1.1 --- /dev/null Thu Jan 01 00:00:00 1970 +0000
1.2 +++ b/mfbt/double-conversion/fast-dtoa.h Wed Dec 31 06:09:35 2014 +0100
1.3 @@ -0,0 +1,88 @@
1.4 +// Copyright 2010 the V8 project authors. All rights reserved.
1.5 +// Redistribution and use in source and binary forms, with or without
1.6 +// modification, are permitted provided that the following conditions are
1.7 +// met:
1.8 +//
1.9 +// * Redistributions of source code must retain the above copyright
1.10 +// notice, this list of conditions and the following disclaimer.
1.11 +// * Redistributions in binary form must reproduce the above
1.12 +// copyright notice, this list of conditions and the following
1.13 +// disclaimer in the documentation and/or other materials provided
1.14 +// with the distribution.
1.15 +// * Neither the name of Google Inc. nor the names of its
1.16 +// contributors may be used to endorse or promote products derived
1.17 +// from this software without specific prior written permission.
1.18 +//
1.19 +// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
1.20 +// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
1.21 +// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
1.22 +// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
1.23 +// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
1.24 +// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
1.25 +// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
1.26 +// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
1.27 +// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
1.28 +// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
1.29 +// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
1.30 +
1.31 +#ifndef DOUBLE_CONVERSION_FAST_DTOA_H_
1.32 +#define DOUBLE_CONVERSION_FAST_DTOA_H_
1.33 +
1.34 +#include "utils.h"
1.35 +
1.36 +namespace double_conversion {
1.37 +
1.38 +enum FastDtoaMode {
1.39 + // Computes the shortest representation of the given input. The returned
1.40 + // result will be the most accurate number of this length. Longer
1.41 + // representations might be more accurate.
1.42 + FAST_DTOA_SHORTEST,
1.43 + // Same as FAST_DTOA_SHORTEST but for single-precision floats.
1.44 + FAST_DTOA_SHORTEST_SINGLE,
1.45 + // Computes a representation where the precision (number of digits) is
1.46 + // given as input. The precision is independent of the decimal point.
1.47 + FAST_DTOA_PRECISION
1.48 +};
1.49 +
1.50 +// FastDtoa will produce at most kFastDtoaMaximalLength digits. This does not
1.51 +// include the terminating '\0' character.
1.52 +static const int kFastDtoaMaximalLength = 17;
1.53 +// Same for single-precision numbers.
1.54 +static const int kFastDtoaMaximalSingleLength = 9;
1.55 +
1.56 +// Provides a decimal representation of v.
1.57 +// The result should be interpreted as buffer * 10^(point - length).
1.58 +//
1.59 +// Precondition:
1.60 +// * v must be a strictly positive finite double.
1.61 +//
1.62 +// Returns true if it succeeds, otherwise the result can not be trusted.
1.63 +// There will be *length digits inside the buffer followed by a null terminator.
1.64 +// If the function returns true and mode equals
1.65 +// - FAST_DTOA_SHORTEST, then
1.66 +// the parameter requested_digits is ignored.
1.67 +// The result satisfies
1.68 +// v == (double) (buffer * 10^(point - length)).
1.69 +// The digits in the buffer are the shortest representation possible. E.g.
1.70 +// if 0.099999999999 and 0.1 represent the same double then "1" is returned
1.71 +// with point = 0.
1.72 +// The last digit will be closest to the actual v. That is, even if several
1.73 +// digits might correctly yield 'v' when read again, the buffer will contain
1.74 +// the one closest to v.
1.75 +// - FAST_DTOA_PRECISION, then
1.76 +// the buffer contains requested_digits digits.
1.77 +// the difference v - (buffer * 10^(point-length)) is closest to zero for
1.78 +// all possible representations of requested_digits digits.
1.79 +// If there are two values that are equally close, then FastDtoa returns
1.80 +// false.
1.81 +// For both modes the buffer must be large enough to hold the result.
1.82 +bool FastDtoa(double d,
1.83 + FastDtoaMode mode,
1.84 + int requested_digits,
1.85 + Vector<char> buffer,
1.86 + int* length,
1.87 + int* decimal_point);
1.88 +
1.89 +} // namespace double_conversion
1.90 +
1.91 +#endif // DOUBLE_CONVERSION_FAST_DTOA_H_
