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