Move files in wtf/ to platform/wtf/ (Part 9).

third_party/WebKit/Source/wtf/dtoa/double-conversion.h

-// Copyright 2010 the V8 project authors. All rights reserved.
-// Redistribution and use in source and binary forms, with or without
-// modification, are permitted provided that the following conditions are
-// met:
-//
-//     * Redistributions of source code must retain the above copyright
-//       notice, this list of conditions and the following disclaimer.
-//     * Redistributions in binary form must reproduce the above
-//       copyright notice, this list of conditions and the following
-//       disclaimer in the documentation and/or other materials provided
-//       with the distribution.
-//     * Neither the name of Google Inc. nor the names of its
-//       contributors may be used to endorse or promote products derived
-//       from this software without specific prior written permission.
-//
-// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
-// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
-// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
-// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
-// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
-// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
-// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
-// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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-// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+// Copyright 2017 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
 
-#ifndef DOUBLE_CONVERSION_DOUBLE_CONVERSION_H_
-#define DOUBLE_CONVERSION_DOUBLE_CONVERSION_H_
+#include "platform/wtf/dtoa/double-conversion.h"
 
-#include "wtf/dtoa/utils.h"
-
-namespace WTF {
-
-namespace double_conversion {
-
-class DoubleToStringConverter {
- public:
-  // When calling ToFixed with a double > 10^kMaxFixedDigitsBeforePoint
-  // or a requested_digits parameter > kMaxFixedDigitsAfterPoint then the
-  // function returns false.
-  static const int kMaxFixedDigitsBeforePoint = 60;
-  static const int kMaxFixedDigitsAfterPoint = 60;
-
-  // When calling ToExponential with a requested_digits
-  // parameter > kMaxExponentialDigits then the function returns false.
-  static const int kMaxExponentialDigits = 120;
-
-  // When calling ToPrecision with a requested_digits
-  // parameter < kMinPrecisionDigits or requested_digits > kMaxPrecisionDigits
-  // then the function returns false.
-  static const int kMinPrecisionDigits = 1;
-  static const int kMaxPrecisionDigits = 120;
-
-  enum Flags {
-    NO_FLAGS = 0,
-    EMIT_POSITIVE_EXPONENT_SIGN = 1,
-    EMIT_TRAILING_DECIMAL_POINT = 2,
-    EMIT_TRAILING_ZERO_AFTER_POINT = 4,
-    UNIQUE_ZERO = 8
-  };
-
-  // Flags should be a bit-or combination of the possible Flags-enum.
-  //  - NO_FLAGS: no special flags.
-  //  - EMIT_POSITIVE_EXPONENT_SIGN: when the number is converted into exponent
-  //    form, emits a '+' for positive exponents. Example: 1.2e+2.
-  //  - EMIT_TRAILING_DECIMAL_POINT: when the input number is an integer and is
-  //    converted into decimal format then a trailing decimal point is appended.
-  //    Example: 2345.0 is converted to "2345.".
-  //  - EMIT_TRAILING_ZERO_AFTER_POINT: in addition to a trailing decimal point
-  //    emits a trailing '0'-character. This flag requires the
-  //    EXMIT_TRAILING_DECIMAL_POINT flag.
-  //    Example: 2345.0 is converted to "2345.0".
-  //  - UNIQUE_ZERO: "-0.0" is converted to "0.0".
-  //
-  // Infinity symbol and nan_symbol provide the string representation for these
-  // special values. If the string is NULL and the special value is encountered
-  // then the conversion functions return false.
-  //
-  // The exponent_character is used in exponential representations. It is
-  // usually 'e' or 'E'.
-  //
-  // When converting to the shortest representation the converter will
-  // represent input numbers in decimal format if they are in the interval
-  // [10^decimal_in_shortest_low; 10^decimal_in_shortest_high[
-  //    (lower boundary included, greater boundary excluded).
