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bignum-dtoa.h
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27 
28 #ifndef V8_BIGNUM_DTOA_H_
29 #define V8_BIGNUM_DTOA_H_
30 
31 namespace v8 {
32 namespace internal {
33 
35  // Return the shortest correct representation.
36  // For example the output of 0.299999999999999988897 is (the less accurate but
37  // correct) 0.3.
39  // Return a fixed number of digits after the decimal point.
40  // For instance fixed(0.1, 4) becomes 0.1000
41  // If the input number is big, the output will be big.
43  // Return a fixed number of digits, no matter what the exponent is.
45 };
46 
47 // Converts the given double 'v' to ASCII.
48 // The result should be interpreted as buffer * 10^(point-length).
49 // The buffer will be null-terminated.
50 //
51 // The input v must be > 0 and different from NaN, and Infinity.
52 //
53 // The output depends on the given mode:
54 // - SHORTEST: produce the least amount of digits for which the internal
55 // identity requirement is still satisfied. If the digits are printed
56 // (together with the correct exponent) then reading this number will give
57 // 'v' again. The buffer will choose the representation that is closest to
58 // 'v'. If there are two at the same distance, than the number is round up.
59 // In this mode the 'requested_digits' parameter is ignored.
60 // - FIXED: produces digits necessary to print a given number with
61 // 'requested_digits' digits after the decimal point. The produced digits
62 // might be too short in which case the caller has to fill the gaps with '0's.
63 // Example: toFixed(0.001, 5) is allowed to return buffer="1", point=-2.
64 // Halfway cases are rounded up. The call toFixed(0.15, 2) thus returns
65 // buffer="2", point=0.
66 // Note: the length of the returned buffer has no meaning wrt the significance
67 // of its digits. That is, just because it contains '0's does not mean that
68 // any other digit would not satisfy the internal identity requirement.
69 // - PRECISION: produces 'requested_digits' where the first digit is not '0'.
70 // Even though the length of produced digits usually equals
71 // 'requested_digits', the function is allowed to return fewer digits, in
72 // which case the caller has to fill the missing digits with '0's.
73 // Halfway cases are again rounded up.
74 // 'BignumDtoa' expects the given buffer to be big enough to hold all digits
75 // and a terminating null-character.
76 void BignumDtoa(double v, BignumDtoaMode mode, int requested_digits,
77  Vector<char> buffer, int* length, int* point);
78 
79 } } // namespace v8::internal
80 
81 #endif // V8_BIGNUM_DTOA_H_
void BignumDtoa(double v, BignumDtoaMode mode, int requested_digits, Vector< char > buffer, int *length, int *decimal_point)
Definition: bignum-dtoa.cc:92