the
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// function returns false.
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static const int kMaxFixedDigitsBeforePoint = 60;
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static const int kMaxFixedDigitsAfterPoint = 60;
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// When calling ToExponential with a requested_digits
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// parameter > kMaxExponentialDigits then the function returns false.
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static const int kMaxExponentialDigits = 120;
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// When calling ToPrecision with a requested_digits
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// parameter < kMinPrecisionDigits or requested_digits > kMaxPrecisionDigits
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// then the function returns false.
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static const int kMinPrecisionDigits = 1;
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static const int kMaxPrecisionDigits = 120;
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enum Flags {
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NO_FLAGS = 0,
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EMIT_POSITIVE_EXPONENT_SIGN = 1,
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EMIT_TRAILING_DECIMAL_POINT = 2,
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EMIT_TRAILING_ZERO_AFTER_POINT = 4,
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UNIQUE_ZERO = 8
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};
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// Flags should be a bit-or combination of the possible Flags-enum.
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// - NO_FLAGS: no special flags.
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// - EMIT_POSITIVE_EXPONENT_SIGN: when the number is converted into exponent
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// form, emits a '+' for positive exponents. Example: 1.2e+2.
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// - EMIT_TRAILING_DECIMAL_POINT: when the input number is an integer and is
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// converted into decimal format then a trailing decimal point is appended.
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// Example: 2345.0 is converted to "2345.".
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// - EMIT_TRAILING_ZERO_AFTER_POINT: in addition to a trailing decimal point
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// emits a trailing '0'-character. This flag requires the
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// EXMIT_TRAILING_DECIMAL_POINT flag.
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// Example: 2345.0 is converted to "2345.0".
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// - UNIQUE_ZERO: "-0.0" is converted to "0.0".
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//
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// Infinity symbol and nan_symbol provide the string representation for these
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// special values. If the string is NULL and the special value is encountered
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// then the conversion functions return false.
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//
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// The exponent_character is used in exponential representations. It is
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// usually 'e' or 'E'.
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//
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// When converting to the shortest representation the converter will
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// represent input numbers in decimal format if they are in the interval
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// [10^decimal_in_shortest_low; 10^decimal_in_shortest_high[
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// (lower boundary included, greater boundary excluded).
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// Example: with decimal_in_shortest_low = -6 and
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// decimal_in_shortest_high = 21:
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// ToShortest(0.000001) -> "0.000001"
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// ToShortest(0.0000001) -> "1e-7"
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// ToShortest(111111111111111111111.0) -> "111111111111111110000"
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// ToShortest(100000000000000000000.0) -> "100000000000000000000"
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// ToShortest(1111111111111111111111.0) -> "1.1111111111111111e+21"
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//
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// When converting to precision mode the converter may add
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// max_leading_padding_zeroes before returning the number in exponential
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// format.
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// Example with max_leading_padding_zeroes_in_precision_mode = 6.
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// ToPrecision(0.0000012345, 2) -> "0.0000012"
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// ToPrecision(0.00000012345, 2) -> "1.2e-7"
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// Similarily the converter may add up to
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// max_trailing_padding_zeroes_in_precision_mode in precision mode to avoid
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// returning an exponential representation. A zero added by the
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// EMIT_TRAILING_ZERO_AFTER_POINT flag is counted for this limit.
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// Examples for max_trailing_padding_zeroes_in_precision_mode = 1:
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// ToPrecision(230.0, 2) -> "230"
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// ToPrecision(230.0, 2) -> "230." with EMIT_TRAILING_DECIMAL_POINT.
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// ToPrecision(230.0, 2) -> "2.3e2" with EMIT_TRAILING_ZERO_AFTER_POINT.
