• Home
  • Line#
  • Scopes#
  • Navigate#
  • Raw
  • Download
1 // © 2018 and later: Unicode, Inc. and others.
2 // License & terms of use: http://www.unicode.org/copyright.html
3 //
4 // From the double-conversion library. Original license:
5 //
6 // Copyright 2010 the V8 project authors. All rights reserved.
7 // Redistribution and use in source and binary forms, with or without
8 // modification, are permitted provided that the following conditions are
9 // met:
10 //
11 //     * Redistributions of source code must retain the above copyright
12 //       notice, this list of conditions and the following disclaimer.
13 //     * Redistributions in binary form must reproduce the above
14 //       copyright notice, this list of conditions and the following
15 //       disclaimer in the documentation and/or other materials provided
16 //       with the distribution.
17 //     * Neither the name of Google Inc. nor the names of its
18 //       contributors may be used to endorse or promote products derived
19 //       from this software without specific prior written permission.
20 //
21 // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
22 // "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
23 // LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
24 // A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
25 // OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
26 // SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
27 // LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
28 // DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
29 // THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
30 // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
31 // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
32 
33 // ICU PATCH: ifdef around UCONFIG_NO_FORMATTING
34 #include "unicode/utypes.h"
35 #if !UCONFIG_NO_FORMATTING
36 
37 #ifndef DOUBLE_CONVERSION_FAST_DTOA_H_
38 #define DOUBLE_CONVERSION_FAST_DTOA_H_
39 
40 // ICU PATCH: Customize header file paths for ICU.
41 
42 #include "double-conversion-utils.h"
43 
44 // ICU PATCH: Wrap in ICU namespace
45 U_NAMESPACE_BEGIN
46 
47 namespace double_conversion {
48 
49 enum FastDtoaMode {
50   // Computes the shortest representation of the given input. The returned
51   // result will be the most accurate number of this length. Longer
52   // representations might be more accurate.
53   FAST_DTOA_SHORTEST,
54   // Same as FAST_DTOA_SHORTEST but for single-precision floats.
55   FAST_DTOA_SHORTEST_SINGLE,
56   // Computes a representation where the precision (number of digits) is
57   // given as input. The precision is independent of the decimal point.
58   FAST_DTOA_PRECISION
59 };
60 
61 // FastDtoa will produce at most kFastDtoaMaximalLength digits. This does not
62 // include the terminating '\0' character.
63 static const int kFastDtoaMaximalLength = 17;
64 // Same for single-precision numbers.
65 static const int kFastDtoaMaximalSingleLength = 9;
66 
67 // Provides a decimal representation of v.
68 // The result should be interpreted as buffer * 10^(point - length).
69 //
70 // Precondition:
71 //   * v must be a strictly positive finite double.
72 //
73 // Returns true if it succeeds, otherwise the result can not be trusted.
74 // There will be *length digits inside the buffer followed by a null terminator.
75 // If the function returns true and mode equals
76 //   - FAST_DTOA_SHORTEST, then
77 //     the parameter requested_digits is ignored.
78 //     The result satisfies
79 //         v == (double) (buffer * 10^(point - length)).
80 //     The digits in the buffer are the shortest representation possible. E.g.
81 //     if 0.099999999999 and 0.1 represent the same double then "1" is returned
82 //     with point = 0.
83 //     The last digit will be closest to the actual v. That is, even if several
84 //     digits might correctly yield 'v' when read again, the buffer will contain
85 //     the one closest to v.
86 //   - FAST_DTOA_PRECISION, then
87 //     the buffer contains requested_digits digits.
88 //     the difference v - (buffer * 10^(point-length)) is closest to zero for
89 //     all possible representations of requested_digits digits.
90 //     If there are two values that are equally close, then FastDtoa returns
91 //     false.
92 // For both modes the buffer must be large enough to hold the result.
93 bool FastDtoa(double d,
94               FastDtoaMode mode,
95               int requested_digits,
96               Vector<char> buffer,
97               int* length,
98               int* decimal_point);
99 
100 }  // namespace double_conversion
101 
102 // ICU PATCH: Close ICU namespace
103 U_NAMESPACE_END
104 
105 #endif  // DOUBLE_CONVERSION_FAST_DTOA_H_
106 #endif // ICU PATCH: close #if !UCONFIG_NO_FORMATTING
107