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fast-dtoa.h
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27 
28 #ifndef V8_FAST_DTOA_H_
29 #define V8_FAST_DTOA_H_
30 
31 namespace v8 {
32 namespace internal {
33 
35  // Computes the shortest representation of the given input. The returned
36  // result will be the most accurate number of this length. Longer
37  // representations might be more accurate.
39  // Computes a representation where the precision (number of digits) is
40  // given as input. The precision is independent of the decimal point.
42 };
43 
44 // FastDtoa will produce at most kFastDtoaMaximalLength digits. This does not
45 // include the terminating '\0' character.
46 const int kFastDtoaMaximalLength = 17;
47 
48 // Provides a decimal representation of v.
49 // The result should be interpreted as buffer * 10^(point - length).
50 //
51 // Precondition:
52 // * v must be a strictly positive finite double.
53 //
54 // Returns true if it succeeds, otherwise the result can not be trusted.
55 // There will be *length digits inside the buffer followed by a null terminator.
56 // If the function returns true and mode equals
57 // - FAST_DTOA_SHORTEST, then
58 // the parameter requested_digits is ignored.
59 // The result satisfies
60 // v == (double) (buffer * 10^(point - length)).
61 // The digits in the buffer are the shortest representation possible. E.g.
62 // if 0.099999999999 and 0.1 represent the same double then "1" is returned
63 // with point = 0.
64 // The last digit will be closest to the actual v. That is, even if several
65 // digits might correctly yield 'v' when read again, the buffer will contain
66 // the one closest to v.
67 // - FAST_DTOA_PRECISION, then
68 // the buffer contains requested_digits digits.
69 // the difference v - (buffer * 10^(point-length)) is closest to zero for
70 // all possible representations of requested_digits digits.
71 // If there are two values that are equally close, then FastDtoa returns
72 // false.
73 // For both modes the buffer must be large enough to hold the result.
74 bool FastDtoa(double d,
75  FastDtoaMode mode,
76  int requested_digits,
77  Vector<char> buffer,
78  int* length,
79  int* decimal_point);
80 
81 } } // namespace v8::internal
82 
83 #endif // V8_FAST_DTOA_H_
const int kFastDtoaMaximalLength
Definition: fast-dtoa.h:46
bool FastDtoa(double v, FastDtoaMode mode, int requested_digits, Vector< char > buffer, int *length, int *decimal_point)
Definition: fast-dtoa.cc:709