-  // Example: with decimal_in_shortest_low = -6 and
-  //               decimal_in_shortest_high = 21:
-  //   ToShortest(0.000001)  -> "0.000001"
-  //   ToShortest(0.0000001) -> "1e-7"
-  //   ToShortest(111111111111111111111.0)  -> "111111111111111110000"
-  //   ToShortest(100000000000000000000.0)  -> "100000000000000000000"
-  //   ToShortest(1111111111111111111111.0) -> "1.1111111111111111e+21"
-  //
-  // When converting to precision mode the converter may add
-  // max_leading_padding_zeroes before returning the number in exponential
-  // format.
-  // Example with max_leading_padding_zeroes_in_precision_mode = 6.
-  //   ToPrecision(0.0000012345, 2) -> "0.0000012"
-  //   ToPrecision(0.00000012345, 2) -> "1.2e-7"
-  // Similarily the converter may add up to
-  // max_trailing_padding_zeroes_in_precision_mode in precision mode to avoid
-  // returning an exponential representation. A zero added by the
-  // EMIT_TRAILING_ZERO_AFTER_POINT flag is counted for this limit.
-  // Examples for max_trailing_padding_zeroes_in_precision_mode = 1:
-  //   ToPrecision(230.0, 2) -> "230"
-  //   ToPrecision(230.0, 2) -> "230."  with EMIT_TRAILING_DECIMAL_POINT.
-  //   ToPrecision(230.0, 2) -> "2.3e2" with EMIT_TRAILING_ZERO_AFTER_POINT.
-  DoubleToStringConverter(int flags,
-                          const char* infinity_symbol,
-                          const char* nan_symbol,
-                          char exponent_character,
-                          int decimal_in_shortest_low,
-                          int decimal_in_shortest_high,
-                          int max_leading_padding_zeroes_in_precision_mode,
-                          int max_trailing_padding_zeroes_in_precision_mode)
-      : flags_(flags),
-        infinity_symbol_(infinity_symbol),
-        nan_symbol_(nan_symbol),
-        exponent_character_(exponent_character),
-        decimal_in_shortest_low_(decimal_in_shortest_low),
-        decimal_in_shortest_high_(decimal_in_shortest_high),
-        max_leading_padding_zeroes_in_precision_mode_(
-            max_leading_padding_zeroes_in_precision_mode),
-        max_trailing_padding_zeroes_in_precision_mode_(
-            max_trailing_padding_zeroes_in_precision_mode) {
-    // When 'trailing zero after the point' is set, then 'trailing point'
-    // must be set too.
-    DCHECK(((flags & EMIT_TRAILING_DECIMAL_POINT) != 0) ||
-           !((flags & EMIT_TRAILING_ZERO_AFTER_POINT) != 0));
-  }
-
-  // Returns a converter following the EcmaScript specification.
-  static const DoubleToStringConverter& EcmaScriptConverter();
-
-  // Computes the shortest string of digits that correctly represent the input
-  // number. Depending on decimal_in_shortest_low and decimal_in_shortest_high
-  // (see constructor) it then either returns a decimal representation, or an
-  // exponential representation.
-  // Example with decimal_in_shortest_low = -6,
-  //              decimal_in_shortest_high = 21,
-  //              EMIT_POSITIVE_EXPONENT_SIGN activated, and
-  //              EMIT_TRAILING_DECIMAL_POINT deactived:
-  //   ToShortest(0.000001)  -> "0.000001"
-  //   ToShortest(0.0000001) -> "1e-7"
-  //   ToShortest(111111111111111111111.0)  -> "111111111111111110000"
-  //   ToShortest(100000000000000000000.0)  -> "100000000000000000000"
-  //   ToShortest(1111111111111111111111.0) -> "1.1111111111111111e+21"
-  //
-  // Note: the conversion may round the output if the returned string
-  // is accurate enough to uniquely identify the input-number.
-  // For example the most precise representation of the double 9e59 equals
-  // "899999999999999918767229449717619953810131273674690656206848", but
-  // the converter will return the shorter (but still correct) "9e59".
-  //
-  // Returns true if the conversion succeeds. The conversion always succeeds
-  // except when the input value is special and no infinity_symbol or
-  // nan_symbol has been given to the constructor.
-  bool ToShortest(double value, StringBuilder* result_builder) const;
-
-  // Computes a decimal representation with a fixed number of digits after the
-  // decimal point. The last emitted digit is rounded.