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DoubleToStringConverter(int flags,
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const char* infinity_symbol,
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const char* nan_symbol,
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char exponent_character,
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int decimal_in_shortest_low,
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int decimal_in_shortest_high,
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int max_leading_padding_zeroes_in_precision_mode,
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int max_trailing_padding_zeroes_in_precision_mode)
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: flags_(flags),
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infinity_symbol_(infinity_symbol),
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nan_symbol_(nan_symbol),
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exponent_character_(exponent_character),
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decimal_in_shortest_low_(decimal_in_shortest_low),
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decimal_in_shortest_high_(decimal_in_shortest_high),
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max_leading_padding_zeroes_in_precision_mode_(
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max_leading_padding_zeroes_in_precision_mode),
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max_trailing_padding_zeroes_in_precision_mode_(
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max_trailing_padding_zeroes_in_precision_mode) {
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// When 'trailing zero after the point' is set, then 'trailing point'
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// must be set too.
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ASSERT(((flags & EMIT_TRAILING_DECIMAL_POINT) != 0) ||
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!((flags & EMIT_TRAILING_ZERO_AFTER_POINT) != 0));
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}
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// Returns a converter following the EcmaScript specification.
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static const DoubleToStringConverter& EcmaScriptConverter();
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// Computes the shortest string of digits that correctly represent the input
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// number. Depending on decimal_in_shortest_low and decimal_in_shortest_high
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// (see constructor) it then either returns a decimal representation, or an
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// exponential representation.
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// Example with decimal_in_shortest_low = -6,
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// decimal_in_shortest_high = 21,
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// EMIT_POSITIVE_EXPONENT_SIGN activated, and
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// EMIT_TRAILING_DECIMAL_POINT deactived:
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// ToShortest(0.000001) -> "0.000001"
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// ToShortest(0.0000001) -> "1e-7"
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// ToShortest(111111111111111111111.0) -> "111111111111111110000"
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// ToShortest(100000000000000000000.0) -> "100000000000000000000"
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// ToShortest(1111111111111111111111.0) -> "1.1111111111111111e+21"
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//
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// Note: the conversion may round the output if the returned string
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// is accurate enough to uniquely identify the input-number.
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// For example the most precise representation of the double 9e59 equals
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// "899999999999999918767229449717619953810131273674690656206848", but
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// the converter will return the shorter (but still correct) "9e59".
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//
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// Returns true if the conversion succeeds. The conversion always succeeds
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// except when the input value is special and no infinity_symbol or
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// nan_symbol has been given to the constructor.
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bool ToShortest(double value, StringBuilder* result_builder) const {
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return ToShortestIeeeNumber(value, result_builder, SHORTEST);
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}
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// Same as ToShortest, but for single-precision floats.
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bool ToShortestSingle(float value, StringBuilder* result_builder) const {
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return ToShortestIeeeNumber(value, result_builder, SHORTEST_SINGLE);
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}
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// Computes a decimal representation with a fixed number of digits after the
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// decimal point. The last emitted digit is rounded.
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//
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// Examples:
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// ToFixed(3.12, 1) -> "3.1"
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// ToFixed(3.1415, 3) -> "3.142"
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// ToFixed(1234.56789, 4) -> "1234.5679"
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// ToFixed(1.23, 5) -> "1.23000"
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// ToFixed(0.1, 4) -> "0.1000"
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// ToFixed(1e30, 2) -> "1000000000000000019884624838656.00"
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// ToFixed(0.1, 30) -> "0.100000000000000005551115123126"
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// ToFixed(0.1, 17) -> "0.10000000000000001"
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//
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// If requested_digits equals 0, then the tail of the result depends on
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// the EMIT_TRAILING_DECIMAL_POINT and EMIT_TRAILING_ZERO_AFTER_POINT.
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// Examples, for requested_digits == 0,
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// let EMIT_TRAILING_DECIMAL_POINT and EMIT_TRAILING_ZERO_AFTER_POINT be
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// - false and false: then 123.45 -> 123
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// 0.678 -> 1
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// - true and false: then 123.45 -> 123.
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// 0.678 -> 1.
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// - true and true: then 123.45 -> 123.0
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// 0.678 -> 1.0
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//
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// Returns true if the conversion succeeds. The conversion always succeeds
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// except for the following cases:
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// - the input value is special and no infinity_symbol or nan_symbol has
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// been provided to the constructor,
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// - 'value' > 10^kMaxFixedDigitsBeforePoint, or
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// - 'requested_digits' > kMaxFixedDigitsAfterPoint.
