| // 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: | |
| // | |
| // * Redistributions of source code must retain the above copyright | |
| // notice, this list of conditions and the following disclaimer. | |
| // * 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. | |
| // * Neither the name of Google Inc. nor the names of its | |
| // contributors may be used to endorse or promote products derived | |
| // from this software without specific prior written permission. | |
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| // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS | |
| // "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT | |
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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 | |