-  //
-  // Examples:
-  //   ToFixed(3.12, 1) -> "3.1"
-  //   ToFixed(3.1415, 3) -> "3.142"
-  //   ToFixed(1234.56789, 4) -> "1234.5679"
-  //   ToFixed(1.23, 5) -> "1.23000"
-  //   ToFixed(0.1, 4) -> "0.1000"
-  //   ToFixed(1e30, 2) -> "1000000000000000019884624838656.00"
-  //   ToFixed(0.1, 30) -> "0.100000000000000005551115123126"
-  //   ToFixed(0.1, 17) -> "0.10000000000000001"
-  //
-  // If requested_digits equals 0, then the tail of the result depends on
-  // the EMIT_TRAILING_DECIMAL_POINT and EMIT_TRAILING_ZERO_AFTER_POINT.
-  // Examples, for requested_digits == 0,
-  //   let EMIT_TRAILING_DECIMAL_POINT and EMIT_TRAILING_ZERO_AFTER_POINT be
-  //    - false and false: then 123.45 -> 123
-  //                             0.678 -> 1
-  //    - true and false: then 123.45 -> 123.
-  //                            0.678 -> 1.
-  //    - true and true: then 123.45 -> 123.0
-  //                           0.678 -> 1.0
-  //
-  // Returns true if the conversion succeeds. The conversion always succeeds
-  // except for the following cases:
-  //   - the input value is special and no infinity_symbol or nan_symbol has
-  //     been provided to the constructor,
-  //   - 'value' > 10^kMaxFixedDigitsBeforePoint, or
-  //   - 'requested_digits' > kMaxFixedDigitsAfterPoint.
-  // The last two conditions imply that the result will never contain more than
-  // 1 + kMaxFixedDigitsBeforePoint + 1 + kMaxFixedDigitsAfterPoint characters
-  // (one additional character for the sign, and one for the decimal point).
-  bool ToFixed(double value,
-               int requested_digits,
-               StringBuilder* result_builder) const;
-
-  // Computes a representation in exponential format with requested_digits
-  // after the decimal point. The last emitted digit is rounded.
-  // If requested_digits equals -1, then the shortest exponential representation
-  // is computed.
-  //
-  // Examples with EMIT_POSITIVE_EXPONENT_SIGN deactivated, and
-  //               exponent_character set to 'e'.
-  //   ToExponential(3.12, 1) -> "3.1e0"
-  //   ToExponential(5.0, 3) -> "5.000e0"
-  //   ToExponential(0.001, 2) -> "1.00e-3"
-  //   ToExponential(3.1415, -1) -> "3.1415e0"
-  //   ToExponential(3.1415, 4) -> "3.1415e0"
-  //   ToExponential(3.1415, 3) -> "3.142e0"
-  //   ToExponential(123456789000000, 3) -> "1.235e14"
-  //   ToExponential(1000000000000000019884624838656.0, -1) -> "1e30"
-  //   ToExponential(1000000000000000019884624838656.0, 32) ->
-  //                     "1.00000000000000001988462483865600e30"
-  //   ToExponential(1234, 0) -> "1e3"
-  //
-  // Returns true if the conversion succeeds. The conversion always succeeds
-  // except for the following cases:
-  //   - the input value is special and no infinity_symbol or nan_symbol has
-  //     been provided to the constructor,
-  //   - 'requested_digits' > kMaxExponentialDigits.
-  // The last condition implies that the result will never contain more than
-  // kMaxExponentialDigits + 8 characters (the sign, the digit before the
-  // decimal point, the decimal point, the exponent character, the
-  // exponent's sign, and at most 3 exponent digits).
-  bool ToExponential(double value,
-                     int requested_digits,
-                     StringBuilder* result_builder) const;
-
-  // Computes 'precision' leading digits of the given 'value' and returns them
-  // either in exponential or decimal format, depending on
-  // max_{leading|trailing}_padding_zeroes_in_precision_mode (given to the
-  // constructor).
-  // The last computed digit is rounded.
-  //
-  // Example with max_leading_padding_zeroes_in_precision_mode = 6.