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// The last two conditions imply that the result will never contain more than
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// 1 + kMaxFixedDigitsBeforePoint + 1 + kMaxFixedDigitsAfterPoint characters
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// (one additional character for the sign, and one for the decimal point).
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bool ToFixed(double value,
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int requested_digits,
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StringBuilder* result_builder) const;
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// Computes a representation in exponential format with requested_digits
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// after the decimal point. The last emitted digit is rounded.
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// If requested_digits equals -1, then the shortest exponential representation
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// is computed.
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//
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// Examples with EMIT_POSITIVE_EXPONENT_SIGN deactivated, and
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// exponent_character set to 'e'.
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// ToExponential(3.12, 1) -> "3.1e0"
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// ToExponential(5.0, 3) -> "5.000e0"
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// ToExponential(0.001, 2) -> "1.00e-3"
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// ToExponential(3.1415, -1) -> "3.1415e0"
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// ToExponential(3.1415, 4) -> "3.1415e0"
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// ToExponential(3.1415, 3) -> "3.142e0"
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// ToExponential(123456789000000, 3) -> "1.235e14"
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// ToExponential(1000000000000000019884624838656.0, -1) -> "1e30"
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// ToExponential(1000000000000000019884624838656.0, 32) ->
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// "1.00000000000000001988462483865600e30"
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// ToExponential(1234, 0) -> "1e3"
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//
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// Returns true if the conversion succeeds. The conversion always succeeds
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// except for the following cases:
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// - the input value is special and no infinity_symbol or nan_symbol has
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// been provided to the constructor,
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// - 'requested_digits' > kMaxExponentialDigits.
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// The last condition implies that the result will never contain more than
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// kMaxExponentialDigits + 8 characters (the sign, the digit before the
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// decimal point, the decimal point, the exponent character, the
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// exponent's sign, and at most 3 exponent digits).
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bool ToExponential(double value,
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int requested_digits,
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StringBuilder* result_builder) const;
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// Computes 'precision' leading digits of the given 'value' and returns them
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// either in exponential or decimal format, depending on
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// max_{leading|trailing}_padding_zeroes_in_precision_mode (given to the
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// constructor).
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// The last computed digit is rounded.
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//
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// Example with max_leading_padding_zeroes_in_precision_mode = 6.
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// ToPrecision(0.0000012345, 2) -> "0.0000012"
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// ToPrecision(0.00000012345, 2) -> "1.2e-7"
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// Similarily the converter may add up to
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// max_trailing_padding_zeroes_in_precision_mode in precision mode to avoid
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// returning an exponential representation. A zero added by the
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// EMIT_TRAILING_ZERO_AFTER_POINT flag is counted for this limit.
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// Examples for max_trailing_padding_zeroes_in_precision_mode = 1:
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// ToPrecision(230.0, 2) -> "230"
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// ToPrecision(230.0, 2) -> "230." with EMIT_TRAILING_DECIMAL_POINT.
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// ToPrecision(230.0, 2) -> "2.3e2" with EMIT_TRAILING_ZERO_AFTER_POINT.
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// Examples for max_trailing_padding_zeroes_in_precision_mode = 3, and no
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// EMIT_TRAILING_ZERO_AFTER_POINT:
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// ToPrecision(123450.0, 6) -> "123450"
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// ToPrecision(123450.0, 5) -> "123450"
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// ToPrecision(123450.0, 4) -> "123500"
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// ToPrecision(123450.0, 3) -> "123000"
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// ToPrecision(123450.0, 2) -> "1.2e5"
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//
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// Returns true if the conversion succeeds. The conversion always succeeds
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// except for the following cases:
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// - the input value is special and no infinity_symbol or nan_symbol has
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// been provided to the constructor,
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// - precision < kMinPericisionDigits
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// - precision > kMaxPrecisionDigits
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// The last condition implies that the result will never contain more than
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// kMaxPrecisionDigits + 7 characters (the sign, the decimal point, the
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// exponent character, the exponent's sign, and at most 3 exponent digits).
