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bignum-dtoa.h
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27 
28 #ifndef DOUBLE_CONVERSION_BIGNUM_DTOA_H_
29 #define DOUBLE_CONVERSION_BIGNUM_DTOA_H_
30 
31 #include "utils.h"
32 
33 #include "pxr/pxr.h"
34 
35 PXR_NAMESPACE_OPEN_SCOPE
36 
37 namespace pxr_double_conversion {
38 
39 enum BignumDtoaMode {
40  // Return the shortest correct representation.
41  // For example the output of 0.299999999999999988897 is (the less accurate but
42  // correct) 0.3.
43  BIGNUM_DTOA_SHORTEST,
44  // Same as BIGNUM_DTOA_SHORTEST but for single-precision floats.
45  BIGNUM_DTOA_SHORTEST_SINGLE,
46  // Return a fixed number of digits after the decimal point.
47  // For instance fixed(0.1, 4) becomes 0.1000
48  // If the input number is big, the output will be big.
49  BIGNUM_DTOA_FIXED,
50  // Return a fixed number of digits, no matter what the exponent is.
51  BIGNUM_DTOA_PRECISION
52 };
53 
54 // Converts the given double 'v' to ascii.
55 // The result should be interpreted as buffer * 10^(point-length).
56 // The buffer will be null-terminated.
57 //
58 // The input v must be > 0 and different from NaN, and Infinity.
59 //
60 // The output depends on the given mode:
61 // - SHORTEST: produce the least amount of digits for which the internal
62 // identity requirement is still satisfied. If the digits are printed
63 // (together with the correct exponent) then reading this number will give
64 // 'v' again. The buffer will choose the representation that is closest to
65 // 'v'. If there are two at the same distance, than the number is round up.
66 // In this mode the 'requested_digits' parameter is ignored.
67 // - FIXED: produces digits necessary to print a given number with
68 // 'requested_digits' digits after the decimal point. The produced digits
69 // might be too short in which case the caller has to fill the gaps with '0's.
70 // Example: toFixed(0.001, 5) is allowed to return buffer="1", point=-2.
71 // Halfway cases are rounded up. The call toFixed(0.15, 2) thus returns
72 // buffer="2", point=0.
73 // Note: the length of the returned buffer has no meaning wrt the significance
74 // of its digits. That is, just because it contains '0's does not mean that
75 // any other digit would not satisfy the internal identity requirement.
76 // - PRECISION: produces 'requested_digits' where the first digit is not '0'.
77 // Even though the length of produced digits usually equals
78 // 'requested_digits', the function is allowed to return fewer digits, in
79 // which case the caller has to fill the missing digits with '0's.
80 // Halfway cases are again rounded up.
81 // 'BignumDtoa' expects the given buffer to be big enough to hold all digits
82 // and a terminating null-character.
83 void BignumDtoa(double v, BignumDtoaMode mode, int requested_digits,
84  Vector<char> buffer, int* length, int* point);
85 
86 } // namespace pxr_double_conversion
87 
88 PXR_NAMESPACE_CLOSE_SCOPE
89 
90 #endif // DOUBLE_CONVERSION_BIGNUM_DTOA_H_