-  //   ToPrecision(0.0000012345, 2) -> "0.0000012"
-  //   ToPrecision(0.00000012345, 2) -> "1.2e-7"
-  // Similarily the converter may add up to
-  // max_trailing_padding_zeroes_in_precision_mode in precision mode to avoid
-  // returning an exponential representation. A zero added by the
-  // EMIT_TRAILING_ZERO_AFTER_POINT flag is counted for this limit.
-  // Examples for max_trailing_padding_zeroes_in_precision_mode = 1:
-  //   ToPrecision(230.0, 2) -> "230"
-  //   ToPrecision(230.0, 2) -> "230."  with EMIT_TRAILING_DECIMAL_POINT.
-  //   ToPrecision(230.0, 2) -> "2.3e2" with EMIT_TRAILING_ZERO_AFTER_POINT.
-  // Examples for max_trailing_padding_zeroes_in_precision_mode = 3, and no
-  //    EMIT_TRAILING_ZERO_AFTER_POINT:
-  //   ToPrecision(123450.0, 6) -> "123450"
-  //   ToPrecision(123450.0, 5) -> "123450"
-  //   ToPrecision(123450.0, 4) -> "123500"
-  //   ToPrecision(123450.0, 3) -> "123000"
-  //   ToPrecision(123450.0, 2) -> "1.2e5"
-  //
-  // Returns true if the conversion succeeds. The conversion always succeeds
-  // except for the following cases:
-  //   - the input value is special and no infinity_symbol or nan_symbol has
-  //     been provided to the constructor,
-  //   - precision < kMinPericisionDigits
-  //   - precision > kMaxPrecisionDigits
-  // The last condition implies that the result will never contain more than
-  // kMaxPrecisionDigits + 7 characters (the sign, the decimal point, the
-  // exponent character, the exponent's sign, and at most 3 exponent digits).
-  bool ToPrecision(double value,
-                   int precision,
-                   StringBuilder* result_builder) const;
-
-  enum DtoaMode {
-    // Produce the shortest correct representation.
-    // For example the output of 0.299999999999999988897 is (the less accurate
-    // but correct) 0.3.
-    SHORTEST,
-    // Produce a fixed number of digits after the decimal point.
-    // For instance fixed(0.1, 4) becomes 0.1000
-    // If the input number is big, the output will be big.
-    FIXED,
-    // Fixed number of digits (independent of the decimal point).
-    PRECISION
-  };
-
-  // The maximal number of digits that are needed to emit a double in base 10.
-  // A higher precision can be achieved by using more digits, but the shortest
-  // accurate representation of any double will never use more digits than
-  // kBase10MaximalLength.
-  // Note that DoubleToAscii null-terminates its input. So the given buffer
-  // should be at least kBase10MaximalLength + 1 characters long.
-  static const int kBase10MaximalLength = 17;
-
-  // Converts the given double 'v' to ascii.
-  // The result should be interpreted as buffer * 10^(point-length).
-  //
-  // The output depends on the given mode:
-  //  - SHORTEST: produce the least amount of digits for which the internal
-  //   identity requirement is still satisfied. If the digits are printed
-  //   (together with the correct exponent) then reading this number will give
-  //   'v' again. The buffer will choose the representation that is closest to
-  //   '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.
-  //  - 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 (+ 1 for the null-character) limits the size of
-  // the output. 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:
-  // 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:
-  // Performs the conversion.
-  // The output parameter 'processed_characters_count' is set to the number
-  // of characters that have been processed to read the number.
-  static double StringToDouble(const char* buffer,
-                               size_t length,
-                               size_t* processed_characters_count);
-
- private:
-  DISALLOW_IMPLICIT_CONSTRUCTORS(StringToDoubleConverter);
-};
-
-}  // namespace double_conversion
-
-}  // namespace WTF
-
-#endif  // DOUBLE_CONVERSION_DOUBLE_CONVERSION_H_
+// The contents of this header was moved to platform/wtf as part of
+// WTF migration project. See the following post for details:
+// https://groups.google.com/a/chromium.org/d/msg/blink-dev/tLdAZCTlcAA/bYXVT8gYCAAJ