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bool ToPrecision(double value,
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int precision,
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StringBuilder* result_builder) const;
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enum DtoaMode {
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// Produce the shortest correct representation.
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// For example the output of 0.299999999999999988897 is (the less accurate
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// but correct) 0.3.
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SHORTEST,
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// Same as SHORTEST, but for single-precision floats.
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SHORTEST_SINGLE,
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// Produce a fixed number of digits after the decimal point.
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// For instance fixed(0.1, 4) becomes 0.1000
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// If the input number is big, the output will be big.
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FIXED,
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// Fixed number of digits (independent of the decimal point).
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PRECISION
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};
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// The maximal number of digits that are needed to emit a double in base 10.
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// A higher precision can be achieved by using more digits, but the shortest
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// accurate representation of any double will never use more digits than
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// kBase10MaximalLength.
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// Note that DoubleToAscii null-terminates its input. So the given buffer
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// should be at least kBase10MaximalLength + 1 characters long.
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static const int kBase10MaximalLength = 17;
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// Converts the given double 'v' to ascii. 'v' must not be NaN, +Infinity, or
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// -Infinity. In SHORTEST_SINGLE-mode this restriction also applies to 'v'
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// after it has been casted to a single-precision float. That is, in this
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// mode static_cast<float>(v) must not be NaN, +Infinity or -Infinity.
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//
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// The result should be interpreted as buffer * 10^(point-length).
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//
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// The output depends on the given mode:
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// - SHORTEST: produce the least amount of digits for which the internal
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// identity requirement is still satisfied. If the digits are printed
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// (together with the correct exponent) then reading this number will give
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// 'v' again. The buffer will choose the representation that is closest to
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// 'v'. If there are two at the same distance, than the one farther away
|
||
|
|
// from 0 is chosen (halfway cases - ending with 5 - are rounded up).
|
||
|
|
// In this mode the 'requested_digits' parameter is ignored.
|
||
|
|
// - SHORTEST_SINGLE: same as SHORTEST but with single-precision.
|
||
|
|
// - FIXED: produces digits necessary to print a given number with
|
||
|
|
// 'requested_digits' digits after the decimal point. The produced digits
|
||
|
|
// might be too short in which case the caller has to fill the remainder
|
||
|
|
// with '0's.
|
||
|
|
// Example: toFixed(0.001, 5) is allowed to return buffer="1", point=-2.
|
||
|
|
// Halfway cases are rounded towards +/-Infinity (away from 0). The call
|
||
|
|
// toFixed(0.15, 2) thus returns buffer="2", point=0.
|
||
|
|
// The returned buffer may contain digits that would be truncated from the
|
||
|
|
// shortest representation of the input.
|
||
|
|
// - PRECISION: produces 'requested_digits' where the first digit is not '0'.
|
||
|
|
// Even though the length of produced digits usually equals
|
||
|
|
// 'requested_digits', the function is allowed to return fewer digits, in
|
||
|
|
// which case the caller has to fill the missing digits with '0's.
|
||
|
|
// Halfway cases are again rounded away from 0.
|
||
|
|
// DoubleToAscii expects the given buffer to be big enough to hold all
|
||
|
|
// digits and a terminating null-character. In SHORTEST-mode it expects a
|
||
|
|
// buffer of at least kBase10MaximalLength + 1. In all other modes the
|
||
|
|
// requested_digits parameter and the padding-zeroes limit the size of the
|
||
|
|
// output. Don't forget the decimal point, the exponent character and the
|
||
|
|
// terminating null-character when computing the maximal output size.
|
||
|
|
// The given length is only used in debug mode to ensure the buffer is big
|
||
|
|
// enough.
|
||
|
|
static void DoubleToAscii(double v,
|
||
|
|
DtoaMode mode,
|
||
|
|
int requested_digits,
|
||
|
|
char* buffer,
|
||
|
|
int buffer_length,
|
||
|
|
bool* sign,
|
||
|
|
int* length,
|
||
|
|
int* point);
|
||
|
|
|
||
|
|
private:
|
||
|
|
// Implementation for ToShortest and ToShortestSingle.
