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// met: | |
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namespace double_conversion { | |
enum BignumDtoaMode { | |
// Return the shortest correct representation. | |
// For example the output of 0.299999999999999988897 is (the less accurate but | |
// correct) 0.3. | |
BIGNUM_DTOA_SHORTEST, | |
// Same as BIGNUM_DTOA_SHORTEST but for single-precision floats. | |
BIGNUM_DTOA_SHORTEST_SINGLE, | |
// Return a fixed number of digits after the decimal point. | |
// For instance fixed(0.1, 4) becomes 0.1000 | |
// If the input number is big, the output will be big. | |
BIGNUM_DTOA_FIXED, | |
// Return a fixed number of digits, no matter what the exponent is. | |
BIGNUM_DTOA_PRECISION | |
}; | |
// Converts the given double 'v' to ascii. | |
// The result should be interpreted as buffer * 10^(point-length). | |
// The buffer will be null-terminated. | |
// | |
// The input v must be > 0 and different from NaN, and Infinity. | |
// | |
// The output depends on the given mode: | |
// - SHORTEST: produce the least amount of digits for which the internal | |
// identity requirement is still satisfied. If the digits are printed | |
// (together with the correct exponent) then reading this number will give | |
// 'v' again. The buffer will choose the representation that is closest to | |
// 'v'. If there are two at the same distance, than the number is round up. | |
// In this mode the 'requested_digits' parameter is ignored. | |
// - FIXED: produces digits necessary to print a given number with | |
// 'requested_digits' digits after the decimal point. The produced digits | |
// might be too short in which case the caller has to fill the gaps with '0's. | |
// Example: toFixed(0.001, 5) is allowed to return buffer="1", point=-2. | |
// Halfway cases are rounded up. The call toFixed(0.15, 2) thus returns | |
// buffer="2", point=0. | |
// Note: the length of the returned buffer has no meaning wrt the significance | |
// of its digits. That is, just because it contains '0's does not mean that | |
// any other digit would not satisfy the internal identity requirement. | |
// - PRECISION: produces 'requested_digits' where the first digit is not '0'. | |
// Even though the length of produced digits usually equals | |
// 'requested_digits', the function is allowed to return fewer digits, in | |
// which case the caller has to fill the missing digits with '0's. | |
// Halfway cases are again rounded up. | |
// 'BignumDtoa' expects the given buffer to be big enough to hold all digits | |
// and a terminating null-character. | |
void BignumDtoa(double v, BignumDtoaMode mode, int requested_digits, | |
Vector<char> buffer, int* length, int* point); | |
} // namespace double_conversion | |