| // Copyright 2010 the V8 project authors. All rights reserved. |
| // Redistribution and use in source and binary forms, with or without |
| // modification, are permitted provided that the following conditions are |
| // met: |
| // |
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| // * Redistributions in binary form must reproduce the above |
| // copyright notice, this list of conditions and the following |
| // disclaimer in the documentation and/or other materials provided |
| // with the distribution. |
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| // from this software without specific prior written permission. |
| // |
| // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS |
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| |
| #ifndef DOUBLE_CONVERSION_BIGNUM_DTOA_H_ |
| #define DOUBLE_CONVERSION_BIGNUM_DTOA_H_ |
| |
| #include "utils.h" |
| |
| 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 |
| |
| #endif // DOUBLE_CONVERSION_BIGNUM_DTOA_H_ |