|
||
|
|
bool ToShortestIeeeNumber(double value,
|
||
|
|
StringBuilder* result_builder,
|
||
|
|
DtoaMode mode) const;
|
||
|
|
|
||
|
|
// If the value is a special value (NaN or Infinity) constructs the
|
||
|
|
// corresponding string using the configured infinity/nan-symbol.
|
||
|
|
// If either of them is NULL or the value is not special then the
|
||
|
|
// function returns false.
|
||
|
|
bool HandleSpecialValues(double value, StringBuilder* result_builder) const;
|
||
|
|
// Constructs an exponential representation (i.e. 1.234e56).
|
||
|
|
// The given exponent assumes a decimal point after the first decimal digit.
|
||
|
|
void CreateExponentialRepresentation(const char* decimal_digits,
|
||
|
|
int length,
|
||
|
|
int exponent,
|
||
|
|
StringBuilder* result_builder) const;
|
||
|
|
// Creates a decimal representation (i.e 1234.5678).
|
||
|
|
void CreateDecimalRepresentation(const char* decimal_digits,
|
||
|
|
int length,
|
||
|
|
int decimal_point,
|
||
|
|
int digits_after_point,
|
||
|
|
StringBuilder* result_builder) const;
|
||
|
|
|
||
|
|
const int flags_;
|
||
|
|
const char* const infinity_symbol_;
|
||
|
|
const char* const nan_symbol_;
|
||
|
|
const char exponent_character_;
|
||
|
|
const int decimal_in_shortest_low_;
|
||
|
|
const int decimal_in_shortest_high_;
|
||
|
|
const int max_leading_padding_zeroes_in_precision_mode_;
|
||
|
|
const int max_trailing_padding_zeroes_in_precision_mode_;
|
||
|
|
|
||
|
|
DISALLOW_IMPLICIT_CONSTRUCTORS(DoubleToStringConverter);
|
||
|
|
};
|
||
|
|
|
||
|
|
|
||
|
|
class StringToDoubleConverter {
|
||
|
|
public:
|
||
|
|
// Enumeration for allowing octals and ignoring junk when converting
|
||
|
|
// strings to numbers.
|
||
|
|
enum Flags {
|
||
|
|
NO_FLAGS = 0,
|
||
|
|
ALLOW_HEX = 1,
|
||
|
|
ALLOW_OCTALS = 2,
|
||
|
|
ALLOW_TRAILING_JUNK = 4,
|
||
|
|
ALLOW_LEADING_SPACES = 8,
|
||
|
|
ALLOW_TRAILING_SPACES = 16,
|
||
|
|
ALLOW_SPACES_AFTER_SIGN = 32
|
||
|
|
};
|
||
|
|
|
||
|
|
// Flags should be a bit-or combination of the possible Flags-enum.
|
||
|
|
// - NO_FLAGS: no special flags.
|
||
|
|
// - ALLOW_HEX: recognizes the prefix "0x". Hex numbers may only be integers.
|
||
|
|
// Ex: StringToDouble("0x1234") -> 4660.0
|
||
|
|
// In StringToDouble("0x1234.56") the characters ".56" are trailing
|
||
|
|
// junk. The result of the call is hence dependent on
|
||
|
|
// the ALLOW_TRAILING_JUNK flag and/or the junk value.
|
||
|
|
// With this flag "0x" is a junk-string. Even with ALLOW_TRAILING_JUNK,
|
||
|
|
// the string will not be parsed as "0" followed by junk.
|
||
|
|
//
|
||
|
|
// - ALLOW_OCTALS: recognizes the prefix "0" for octals:
|
||
|
|
// If a sequence of octal digits starts with '0', then the number is
|
||
|
|
// read as octal integer. Octal numbers may only be integers.
|
||
|
|
// Ex: StringToDouble("01234") -> 668.0
|
||
|
|
// StringToDouble("012349") -> 12349.0 // Not a sequence of octal
|
||
|
|
// // digits.
