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27
28#ifndef DOUBLE_CONVERSION_BIGNUM_DTOA_H_
29#define DOUBLE_CONVERSION_BIGNUM_DTOA_H_
30
31#include <wtf/dtoa/utils.h>
32
33namespace WTF {
34namespace double_conversion {
35
36enum BignumDtoaMode {
37 // Return the shortest correct representation.
38 // For example the output of 0.299999999999999988897 is (the less accurate but
39 // correct) 0.3.
40 BIGNUM_DTOA_SHORTEST,
41 // Same as BIGNUM_DTOA_SHORTEST but for single-precision floats.
42 BIGNUM_DTOA_SHORTEST_SINGLE,
43 // Return a fixed number of digits after the decimal point.
44 // For instance fixed(0.1, 4) becomes 0.1000
45 // If the input number is big, the output will be big.
46 BIGNUM_DTOA_FIXED,
47 // Return a fixed number of digits, no matter what the exponent is.
48 BIGNUM_DTOA_PRECISION
49};
50
51// Converts the given double 'v' to ascii.
52// The result should be interpreted as buffer * 10^(point-length).
53// The buffer will be null-terminated.
54//
55// The input v must be > 0 and different from NaN, and Infinity.
56//
57// The output depends on the given mode:
58// - SHORTEST: produce the least amount of digits for which the internal
59// identity requirement is still satisfied. If the digits are printed
60// (together with the correct exponent) then reading this number will give
61// 'v' again. The buffer will choose the representation that is closest to
62// 'v'. If there are two at the same distance, than the number is round up.
63// In this mode the 'requested_digits' parameter is ignored.
64// - FIXED: produces digits necessary to print a given number with
65// 'requested_digits' digits after the decimal point. The produced digits
66// might be too short in which case the caller has to fill the gaps with '0's.
67// Example: toFixed(0.001, 5) is allowed to return buffer="1", point=-2.
68// Halfway cases are rounded up. The call toFixed(0.15, 2) thus returns
69// buffer="2", point=0.
70// Note: the length of the returned buffer has no meaning wrt the significance
71// of its digits. That is, just because it contains '0's does not mean that
72// any other digit would not satisfy the internal identity requirement.
73// - PRECISION: produces 'requested_digits' where the first digit is not '0'.
74// Even though the length of produced digits usually equals
75// 'requested_digits', the function is allowed to return fewer digits, in
76// which case the caller has to fill the missing digits with '0's.
77// Halfway cases are again rounded up.
78// 'BignumDtoa' expects the given buffer to be big enough to hold all digits
79// and a terminating null-character.
80void BignumDtoa(double v, BignumDtoaMode mode, int requested_digits,
81 BufferReference<char> buffer, int* length, int* point);
82
83} // namespace double_conversion
84} // namespace WTF
85
86#endif // DOUBLE_CONVERSION_BIGNUM_DTOA_H_
87