|
||
|
|
// In StringToDouble("01234.56") the characters ".56" are trailing
|
||
|
|
// junk. The result of the call is hence dependent on
|
||
|
|
// the ALLOW_TRAILING_JUNK flag and/or the junk value.
|
||
|
|
// In StringToDouble("01234e56") the characters "e56" are trailing
|
||
|
|
// junk, too.
|
||
|
|
// - ALLOW_TRAILING_JUNK: ignore trailing characters that are not part of
|
||
|
|
// a double literal.
|
||
|
|
// - ALLOW_LEADING_SPACES: skip over leading spaces.
|
||
|
|
// - ALLOW_TRAILING_SPACES: ignore trailing spaces.
|
||
|
|
// - ALLOW_SPACES_AFTER_SIGN: ignore spaces after the sign.
|
||
|
|
// Ex: StringToDouble("- 123.2") -> -123.2.
|
||
|
|
// StringToDouble("+ 123.2") -> 123.2
|
||
|
|
//
|
||
|
|
// empty_string_value is returned when an empty string is given as input.
|
||
|
|
// If ALLOW_LEADING_SPACES or ALLOW_TRAILING_SPACES are set, then a string
|
||
|
|
// containing only spaces is converted to the 'empty_string_value', too.
|
||
|
|
//
|
||
|
|
// junk_string_value is returned when
|
||
|
|
// a) ALLOW_TRAILING_JUNK is not set, and a junk character (a character not
|
||
|
|
// part of a double-literal) is found.
|
||
|
|
// b) ALLOW_TRAILING_JUNK is set, but the string does not start with a
|
||
|
|
// double literal.
|
||
|
|
//
|
||
|
|
// infinity_symbol and nan_symbol are strings that are used to detect
|
||
|
|
// inputs that represent infinity and NaN. They can be null, in which case
|
||
|
|
// they are ignored.
|
||
|
|
// The conversion routine first reads any possible signs. Then it compares the
|
||
|
|
// following character of the input-string with the first character of
|
||
|
|
// the infinity, and nan-symbol. If either matches, the function assumes, that
|
||
|
|
// a match has been found, and expects the following input characters to match
|
||
|
|
// the remaining characters of the special-value symbol.
|
||
|
|
// This means that the following restrictions apply to special-value symbols:
|
||
|
|
// - they must not start with signs ('+', or '-'),
|
||
|
|
// - they must not have the same first character.
|
||
|
|
// - they must not start with digits.
|
||
|
|
//
|
||
|
|
// Examples:
|
||
|
|
// flags = ALLOW_HEX | ALLOW_TRAILING_JUNK,
|
||
|
|
// empty_string_value = 0.0,
|
||
|
|
// junk_string_value = NaN,
|
||
|
|
// infinity_symbol = "infinity",
|
||
|
|
// nan_symbol = "nan":
|
||
|
|
// StringToDouble("0x1234") -> 4660.0.
|
||
|
|
// StringToDouble("0x1234K") -> 4660.0.
|
||
|
|
// StringToDouble("") -> 0.0 // empty_string_value.
|
||
|
|
// StringToDouble(" ") -> NaN // junk_string_value.
|
||
|
|
// StringToDouble(" 1") -> NaN // junk_string_value.
|
||
|
|
// StringToDouble("0x") -> NaN // junk_string_value.
|
||
|
|
// StringToDouble("-123.45") -> -123.45.
|
||
|
|
// StringToDouble("--123.45") -> NaN // junk_string_value.
|
||
|
|
// StringToDouble("123e45") -> 123e45.
|
||
|
|
// StringToDouble("123E45") -> 123e45.
|
||
|
|
// StringToDouble("123e+45") -> 123e45.
|
||
|
|
// StringToDouble("123E-45") -> 123e-45.
|
||
|
|
// StringToDouble("123e") -> 123.0 // trailing junk ignored.
|
||
|
|
// StringToDouble("123e-") -> 123.0 // trailing junk ignored.
|
||
|
|
// StringToDouble("+NaN") -> NaN // NaN string literal.
|
||
|
|
// StringToDouble("-infinity") -> -inf. // infinity literal.
|
||
|
|
// StringToDouble("Infinity") -> NaN // junk_string_value.
|
||
|
|
//
|
||
|
|
// flags = ALLOW_OCTAL | ALLOW_LEADING_SPACES,
|
||
|
|
// empty_string_value = 0.0,
|
||
|
|
// junk_string_value = NaN,
|
||
|
|
// infinity_symbol = NULL,
|
||
|
|
// nan_symbol = NULL:
|
||
|
|
// StringToDouble("0x1234") -> NaN // junk_string_value.
|
||
|
|
// StringToDouble("01234") -> 668.0.
|
||
|
|
// StringToDouble("") -> 0.0 // empty_string_value.
|
||
|
|
// StringToDouble(" ") -> 0.0 // empty_string_value.
|
||
|
|
// StringToDouble(" 1") -> 1.0
|
||
|
|
// StringToDouble("0x") -> NaN // junk_string_value.
|
||
|
|
// StringToDouble("0123e45") -> NaN // junk_string_value.
|
||
|
|
// StringToDouble("01239E45") -> 1239e45.
|
||
|
|
// StringToDouble("-infinity") -> NaN // junk_string_value.
|
||
|
|
// StringToDouble("NaN") -> NaN // junk_string_value.
|
||
|
|
StringToDoubleConverter(int flags,
|
||
|
|
double empty_string_value,
|
||
|
|
double junk_string_value,
|
||
|
|
const char* infinity_symbol,
|
||
|
|
const char* nan_symbol)
|
||
|
|
: flags_(flags),
|
||
|
|
empty_string_value_(empty_string_value),
|
||
|
|
junk_string_value_(junk_string_value),
|
||
|
|
infinity_symbol_(infinity_symbol),
|
||
|
|
nan_symbol_(nan_symbol) {
|
||
|
|
}
|
||
|
|
|
||
|
|
// Performs the conversion.
|
||
|
|
// The output parameter 'processed_characters_count' is set to the number
|
||
|
|
// of characters that have been processed to read the number.
|
||
|
|
// Spaces than are processed with ALLOW_{LEADING|TRAILING}_SPACES are included
|
||
|
|
// in the 'processed_characters_count'. Trailing junk is never included.
|
||
|
|
double StringToDouble(const char* buffer,
|
||
|
|
int length,
|
||
|
|
int* processed_characters_count) const {
|
||
|
|
return StringToIeee(buffer, length, processed_characters_count, true);
|
||
|
|
}
|
||
|
|
|
||
|
|
// Same as StringToDouble but reads a float.
|
||
|
|
// Note that this is not equivalent to static_cast<float>(StringToDouble(...))
|
||
|
|
// due to potential double-rounding.
|
||
|
|
float StringToFloat(const char* buffer,
|
||
|
|
int length,
|
||
|
|
int* processed_characters_count) const {
|
||
|
|
return static_cast<float>(StringToIeee(buffer, length,
|
||
|
|
processed_characters_count, false));
|
||
|
|
}
|
||
|
|
|
||
|
|
private:
|
||
|
|
const int flags_;
|
||
|
|
const double empty_string_value_;
|
||
|
|
const double junk_string_value_;
|
||
|
|
const char* const infinity_symbol_;
|
||
|
|
const char* const nan_symbol_;
|
||
|
|
|
||
|
|
double StringToIeee(const char* buffer,
|
||
|
|
int length,
|
||
|
|
int* processed_characters_count,
|
||
|
|
bool read_as_double) const;
|
||
|
|
|
||
|
|
DISALLOW_IMPLICIT_CONSTRUCTORS(StringToDoubleConverter);
|
||
|
|
};
|
||
|
|
|
||
|
|
} // namespace double_conversion
|
||
|
|
|
||
|
|
#endif // DOUBLE_CONVERSION_DOUBLE_CONVERSION_H_
|